Within lignocellulosic biomass, xylose is the second most abundant sugar after glucose. As a renewable and sustainable substrate, it is gaining attention as a feedstock for microbial bioprocesses. In this study, we demonstrated the co-production of polyhydroxybutyrate (PHB) and violacein from xylose. We initially confirmed the feasibility of co-production through genome-scale metabolic simulations, followed by optimization using a hybrid expression system that combines a conventional tac promoter and synthetic promoter-ribosome-binding site-terminator (semi-endo PRT) elements in dual plasmids. Additionally, we assessed the antimicrobial activity of violacein against type I methanotrophs. Recombinant Escherichia coli DH5α harboring a hybrid system produced 111.3 ± 19.7 and 0.88 ± 0.23 mg/L of PHB and violacein, respectively, in M9 using xylose as the sole carbon source, without tryptophan supplementation. Using the synthetic PRT system, 528.9 ± 104 mg/g dry cell weight (DCW) of PHB was obtained. Additionally, violacein inhibits the growth of Methylomicrobium alcaliphilum 20Z at 9 µg/mL in nitrate mineral salt medium containing methanol as the sole carbon source. The use of lignocellulose-derived sugars for co-production offers an environmentally sustainable bio-manufacturing approach that contributes to greenhouse gas mitigation and supports the transition toward a circular bioeconomy.

Lignin, the second most abundant biopolymer after cellulose, is still largely combusted as low-value fuel, yet it offers significant potential as a versatile carbon resource for low-emission materials and processes that reduce carbon footprints in high-emitting industries. This review critically analyzes how lignin valorization can contribute to carbon neutrality across power generation, transportation, construction materials, and carbon capture and utilization (CCU). We synthesize recent advances in lignin-based adsorbents and catalysts, polymer composites, biofuels, and electroactive materials relevant to these sectors. The study introduces a technological readiness levels (TRLs)-based framework to assess the maturity of lignin applications, revealing disparities across sectors from early-stage developments in energy storage and biofuels to commercial-ready solutions such as activated carbon. We further discuss key bottlenecks including lignin’s structural heterogeneity, high extraction costs, and varying TRLs which impede large-scale implementation. Finally, this review emphasizes the need for cross-disciplinary strategies, standardized processing methods, pilot-scale demonstrations, and life-cycle assessments, highlighting that comprehensive assessments are crucial for integrating lignin into a circular bioeconomy and for maximizing its contribution to global carbon neutrality efforts.

Tyrosinase is a copper-dependent enzyme essential for melanin biosynthesis and a validated target for managing hyperpigmentation. To discover potent inhibitors, we synthesized and screened 120 resorcinol-based analogues using mushroom tyrosinase (abTYR) assays and B16 melanoma cell models. This experimental workflow identified five promising candidates for further evaluation. Compound 3 consistently emerged as the lead inhibitor, demonstrating submicromolar potency against abTYR (IC50 = 0.2 μM), strong cellular efficacy in suppressing melanogenesis (IC50 = 1.6 μM) in B16 cells, and the broadest safety margin (LD50 = 345.9 μM; TI ≈ 216). To elucidate its mechanism, a homology model of human tyrosinase (hsTYR) was constructed and analyzed through molecular docking, molecular dynamics simulations, and MM-PBSA free energy calculations, which confirmed stable interactions with the conserved binuclear copper center. These results highlight the value of combining experiment-driven prioritization with structure-guided modeling and identify compound 3 as a promising and selective inhibitor of hsTYR for therapeutic and cosmetic applications.

