Antimicrobial resistance (AMR) is a critical global threat to human, animal and environmental health, exacerbated by horizontal gene transfer (HGT) via mobile genetic elements. This poses significant challenges that have a negative impact on the sustainability of the One Health approach, hindering its long-term viability and effectiveness in addressing the interconnectedness of global health. Recent studies on livestock animals, specifically ruminants, indicate that culturable ruminal bacteria harbour AMR genes with the potential for HGT. However, these studies have focused predominantly on using the faecobiome as a proxy to the rumen microbiome or using easily isolated and culturable bacteria, overlooking the unculturable population. These unculturable microbial groups could have a profound influence on the rumen resistome and AMR dynamics within livestock ecosystems, potentially holding critical insights for advanced understanding of AMR in One Health. In order to address this gap, this review of current research on the burden of AMR in livestock was undertaken, and it is proposed that combined study of the rumen microbiome and faecobiome, termed the 'rumenofaecobiome', should be performed to enhance understanding of the risks of AMR in ruminant livestock. This review discusses the complexities of the rumen microbiome and the risks of AMR transmission in this microbiome in a One Health context. AMR transmission dynamics and methodologies for assessing the risks of AMR in livestock are summarized, and future considerations for researching the impact of AMR in the rumen microbiome and the implications within the One Health framework are discussed.

The utilization of microorganisms to transform biomass into biofuels and biochemicals presents a viable and competitive alternative to conventional petroleum refining processes. Halomonas species are salt-tolerant and alkaliphilic, endowed with various beneficial properties rendering them as contamination resistant platforms for industrial biotechnology, facilitating the commercial-scale production of valuable bioproducts. Here we summarized the metabolic and genomic engineering approaches, as well as the biochemical products synthesized by Halomonas. Methods were presented for expanding substrates utilization in Halomonas to enhance its capabilities as a robust workhorse for bioproducts. In addition, we briefly reviewed the Next Generation Industrial Biotechnology (NGIB) based on Halomonas for open and continuous fermentation. In particular, we proposed the industrial attempts from Halomonas chassis and the rising prospects and essential strategies to enable the successful development of Halomonas as microbial NGIB manufacturing platforms.

The effective prevention and treatment of anastomotic leakage after intestinal anastomosis for colorectal diseases is still a major clinical challenge. In order to assist intestinal anastomosis healing and avoid anastomotic leakage caused by high tension, low blood supply or infection, we designed a double-layer nanofiber intestinal anastomosis scaffold, which was composed of electrospun PTMC/PHA nanofibers as the main layer, and electrospun PVA/OHA-Gs nanofibers with antibacterial properties as the antibacterial surface layer. This double-layer scaffold has good toughness, its maximum tensile force value could reach 8 N, elongation could reach 400 %, and it has hydrophilic properties, and its contact angle was about 60°. On the basis of reducing anastomotic tension and isolating intestinal contents, this double-layer nanofiber anastomotic scaffold not only played an antibacterial effect in the short term after surgery to reduce inflammatory response, but also had the characteristics of multiple three-dimensional network structure like extracellular matrix which could promote tissue healing. The PVA/OHA-Gs@PTMC/PHA scaffold was implanted into a rabbit model simulating mechanical intestinal obstruction, and the results showed that the nanofibers of the scaffold could be degraded in vivo while maintaining a certain stability, that is, the overall structure of the PVA/OHA-Gs@PTMC/PHA scaffold would not shrink and deform due to degradation in a certain period of time. Therefore, the treatment with this scaffold showed better healing at the anastomotic site. Compared to the direct anastomosis group and pure PTMC scaffold group, the double-layer scaffold group promoted a faster return to normal anastomotic strength within 7 days. This PVA/OHA-Gs@PTMC/PHA double-layer nanofiber flexible scaffold appears to be a promising therapeutic strategy to prevent anastomotic leakage after intestinal anastomosis.

Polyhydroxyalkanoates are promising biomaterials, but their application in cartilage repair is still limited. In this study, an injectable thermosensitive hydrogel poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate)-Polyethylene Glycol (PEG)/hyaluronic acid/kartogenin was prepared from 3-hydroxybutyrate, 3-hydroxyvalerate, 3-hydroxyhexanoate, hyaluronic acid, and kartogenin. The hydrogels are porous, temperature-sensitive, and hydrophilic and have good compressive modulus. Mesenchymal stem cells derived from peripheral blood can proliferate on the hydrogels under two- and three-dimensional cultures. In addition, the hydrogel has the ability to induce chondrogenic differentiation of stem cells and induce M2 differentiation of macrophages. The hydrogel loaded with peripheral blood mesenchymal stem cells can repair cartilage defects in the knee joints of New Zealand rabbits and the newly formed cartilage was identified as type II collagen. Overall, this newly developed system could provide a new treatment option for repairing cartilage defects. Impact Statement In this study, poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) was modified with hyaluronic acid and kartogenin to synthesize a thermosensitive injectable hydrogel scaffold. The scaffold has anti-inflammatory and cartilage-promoting effects. This study used the scaffold to carry peripheral blood mesenchymal stem cells to repair cartilage defects in rabbit knee joints, providing a new idea for the treatment of cartilage defects.

This study presented the cultivation of Haloferax mediterranei for polyhydroxyalkanoates (PHA) production from dairy co-products with spent salts recycling and provided the first insights of dissolved oxygen (DO) in regulating PHA biosynthesis by halophiles. PHA had yields up to 0.40 ± 0.02 g/g substrate from whey sugar and up to 0.17 ± 0.12 g/g substrate from delactosed permeate. A higher log-phase DO led to faster biosynthesis, but a lower final PHA production (2.0 ± 0.3 g/L) compared to lower DO levels (3.0 ± 0.1 g/L). This was later elucidated through mathematical modelling by the kinetic parameters and metabolic reaction rates. A novel approach was established to recycle up to 90 % salts and nutrients in the system and achieved consistent production and product quality. This study develops a sustainable biotechnology of converting dairy co-products to biomaterials, improve the economics of PHA and has the potential scalability for industrial applications.

