Biosynthesis of polyhydroxyalkanoates using Cupriavidus necator H16 and its application for particleboard production

Embracing Sustainability: The World of Bio-Based Polymers in a Mini Review

The proliferation of polymer science and technology in recent decades has been remarkable, with synthetic polymers derived predominantly from petroleum-based sources dominating the market. However, concerns about their environmental impacts and the finite nature of fossil resources have sparked interest in sustainable alternatives. Bio-based polymers, derived from renewable sources such as plants and microbes, offer promise in addressing these challenges. This review provides an overview of bio-based polymers, discussing their production methods, properties, and potential applications. Specifically, it explores prominent examples including polylactic acid (PLA), polyhydroxyalkanoates (PHAs), and polyhydroxy polyamides (PHPAs). Despite their current limited market share, the growing awareness of environmental issues and advancements in technology are driving increased demand for bio-based polymers, positioning them as essential components in the transition towards a more sustainable future.

Evaluation of different nutrient limitation strategies for the efficient production of poly(hydroxybutyrate-co-hydroxyvalerate) from waste frying oil and propionic acid in high cell density fermentations of Cupriavidus necator H16

Because of its application potential and biodegradability, poly(3-hydroxybutyrate-co-3-hydroxyvalerate;PHBV), a member of the polyhydroxyalkanoates (PHA) biopolymer family, is one of the most extensively studied PHA. High PHBV productivity with a significant amount of hydroxyvalerate (HV) content is very appealing for commercial scale production. The goal of this study was to investigate the efficiency of various defined limitation strategies, namely nitrogen, phosphorus, and oxygen-limitation, for high yield PHBV production by Cupriavidus necator H16 with increased HV unit using waste frying vegetable oil (WFO) and propionic acid (PA) in a high cell density culture (5 L bioreactor). With optimized WFO and PA feeding, highest PHBV harvest (121.7 ± 2.59 g/L; HV 13.9 ± 0.44% (w/w)) and volumetric productivity (2.03 ± 0.04 gPHBV/L·h) were obtained in oxygen-limited operation, while highest HV content (19.8 ± 0.28 wt%) and yield coefficient (0.43 ± 0.017 gHV/gPA) were observed during phosphorus-limited cultivation. Although nitrogen limitation is widely applied in the production of PHA, nitrogen-limited cultivation had the lowest cell dry matter, PHBV production, volumetric productivity, oil-to-HB and PA-to-HV yield coefficients for the given conditions. The results of the present study demonstrate the highest PHBV yield together with the highest HV content using WFO as main carbon source and PA as the HV precursor ever reported in the literature.

A fermentation process for the production of poly(3-hydroxybutyrate) using waste cooking oil or waste fish oil as inexpensive carbon substrate

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Both WCO and WFO can be used as promising substrates for PHA production.

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First report of a fed-batch fermentation process using WFO as sole carbon source for PHA production.

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High PHB yields of 0.8 g/g and 0.92 g/g were produced from WCO and WFO, respectively.

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Highest PHB productivity (1.73 g/L/h) was achieved when using waste oil as carbon source.

The utilization of waste cooking oil (WCO) or waste fish oil (WFO) as inexpensive carbon substrate for the production of poly(3-hydroxybutyrate) (PHB) by Cupriavidus necator H16 was investigated. Fed-batch cultivation mode in bioreactor was applied in this study. High cell dry weight (CDW) of 135.1 g/L, PHB content of 76.9 wt%, PHB productivity of 1.73 g/L/h, and PHB yield of 0.8 g/g were obtained from WCO. In the case of WFO, the CDW, PHB content, PHB productivity, and PHB yield were 114.8 g/L, 72.5 wt%, 1.73 g/L/h, and 0.92 g/g, respectively. The PHB productivity and yield obtained in the current study from WCO or WFO are among the highest reported so far for PHA production using oils as sole carbon substrate, suggesting that both WCO and WFO can be used as inexpensive carbon substrates for the production of PHA on an industrial scale.

Polyhydroxyalkanoate and its efficient production: an eco-friendly approach towards development

Polyhydroxyalkanoate (PHA) is the most promising solution to major ecological problem of plastic accumulation. The biodegradable and biocompatible properties of PHA make it highly demanding in the biomedical and agricultural field. The limited market share of PHA industries despite having tremendous demand as concerned with environment has led to knock the doors of scientific research for finding ways for the economic production of PHA. Therefore, new methods of its production have been applied such as using a wide variety of feedstock like organic wastes and modifying PHA synthesizing enzyme at molecular level. Modifying metabolic pathways for PHA production using new emerging techniques like CRISPR/Cas9 technology has simplified the process spending less amount of time. Using green solvents under pressurized conditions, ionic liquids, supercritical solvents, hypotonic cell disintegration for release of PHA granules, switchable anionic surfactants and even digestion of non-PHA biomass by animals are some novel strategies for PHA recovery which play an important role in sustainable production of PHA. Hence, this review provides a view of recent applications, significance of PHA and new methods used for its production which are missing in the available literature.

Bioconversion of plant biomass hydrolysate into bioplastic (polyhydroxyalkanoates) using Ralstonia eutropha 5119

Pretreatment of lignocellulosic biomass results in the formation of byproducts (furfural, hydroxymethylfurfural [HMF], vanillin, acetate etc.), which affect microbial growth and productivity. Furfural (0.02%), HMF (0.04%), and acetate (0.6%) showed positive effects on Ralstonia eutropha 5119 growth and polyhydroxyalkanoate (PHA) production, while vanillin exhibited negative effects. Response optimization and interaction studies between the variables glucose, ammonium chloride, furfural, HMF, and acetate using the response surface methodology resulted in maximum PHA production (2.1 g/L) at optimal variable values of 15.3 g/L, 0.43 g/L, 0.04 g/L, 0.05 g/L, and 2.34 g/L, respectively. Different lignocellulosic biomass hydrolysates (LBHs), including barley biomass hydrolysate (BBH), Miscanthus biomass hydrolysate (MBH), and pine biomass hydrolysate (PBH), were evaluated as potential carbon sources for R. eutropha 5119 and resulted in 1.8, 2.0, and 1.7 g/L PHA production, respectively. MBH proved the best carbon source, resulted in higher biomass (Y_x/s, 0.31 g/g) and PHA (Y_p/s, 0.14 g/g) yield.