Polyhydroxyalkanoates (PHAs) are biodegradable polyesters produced by some bacteria and archaea as intracellular carbon and energy reserves. This study investigated the use of shea butter (SB), an underutilized lipid-rich agricultural product, as a carbon source for PHA biosynthesis by Cupriavidus necator Re2058/pCB113. Different emulsifiers (Tween 80 and gum arabic) and substrate combinations (shea butter, palm olein, waste cooking oil) were carefully controlled to enhance PHA yield. Shake-flask and bioreactor experiments were conducted under nitrogen-limited conditions. Emulsifying 10 g/L shea butter with Tween 80, yielded 6.6 ± 0.8 g/L CDW, 66.5 ± 7.6 wt% of PHA content, and 4.4 g/L PHA concentration. In a 5 L bioreactor, the highest yield was achieved at 40 h with 7.5 ± 0.5 g/L CDW and 78.7 ± 1.4% PHA content, comprising 89.9 mol% 3-hydroxybutyrate (3HB) and 10.1 mol% poly 3-hydroxybutyrate co-3-hydroxyhexanoate copolymer. Further emulsification strategy enhanced biomass yield, producing 10 g/L CDW and 9.7 ± 0.3 g/L PHA. The results demonstrate the feasibility of using unrefined shea butter as an inexpensive lipid substrate for PHA production, contributing to sustainable biopolymer development.

Chitosan membranes have attracted growing interest for separation and sensing applications owing to their biodegradability, chemical functionality, and film-forming ability. However, strong adhesion to the casting surface makes conventional Petri dish fabrication challenging. In this study, a three-dimensional (3D) membrane caster was fabricated via fused deposition modeling (FDM) with a removable Teflon base sheet, enabling reliable casting and easy detachment of membranes. The caster is reusable, customizable in size and geometry, and compatible with both of the conventional filaments, polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS) filaments, without interfering with membrane integrity. Characterization by fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and EDX confirmed comparable results between membranes cast on the 3D caster and a conventional glass Petri dish. Water uptake (∼93-94%) and thickness distribution (∼35-43 μm) were consistent across all casting platforms, indicating negligible differences in swelling behavior and uniformity. This scalable approach is readily adaptable to other membrane types and offers a practical fabrication model for liquid membranes (LMs) and polymer inclusion membranes (PIMs) in future separation systems.

Polyhydroxyalkanoates (PHAs) are biodegradable polymers with significant potential for drug delivery. However, a challenge remains in their application for encapsulating highly water-soluble drugs. This study aims to develop and optimise PHA-based nanoparticles (NPs) and microparticles (MPs) for the delivery of verapamil hydrochloride (VRP·HCl) using a systematic statistical approach. A quaternary PHA copolymer, poly(3-hydroxybutyrate-co-4-hydroxybutyrate-co-5-hydroxyvalerate-co-3-hydroxyhexanoate) [P(3HB-co-4HB-co-5HV-co-3HHx)], was biosynthesised using genetically modified Cupriavidus necator. Polymer characterisation by Nuclear Magnetic Resonance (1H NMR), Gas Chromatography (GC), Gel Permeation Chromatography (GPC), and Limulus Amebocyte Lysate (LAL) assay confirmed a high-purity (97 ± 5 wt%) and endotoxin-free P(3HB-co-4HB-co-5HV-co-3HHx) copolymer with a monomer composition of 69 mol% 3HB, 14 mol% 4HB, 12 mol% 5HV, and 5 mol% 3HHx. VRP·HCl-loaded NPs and MPs were prepared via a double-emulsion solvent evaporation method and optimised using response surface methodology (RSM) based on a central composite design (CCD) to predict and evaluate the influence of polymer mass, drug mass, and stabiliser concentration on particle size, drug loading (DL), and encapsulation efficiency (EE). Particle size, polydispersity index (PDI), zeta potential (ZP), DL, and EE were evaluated experimentally. The optimised NP and MP formulations achieved mean particle sizes of 245.06 ± 0.01 nm and 2.23 ± 1.50 µm, with maximum EE of 38.95 ± 20.37% and 45.23 ± 2.85%, respectively. The corresponding DL values for NPs and MPs were 23.37 ± 12.22% and 18.09 ± 1.14%, respectively. Statistical analysis demonstrated good model predictability within the explored design space, enabling the identification of formulation regions governed primarily by polymer mass, drug distribution, and emulsion characteristics. In conclusion, this study demonstrates the feasibility of encapsulating a hydrophilic drug within a fully hydrophobic, biodegradable PHA matrix while establishing a systematic optimisation framework for the development of PHA-based NP and MP drug delivery systems.