The effect of oxidation on the structure and properties of polyesters remains an urgent issue due to the prospects for regulating the stability of the polymer and modifying its surface. The available data on the effect of ozone on the structure and properties of poly-3-hydroxybutyrate (PHB), in particular on the rate of its destruction, are contradictory. So, the purpose of the work was to study the effect of ozone oxidation on structure and properties of PHB to find the impact of the ozone treatment on controlling the rate of the biodegradation in environmental conditions. The surface of PHB films was modified using ozone treatment to accelerate its biodegradation rate in soil. The essence of ozonation is in the accumulation of various oxygen-containing functional groups, which leads to increased intermolecular interaction of PHB chains, which leads to the hardening of the surface. It was shown that the ozone treatment of the surface slowed down the diffusion of destructors to the volume of the PHB and prevented the fragmentation of the film. In addition, the strength of the films after 5 h of ozonation increased from 25 to 42 MPa, but the wetting angle did not change and no significant change in the surface crystallinity were detected before the soil exposure of the films. The soil burial test showed an approximately 1.5-fold decrease in the biodegradation rate for the ozone-treated sample. This study demonstrated that the surface morphology created by ozone treatment formed a unique outer layer of a new morphology. Ozonated PHB films were more resistant to fragmentation and remained stable in the soil for 300 days, while the control sample of PHB completely decomposed in 240 days. The paper discusses the causes and consequences of these observations and the role of ozone treatment for the modification of PHB surface. The results obtained can be used to control the rate of degradation and to predict the behavior of sterilized products in the field of packaging, medical products, and products with a limited service life due to the understanding of mechanism of surface modification.

Utilizing agricultural waste is a sustainable approach to reduce the production cost of bio-based products. Here, we report a novel haloalkaliphilic strain, Halomonas nigrificans X339, which exhibits an exceptional ability to utilize various low-cost carbon sources. Compared to other halophiles, X339 could be cultivated at an optimal salinity as low as 2 % (w/v). X339 accumulated extraordinarily large granules of polyhydroxybutyrate (PHB). In open batch fermentation, X339 produced 5.11 g/L of PHB from wheat straw hydrolysate (WSH) at 3 % salinity and pH 9, with a PHB/carbon source conversion rate of 0.30 g/g. This represents the highest PHB yield reported from straw hydrolysates in shake-flask fermentation by halophiles. Additionally, whole genome of X339 was sequenced to identify candidate genes related to carbon source utilization. Our findings will benefit researchers in developing a suitable chassis for Next Generation Industrial Biotechnology, and offer a sustainable and eco-friendly solution for bio-based products.

The use of biodegradable active materials is being explored as a strategy to reduce food loss and waste. The aim is to extend the shelf life of food and to ensure biodegradation when these materials are discarded. The utilization of biodegradable polymers remains limited due to their inherent properties and cost-effectiveness. An alternative approach involves the fabrication of bionanocomposites, which offer a potential solution to address these challenges. Therefore, this study investigates the production of a polyhydroxybutyrate/biochar/clay/essential oil (Tepa:Eugenol) bionanocomposite with antioxidant and antimicrobial properties. The morphological, physicochemical, and antioxidant properties of the materials were evaluated in comparison to those of the original PHB. The materials obtained showed a porous surface with cavities, associated with the presence of biochar. It was also determined that it presented an intercalated-exfoliated morphology by XRD. Thermal properties showed minor improvements over those of PHB, indicating that the components did not substantially influence properties such as crystallization temperature, decomposition temperature, or degree of crystallinity; the melting temperature decreased up to 11%. In addition, the PHB/biochar_7/MMT-OM_3/EO_3 bionanocomposites showed a tendency toward hydrophobicity and the highest elastic modulus with respect to PHB. Finally, all essential-oil-loaded bionanocomposites exhibited excellent antioxidant properties against DPPH and ABTS radicals. The results highlight the potential of these bionanocomposites for the development of antioxidant active packaging.

Rhamnolipid, poly(R)-3-hydroxybutyrate (PHB), and ectoine are sustainable compounds produced by specific bacteria known for their protective benefits, including promoting skin health in applications, such as facial wash, sunscreens, and moisturizers. These compounds have been extensively studied due to their unique physicochemical properties and biocompatibility. Leveraging these beneficial properties, this study aimed to create a multifunctional protective formulation by synthesizing nanoparticles from PHB and ectoine, which are acknowledged for their anti-ultraviolet B (UVB) and anti-irritation properties. The covalent bonding of PHB and ectoine was achieved using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), and the nanoparticles were produced through centrifugation. The synthesized nanoparticle (PHB-ectoine NPs) was physicochemically characterized and tested for anti-irritation and anti-UVB properties in vitro. The characterization revealed a homogeneous spherical shape with a distinct layered structure, primarily composed of carbon and oxygen. The PHB-ectoine NPs measured 527 ± 228 nm in size, had a zeta potential of -61.47 ± 0.64 mV, and exhibited notably higher anti-irritant and anti-UVB activities compared to PHB alone, by over 10 and 4 times, respectively. Furthermore, the addition of a rhamnolipid solution as a dispersant provided the nanofluid with antibacterial properties againstStaphylococcus aureus. These results indicate that the rhamnolipid-PHB-ectoine nanoformulation shows significant potential as a multifunctional skin protective agent with anti-irritation, anti-UVB, and antibacterial capabilities.

Polyhydroxyalkanoates (PHAs) are biodegradable biopolymers synthesized by microorganisms and serve as sustainable alternatives to petroleum-based plastics. While traditional PHA production relies on refined carbon sources and pure cultures, high costs and scalability challenges limit commercial viability. Extremophiles, particularly halophiles, have emerged as promising candidates for cost-effective, large-scale production of PHAs. Their ability to thrive in extreme environments reduces contamination risks, minimizes the need for sterilization, and lowers operational costs. Advancements in metabolic engineering, synthetic biology, and CRISPR-based genome editing have enhanced PHA yields by optimizing metabolic flux and cell morphology. Additionally, utilizing alternative feedstocks such as biowaste, syngas, methane, and CO₂ improves economic feasibility. Next-generation industrial biotechnology integrates extremophilic microbes with AI-driven fermentation and eco-friendly downstream processing to enhance scalability. Industrial-scale production of PHAs using Halomonas spp. and other extremophiles demonstrates significant progress toward commercialization, paving the way for sustainable biopolymer applications in reducing plastic pollution.