Growing concerns over plastic waste and fossil-based polymers highlight the need for sustainable elastomers. Conventional polyurethane elastomers exhibit limited degradability, while bio-based alternatives using lignin or poly(3-hydroxybutyrate) (PHB) alone often compromise mechanical performance or processability. This study introduces a dual-feedstock strategy incorporating liquefied organosolv lignin polyol and PHB-diol as co-reactive polyols within a poly(ethylene glycol)-isophorone diisocyanate (PEG-IPDI) network. Elastomer films with varying PEG/IPDI ratios were synthesized and characterized by FTIR spectroscopy, thermogravimetric analysis, differential scanning calorimetry, atomic force microscopy, and tensile testing. FTIR carbonyl deconvolution confirms covalent incorporation of both biopolyols and quantifies a high degree of urethane hydrogen bonding (DU% = 83.1-85.6%) in the dual-feedstock LPPU series, consistent with a well-developed hard-segment domain structure. The optimized LPPU2 formulation (PEG600:IPDI = 1:4, 1 g each lignin polyol and PHB-diol) exhibits markedly improved thermal stability, with a 5% weight-loss temperature of 260.2 °C and 2.80 wt% char residue at 600 °C, compared with 158.9 °C and 1.75 wt% for neat PU. Tensile measurements show that LPPU2 achieves an ultimate tensile strength of 40.1 ± 5.6 MPa at 281 ± 24% elongation at break - a nearly four-fold strength increase over neat PU while maintaining elastomeric extensibility. AFM phase imaging confirms that PHB-diol co-incorporation yields the most uniform domain morphology (Ra = 2.38°) among all formulations, correlating with LPPU2's superior toughness. Overall, this study demonstrates that rational co-incorporation of chemically distinct bio-based polyols enables dual-crosslinked polyurethane networks that synergistically balance stiffness, elasticity, and thermal stability.

The global transition toward a sustainable bioeconomy requires efficient microbial platforms for converting renewable feedstocks into energy-dense chemicals. Yarrowia lipolytica is a well-established oleaginous yeast used in lipid biotechnology because of its acetyl-CoA metabolism and genetic tractability. However, lipid biosynthesis is frequently limited by restricted intracellular NADPH availability, creating a common redox bottleneck. To address this, we investigated the use of formate as an auxiliary electron donor in combination with heterologous NADP+-dependent formate dehydrogenase (FDH) and lipid-pathway engineering. We overexpressed the highly NADP⁺-specific formate dehydrogenase (FDH) from Pseudomonas sp. 101 and observed an increase of up to 47.8

We report a biosynthetic method for producing poly(3-hydroxybutyrate-co-3-hydroxypropionate) [P(3HB-co-3HP)] copolymer from methane alone; we developed a 3-hydroxypropionate (3HP) biosynthetic pathway starting from methane in Methylosinus trichosporium OB3b and overexpressed 3HP-CoA transferase to optimize 3HP incorporation into P(3HB-co-3HP) copolymers. Upon comparing the β-alanine and malonyl-CoA pathways, we discovered that the latter showed greater potential for the formation of 3HP monomers. In addition, we examined the activities of 3HP-CoA synthetases from three distinct sources and found that the enzyme from Metallosphaera sedula was the most effective for 3HP incorporation. Using methane as the sole carbon source in a shake-flask culture, we developed recombinant strains and found that the best strain was OB3b-MCRM-3S, which formed a P(3HB-co-3HP) copolymer, up to 25.62 % of the biomass, with a maximum 3HP level of 9.02 mol%. Our research demonstrates the successful production of a biopolymer, the P(3HB-co-3HP) copolymer, via methane bioconversion using methanotrophs.

Methane gas is recognized as a promising carbon substrate for the biosynthesis of value-added products due to its abundance and low price. Methanotrophs utilized methane as their sole source of carbon and energy, thus they can serve as efficient biocatalysts for methane bioconversion. Methanotrophs-catalyzed microbial bioconversion offer numerous advantages, compared to chemical processes. Current indirect chemical conversions of methane suffer from their energy-intensive processes and high capital expenditure. Methanotrophs can be cell factories capable of synthesizing various value-added products from methane such as methanol, organic acids, ectoine, polyhydroxyalkanoates, etc. However, the large-scale commercial implementation using methanotrophs remains a formidable challenge, primarily due to limitations in gas-liquid mass transfer and low metabolic capacity. This review explores recent advancements in methanotroph research, providing insights into their potential for enabling methane bioconversion.

