Sustainable conversion of lignocellulose hydrolysates without detoxification treatment to biodegradable poly (3hydroxybutyrate) by a Halomonas venusta DSM4743 cell factory

Abstract

Lignocellulosic biomass resources as substrate feedstock have become an effective way to reduce polyhydroxyalkanoates (PHA) production costs. In this work, poly(3-hydroxybutyrate) (PHB) was synthesized by Halomonas venusta DSM4743 using rubberwood hydrolysates (RWH) without detoxification treatment as carbon substrate. Compositional analysis revealed that glucose (61.3 g/L) was consumed more efficiently than xylose (19.6 g/L), confirming preferential carbon utilization in RWH. The highest PHB production of 1.23 g/L was achieved at 20 g/L RWH initial concentration. Notably, the tolerance thresholds of Halomonas venusta DSM4743 to furfural and 5-HMF in RWH were identified as 0.75 g/L and 0.6 g/L, respectively. Low-concentration furfural was found to enhance glucose and xylose utilization rates by 15.81% and 30.51%, alleviating glucose inhibition, but simultaneously suppressed PHB biosynthesis. In contrast, 5-HMF supplementation promoted late-stage xylose consumption but inhibited microbial growth. Under optimized conditions, the synthetic PHB exhibited a tensile strength of 17.17 MPa. Compared to commercial PHB, the polymer derived RWH displayed a uniform molecular weight distribution, reduced melting temperature, and improved processability, highlighting its suitability for industrial applications. This study provided a sustainable pathway for efficiently utilizing agro-forestry