Poly(3-hydroxybutyrate) (PHB) derivatives are attractive for sustainable polymer production, yet their role in controlling radical polymerization kinetics remains underexplored. In this study, we compare the polymerization kinetics of methyl methacrylate (MMA) using two PHB-based macroinitiators: a macro chain transfer agent (PHB-macro reversible addition-fragmentation chain transfer (RAFT)) and a macroazo initiator (PHBai). RAFT polymerizations (PHB-R-PMMA) were conducted at 70 °C with PHB-macro RAFT in the presence of 2,2'-azobis(isobutyronitrile), while conventional free radical polymerizations (PHBaiPMMA) were carried out using PHBai under identical conditions. The RAFT system exhibited a slightly lower overall rate constant (k = 1.11 × 10-4 L/mol·s) compared to the azo-initiated system (k = 1.28 × 10-4 L/mol·s). Both systems showed a gradual decrease in the PHB content over time, indicating effective copolymer formation with increasing MMA incorporation. Activation energies for PHB-macro RAFT and PHBai were calculated as 0.88 and 1.05 kJ/mol, respectively, demonstrating RAFT's superior control over molecular architecture. The resulting PHB-PMMA block copolymers offer promising applications in orthopedic surgery (e.g., bone cements), packaging, medical implants, drug delivery, and dental materials. This study provides the first direct comparison of PHB-based macro RAFT and azo systems for MMA polymerization, highlighting RAFT's advantage in achieving controlled polymer architectures and expanding biomedical and industrial utility.

Poly(4-hydroxybutyrate) (P4HB) is a high-performance, well-recyclable, and biodegradable polyhydroxyalkanoate (PHA). However, conventional bioproduction of homopolymeric P4HB involves complex and costly processes with C4 feedstocks, particularly 1,4-butanediol (BDO), and enzyme-coenzyme systems in genetically engineered bacteria. An alternative extracellular chemical route utilizing aerial oxidation of BDO offers cost and energy benefits but struggle with conversion efficiency. Inspired by efficient intracellular oxidation of primary alcohols, we propose a ruthenium-phosphine synergistic catalytic system that mimics enzyme-coenzyme functionality. This system effectively catalyzed the air-mediated, solvent-free oxidation of BDO to produce γ-butyrolactone (γ-BL) and oligomeric P4HB, with a space-time yield (10.37 g [γ-BL unit] g-1 catalyst h-1) surpassing the values (<5.5) of previous approaches. The oligomer-containing products were reversibly converted to γ-BL and then to P4HB (28.9 kDa) via ring-opening polymerization, exceeding reported values (<16 kDa). This study provides the potential for large-scale synthesis of high-value PHAs from diverse non-grain-based diols, offering economic and environmental advantages.

Polyhydroxyalkanoates (PHAs) have attracted broad interest as promising sustainable materials to address plastic pollution and resource scarcity. However, the chemical synthesis of stereoregular PHAs via ring-opening polymerization (ROP) has long been an elusive endeavor. In this contribution, we exploited a robust spiro-salen yttrium complex (Y3) as the catalyst to successfully prepare syndiotactic PHAs with diverse pendent groups. Simply altering the ratio of enantiomeric catalysts allowed to access of PHAs with diverse syndiotacticity (Pr=0.5-0.99, from sticky oil to tough materials), delivering tunable thermal properties (glass transition temperature, Tg from -52 to 70 °C and melting transition temperature, Tm from 38 to 223 °C). A combined experimental and computational study suggested a polymeric exchange mechanism could boost the polymerization activity and control the syndioselectivity.

The escalating emissions of anthropogenic carbon dioxide (CO2) and the pervasive issue of nondegradable plastic pollution underscore dual urgent challenges in pursuit of a sustainable society. Achieving such sustainability in the plastic industry, while effectively addressing these environmental concerns, necessitates the development and implementation of innovative strategies for the synthesis of biodegradable polymers utilizing CO2 as feedstocks. The technologies not only facilitate the mitigation of elevated atmospheric CO2 concentrations but also introduce a renewable carbon resource for polymer manufacturing. While considerable research has been undertaken in CO2 upgrading to various C1-3 products, the production of biodegradable polymers from CO2 remains a formidable challenge. Here, we delineate the principal methodologies for catalytic CO2 upgrading to biodegradable polymers, encompassing photocatalytic-biological processes and electrocatalytic-biological approaches. The emphasis of this perspective is on the optimization of production processes and catalyst efficiency, which are paramount in addressing the imperative challenge of decarbonization in the plastic industry, thereby aligning with global environmental sustainability goals.

Commercial adhesives are petroleum-based thermoset networks or nonbiodegradable thermoplastic hot melts, making them ideal targets for replacement by biodegradable alternatives. Poly(3-hydroxybutyrate) (P3HB) is a biorenewable and biodegradable alternative to conventional plastics, but microbial P3HB, which has a stereoperfect stereomicrostructure, exhibits no adhesion. In this study, by elucidating the fundamental relationship between chemocatalytically engineered P3HB stereomicrostructures and adhesion properties, we found that biodegradable syndio-rich P3HB exhibits high adhesion strength and outperforms common commercial adhesives, whereas syndiotactic, isotactic, or iso-rich P3HB shows no measurable adhesion. The syndio-rich stereomicrostructure brings about desired thermomechanical and viscoelastic properties of P3HB that enable strong adhesion to a range of substrates tested, including aluminum, steel, glass, and wood, and its performance is insensitive to molar mass and reprocessing or reuse.

Conventional plastics pose significant environmental and health risks across their life cycle, driving intense interest in sustainable alternatives. Among these, polyhydroxyalkanoates (PHAs) stand out for their biocompatibility, degradation characteristics, and diverse applications. Yet, challenges like production cost, scalability, and limited chemical variety hinder their widespread adoption, impacting material selection and design. This review examines PHA research through the lens of the classical materials tetrahedron, exploring property-structure-processing-performance (PSPP) relationships. By analyzing recent literature and addressing current limitations, we gain valuable insights into PHA development. Despite challenges, we remain optimistic about the role of PHAs in transitioning towards a circular plastic economy, emphasizing the need for further research to unlock their full potential.

In pursuit of reliable and efficient industrial microbes, this study integrates cutting-edge systems biology tools with Halomonas bluephagenesis TD01, a robust halophilic bacterium. We generated the complete and annotated circular genome sequence for this model organism, constructed and meticulously curated a genome-scale metabolic network, achieving striking 86.32% agreement with Biolog Phenotype Microarray data and visualize the network via an interactive Electron/Thrift server architecture. We then analyzed the genome-scale network using vertex sampling analysis (VSA) and found that productions of biomass, polyhydroxyalkanoates (PHA), citrate, acetate, and pyruvate are mutually competing. Recognizing the dynamic nature of H. bluephagenesis TD01, we further developed and implemented the hyper-cube-shrink-analysis (HCSA) framework to predict effects of nutrient availabilities and metabolic reactions in the model on biomass and PHA accumulation. We then, based on the analysis results, proposed and validate multi-step feeding strategies tailored to different fermentation stages. This integrated approach yielded remarkable results, with fermentation culminating in a cell dry weight of 100.4 g/L and 70% PHA content, surpassing previous benchmarks. Our findings exemplify the powerful potential of system-level tools in the design and optimization of industrial microorganisms, paving the way for more efficient and sustainable bio-based processes.

