Polyhydroxyalkanoates Production Research Articles

Dead Sea water as a sustainable source for the production of microbial bioplastics polyhydroxyalkanoates by halophiles

The Dead Sea is a unique salt-saturated water body. This work utilized the Dead Sea water (DSW) as a medium instead of fresh water for the biosynthesis of polyhydroxyalkanoates (PHAs) by Haloferax mediterranei. The intracellular content of PHAs reached a maximum (6.35 %) at 40 % DSW. An artificial DSW media that mimics the DSW composition was prepared and used for PHAs production by H. mediterranei. The cell dry mass (CDM) and PHAs comcentration (32.61 g L−1 and 4.56 g L−1, respectively) were significantly higher than the results obtained from the reported H. mediterranei highly saline medium. The PHAs production was scaled-up to fed-batch utilizing no-cost date fruit waste and resulted in CDM and PHA concentration of 46.89 g L−1 and 12.77 g L−1, respectively under non-sterile conditions. H. mediterranei accumulated poly-3-(hydroxybutyrate-co-9 %-hydroxyvalerate) with molar mass 916.0 kDa and melting point at 143.2 °C. These results indicate the production of a high-quality biopolymer.

Recent Trends in the Production and Recovery of Bioplastics Using Polyhydroxyalkanoates Copolymers

Polyhydroxyalkanoates (PHAs) are polyesters synthesized as a carbon and energy reserve material by a wide number of bacteria. These polymers are characterized by their thermoplastic properties similar to those of plastics derived from the petrochemical industry, such as polyethylene and polypropylene. PHAs are widely used in the medical field and have the potential to be used in other applications due to their biocompatibility and biodegradability. Among PHAs, P(3HB-co-3HV) copolymers are thermo-elastomeric polyesters that are typically soft and flexible with low to no crystallinity, which can expand the range of applications of these bioplastics. Several bacterial species, such as Cupriavidus necator, Azotobacter vinelandii, Halomonas sp. and Bacillus megaterium, have been successfully used for P(3HB-co-3HV) production, both in batch and fed-batch cultures using different low-cost substrates, such as vegetable and fruit waste. Nevertheless, in recent years, several fermentation strategies using other microbial models, such as methanotrophic bacterial strains as well as halophilic bacteria, have been developed in order to improve PHA production in cultivation conditions that are easily implemented on a large scale. This review aims to summarize the recent trends in the production and recovery of PHA copolymers by fermentation, including different cultivation modalities, low-cost raw materials, as well as downstream strategies that have recently been developed with the purpose of producing copolymers, such as P(3HB-co-3HV), with suitable mechanical properties for applications in the biomedical field.

Is It Possible to Produce Polyhydroxyalkanoate (PHA) Bioplastics of Consistent Composition from Organic Wastes? A Review

Is It Possible to Produce Polyhydroxyalkanoate (PHA) Bioplastics of Consistent Composition from Organic Wastes? A Review

Waste to wealth: Polyhydroxyalkanoates (PHA) production from food waste for a sustainable packaging paradigm

The growing demand for sustainable food packaging and the increasing concerns regarding environmental pollution have driven interest in biodegradable materials. This paper presents an in-depth review of the production of Polyhydroxyalkanoates (PHA), a biodegradable polymer, from food waste. PHA-based bioplastics, particularly when derived from low-cost carbon sources such as volatile fatty acids (VFAs) and waste oils, offer a promising solution for reducing plastic waste and enhancing food packaging sustainability. Through optimization of microbial fermentation processes, PHA production can achieve significant efficiency improvements, with yields reaching up to 87 % PHA content under ideal conditions. This review highlights the technical advancements in using PHA for food packaging, emphasizing its biodegradability, biocompatibility, and potential to serve as a biodegradable alternative to petroleum-based plastics. However, challenges such as high production costs, mechanical limitations, and the need for scalability remain barriers to industrial adoption. The future of PHA in food packaging hinges on overcoming these challenges through further research and innovation in production techniques, material properties, and cost reduction strategies, along with necessary legislative support to promote widespread use.