Escalating environmental pollution caused by persistent chemical contaminants demands the development of efficient and sustainable remediation solutions. Bioremediation offers a promising path, and whole-cell immobilization is a key strategy to enhance its performance by protecting microorganisms from harsh conditions and enabling their reuse. Among various carriers, alginate, a renewable biopolymer derived from seaweed, is an exceptional matrix due to its mild gelation, biocompatibility, and low cost. This review critically examines how the strategic engineering of alginate-based materials overcomes the limitations of the pristine biopolymer. A comprehensive analysis of key modification strategies is provided, including covalent crosslinking, the formation of interpenetrating polymer networks (IPNs) with materials like PVA and chitosan, and the development of advanced composites and hybrids incorporating functional adsorbents such as biochar, clays, and nanomaterials. The review then systematically summarizes recent advancements in the application of these engineered biocatalysts for the remediation of a wide range of pollutants, highlighting their enhanced performance in heavy metal sequestration, degradation of recalcitrant organic pollutants, and removal of industrial dyes. By bridging materials science with environmental biotechnology, this review elucidates the principles for designing next-generation “living catalysts” for robust and effective environmental cleanup.

The use of fossil fuels in the aviation sector is accelerating global warming by emitting carbon dioxide into the atmosphere, calling for carbon neutral jet fuels. Unlike road transport, which is transitioning to electrification, aviation requires high-energy–density fuels, making liquid alternatives essential. Here we review the production of jet biofuels with emphasis on current production technologies, microbial engineering for lipid synthesis, catalytic conversion of lipids, and economic and life cycle assessment aspects. Microbial lipids, including free fatty acids, can be produced from various carbon sources such as sugars, lignocellulose, methane, methanol, and formate. Catalytic upgrading of lipids can be achieved by hydroprocessing, hydrodeoxygenation, hydrocracking, and hydroisomerization. Metabolic engineering strategies to enhance lipid biosynthesis include increasing the precursor supply, repressing β-oxidation, controlling fatty acid chain length, and applying systems-level optimization using flux balancing, biosensor-guided regulation, and evolutionary engineering. These strategies have enabled the production of 98.9 g lipids and 50 g free fatty acids per liter. Pichia pastoris employing methanol as a substrate can produce up to 23 g/L of free fatty acids. Catalytic upgrading via hydrodeoxygenation and hydrocracking achieves conversion efficiencies over 90

This study investigates the production of polyhydroxybutyrate (PHB) using the thermophilic bacterium Caldimonas thermodepolymerans in fed-batch fermentation. This research highlights the potential of thermophilic bacteria in biopolymer production due to their ability to operate at high temperatures, which reduces contamination risks and enhances energy efficiency. Optimal fermentation conditions were identified at a temperature of 50 degrees C, with the strain achieving a maximum specific growth rate (mu max) of 0.57 h- 1 and high biomass concentration of 63.1 gCDW/L. PHB production reached a peak concentration of 31.9 g/L with a productivity of 1.30 gPHB/L/h. The high cell density approach in fed-batch fermentation not only maximizes the productivity and yield of PHB, but also optimizes the production process, making it more suitable for industrial-scale applications. The findings highlight the potential of thermophilic bacteria as a sustainable solution for enhancing PHB production and advancing biodegradable polymer synthesis.

Synthetic one-carbon assimilation pathways can offer faster and more efficient alternatives to their native counterparts, enabling enhanced bio-based production of fuels and chemicals from one-carbon substrates.

Polyhydroxybutyrate (PHB) production using methanotrophs offers an economical solution to counter increasing environmental pollution. However, the substrate specificity of methanotrophs limits their ability to use multiple gases for chemical production. In this study, a synthetic heterotrophic and methanotrophic co-culture system was developed to co-utilize methane and propane for PHB production. First, a heterologous pathway was constructed in Escherichia coli BL21 (DE3) to produce PHB from acetone. Later, Methylocystis sp. OK1 produced acetone from propane; however, its PHB content decreased when methane and propane were co-utilized. Subsequently, the recombinant E. coli strain was co-cultured with Methylocystis sp. OK1 in the presence of methane and propane, which enhanced the PHB yield by 35%, 65%, and 100% with propane concentrations of 7% (v/v), 13% (v/v), and 20% (v/v), respectively, compared to the mono-cultures of Methylocystis sp. OK1. The results demonstrated PHB production in heterotrophic and methanotrophic co-cultures through co-utilization of methane and propane.