Within the large poly(3-hydroxyalkanoate) (PHA) family, C3 propionates are much less studied than C4 butyrates, with the exception of α,α-disubstituted propionate PHAs, particularly poly(3-hydroxy-2,2-dimethylpropionate), P3H(Me)2P, due to its high melting temperature (Tm ∼ 230 °C) and crystallinity (∼76%). However, inefficient synthetic routes to its monomer 2,2-dimethylpropiolactone [(Me)2PL] and extreme brittleness of P3H(Me)2P largely hinder its broad applications. Here, we introduce simple, efficient step-growth polycondensation (SGP) of a hydroxyacid or methyl ester to afford P3H(Me)2P with low to medium molar mass, which is then utilized to produce lactones through base-catalyzed depolymerization. The ring-opening polymerization (ROP) of the 4-membered lactone leads to high-molar-mass P3H(Me)2P, which can be depolymerized by hydrolysis to the hydroxyacid in 99% yield or methanolysis to the hydroxyester in 91% yield, achieving closed-loop recycling via both SGP and ROP routes. Intriguingly, the chain end of the SGP-P3H(Me)2P determines the depolymerization selectivity toward 4- or 12-membered lactone formation, while both can be repolymerized back to P3H(Me)2P. Through the formation of copolymers P3H(Me/R)2P (R = Et, nPr), PHAs with high tensile strength and ductility, coupled with high barriers to water vapor and oxygen, have been created. Notably, the PHA structure-property study led to P3H(nPr)2P with a record-high Tm of 266 °C within the PHA family.

Bioconversion of high-volume waste streams into value-added products will be an integral component of the growing bioeconomy. Volatile fatty acids (VFAs) (e.g., butyrate, valerate, and hexanoate) are an emerging and promising waste-derived feedstock for microbial carbon upcycling. Cupriavidus necator H16 is a favorable host for conversion of VFAs into various bioproducts due to its diverse carbon metabolism, ease of metabolic engineering, and use at industrial scales. Here, we report that a common strategy to improve product titers in C. necator, deletion of the polyhydroxybutyrate (PHB) biosynthetic operon, results in a significant growth defect on VFA substrates. Using adaptive laboratory evolution, we identify mutations to the regulator gene phaR, the two-component response regulator-histidine kinase pair encoded by H16_A1372/H16_A1373, and the tripartite transporter assembly encoded by H16_A2296-A2298 as causative for improved growth on VFA substrates. Deletion of phaR and H16_A1373 led to significantly reduced NADH abundance accompanied by large changes to expression of genes involved in carbon metabolism, balance of electron carriers, and oxidative stress tolerance that may be responsible for improved growth of these engineered strains. These results provide insight into the role of PHB biosynthesis in carbon and energy metabolism and highlight a key role for the regulator PhaR in global regulatory networks. By combining mutations, we generated platform strains with significant growth improvements on VFAs, which can enable improved conversion of waste-derived VFA substrates to target bioproducts.

Polyhydroxyalkanoates (PHAs) are optimal potential materials for industrial and medical uses, characterized by exceptional sustainability, biodegradability, and biocompatibility. These are primarily from various bacteria and archaea. Bacterial strains with effective PHA formation capabilities and minimal production cost form the foundation for PHA production. Detailed genomic analysis of these PHA-generating bacteria is vital to understand their PHA production pathways and enhance their synthesis capability.

ZZQ-149, a halophilic, PHA-producing bacterium, was isolated from the sediment of China's Qinghai Lake. Here, we decoded the full genome of ZZQ-149 using Single Molecule Real Time (SMRT) technology based on PacBio RS II platform, coupled with Illumina sequencing platforms. Physiological, chemotaxonomic traits, and phylogenetic analysis based on 16 S rRNA gene and single copy core genes of ninety-nine Halomonas type strains identified ZZQ-149 as the type strain of Halomonas qinghailakensis. Furthermore, a low average nucleotide identity (ANI, < 95%) delineated the genetic differences between ZZQ-149 and other Halomonas species. The ZZQ-149 genome, with a DNA G + C content of 52%, comprises a chromosome (3, 798, 069 bps) and a plasmid (6, 107 bps). The latter encodes the toxin-antitoxin system, BrnT/BrnA. Through comprehensive genome sequencing and analysis, we identified multiple PHA-synthesizing enzymes and an unprecedented combination of eight PHA-synthesizing pathways in ZZQ-149.

Being a halophilic, PHA-producing bacterium, ZZQ-149 exhibits potential as a high PHA producer for engineered bacteria via genome editing while ensuring low-cost PHA production through continuous, unsterilized fermentation.

Synthetic biology encompasses many kinds of ideas and techniques with the common theme of creating something novel. The industrially relevant microorganism, Ralstonia eutropha (also known as Cupriavidus necator), has long been a subject of metabolic engineering efforts to either enhance a product it naturally makes (polyhydroxyalkanoate) or produce novel bioproducts (e.g., biofuels and other small molecule compounds). Given the metabolic versatility of R. eutropha and the existence of multiple molecular genetic tools and techniques for the organism, development of a synthetic biology toolkit is underway. This toolkit will allow for novel, user-friendly design that can impart new capabilities to R. eutropha strains to be used for novel application. This article reviews the different synthetic biology techniques currently available for modifying and enhancing bioproduction in R. eutropha. KEY POINTS: • R. eutropha (C. necator) is a versatile organism that has been examined for many applications. • Synthetic biology is being used to design more powerful strains for bioproduction. • A diverse synthetic biology toolkit is being developed to enhance R. eutropha's capabilities.

In this study, we explore an approach to enhance the mechanical performance of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) by utilizing the self-reinforcing effect of β-phase-induced PHBV electrospun nanofiber mats. This involves electrospinning combined with low-temperature postspun vapor solvent interfiber welding. Scanning electron microscopy imaging confirmed fiber alignment, while XRD diffraction revealed the presence of both α and β crystalline phases under optimized electrospinning conditions. The resulting composite exhibited significant improvements in mechanical properties attributed to the formation of more perfectly structured α and β polymorphs and enhanced interfacial adhesion of electrospun nanofibers after vapor solvent treatment. This approach offers entirely recyclable and biodegradable materials, presenting the potential for a new family of sustainable bioplastics.