A Review of Polyhydroxyalkanoates: Characterization, Production, and Application from Waste

The search for alternatives to petrochemical plastics has intensified, with increasing attention being directed toward bio-based polymers (bioplastics), which are considered healthier and more environmentally friendly options. In this review, a comprehensive overview of polyhydroxyalkanoates (PHAs) is provided, including their characterization, applications, and the mechanisms underlying their biosynthesis. PHAs are natural polyesters produced by a wide range of prokaryotic and some eukaryotic organisms, positioning them as a significant and widely studied type of bioplastic. Various strategies for the production of PHAs from agroindustrial waste, such as cacao shells, cheese whey, wine, wood, and beet molasses, are reviewed, emphasizing their potential as sustainable feedstocks. Industrial production processes for PHAs, including the complexities associated with extraction and purification, are also examined. Although the use of waste materials offers promise in reducing costs and environmental impact, challenges remain in optimizing these processes to enhance efficiency and cost-effectiveness. The need for continued research and development to improve the sustainability and economic viability of PHA production is emphasized, positioning PHAs as a viable and eco-friendly alternative to conventional petroleum-based plastics.

Towards a high-rate operation of contact stabilization process: A microscopic view of carbon capture properties

Carbon capture performance is a key factor determining the chemical energy recovery potential of the high-rate contact stabilization (HiCS) process. However, the mechanisms of organic carbon capture are complex, involving surface adsorption, extracellular adsorption, and intracellular storage. A unique characteristic of the HiCS process is its low sludge residence time (SRT). Unfortunately, the influence of SRT on carbon capture has not been thoroughly studied, especially in terms of the underlying mechanisms. In this study, the microscopic changes in carbon capture performance during the transition from a conventional contact stabilized (CS) system to a high-rate mode of operation were demonstrated using intracellular carbon sources, extracellular polymeric substances (EPS), signaling molecules, and microbial community assays. The results showed that the extracellular carbon adsorption and intracellular carbon storage performance increased, and the microbial community structure changed significantly with converting the CS system to the high-rate operation mode. The enhancement of extracellular carbon adsorption performance mainly relied on the growth of EPS, which was accomplished by the strong growth of the relative abundance of the dominant bacterial group Cloacibacterium within the HiCS system, offsetting the negative effect produced by the decline of acyl-homoserine lactones. 98 mgCOD/gSS, 343 mgCOD/gSS, and 500 mgCOD/gSS of polyhydroxyalkanoates (PHAs) per sludge unit were obtained at SRT-24d, 8d, and 2d, respectively, suggesting that the HiCS system is more advantageous for rapid PHAs production.

Genome-Scale Metabolic Modeling of Halomonas elongata 153B Explains Polyhydroxyalkanoate and Ectoine Biosynthesis in Hypersaline Environments.

Halomonas elongata thrives in hypersaline environments producing polyhydroxyalkanoates (PHAs) and osmoprotectants such as ectoine. Despite its biotechnological importance, several aspects of the dynamics of its metabolism remain elusive. Here, we construct and validate a genome-scale metabolic network model for H. elongata 153B. Then, we investigate the flux distribution dynamics during optimal growth, ectoine, and PHA biosynthesis using statistical methods, and a pipeline based on shadow prices. Lastly, we use optimization algorithms to uncover novel engineering targets to increase PHA production. The resulting model (iEB1239) includes 1534 metabolites, 2314 reactions, and 1239 genes. iEB1239 can reproduce growth on several carbon sources and predict growth on previously unreported ones. It also reproduces biochemical phenotypes related to Oad and Ppc gene functions in ectoine biosynthesis. A flux distribution analysis during optimal ectoine and PHA biosynthesis shows decreased energy production through oxidative phosphorylation. Furthermore, our analysis unveils a diverse spectrum of metabolic alterations that extend beyond mere flux changes to encompass heightened precursor production for ectoine and PHA synthesis. Crucially, these findings capture other metabolic changes linked to adaptation in hypersaline environments. Bottlenecks in the glycolysis and fatty acid metabolism pathways are identified, in addition to PhaC, which has been shown to increase PHA production when overexpressed. Overall, our pipeline demonstrates the potential of genome-scale metabolic models in combination with statistical approaches to obtain insights into the metabolism of H. elongata. Our platform can be exploited for researching environmental adaptation, and for designing and optimizing metabolic engineering strategies for bioproduct synthesis.