The excessive reliance on petroleum-based plastics has intensified the search for biodegradable alternatives such as polyhydroxyalkanoates (PHAs). However, improving their flexibility and thermal properties remains a major challenge. Incorporation of 3-hydroxyhexanoate (3HHx) monomers into poly(3-hydroxybutyrate) [P(3HB)] produces the copolymer, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx)], which exhibits enhanced polymer properties. The 3-ketoacyl-ACP reductase (FabG), an enzyme involved in fatty acid beta-oxidation, catalyses the conversion of 3-ketoacyl-CoA into (R)-3-hydroxyacyl-CoA, thereby supplying precursors for 3HHx incorporation. In this study, FabG homologs from Burkholderia sp. USM (JCM 15050), Aquitalea pelogenes USM4 (JCM 19919), and Streptomyces sp. strain CFMR7 (JCM 30950) were screened and evaluated by heterologous expression in Cupriavidus necator PHB-4 along with the phaC2 gene from Rhodococcus aetherivorans I24 (phaCRa). The recombinant strains accumulated P(3HB-co-3HHx) with 3HHx fractions ranging from 4 to 21 mol %, achieving dry cell weights of 2.3 to 4.4 g/L and PHA contents of 31.6 to 55.2 wt%. Notably, FabG1Ap from A. pelogenes USM4 (JCM 19919) yielded the highest 3HHx incorporation at 21 mol% despite only expression at 2.05-fold. Thermal analysis revealed that higher 3HHx incorporation resulted in reduced melting temperature (Tm) from 138.06 degrees C for 6 mol% 3HHx to 99.63 degrees C for 21 mol% 3HHx, indicating controllable polymer thermal properties. This study demonstrates, for the first time in C. necator PHB-4, the potential of FabG enzymes from diverse bacterial sources to control the 3HHx supply and improve P(3HB-co-3HHx) copolymer properties, thereby providing a novel strategy for tailoring biopolymers with improved performance.

Conventional agricultural materials are largely manufactured from non-biodegradable plastics, resulting in persistent macro- and microplastic accumulation in soils. Polyhydroxyalkanoates (PHAs) represent promising biodegradable alternatives; however, their degradation behavior under realistic agricultural conditions remains insufficiently understood. This study investigates the biodegradation of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHx) by indigenous soil bacteria isolated from oil palm plantation soils, a major agricultural ecosystem in Malaysia. Nine PHA-degrading bacterial strains were isolated and identified as Streptomyces spp. through 16S rRNA gene sequencing, indicating Streptomyces as the dominant group among the cultivable PHA degraders recovered under the applied screening conditions. All isolates produced clear zones on P(3HB), PHBHx-8%, and PHBHx-27% agar plates, with Streptomyces sp. S1C-B4 exhibiting the highest depolymerization activity. Biodegradation of solvent-cast PHBHx films by Streptomyces sp. S1C-B4 in liquid mineral medium resulted in 85.6% degradation for PHBHx-8% and complete degradation for PHBHx-27% within 14 days. Film degradation was confirmed by morphological and structural changes observed via scanning electron microscopy (SEM) and X-ray diffraction (XRD). Whole-genome in silico analysis of Streptomyces sp. S1C-B4 revealed two different phaZ genes encoding a type I short-chain-length PHA depolymerase, providing the genetic basis for its observed PHA degradation activity. Additionally, the genome mining of Streptomyces sp. S1C-B4 revealed several genes encoding lignocellulolytic enzymes, which underscores its dual biopolymer degrading potential. To the best of our knowledge, this study is the first to report soil bacteria from oil palm plantations exhibiting both PHA- and cellulose-degrading capability. This highlights the potential of Streptomyces sp. as a key biological agent in bioplastics and agricultural waste degradation.