Blood vessels are highly dynamic and complex structures with a variety of physiological functions, including the transport of oxygen, nutrients, and metabolic wastes. Their normal functioning involves the close and coordinated cooperation of a variety of cells. However, adverse internal and external environmental factors can lead to vascular damage and the induction of various vascular diseases, including atherosclerosis and thrombosis. This can have serious consequences for patients, and there is an urgent need for innovative techniques to repair damaged blood vessels. Polyesters have been extensively researched and used in the treatment of vascular disease and repair of blood vessels due to their excellent mechanical properties, adjustable biodegradation time, and excellent biocompatibility. Given the high complexity of vascular tissues, it is still challenging to optimize the utilization of polyesters for repairing damaged blood vessels. Nevertheless, they have considerable potential for vascular tissue engineering in a range of applications. This summary reviews the physicochemical properties of polyhydroxyalkanoate (PHA), polycaprolactone (PCL), poly-lactic acid (PLA), and poly(lactide-co-glycolide) (PLGA), focusing on their unique applications in vascular tissue engineering. Polyesters can be prepared not only as 3D scaffolds to repair damage as an alternative to vascular grafts, but also in various forms such as microspheres, fibrous membranes, and nanoparticles to deliver drugs or bioactive ingredients to damaged vessels. Finally, it is anticipated that further developments in polyesters will occur in the near future, with the potential to facilitate the wider application of these materials in vascular tissue engineering.

Microbial biopolymers such as poly-3-hydroxybutyrate (PHB) are emerging as promising alternatives for sustainable production of biodegradable bioplastics. Their promise is heightened by the potential utilisation of photosynthetic organisms, thus exploiting sunlight and carbon dioxide as source of energy and carbon, respectively. The cyanobacterium Synechocystis sp. B12 is an attractive candidate for its superior ability to accumulate high amounts of PHB as well as for its high-light tolerance, which makes it extremely suitable for large-scale cultivation. Beyond its practical applications, B12 serves as an intriguing model for unravelling the molecular mechanisms behind PHB accumulation.

Through a multifaceted approach, integrating physiological, genomic and transcriptomic analyses, this work identified genes involved in the upregulation of chlorophyll biosynthesis and phycobilisome degradation as the possible candidates providing Synechocystis sp. B12 an advantage in growth under high-light conditions. Gene expression differences in pentose phosphate pathway and acetyl-CoA metabolism were instead recognised as mainly responsible for the increased Synechocystis sp. B12 PHB production during nitrogen starvation. In both response to strong illumination and PHB accumulation, Synechocystis sp. B12 showed a metabolic modulation similar but more pronounced than the reference strain, yielding in better performances.

Our findings shed light on the molecular mechanisms of PHB biosynthesis, providing valuable insights for optimising the use of Synechocystis in economically viable and sustainable PHB production. In addition, this work supplies crucial knowledge about the metabolic processes involved in production and accumulation of these molecules, which can be seminal for the application to other microorganisms as well.

Within bioplastics, natural poly(3-hydroxybutyrate) (PHB) stands out as fully biocompatible and biodegradable, even in marine environments; however, its high isotacticity and crystallinity limits its mechanical properties and hence its applications. PHB can also be synthesized with different tacticities via a catalytic ring-opening polymerization (ROP) of rac-β-butyrolactone (BBL), paving the way to PHB with better thermomechanical and processability properties. In this work, the catalyst family is extended based on aluminum phenoxy-imine methyl catalyst [AlMeL2], that reveals efficient in the ROP of BBL, to the halogeno analogous complex [AlClL2]. As well, the impact on the ROP mechanism of different initiators is further explored with a particular focus in dimethylaminopyridine (DMAP), a hardly studied initiator for the ROP of BBL. A thorough mechanistic study is performed that evidences the presence of two concomitant DMAP-mediated mechanisms, that lead to either a DMAP or a crotonate end-capping group. Besides, in order to increase the possibilities of PHB post-polymerization functionalization, the introduction of a side-chain functionality is explored, establishing the copolymerization of BBL with β-allyloxymethylene propiolactone (BPLOAll), resulting in well-defined P(BBL-co-BPLOAll) copolymers.

Microbial instability is a common problem during bio-production based on microbial hosts. Halomonas bluephagenesis has been developed as a chassis for next generation industrial biotechnology (NGIB) under open and unsterile conditions. However, the hidden genomic information and peculiar metabolism have significantly hampered its deep exploitation for cell-factory engineering. Based on the freshly completed genome sequence of H. bluephagenesis TD01, which reveals 1889 biological process-associated genes grouped into 84 GO-slim terms. An enzyme constrained genome-scale metabolic model Halo-ecGEM was constructed, which showed strong ability to simulate fed-batch fermentations. A visible salt-stress responsive landscape was achieved by combining GO-slim term enrichment and CVT-based omics profiling, demonstrating that cells deploy most of the protein resources by force to support the essential activity of translation and protein metabolism when exposed to salt stress. Under the guidance of Halo-ecGEM, eight transposases were deleted, leading to a significantly enhanced stability for its growth and bioproduction of various polyhydroxyalkanoates (PHA) including 3-hydroxybutyrate (3HB) homopolymer PHB, 3HB and 3-hydroxyvalerate (3HV) copolymer PHBV, as well as 3HB and 4-hydroxyvalerate (4HB) copolymer P34HB. This study sheds new light on the metabolic characteristics and stress-response landscape of H. bluephagenesis, achieving for the first time to construct a long-term growth stable chassis for industrial applications. For the first time, it was demonstrated that genome encoded transposons are the reason for microbial instability during growth in flasks and fermentors.

While poly (3-hydroxybutyrate) (PHB) holds promise as a bioplastic, its commercial utilization has been hampered by the high cost of raw materials. However, glycerol emerges as a viable feedstock for PHB production, offering a sustainable production approach and substantial cost reduction potential. Glycerol stands out as a promising feedstock for PHB production, offering a pathway toward sustainable manufacturing and considerable cost savings. The identification and characterization of strains capable of converting glycerol into PHB represent a pivotal strategy in advancing PHB production research. In this study, we isolated a strain, Ralstonia sp. RRA (RRA). The strain exhibits remarkable proficiency in synthesizing PHB from glycerol. With glycerol as the carbon source, RRA achieved a specific growth rate of 0.19 h-1, attaining a PHB content of approximately 50% within 30 h. Through third-generation genome and transcriptome sequencing, we elucidated the genome composition and identified a total of eight genes (glpR, glpD, glpS, glpT, glpP, glpQ, glpV, and glpK) involved in the glycerol metabolism pathway. Leveraging these findings, the strain RRA demonstrates significant promise in producing PHB from low-cost renewable carbon sources.

