Enhanced polyhydroxybutyrate production from biomass using engineered Halomonas sp. YLGW01 with improved xylose metabolism

초록

Polyhydroxybutyrate (PHB) is a biodegradable polymer that can be accumulated by microorganisms as a carbon and energy storage compound. PHB is an attractive alternative to petroleum-based plastics for sustainable bioplastic production. Utilizing lignocellulosic biomass for PHB production provides environmental, economic, and sustainable benefits. Therefore, developing a strain capable of utilizing all sugars derived from lignocellulosic biomass is a practical strategy for efficient microbial production of PHB. In this study, xylose metabolism-related genes were introduced into the PHB-producing Halomonas sp. YLGW01 strain to enable PHB production from xylose. The introduction of xylose isomerase (xylA) and xylulokinase (xylB) enhanced xylose metabolism in Halomonas sp. YLGW01. Optimizing the medium composition, including xylose concentration, nitrogen source, and yeast extract concentration, resulted in a PHB titer of 0.73 g/L. The engineered strain exhibited high dry cell weight (DCW) and PHB production from xylose alone and from mixed sugars, including sucrose and glucose. Furthermore, lignocellulosic biomass hydrolysate, primarily composed of xylose and glucose, was used as the substrate, and PHB production reached 3.11 g/L with a PHB content of 61.7 %. This study is the first to effectively engineer Halomonas sp. YLGW01, providing an efficient strategy for microbial compound biosynthesis and demonstrating its potential for compound utilization.

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