Polyhydroxyalkanoates (PHAs) are sustainable alternatives to petroleum-based plastics, yet their commercialisation remains limited by the lack of efficient strains and high production costs. To address this challenge, an improved PHA synthase, PhaCG8 was cloned into Cupriavidus necator Re2058. Compared with its parental synthase, PhaCG8 was shown to promote the formation of higher-molecular-weight polymers and fewer but larger intracellular PHA granules. The performance of the new recombinant strain was evaluated using crude palm kernel oil (CPKO) and fructose, revealing higher polymer molecular weight with fewer and larger granules compared to C. necator Re2058/pHT1-CBP-M-CPF4 although a direct mechanistic relationship between granule morphology and Mw has yet to be established. To tackle the high production cost, solvent-extracted non-edible palm fibre oil (PFO) was evaluated as a sustainable carbon source for PHA production using the new recombinant strain. PFO used in this study supported efficient growth and polymer accumulation, achieving 124.3 g/L biomass with 83.1 g/L PHA under fed-batch conditions, corresponding to a polymer yield coefficient of 0.64 g/g and a volumetric productivity of 1.07 g/L·h. A biological recovery approach using mealworms (Tenebrio molitor) was also implemented, achieving 82

Polyhydroxyalkanoates (PHA) are biodegradable and biocompatible microbial polyesters that can greatly aid the transition toward a sustainable economy. However, high production costs hinder their commercialization. PHA production from alternative biomass feedstocks via integrated biorefining could provide the technical and economic benefits that the nascent PHA industry needs to compete with traditional polymers. Simultaneously, this will also provide a route to utilize and valorize the abundant biomass wastes and by-products from various industries via industrial biotechnology, the production of bioproducts, and the extraction of valuable biomass fractions. To aid the development of PHA production within integrated biorefining, this in-depth review provides notable trends, performances, achievements, challenges, and recommendations for future studies. The potential roles of metabolic engineering are also discussed, due to their potential as an important tool in improving the viability of PHA production via biorefining, via improved substrate utilization, and novel PHA synthesis in recombinant organisms. The updated perspectives and insights provided by this review should aid the future development of PHA production from alternative biomass feedstocks, integrated biorefining schemes, and industrial biotechnology as a whole.

Polyhydroxyalkanoates (PHAs) are a class of intracellular polyesters synthesized by diverse prokaryotic organisms. These microbial polymers are both biodegradable and thermoprocessable, exhibiting material properties comparable to many synthetic plastics. This study presents the whole genome analysis of the mangrove-derived Priestia sp. strain USM5, which uniquely exhibits simultaneous PHA degradation and biosynthesis capabilities. The assembled genome comprises similar to 5.62 Mb with a GC content of 37.94 %, organized into 22 contigs including at least 11 plasmids and a chromosome. Annotation via NCBI Prokaryotic Genome Annotation Pipeline (PGAP) predicted 5596 protein-coding genes, 142 tRNAs, and 43 rRNAs. Average nucleotide identity (ANI) analysis suggested its taxonomic classification within the Priestia genus. Genomic mining identified a canonical PHA metabolic network, including a class IV synthase operon (phaR-phaB-phaC) and its opposing regulatory unit (phaP-phaQ), alongside four PHA depolymerase genes (phaZ1 to phaZ4). Shake-flask fermentation showed that Priestia sp. strain USM5 could accumulate PHA from various carbon sources, especially sugars. Precursor cofeeding strategies suggested that the PHA synthase of Priestia sp. strain USM5 can incorporate 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), 4-hydroxybutyrate (4HB), 5-hydroxyvalerate (5HV), and 3-hydroxy-4-methylvalerate (3H4MV). Moreover, secreted depolymerases eroded PHA film surfaces within 72 h. The genome sequence of this dual-functional strain, along with its putative circular genetic architecture, proposes a biological route for "closed-loop" PHA upcycling that will require future functional assembly and validation.