This review addresses the critical issue of a rapidly increasing worldwide waste stream and the need for sustainable management. The paper proposes an integrated transformation toward a next-generation methanization process, which leads not only to treating waste but also to converting it into higher value compounds and greener energy. Although the current and commonly used anaerobic digestion process is useful for biogas production, it presents limitations of resource exploitation and some negative environmental impacts. Focusing on the acidogenic stage in waste stream processing, the paper discusses the recent strategies to enhance the recovery of volatile fatty acids (VFAs). These acids serve as precursors for synthesizing a variety of biochemicals and biofuels, offering higher value products than solely energy recovery and soil fertilizers. Additionally, the importance of recycling the fermentation residues back into the biorefinery process is highlighted. This recycling not only generates additional VFAs but also contributes to generating clean energy, thereby enhancing the overall sustainability and efficiency of the waste management system. Moreover, the review discusses the necessity to integrate life cycle assessment (LCA) and techno-economic analysis (TEA) to evaluate the environmental impacts, sustainability, and processing costs of the proposed biorefinery.

Although the use of biodegradable plastics is suitable for unrecoverable, single-use plastic, their high production cost and much lower variety compared to commodity plastics limit their application. In this study, we developed a new polymer with potential biodegradability, poly(ketone/ester), synthesized from propylene and carbon monoxide. Propylene and carbon monoxide are easily available at low costs from fossil resources, and they can also be derived from biomass. Using an atom insertion reaction to the main chain of the polymer, the main-chain editing of the polymer molecule proceeded with up to 89% selectivity for atom insertion over main-chain cleavage.

This article addresses the entire life cycle of the all-green fibrous materials based on poly(3-hydroxybutyrate) (PHB) containing a natural biocompatible additive Hemin (Hmi): from preparation, service life, and the end of life upon in-soil biodegradation. Fibrous PHB/Hmi materials with a highly developed surface and interconnected porosity were prepared by electrospinning (ES) from Hmi-containing feed solutions. Structural organization of the PHB/Hmi materials (porosity, uniform structure, diameter of fibers, surface area, distribution of Hmi within the PHB matrix, phase composition, etc.) is shown to be governed by the ES conditions: the presence of even minor amounts of Hmi in the PHB/Hmi (below 5 wt %) serves as a powerful tool for the control over their structure, performance, and biodegradation. Service characteristics of the PHB/Hmi materials (wettability, prolonged release of Hmi, antibacterial activity, breathability, and mechanical properties) were studied by different physicochemical methods (scanning electron microscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, differential scanning calorimetry, contact angle measurements, antibacterial tests, etc.). The effect of the structural organization of the PHB/Hmi materials on their in-soil biodegradation at the end of life was analyzed, and key factors providing efficient biodegradation of the PHB/Hmi materials at all stages (from adaptation to mineralization) are highlighted (high surface area and porosity, thin fibers, release of Hmi, etc.). The proposed approach allows for target-oriented preparation and structural design of the functional PHB/Hmi nonwovens when their structural supramolecular organization with a highly developed surface area controls both their service properties as efficient antibacterial materials and in-soil biodegradation upon the end of life.

Polyesters carrying polar main-chain ester linkages exhibit distinct material properties for diverse applications and thus play an important role in today's plastics economy. It is anticipated that they will play an even greater role in tomorrow's circular plastics economy that focuses on sustainability, thanks to the abundant availability of their biosourced building blocks and the presence of the main-chain ester bonds that can be chemically or biologically cleaved on demand by multiple methods and thus bring about more desired end-of-life plastic waste management options. Because of this potential and promise, there have been intense research activities directed at addressing recycling, upcycling or biodegradation of existing legacy polyesters, designing their biorenewable alternatives, and redesigning future polyesters with intrinsic chemical recyclability and tailored performance that can rival today's commodity plastics that are either petroleum based and/or hard to recycle. This review captures these exciting recent developments and outlines future challenges and opportunities. Case studies on the legacy polyesters, poly(lactic acid), poly(3-hydroxyalkanoate)s, poly(ethylene terephthalate), poly(butylene succinate), and poly(butylene-adipate terephthalate), are presented, and emerging chemically recyclable polyesters are comprehensively reviewed.

As thermoplastic, nontoxic, and biocompatible polyesters, polyhydroxyalkanoates (PHAs) are considered promising biodegradable plastic candidates for diverse applications. Short-chain-length/medium-chain-length (SCL/MCL) PHA copolymers are flexible and versatile PHAs that are typically produced from fatty acids, which are expensive and toxic. Therefore, to achieve the sustainable biosynthesis of SCL/MCL-PHAs from renewable non-fatty acid carbon sources (e.g., sugar or CO2), we used the lithoautotrophic bacterium Cupriavidus necator H16 as a microbial platform. Specifically, we synthesized tailored PHA copolymers with varying MCL-3-hydroxyalkanoate (3HA) compositions (10-70 mol%) from fructose by rewiring the MCL-3HA biosynthetic pathways, including (i) the thioesterase-mediated free fatty acid biosynthetic pathway coupled with the beta-oxidation cycle and (ii) the hydroxyacyl transferase-mediated fatty acid de novo biosynthetic pathway. In addition to sugar-based feedstocks, engineered strains are also promising platforms for the lithoautotrophic production of SCL/MCL-PHAs from CO2. The set of engineered C. necator strains developed in this study provides greater opportunities to produce customized polymers with controllable monomer compositions from renewable resources.

Polyhydroxyalkanoates (PHA) have evolved into versatile biopolymers, transcending their origins as mere bioplastics. This extensive review delves into the multifaceted landscape of PHA applications, shedding light on the diverse industries that have harnessed their potential. PHA has proven to be an invaluable eco-conscious option for packaging materials, finding use in films foams, paper coatings and even straws. In the textile industry, PHA offers a sustainable alternative, while its application as a carbon source for denitrification in wastewater treatment showcases its versatility in environmental remediation. In addition, PHA has made notable contributions to the medical and consumer sectors, with various roles ranging from 3D printing, tissue engineering implants, and cell growth matrices to drug delivery carriers, and cosmetic products. Through metabolic engineering efforts, PHA can be fine-tuned to align with the specific requirements of each industry, enabling the customization of material properties such as ductility, elasticity, thermal conductivity, and transparency. To unleash PHA's full potential, bridging the gap between research and commercial viability is paramount. Successful PHA production scale-up hinges on establishing direct supply chains to specific application domains, including packaging, food and beverage materials, medical devices, and agriculture. This review underscores that PHA's future rests on ongoing exploration across these industries and more, paving the way for PHA to supplant conventional plastics and foster a circular economy.

