Inactivation of the Levansucrase Gene in Paenibacillus polymyxa DSM 365 Diminishes Exopolysaccharide Biosynthesis during 2,3-Butanediol Fermentation

Abstract

Given the current barrage of attention and research investments toward the production of next-generation fuels and chemicals, of which 2,3-butanediol (2,3-BD) produced by nonpathogenic Paenibacillus species is perhaps one of the most vigorously pursued, tools for engineering Paenibacillus species are intensely sought after. Exopolysaccharide (EPS) production during 2,3-BD fermentation constitutes a problem during downstream processing. Specifically, EPS negatively impacts 2,3-BD separation from the fermentation broth, thereby increasing the overall cost of 2,3-BD production. The results presented here demonstrate that inactivation of the levansucrase gene in P. polymyxa leads to diminished EPS accumulation. Additionally, a new method for an EPS assay and a simple protocol employing protoplasts for enhanced transformation of P. polymyxa were developed. Overall, although our study shows that levan is not the only EPS produced by P. polymyxa , it represents a significant first step toward developing cost-effective 2,3-BD fermentation devoid of EPS-associated complications during downstream processing.