Assessing the aerobic/anoxic enrichment efficiency at different C/N ratios: pilot scale polyhydroxyalkanoates production from waste activated sludge

Polyhydroxyalkanoates (PHA) can be produced using fermentation products of an excess sewage sludge fermentation process. An efficient method to enrich a PHA-producing community is an aerobic-feast/anoxic-famine enrichment strategy. The effect of different carbon to nitrogen (C/N) feed ratios of 1, 2 and 3.5 g COD/g N on the process performance was studied. The study was executed on a pilot plant scale using fermented waste activated sludge as the organic carbon source. The system's performance was monitored in terms of removing contaminants, producing PHA, and reducing N2O emissions. The results indicated that a lower C/N ratio results in lower PHA production, with PHA content in the sludge of 20, 24 and 36 % w/w for C/N ratios of 1, 2 and 3.5 g COD/g N, respectively. At the lowest C/N ratio, the highest nitrite accumulation rate (77%), nitrification efficiency (89%) and denitrification efficiency (89%) were observed, but the N2O production was also the highest (0.77 mg N2O-N/L). The long-term comprehensive monitoring carried out in this study revealed high carbon and ammonia removal efficiencies (never below 80%) despite the C/N shifts and high COD and ammonia concentrations. At the same time, the system showed relatively low PHA production and high environmental impact in terms of high gaseous N2O emission. These findings question the sustainability of the aerobic-feast/anoxic-famine enrichment strategy for PHA production in full-scale plants.

Structure Assessment and Impacts of Lipids' Chemistry on the Structuration of Polyhydroxyalkanoate Biosynthesized by Bacillus licheniformis AZU-A5.

The current study exploited cheese whey supernatant (CWS) as a renewable resource for polyhydroxyalkanoates (PHAs) formation. Structure identification and investigating the influence of lipid membranes' chemistry on PHA structuration were detailed. Approximately 66 bacterial isolates from dairy products companies in Egypt were screened for PHA production, and the bacterial isolate AZU-A5, identified as Bacillus licheniformis strain AZU-A5, showed the highest production PHA 0.93 g L-1) using whey lactose. The highest PHA rate in the individual design was 1.59 g L-1 with a recovery yield of 33.08% (w w-1), while the production rate in the statistical design reached 1.75 g L-1 PHA and 51.60% PHA content. Structurally, the PHA was identified as polyhydroxy-3R-butyrate (R-PH3B). The fibrous texture by SEM highlighted the self-assembly of PHB. The CD analysis of the PHA films suggested favorable hydrophobic interactions between lipids and PHB. Higher lipid contents not only caused a decrement in the CD signal of PHB but also bathochromic effects occurred. The chain length of lipids exerted high impacts on interactions (CD) and structuration of PHB (Δλ). The unsaturation showed little influence on CD and negligible effect on Δλ, while the head group exerted no effect on CD with a considerable impact on Δλ.

Strategic Use of Vegetable Oil for Mass Production of 5-Hydroxyvalerate-Containing Polyhydroxyalkanoate from δ-Valerolactone by Engineered Cupriavidus necator.

Although efforts have been undertaken to produce polyhydroxyalkanoates (PHA) with various monomers, the low yield of PHAs because of complex metabolic pathways and inhibitory substrates remains a major hurdle in their analyses and applications. Therefore, we investigated the feasibility of mass production of PHAs containing 5-hydroxyvalerate (5HV) using δ-valerolactone (DVL) without any pretreatment along with the addition of plant oil to achieve enough biomass. We identified that PhaCBP-M-CPF4, a PHA synthase, was capable of incorporating 5HV monomers and that C. necator PHB-4 harboring phaCBP-M-CPF4 synthesized poly(3HB-co-3HHx-co-5HV) in the presence of bean oil and DVL. In fed-batch fermentation, the supply of bean oil resulted in the synthesis of 49 g/L of poly(3HB-co-3.7 mol% 3HHx-co-5.3 mol%5HV) from 66 g/L of biomass. Thermophysical studies showed that 3HHx was effective in increasing the elongation, whereas 5HV was effective in decreasing the melting point. The contact angles of poly(3HB-co-3HHx-co-5HV) and poly(3HB-co-3HHx) were 109 and 98°, respectively. In addition, the analysis of microbial degradation confirmed that poly(3HB-co-3HHx-co-5HV) degraded more slowly (82% over 7 days) compared to poly(3HB-co-3HHx) (100% over 5 days). Overall, the oil-based fermentation strategy helped produce more PHA, and the mass production of novel PHAs could provide more opportunities to study polymer properties.