A novel α-amylase Amy03713 was screened and cloned from the starch utilization strain Vibrio alginolyticus LHF01. When heterologously expressed in Escherichia coli, Amy03713 exhibited the highest enzyme activity at 45 °C and pH 7, maintained >50 % of the enzyme activity in the range of 25-75 °C and pH 5-9, and sustained >80 % of the enzyme activity in 25 % (w/v) of NaCl solution, thus showing a wide range of adapted temperatures, pH, and salt concentrations. Halomonas bluephagenesis harboring amy03713 gene was able to directly utilize starch. With optimized amylase expression, H. bluephagenesis could produce poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB). When cultured for PHB production, recombinant H. bluephagenesis was able to grow up to a cell dry weight of 11.26 g/L, achieving a PHB titer of 6.32 g/L, which is the highest titer that has been reported for PHB production from starch in shake flasks. This study suggests that Amy03713 is an ideal amylase for PHA production using starch as the carbon source in H. bluephagenesis.

Bioplastics are one of the answers that can point society toward a sustainable future. Under this premise, the synthesis of polymers with competitive properties using low-cost starting materials is a highly desired factor in the industry. Also, tackling environmental issues such as nonbiodegradable waste generation, high carbon footprint, and consumption of nonrenewable resources are some of the current concerns worldwide. The scientific community has been placing efforts into the biosynthesis of polymers using bacteria and other microbes. These microorganisms can be convenient reactors to consume food and agricultural wastes and convert them into biopolymers with inherently attractive properties such as biodegradability, biocompatibility, and appreciable mechanical and chemical properties. Such biopolymers can be applied to several fields such as packing, cosmetics, pharmaceutical, medical, biomedical, and agricultural. Thus, intending to elucidate the science of microbes to produce polymers, this review starts with a brief introduction to bioplastics by describing their importance and the methods for their production. The second section dives into the importance of bacteria regarding the biochemical routes for the synthesis of polymers along with their advantages and disadvantages. The third section covers some of the main parameters that influence biopolymers' production. Some of the main applications of biopolymers along with a comparison between the polymers obtained from microorganisms and the petrochemical-based ones are presented. Finally, some discussion about the future aspects and main challenges in this field is provided to elucidate the main issues that should be tackled for the wide application of microorganisms for the preparation of bioplastics.

Among the polyhydroxyalkanoate (PHA), poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] [P(3HB-co-3HHx)] is reported to closely resemble polypropylene and low-density polyethylene. Studies have shown that PHA synthase (PhaC) from mangrove soil (PhaCBP-M-CPF4) is an efficient PhaC for P(3HB-co-3HHx) production and N-termini of PhaCs influence its substrate specificity, dimerization, granule morphology, and molecular weights of PHA produced. This study aims to further improve PhaCBP-M-CPF4 through N-terminal truncation.

The N-terminal truncated mutants of PhaCBP-M-CPF4 were constructed based on the information of the predicted secondary and tertiary structures using PSIPRED server and AlphaFold2 program, respectively. The N-terminal truncated PhaCBP-M-CPF4 mutants were evaluated in C. necator mutant PHB-4 based on the cell dry weight, PHA content, 3HHx molar composition, molecular weights, and granule morphology of the PHA granules. The results showed that most transformants harbouring the N-terminal truncated PhaCBP-M-CPF4 showed a reduction in PHA content and cell dry weight except for PhaCBP-M-CPF4 G8. PhaCBP-M-CPF4 G8 and A27 showed an improved weight-average molecular weight (Mw) of PHA produced due to lower expression of the truncated PhaCBP-M-CPF4. Transformants harbouring PhaCBP-M-CPF4 G8, A27, and T74 showed a reduction in the number of granules. PhaCBP-M-CPF4 G8 produced higher Mw PHA in mostly single larger PHA granules with comparable production as the full-length PhaCBP-M-CPF4.

This research showed that N-terminal truncation had effects on PHA accumulation, substrate specificity, Mw, and granule morphology. This study also showed that N-terminal truncation of the amino acids that did not adopt any secondary structure can be an alternative to improve PhaCs for the production of PHA with higher Mw in mostly single larger granules.

The mutant strain Halomonas bluephagenesis (TDH4A1B5P) was found to produce PHA under low-salt, non-sterile conditions, but the yield was low. To improve the yield, different nitrogen sources were tested. It was discovered that urea was the most effective nitrogen source for promoting growth during the stable stage, while ammonium sulfate was used during the logarithmic stage. The growth time of H. bluephagenesis (TDH4A1B5P) and its PHA content were significantly prolonged by the presence of sulfate ions. After 64 hr in a 5-L bioreactor supplemented with sulfate ions, the dry cell weight (DCW) of H. bluephagenesis weighed 132 g/L and had a PHA content of 82%. To promote the growth and PHA accumulation of H. bluephagenesis (TDH4A1B5P), a feeding regimen supplemented with nitrogen sources and sulfate ions with ammonium sodium sulfate was established in this study. The DCW was 124 g/L, and the PHA content accounted for 82.3% (w/w) of the DCW, resulting in a PHA yield of 101 g/L in a 30-L bioreactor using the optimized culture strategy. In conclusion, stimulating H. bluephagenesis (TDH4A1B5P) to produce PHA is a feasible and suitable strategy for all H. bluephagenesis.

A large number of non-degradable materials have severely damaged the ecological environment. Now, people are increasingly pursuing the use of environmentally friendly materials to replace traditional chemical materials. Polyhydroxyalkonates (PHAs) are receiving increasing attention because of the unique biodegradability and biocompatibility they offer. However, the applications of PHAs are still limited due to high production costs and insufficient study. This project examines the optimal electrospinning parameters for the production of PHA-based fibrous membranes for air filtration. A common biodegradable polyester, Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), was electrospun into a nanofibrous membrane with a well-controlled surface microstructure. In order to produce smooth, bead-free fibers with micron-scale diameters, the effect of the process parameters (applied electric field, solution flow rate, inner diameter of hollow needle, and polymer concentration) on the electrospun fiber microstructure was optimized. The well-defined fibrous structure was optimized at an applied electric field of 20 kV, flow rate of 0.5 mL/h, solution concentration of 12 wt.%, and needle inner diameter of 0.21 mm. The morphology of the electrospun PHBV fibrous membrane was observed by scanning electron microscopy (SEM). Fourier transform infrared (FTIR) and Raman spectroscopy were used to explore the chemical signatures and phases of the electrospun PHBV nanofiber. The ball burst strength (BBS) was measured to assess the mechanical strength of the membrane. The small pore size of the nanofiber membranes ensured they had good application prospects in the field of air filtration. The particle filtration efficiency (PFE) of the optimized electrospun PHBV fibrous membrane was above 98% at standard atmospheric pressure.

