Biosynthesis and properties of polyhydroxyalkanoates synthesized from mixed C < sub > 5 < /sub > and C < sub > 6 < /sub > sugars obtained from hardwood hydrolysis

N Biotechnol. 2023 Jun 28;77:40-49. doi: 10.1016/j.nbt.2023.06.005. Online ahead of print.ABSTRACTGlucose and xylose are fermentable sugars readily available from lignocellulosic biomass, and are a sustainable carbon substrate supporting industrial biotechnology. Three strains were assessed in this work - Paraburkholderia sacchari, Hydrogenophaga pseudoflava, and Bacillus megaterium - for their ability to uptake both C5 and C6 sugars contained in a hardwood hydrolysate produced via a thermomechanical pulping-based process with concomitant production of poly(3-hydroxyalkanoate) (PHA) biopolymers. In batch conditions, B. megaterium showed poor growth after 12 h, minimal uptake of xylose throughout the cultivation, and accumulated a maximum of only 25 % of the dry biomass as PHA. The other strains simultaneously utilized both sugars, although glucose uptake was faster than xylose. From hardwood hydrolysate, P. sacchari accumulated 57 % of its biomass as PHA within 24 h, whereas H. pseudoflava achieved an intracellular PHA content of 84 % by 72 h. The molecular weight of the PHA synthesized by H. pseudoflava (520.2 kDa) was higher than that of P. sacchari (265.5 kDa). When the medium was supplemented with propionic acid, the latter was rapidly consumed by both strains and incorporated as 3-hydroxyvalerate subunits into the polymer, demonstrating the potential for production of polymers with improved properties and value. H. pseudoflava incorporated 3-hydroxyvalerate subunits with...

Source: New Biotechnology - June 30, 2023 Category: Biotechnology Authors: Warren Blunt Purnank Shah Vinicio Vasquez Mengwei Ye Christopher Doyle Yali Liu Sajjad Saeidlou Fanny Monteil-Rivera Source Type: research