Novel genomic and phenotypic traits of polyhydroxyalkanoate-producing bacterium ZZQ-149, the type strain of Halomonas qinghailakensis

BackgroundPolyhydroxyalkanoates (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.ResultsZZQ-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.ConclusionsBeing 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.

Multiscale modeling and experimental study of molecular weight distribution and monomeric ratio in PHA production

While plastics have brought considerable convenience to our daily lives, most of them are still made up of petroleum-based materials. The plastic production industry accounts for a substantial portion of greenhouse gas emissions, and these products cause serious environmental pollution due to their poor degradability. Hence, bio-derived polymers have gained much research interest to substitute the existing plastic materials. Among them, polyhydroxyalkanoates (PHAs) are regarded as the most promising candidate owing to their biocompatible and biodegradable nature. In particular, poly(3-hydroxybutyrate-co-4-hydroxybutyrate), P(3HB-co-4HB) is now in the limelight for its unique mechanical properties. However, understanding the sophisticated mechanism and structure is quite challenging, posing obstacles to its successful commercialization. In response to this difficulty, we devised a multiscale model using the kinetic Monte Carlo (kMC) algorithm to enable capturing the extensive characteristics of PHA, including molecular weight distribution and monomeric ratio. Considering the different time and length scales of the overall process, the model is developed with two layers for the fermentation and polymerization reactions, and they are successfully integrated. The results not only validate the experimental results but also showcase a wide range of PHA information that cannot be measured through instrumental analyses.

Effect of culture history and carbon sources on polyhydroxyalkanoates production in activated sludge systems

ABSTRACT Polyhydroxyalkanoates (PHAs) are important and completely biodegradable alternatives to regular plastics, and they can be produced by activated sludge systems during wastewater treatment. Wastewaters with high organic content are being used for PHA production, which is an important resource recovery option. In this context, the effect of sludge retention time and different carbon sources, such as acetate, peptone-mixture and industrial wastewater (containing acetic acid (AA), lactic acid (LA) and propionic acid (PA)), on PHA storage was investigated. Oxygen utilisation rate (OUR) profiles were generated in respirometric tests and were evaluated by activated sludge modelling. Results showed that high storage (AA: 70%; LA: 49%; PA: 60% and industrial wastewater: 52%) was achievable in the feast phase even when the biomass was fed with a high organic acid content substrate to which it is not acclimated.

Polyhydroxyalkanoates production from cheese whey under near-seawater salinity conditions

Treating saline streams presents considerable challenges due to their adverse effects on conventional biological processes, thereby leading to increased expenses in managing those side streams. With this in consideration, this study explores into the potential for valorizing fermented cheese whey (CW), a by-product of the dairy industry, into polyhydroxyalkanoates (PHA) using mixed microbial cultures (MMC) under conditions of near-seawater salinity (30 gNaCl/L). The selection of a PHA-accumulating MMC was successfully achieved using a sequential batch reactor operated under a feast and famine regime, with a hydraulic retention time of 14.5 h, a variable solids retention time of 3 and 4.5 days, and an organic loading rate (OLR) of 60 Cmmol/(L d). The selected culture demonstrated efficient PHA production rates and yields, maintaining robust performance even under high salinity conditions. During PHA accumulation, a maximum PHA content in biomass of 56.4 % wt. was achieved for a copolymer P(3HB-co-3HHx) with a 3HHx content of 7 %. Additionally, to asses the capacity of the culture to produce polymers with different compositions, valeric acid was supplemented to the real fermented feedstock which resulted in the production of terpolymers P(3HB-co-3HV-co-3HHx) with varied monomeric content and a higher maximum PHA content of 62 % wt. Additionally, this study highlights the potential utilization of seawater as alternative to freshwater for PHA production, thereby enhancing circular economy principles and promoting environmental sustainability.