Historically, the genus Aloe has been an indispensable part of both traditional and modern medicine. Decades of intensive research have unveiled the major bioactive secondary metabolites of this plant. Recent pandemic outbreaks have revitalized curiosity in aloe metabolites, as they have proven pharmacokinetic profiles and repurposable chemical space. However, the structural complexity of these metabolites has hindered scientific advances in the chemical synthesis of these compounds. Multi-omics research interventions have transformed aloe research by providing insights into the biosynthesis of many of these compounds, for example, aloesone, aloenin, noreugenin, aloin, saponins, and carotenoids. Here, we summarize the biological activities of major aloe secondary metabolites with a focus on their mechanism of action. We also highlight the recent advances in decoding the aloe metabolite biosynthetic pathways and enzymatic machinery linked with these pathways. Proof-of-concept studies on in vitro, whole-cell, and microbial synthesis of aloe compounds have also been briefed. Research initiatives on the structural modification of various aloe metabolites to expand their chemical space and activity are detailed. Further, the technological limitations, patent status, and prospects of aloe secondary metabolites in biomedicine have been discussed.

Recently, methane has been considered a next-generation carbon feedstock due to its abundance and it is main component of shale gas and biogas. Methylomonas sp. DH-1 has been evaluated as a promising industrial bio-catalyst candidate. Succinate is considered one of the top building block chemicals in the agricultural, food, and pharmaceutical industries. In this study, succinate production by Methylomonas sp. DH-1 was improved by combining adaptive laboratory evolution (ALE) technology with genetic engineering in the chromosome of Methylomonas sp. DH-1, such as deletion of bypass pathway genes (succinate dehydrogenase and succinate semialdehyde dehydrogenase) or overexpression of genes related with succinate production (citrate synthase, pyruvate carboxylase and phosphoenolpyruvate carboxylase). Through ALE, the maximum consumption rate of substrate gases (methane and oxygen) and the duration maintaining high substrate gas consumption rates was enhanced compared to those of the parental strain. Based on the improved methane consumption, cell growth (OD600) increased more than twice, and the succinate titer increased by 48

Poly(3-hydroxybutyrate) (PHB) is an important class of renewable and biodegradable polymers that have recently attracted significant interest. However, the limitations of the physical properties of PHB, owing to its brittle nature, hinder its application in versatile polymers. In this study, we propose an efficient conversion of microbial PHB produced and recovered from methanotrophs to produce the oligomer PHB-diol. The PHB transesterification was conducted using different alcohols and the reaction conditions were optimized to obtain a liquid-like PHB-diol product, a low-molar-mass polyol with a molecular weight of 1000-1400 g/mol for polyurethane (PU) synthesis. A comprehensive characterization of PU samples made from PHB-derived polyol suggested that it could be a viable substitute for 50 wt% traditional petroleum-derived polyol in PU synthesis. In contrast to petroleum-based PU, the synthetic PU film made from microbiologically generated PHB-diol showed noteworthy self-healing ability with a healing efficiency of up to 91.08 % at moderate temperatures after a simple drying process. Self-healing ability is highly desirable and significant for the sustainable manufacturing of advanced materials from bioresources for a wide range of practical applications in electronic devices, coatings, biomedicine, and aerospace.

Owing to the unmet demand, the pharmaceutical industry is investigating an alternative host to mammalian cells to produce antibodies for a variety of therapeutic and research applications. Regardless of some disadvantages, Escherichia coli and Pichia pastoris are the preferred microbial hosts for antibody production. Despite the fact that the production of full-length antibodies has been successfully demonstrated in E. coli, which has mostly been used to produce antibody fragments, such as: antigen-binding fragments (Fab), single-chain fragment variable (scFv), and nanobodies. In contrast, Pichia, a eukaryotic microbial host, is mostly used to produce glycosylated full-length antibodies, though hypermannosylated glycan is a major challenge. Advanced strategies, such as the introduction of human-like glycosylation in endotoxin-edited E. coli and cell-free system-based glycosylation, are making progress in creating human-like glycosylation profiles of antibodies in these microbes. This review begins by explaining the structural and functional requirements of antibodies and continues by describing and analyzing the potential of E. coli and P. pastoris as hosts for providing a favorable environment to create a fully functional antibody. In addition, authors compare these microbes on certain features and predict their future in antibody production. Briefly, this review analyzes, compares, and highlights E. coli and P. pastoris as potential hosts for antibody production.