This study investigates the enzymatic degradation processes of different classes of polyhydroxyalkanoates (PHAs), a group of biopolymers naturally synthesized by various microorganisms. Medium chain length PHAs (mcl-PHAs) are distinguished biopolymers due to their biodegradability and diverse material properties. Using quartz crystal microbalance measurements as a valuable tool for accurate real-time monitoring of the enzymatic degradation process, the research provides detailed kinetic data, describing the interaction between enzymes and substrates during the enzymatic degradation process. Thin films of poly-3-hydroxybutyrate (PHB) and polyhydroxyoctanoate copolymer (PHO), containing molar fractions of about 84% 3-hydroxyoctanoate and 16% 3-hydroxyhexanoate, were exposed to scl-depolymerases from Pseudomonas lemoignei LMG 2207 and recombinant mcl-depolymerase produced in Escherichia coli DH5α harboring the plasmid pMAD8, respectively. Analyses based on a heterogeneous kinetic model for the polymer degradation indicated a six-fold stronger adsorption equilibrium constant of mcl-depolymerase to PHO. Conversely, the degradation rate constant was approximately twice as high for scl-depolymerases acting on PHB. Finally, the study highlights the differences in enzyme-substrate interactions and degradation mechanisms between the investigated scl- and mcl-PHAs.

The bio-manufacturing of products with substantial commercial value, particularly polyhydroxyalkanoates (PHA), using cost-effective carbon sources through microorganisms, has garnered heightened attention from both the scientific community and industry over the past few decades. Opting for industrial PHA production from various organic wastes, spanning industrial, agricultural, municipal, and food-based sources, emerges as a wiser choice. This strategy not only eases the burden of recycling organic waste and curbs environmental pollution but also trims down PHA production costs, rendering these materials more competitive in commercial markets. In addition, PHAs are a family of renewable, environmentally friendly, fully biodegradable and biocompatible polyesters with a multitude of applications. This review provides an overview of recent developments in PHA production from organic wastes. It covers the optimization of diverse metabolic pathways for producing various types of PHA from organic waste sources, pre-treatment and downstream processing for PHA using unrelated organic wastes, and challenges in industrial production of PHA using unrelated organic waste feedstocks and the challenges faced in industrial PHA production from organic wastes, along with potential solutions. Lastly, this study suggests underlying research endeavors aimed at further enhancing of the feasibility of industrial PHA production from organic wastes as an alternative to current petroleum-based plastics in the near future.

Poly(3-hydroxybutyrate) (P3HB), a biologically produced, biodegradable natural polyester, exhibits excellent thermal and barrier properties but suffers from mechanical brittleness, largely limiting its applications. Here we report a mono-material product design strategy to toughen stereoperfect, brittle bio or synthetic P3HB by blending it with stereomicrostructurally engineered P3HB. Through tacticity ([mm] from 0 to 100 %) and molecular weight (Mn to 788 kDa) tuning, high-performance synthetic P3HB materials with tensile strength to ≈30 MPa, fracture strain to ≈800 %, and toughness to 126 MJ m-3 (>110× tougher than bio-P3HB) have been produced. Physical blending of the brittle P3HB with such P3HB in 10 to 90 wt % dramatically enhances its ductility from ≈5 % to 95-450 % and optical clarity from 19 % to 85 % visible light transmittance while maintaining desirably high elastic modulus (>1 GPa), tensile strength (>35 MPa), and melting temperature (160-170 °C). This P3HB-toughening-P3HB methodology departs from the traditional approach of incorporating chemically distinct components to toughen P3HB, which hinders chemical or mechanical recycling, highlighting the potential of the mono-material product design solely based on biodegradable P3HB to deliver P3HB materials with diverse performance properties.

With the growing demand for next-generation health care, the integration of electronic components into implantable medical devices (IMDs) has become a vital factor in achieving sophisticated healthcare functionalities such as electrophysiological monitoring and electroceuticals worldwide. However, these devices confront technological challenges concerning a noninvasive power supply and biosafe device removal. Addressing these challenges is crucial to ensure continuous operation and patient comfort and minimize the physical and economic burden on the patient and the healthcare system. This Review highlights the promising capabilities of bioresorbable triboelectric nanogenerators (B-TENGs) as temporary self-clearing power sources and self-powered IMDs. First, we present an overview of and progress in bioresorbable triboelectric energy harvesting devices, focusing on their working principles, materials development, and biodegradation mechanisms. Next, we examine the current state of on-demand transient implants and their biomedical applications. Finally, we address the current challenges and future perspectives of B-TENGs, aimed at expanding their technological scope and developing innovative solutions. This Review discusses advancements in materials science, chemistry, and microfabrication that can advance the scope of energy solutions available for IMDs. These innovations can potentially change the current health paradigm, contribute to enhanced longevity, and reshape the healthcare landscape soon.

With concerns about depletion of fossil fuel and environmental pollution, synthesis of biofuels such as isobutanol from low-cost substrate by microbial cell factories has attracted more and more attention. As one of the most promising carbon sources instead of food resources, acetate can be utilized by versatile microbes and converted into numerous valuable chemicals.

An isobutanol synthetic pathway using acetate as sole carbon source was constructed in E. coli. Pyruvate was designed to be generated via acetyl-CoA by pyruvate-ferredoxin oxidoreductase YdbK or anaplerotic pathway. Overexpression of transhydrogenase and NAD kinase increased the isobutanol titer of recombinant E. coli from 121.21 mg/L to 131.5 mg/L under batch cultivation. Further optimization of acetate supplement concentration achieved 157.05 mg/L isobutanol accumulation in WY002, representing the highest isobutanol titer by using acetate as sole carbon source.

The utilization of acetate as carbon source for microbial production of valuable chemicals such as isobutanol could reduce the consumption of food-based substrates and save production cost. Engineering strategies applied in this study will provide a useful reference for microbial production of pyruvate derived chemical compounds from acetate.