Several studies have reported the biodegradation of commodity plastics by mealworms and other insects. In this study, we compared the indigestibility and biodegradation of polyhydroxyalkanoate (PHA), a type of biodegradable plastic, with that of several commodity plastics. We also examined the mealworms' preference for different plastic types and their effect on larval growth. Additionally, the faeces were quantified and analyzed for the presence of microplastics. Mealworms were fed 9 cm plastic films of low-density polyethylene (LDPE) (trash bin liner and single-use plastic bag), high-density polyethylene (HDPE) (shopping bag), starch-based single-use plastic bags, and three different PHAs: poly(3-hydroxybutyrate) [P(3HB)], poly(3HB-co-11 mol% 3-hydroxyhexanoate) [11 mol% HHx], poly(3HB-co-18 mol% 3-hydroxyhexanoate) [18 mol% HHx], and poly(3HB-co-27 mol% 3-hydroxyhexanoate) [27 mol% HHx]. These plastics were provided as the sole diet for 21 days. The oat diet served as a control. To detect the presence of PHA-degrading bacteria, the mealworm gut contents were plated on PHA agar plates. The mealworms' ingestion capability was significantly influenced by the type of plastic. The mealworms fully ingested the starch-based film, 11 mol% HHx, 18 mol% HHx, and 27 mol% HHx films within 6 h, 7 days, 7 days, and 15 days, respectively. The trash bin liner, P(3HB), and single-use plastic bags were steadily ingested at 68%, 83%, and 85%, respectively, while the shopping bag was not consumed. A decline in larval weight from day one suggests that a long-term sole plastic diet does not support mealworm growth, although cannibalism may have influenced survival outcomes. Plastics excreted in the larval faeces were visible under an optical microscope, and gas chromatography analysis revealed near-complete recovery for the ingested HHx-containing PHA. The reduction in Mw of the PHA films by 13% to 35% indicates that the polymers underwent physicochemical modification during gut passage, potentially involving both mechanical and biological processes.

Oil palm trunks (OPT) present a major waste management challenge in Malaysia. This study evaluated OPT fibres as a sustainable alternative substrate to traditional rubberwood sawdust (RWS) for Ganoderma lucidum cultivation across five formulations (0–100% OPT substitution). Notably, 100% OPT (Formulation D) achieved the highest yield (30.40 ± 7.42 g/kg) and biological efficiency (15.20 ± 3.88%), producing larger fruiting bodies with enhanced carbohydrate (19.0%), protein (10.9%), crude fibre (16.3%), and potassium content. Ethanolic extracts from this formulation also exhibited superior bioactive properties, including high total phenolic (220.66 ± 10.52 mg GAE/g) and triterpenoid (450.33 ± 0.96 mg UAE/g extract) contents, alongside potent antioxidant activity (EC50: 66.83 ± 0.41–240.63 ± 1.95 μg/mL). These findings demonstrate that OPT fibres are a highly viable, eco-friendly alternative substrate that reduces RWS reliance while offering an effective strategy for agro-waste valorization and sustainable mushroom production.

The escalating global demand for plastics has profoundly impacted various industries, including mushroom cultivation, which predominantly relies on plastic substrate bags. Improper disposal of these plastic bags, a byproduct of traditional mushroom cultivation techniques, has significantly contributed to environmental pollution, highlighting the urgent need for sustainable alternatives. This study explores the potential of polyhydroxyalkanoate (PHA) as an eco-friendly substitute for conventional plastic substrate bags in mushroom cultivation. Poly(3-hydroxybutyrate-co-13 mol% 3-hydroxyhexanoate) [P(3HB-co-13 mol% 3HHx)] was synthesized using the Cupriavidus necator transformant strain Re2160/pHT1-CBP-M-CPF4, with waste cooking oil (WCO) as the sole carbon source in a 13 L bioreactor. The synthesized PHA underwent comprehensive characterization before being fabricated into substrate bags for cultivating Pleurotus ostreatus. A detailed investigation into the biodegradability of PHA films, conducted under varying ratios of spent mushroom substrate (SMS) and soil, identified two PHA-degrading bacteria: Acidovorax sp. and Schlegella sp. This study underscores the potential of PHA-based mushroom substrate bags as a sustainable solution to mitigate plastic pollution in mushroom cultivation. By fostering environmentally conscious practices, the findings pave the way for broader applications of PHA-based materials across diverse industries, advocating for a circular economy and sustainable development.