Methane (CH4) and carbon dioxide (CO2) are the dominant greenhouse gases (GHGs) that are increasing at an alarming rate. Methanotrophs have emerged as potential CH4 and CO2 biorefineries. This study demonstrated the synchronous incorporation of CH4 and CO2 into polyhydroxybutyrate (PHB) for the first time using 13C-labeling experiments in methanotrophs. By supplying substantial amounts of CO2, PHB content was enhanced in all investigated type II methanotrophic strains by 140 %, 146 %, and 162 %. The highest content of PHB from CH4 and CO2 in flask-scale cultivation reached 38 % dry cell weight in Methylocystis sp. MJC1, in which carbon percentage in PHB from CO2 was 45 %. Flux balance analysis predicted the critical roles of crotonyl-CoA carboxylase/reductase and phosphoenolpyruvate carboxylase in CO2 recycling. This study provided proof of the conversion of GHGs into a valuable and practical product using methanotrophic bacteria, contributing to addressing GHG emissions.

Lignin, a biopolymer derived from plant biomass, is recognized as a highly promising substance for developing self-healing polymers owing to its dynamic linkages and functional groups. This paper provides a thorough review of lignin-based self-healing polymer, from the process of extracting lignin, chemical modification, synthesis techniques such as via reversible addition-fragmentation chain transfer (RAFT) polymerization, crosslinking with polymers like polyvinyl alcohol (PVA) and chitosan, and reactions with isocyanates to create lignin-based networks with reversible interactions. This work also summarizes the optimization of self-healing ability, such as including dynamic copolymers, encapsulating healing agents like dicyclopentadiene and polycaprolactone (PCL), and chain extenders with disulfide or Diels-Alder (DA) moieties. The material's characterization focuses on its capacity to recover via hydrogen bonding and dynamic re-associations, improved mechanical properties from lignin's rigid structure, and enhanced temperature resistance. Primary obstacles involve the optimization of lignin extraction, enhancement of polymer compatibility, and the establishment of efficient procedures for synthesis and characterization. Overall, lignin shows great potential as a renewable component of self-healing polymers, with plenty of opportunities for further development.

This study explores the ability of methanotrophs to convert biogas into biopolymers, addressing H 2 S as a limitation in the utilization of biogas as a carbon source for bioconversion. Transcriptomic analysis was conducted to understand the growth and changes in the expression patterns of Type I and II methanotrophs under varying H 2 S concentrations. Results suggested that Type II methanotrophs can possess a native H 2 S utilization pathway. Both Type I and II methanotrophs were evaluated for their growth and polyhydroxybutyrate (PHB) production from biogas. Methylocystis sp. MJC1 and Methylocystis sp. OK1 exhibited a maximum biomass production of 4.0 and 4.5 gDCW/L, respectively, in fed -batch culture, aligning with the transcriptome data. Furthermore, Methylocystis sp. MJC1 produced 2.9 g PHB/L from biogas through gas fermentation. These findings underscore biogas-based biotechnology as an innovative solution for environmental and industrial challenges with further optimization and productivity enhancement research expected to broaden the potential in this field.

The biological conversion of methane under ambient conditions can be performed by methanotrophs that utilize methane as both a sole source of energy and a carbon source. However, compared to the established microbial chassis used for general fermentation with sugar as a feedstock, the productivity of methanotrophs is low. The fundamental knowledge of their metabolic or cellular bottlenecks is limited. In this review, the industrial-scale potential of methane bioconversion was evaluated. In particular, the enzyme kinetics associated with the oxidation and assimilation of methane were investigated to evaluate the potential of methane fermentation. The kinetics of enzymes involved in methane metabolism were compared with those used in the metabolic processes of traditional fermentation (glycolysis). Through this analysis, the current limitations of methane metabolism were identified. Methods for increasing the efficiency of methane bioconversion and directions for the industrial application of methane-based fermentation were discussed.