A biotechnological approach for degradation of inhibitory compounds present in lignocellulosic biomass hydrolysate liquor using Bordetella sp. BTIITR

Abstract

Biochemical conversion of lignocellulosic feedstock to biofuels and other valuable chemicals through sugar-platform process involves a pretreatment step that facilitates the conversion of polysaccharides to simple sugars. A major drawback of pretreatment process is the formation of lignocellulose-derived by-products, such as furfural and 5-hydroxy-2-methylfurfural (HMF), which inhibit the downstream enzymatic hydrolysis and microbial growth during fermentation. Hence, an efficient and environment friendly technique for removal of these inhibitors is essential. The present study reports isolation of a bacterium from soil that exhibited capability to degrade furfural and HMF present in lignocellulosic hydrolysate liquor. The isolated bacterium, Bordetella sp. BTIITR, was able to degrade 100% of furfural and 80% of HMF from simulated hydrolysate liquor in 16h of incubation period. For the actual sugarcane bagasse hydrolysate liquor, it was able to remove 100% of furfural, 94% of HMF and 82% of acetic acid in 16h of incubation period. It was also intriguing to observe that the bacterium selectively consumed furfural and HMF initially without significantly affecting the fermentable sugars. Once furfural and HMF were degraded to a lower concentration, consumption of sugars accelerated. This substrate priority of Bordetella sp. BTIITR for furfural and HMF over sugars renders it as a potential candidate for biodetoxification of inhibitory compounds present in the lignocellulosic hydrolysate liquor.