Promotion of polyhydroxyalkanoates-producing granular sludge formation by lactic acid using anaerobic dynamic feeding process

To promote the formation of granular sludge with high polyhydroxyalkanoates (PHAs) synthesis ability, an anaerobic dynamic feeding process (AnDF) was proposed. This process combines the feast-famine mode with an anaerobic plug flow feeding process and involving variations in cycle length and settling time. The effects of lactic acid (LA) content (0 %, 20 %, and 40 % COD) on sludge granulation and PHAs production were investigated using three AnDF reactors (R1, R2, and R3). The results showed that the AnDF process feeding with LA not only effectively promoted sludge granulation but also improved its PHAs synthesis ability. The granules were quickly observed in R3 after 50 days of cultivation, with an average diameter of 0.69 mm. The maximum PHAs content reached 47.0 wt% in R3, representing a 30.09 % increase compared to R1. Additionally, extracellular polymeric substances (EPS)-producing bacteria observed in granular sludge may be the prime drivers of the formation of PHAs-producing granular sludge (PHAGS), which was defined as granular sludge with an average particle size larger than 0.30 mm and PHAs content above 40 % cell dry weight (CDW) of sludge samples.

Halorubrum miltondacostae sp. nov., a potential polyhydroxyalkanoate producer isolated from an inland solar saltern in Rio Maior, Portugal

One hundred and sixty-three extreme halophiles were recovered from a single sample collected from an inland solar saltern in Rio Maior. Based on random amplified polymorphic DNA (RAPD) profiles and partial 16S rRNA gene sequencing 125 isolates were identified as members of the Archaea domain within the genus Halorubrum. Two strains, RMP-11T and RMP-47, showed 99.1 % sequence similarity with the species Halorubrum californiense based on phylogenetic analysis of the 16S rRNA gene sequence. However, phylogenetic analysis based on five housekeeping genes, atpB, EF-2, glnA, ppsA and rpoB’, showed Halorubrum coriense as the closest related species with 96.7 % similarity. The average nucleotide identity (ANI) of strains RMP-11T, RMP-47 and species Hrr. coriense were within the range of 90.0–90.5 %, supporting that strains RMP-11T and RMP-47 represent a novel species of the genus Halorubrum. These strains formed red-pigmented colonies that were able to grow in a temperature range of 25–50 °C. Polyhydroxyalkanoate (PHA) granules were detected in both strains. The polar lipid profile was identical to the neutrophilic species of the genus Halorubrum. The Rio Maior sample from which both strains were isolated was metagenome sequenced. We identified five metagenome-assembled genomes representing novel Halorubrum species but distinct from the species represented by strains RMP-11T and RMP-47. Based on phylogenetic, phylogenomic, comparative genomics, physiological and chemotaxonomic parameters, we describe a new species of the genus Halorubrum represented by strains RMP-11T (=CECT 30760T = DSM 115521T) and RMP-47 (=CECT 30761 = DSM 115541) for which we propose the name Halorubrum miltondacostae sp. nov.

Polyhydroxyalkanoate Production by Methanotrophs: Recent Updates and Perspectives.

Methanotrophs are bacteria that consume methane (CH4) as their sole carbon and energy source. These microorganisms play a crucial role in the carbon cycle by metabolizing CH4 (the greenhouse gas), into cellular biomass and carbon dioxide (CO2). Polyhydroxyalkanoates (PHAs) are biopolymers produced by various microorganisms, including methanotrophs. PHA production using methanotrophs is a promising strategy to address growing concerns regarding plastic pollution and the need for sustainable, biodegradable materials. Various factors, including nutrient availability, environmental conditions, and metabolic engineering strategies, influence methanotrophic production. Nutrient limitations, particularly those of nitrogen or phosphorus, enhance PHA production by methanotrophs. Metabolic engineering approaches, such as the overexpression of key enzymes involved in PHA biosynthesis or the disruption of competing pathways, can also enhance PHA yields by methanotrophs. Overall, PHA production by methanotrophs represents a sustainable and versatile approach for developing biomedical materials with numerous potential applications. Additionally, alternative feedstocks, such as industrial waste streams or byproducts can be explored to improve the economic feasibility of PHA production. This review briefly describes the potential of methanotrophs to produce PHAs, with recent updates and perspectives.

