An efficient approach for the production of polyhydroxybutyrate from lignin by alkali-halophile Halomonas alkalicola M2

Abstract

Lignin bioconversion into polyhydroxybutyrate (PHB) has emerged as a promising valorization, however, it is suffering from inadequate conversion efficiency. Herein, an efficient strategy for addressing this challenge by employing an alkali-halophilic strain Halomonas alkalicola M2 is developed. Up to 58.5% of lignin is degraded when incubates in the non-sterilized lignin (NSL) medium under a glucose concentration of 1.055 g/L, peptone concentration of 0.596 g/L, and incubation time of 6.89 d, demonstrating enhanced proficiency compared to thermally sterilized lignin (TSL) method due to the improved cell growth, lignin-degrading enzyme activities, and secreted protein contents. Consequently, PHB production demonstrates a 50% increase using NSL method compared to TSL method. A separate route of enzymatic hydrolysis and fermentation (SHF) is proposed to further improve the PHB production, resulting in a record yield of PHB which is 1.89 g/L. This work creatively develops a non-sterilization strategy to improve PHB production from lignin, showing great potential for promoting biological lignin valorization.