Systematic N‑terminal domain exchange between two phylogenetically divergent PHA synthases, PhaCCs from Chromobacterium sp. USM2 (class I) and PhaC2Ra from Rhodococcus aethirovorans I24 (class II), yielded ten functional chimeric variants from complementary series. A pronounced directional asymmetry emerged: the PhaCCs catalytic scaffold tolerated heterologous N‑terminal substitutions up to 191 residues, whereas the PhaC2Ra scaffold was inactivated by replacements extending beyond approximately 41 residues. Substrate incorporation followed a hierarchical pattern in which the catalytic domain determined permissivity, with 3‑hydroxyhexanoate (3HHx) requiring the PhaC2Ra catalytic domain and 4‑hydroxybutyrate (4HB) and 5‑hydroxyvalerate (5HV) requiring the PhaCCs catalytic domain. The N‑terminal region modulated efficiency, with 4HB and 5HV incorporation declining progressively as the heterologous segment extended beyond the α2 helix of PhaCCs; chimeras carrying substitutions within the α2 helix of PhaCCs (RACS1A and RACS1) retained 4HB fractions of 20–23 mol% and 5HV fractions of 30–35 mol%, comparable to parental PhaCCs levels, whereas further substitutions sharply reduced or abolished incorporation. 3‑hydroxyvalerate (3HV) was accommodated by both scaffolds at moderate levels but also declined in RACS chimeras when substitutions extended beyond the α2 helix boundary. Short N‑terminal segments sufficed to shift PHA granule morphology, as evidenced by contrasting granule phenotypes among chimeric variants. The α2 helix of PhaCCs marked a critical transition point for both substrate selectivity and granule architecture. These results establish N‑terminal exchange as a practical strategy for tuning PhaC properties and reveal a two-tier architecture that governs monomer incorporation and granule morphology, providing a framework for designing chimeric PHA synthases with tailored properties.

Innovative approaches are required to transition from a linear to a circular (bio)economy. Natural plastic alternatives, such as polyhydroxyalkanoates (PHAs), have great potential to promote this transition. In this study, we demonstrate the feasibility of converting solid waste animal fat (WAF) into the PHA copolymer poly(hydroxybutyrate-co-hydroxyhexanoate) (P(HB-co-HHx)) via bacterial fed-batch fermentation at 750-L pilot-scale using the engineered strain Cupriavidus necator Re2058/pCB113. A total of 48 kg of PHA-rich dried cells were produced and subjected to pilot-scale biological downstream processing via mealworms (Tenebrio molitor), resulting in 19 kg of high-purity (>99 %) PHA powder. Material characterization confirmed that the molecular weight remained stable throughout the entire downstream process, which included drum drying, cell wall digestion by mealworms, and final polymer purification using water, sodium hydroxide and sodium hypochlorite.

An obstacle to the commercial application of polyhydroxyalkanoates (PHAs) and a co-product exopolysaccharide, alginate, is their high production cost. In this study, waste cooking oil (WCO) was used as an inexpensive carbon source for biopolymer production by Pseudomonas mendocina PSU. The highest biomass of 4.60 ± 0.06 g/L and PHA concentration of 2.58 ± 0.03 g/L (accounting for about 54% DCW) were achieved with a productivity of 0.072 g/L/h under optimal conditions determined by response surface methodology. Additionally, a maximum alginate yield of 8.85 ± 0.24 g/L was obtained as the co-product. The WCO, which primarily contained oleic acid (C18:1), palmitic acid (C16:0), and linoleic acid (C18:2) influenced the monomer composition of the produced PHA. The results demonstrated the presence of both SCL-PHA monomers such as 3HB (3-hydroxybutyrate) and MCL-PHA monomers including 3HHx (3-hydroxyhexanoate), 3HO (3-hydroxyoctanoate), 3HD (3-hydroxydecanoate), and 3HDD (3-hydroxydodecanoate) in varying molar fractions. Moreover, an average molecular weight of approximately 104 Da and a polydispersity index of 1.58 were determined in the produced PHA, consisting predominantly of 3HB (86 mol%) when the cells were grown in 2.0% (v/v) WCO. Furthermore, the melting temperature (Tm) and glass transition temperature (Tg) were around 157°C and -20°C, respectively. Additionally, the produced alginate from P. mendocina PSU exhibited functional acetyl groups, which are a distinguishing feature of bacterial alginate, and showed an apparent viscosity comparable to commercial alginate from brown seaweed. These biopolymer characteristics demonstrate strong potential for biomaterial applications, adding value to WCO and reducing overall production costs.