Enhanced polyhydroxyalkanoate production from Mesobacillus aurentius: Statistical optimization, characterization and industrial application

Synthetic plastics pose a major environmental threat and it is necessary to produce an alternative biopolymer. In the current study, the production of polyhydroxybutyrate (PHB) by Mesobacillus aurentius was enhanced using Response surface methodology (Box–Behnken design). This study explores the potential of aquabiofloc systems as a source of polyhydroxyalkanoates (PHB)-producing bacteria. The optimized medium conditions, as determined by Response Surface Methodology (RSM), included 18.68 g of sucrose, 4.0 g of yeast, an incubation period of 69.57 h, and a pH of 7.1. The ANOVA results revealed that the model developed for predicting PHA yield was highly significant (p < 0.05). The predicted PHA yield was 63.12%, while the experimental yield was 65.35%. The maximum production of PHA was obtained with sucrose and yeast as carbon and nitrogen sources. The extracted polymer was characterized using UV, FTIR, 1H NMR, and SEM-EDAX analysis confirming the polymer to be PHB. The thermal stability of the produced PHA showed degradation temperatures ranging from 310 °C. The mechanical properties of the extracted PHA were also assessed, demonstrating tensile strength and viscosity of 22.4 MPa and 1.23 MPa. respectively. The antimicrobial activity of the produced PHA was evaluated, demonstrating significant inhibitory effects against both Gram-positive and Gram-negative bacterial strains as well as fungal strains. The Cytotoxicity assessment in HepG2 cells indicated that PHB is less toxic in nature. The findings highlight the promising role of marine bacteria, Mesobacillus aurentius, in the development of environmentally friendly biopolymers. This bacterium represents a novel candidate for PHB production, offering a potential alternative to petroleum-based plastics.

Production of Polyhydroxybutyrate by halotolerant Halomonas cerina YK44 using sugarcane molasses and soybean flour in tap water

As environmental pollution intensifies, the interest in bioplastics is growing. The bioplastic polyhydroxyalkanoates (PHAs), which are produced and degraded by microorganisms, have received considerable attention. However, the production cost of PHA is still high, and several ways to increase economy of PHA production have been studied. Therefore, as one way of solution, Halomonas species were screened and evaluated with cheap substrates such as molasses and soybean flour. Among tested strains, Halomonas cerina YK44 was selected and used for polyhydroxybutyrate (PHB) production with molasses and soybean flour together, whose combination was not evaluated well before, in tap water. The medium composition optimization showed maximum PHB production at 4 % sugarcane molasses, 2 % NaCl, 0.05 % soybean flour, and pH 8 in tap water (9.2 g/L DCW, 7.3 g/L PHB, and 79.7 % PHB contents). However, cell growth of halotolerant H. cerina YK44 was disturbed by 0.2 % furfural, which existed in biomass based sugars as inhibitors. Physical and thermal analyses revealed that PHB film started from sugarcane molasses and soybean flour was no different from that initiated from simple sugars (Tm was 175.8 °C and 176.2 °C, PDI was 1.29, and 1.31, respectively).

Advancing Sustainability: Utilizing Bacterial Polyhydroxyalkanoate for Food Packaging

Polyhydroxyalkanoates (PHAs) are promising biodegradable polymers known for their biodegradability and eco-friendly properties. Recent studies indicate that PHAs can reduce the environmental impact by up to 50% compared to petroleum-based plastics. This comprehensive review evaluates the application of PHAs in sustainable food packaging, covering over 100 studies published between 2018 and 2023. The review highlights advancements in PHA production, with a focus on submerged and solid-state fermentation methods, achieving up to a 60% improvement in production efficiency through optimized culture selection. Sustainable extraction and purification methods have been identified, reducing energy consumption by 30%. Blending PHAs with other biodegradable polymers like polylactic acid, starch, and cellulose enhances material performance, with up to a 40% improvement in mechanical properties. The incorporation of antimicrobial agents and essential oils has been shown to extend the shelf life by 25% while maintaining food safety standards. This review underscores the potential of active PHA-based packaging in improving the barrier properties by 35% when combined with coatings, positioning PHA as a key material for the future of environmentally responsible and safe food packaging.