Polyhydroxyalkanoate Synthesis by Burkholderia glumae into a Sustainable Sugarcane Biorefinery Concept

Abstract

Polyhydroxyalkanoate (PHA) bioplastic was synthesized by Burkholderia glumae MA13 from carbon sources and industrial byproducts related to sugarcane biorefineries: sucrose, xylose, molasses, vinasse, bagasse hydrolysate, yeast extract, yeast autolysate, and inactivated dry yeast besides different inorganic nitrogen sources. Sugarcane molasses free of pre-treatment was the best carbon source, even compared to pure sucrose, with intracellular polymer accumulation values of 41.1–46.6% cell dry weight. Whereas, xylose and bagasse hydrolysate were poor inducers of microbial growth and polymer synthesis, the addition of 25% (v/v) sugarcane vinasse to the culture media containing molasses was not deleterious and resulted in a statistically similar maximum polymer content of 44.8% and a maximum PHA yield of 0.18 g/g, at 34°C and initial pH of 6.5, which is economic and ecologically interesting to save water required for the industrial processes and especially to offer a fermentative recycling for this final byproduct from bioethanol industry, as an alternative to its inappropriate disposal in water bodies and soil contamination. Ammonium sulfate was better even than tested organic nitrogen sources to trigger the PHA synthesis with polymer content ranging from 29.7 to 44.8%. GC-MS analysis showed a biopolymer constituted mainly of poly(3-hydroxybutyrate) although low fractions of 3-hydroxyvalerate monomer were achieved, which were not higher than 1.5 mol% free of copolymer precursors. B. glumae MA13 has been demonstrated to be adapted to synthesize bioplastics from different sugarcane feedstocks and corroborates to support a biorefinery concept with value-added green chemicals for the sugarcane productive chain with additional ecologic benefits into a sustainable model.

Polyhydroxyalkanoate (PHA) Biopolymer Synthesis by Marine Bacteria of the Malaysian Coral Triangle Region and Mining for PHA Synthase Genes

“…The distinct environmental conditions in marine sponges (e.g., anaerobic regions) place bacterial populations in unfavourable living environments, such as conditions with low availability of electron acceptors, oxygen, essential nutrients, space, light, and other growth factors [ 53 ]. To compete for survival in inconsistent living conditions, some bacteria utilised alternative pathways to synthesise and accumulate PHA as an alternative energy source [ 50 ].…”

Developing Microbial Co-Culture System for Enhanced Polyhydroxyalkanoates (PHA) Production Using Acid Pretreated Lignocellulosic Biomass

“…The production of PHA using various lignocellulosic biomass is especially advantageous in achieving simultaneous resource recovery and pollution prevention, and it makes the process fruitful and eco-friendly. However, during acid and ASC pretreatment of SCB, some toxic compounds, for instance, furfural and hydroxymethylfurfural, formic, acetic acid, and various lignin degraded aromatics, are generated, which directly influences the microbial growth during fermentation and consequently PHA production [31,32]. To overcome the effects of fermentation inhibitors in the SCB hydrolysates, many investigators have proposed some solutions, mainly, adaptation of potential microbial strains to the inhibitors [31,33]; detoxification of hydrolysates before PHA production [34]; addition of a higher quantity of inoculum size for ef- Similarly, a sharp decrease in intensity at approximately 1652 cm −1 demonstrated lignin removal, since this peak was attributed to the stretching vibration of aromatic rings and phenyl ester side-chain C=O bonds of lignin (Figure 3b).…”

“…However, during acid and ASC pretreatment of SCB, some toxic compounds, for instance, furfural and hydroxymethylfurfural, formic, acetic acid, and various lignin degraded aromatics, are generated, which directly influences the microbial growth during fermentation and consequently PHA production [31,32]. To overcome the effects of fermentation inhibitors in the SCB hydrolysates, many investigators have proposed some solutions, mainly, adaptation of potential microbial strains to the inhibitors [31,33]; detoxification of hydrolysates before PHA production [34]; addition of a higher quantity of inoculum size for effective PHA production [27]. Ralstonia eutropha showed less capability to utilize 5C sugars and oligosaccharides in LC biomass hydrolysates.…”

Technical-Economical Approach for PHB Production by Ralstonia Eutropha Strain Using Concentrated Vinasse as Carbon Source and Other Biotechnological Applications

“…Other authors have investigated the combined use of vinasses and molasses in culture media for polyhydroxyalkanoates production. Paula et al (2021) cultivated Burkholderia gluma MA13 in shake flasks with basal mineral medium; they evaluated volumetric dilutions of 25% and 50% of in natura vinasse and sugarcane molasse was used as carbon source (20 g L -1 ). PHA cellular content was between 14.07 -29.4% and rCDW concentrations between 0.52 -1.31 g L -1 were determined.…”