The escalating health and environmental threats posed by microplastics and nanoplastics (MNPs) highlight the urgent need for sustainable alternatives like polyhydroxyalkanoates (PHAs), biodegradable polyesters synthesized by bacterial PHA synthases (PhaCs). However, natural PhaCs exhibit suboptimal substrate specificity and polymer heterogeneity, limiting industrial scalability. To address this, chimeric PhaCs were engineered by swapping N-terminal domains between PhaC from mangrove soil metagenome (PhaCBP-M-CPF4; low 3-hydroxyhexanoate [3HHx] content, fewer but larger granules) and PhaC2 of Rhodococcus aetherivorans I24 (PhaC2Ra; high 3HHx, numerous small granules). This strategy aimed to combine enhanced 3HHx incorporation with controlled granule morphology. Using structural predictions, chimeric enzymes were constructed and tested, revealing that the C-terminal domain retained compatibility with diverse N-terminal regions. The resulting chimeras exhibited improved PHA production, enhanced 3HHx incorporation, and optimized granule formation, overcoming historical challenges in chimeric enzyme design by avoiding β-strand interference. Among the chimeras, distinct strains achieved: (i) up to 200 % increase in PHA production; (ii) up to 45 mol% 3HHx incorporation; and (iii) optimized granule formation, approaching a single-granule-per-cell phenotype (mean count: 1.079) and a granule size increase of up to 7.2-fold (mean area: 1.272 µm2). This approach provides a robust framework for tailoring PhaCs to produce high-performance copolymers. By elucidating domain compatibility, the study advances strategies in synthetic biology for creating modular enzymes with tailored functionalities, offering transformative potential in sustainable materials, protein engineering, and innovation in biodegradable plastics.

The bioeconomy today relies mostly on sugar and physicochemical extraction processes, which limit both cost reduction and scale-up potential, yet these two aspects are vital for the market success of circular bioeconomy products. Gas fermentation is a platform technology that utilizes all kinds of waste biomass streams through low-cost, clean, and well-defined gaseous substrates. It can be used to obtain bioplastics. In this work, methane (CH4) was subjected to methanotrophic conversion by Methylocystis sp. GB 25. The freeze-dried bacterial biomass containing 47 wt% P(3HB) – poly(3-hydroxybutyrate), was subsequently fed to mealworms. The cells were fully consumed, and the P(3HB) granules were recovered within 24 h. The final PHB purity obtained was 95 % through a simple purification step. This work demonstrated that a simple bioprocess for biopolymer extraction can be applied to small bacterial cells like methanotrophs, offering a viable alternative to classic downstream processing steps such as chlorinated solvent extraction. The methanotrophic PHB was found to exhibit high molecular weight, making it an interesting biobased, biodegradable polymer.

Biopolymers derived from biogas offer a sustainable approach to mitigating plastic pollution and greenhouse gas emissions. This study focused on the enrichment and isolation of polyhydroxybutyrate (PHB)-producing methanotrophs using a simple two-step dilution method, and evaluated PHB production from biogas generated from oil palm sap (OPS). Amplicon sequencing post-enrichment identified a microbial community dominated by Methylophilaceae (42.3 %) and Methylocystis (41.5 %). Methylocystis sp. NK4-5-1 was successfully isolated and demonstrated PHB synthesis from synthetic methane. The strain preferred ammonium sulfate over potassium nitrate as a nitrogen source at 0.1 g N/L, with optimum conditions at 25 degrees C and pH 6.5. Under optimized conditions with synthetic methane, the strain achieved a maximum PHB content of 29 % +/- 3.8 % (w/w) within 48 h. Moreover, the cultivation of Methylocystis sp. NK4-5-1 on OPSderived biogas under fed-batch conditions with a final methane concentration of 30 % yielded a cell dry weight of 0.59 +/- 0.06 g/L and a PHB content of 13.1 +/- 3.8 % (w/w) after 10 days, confirming effective biogas valorization. 1H NMR analysis verified the structural identity of PHB from both substrates. Notably, biogas-derived PHB exhibited higher molecular weight and melting temperature (Mw = 536 kDa; Tm = 176 degrees C) than that from synthetic methane (Mw = 348 kDa; Tm = 170 degrees C), indicating improved thermal stability and material performance. These findings demonstrate the potential of biogas valorization for sustainable bioplastic production and provide practical criteria for strain selection and process optimization.