(690c) Biological Detoxification of Lignocellulosic Biomass Hydrolysate Liquor for Enhanced Ethanol Production

Acid pretreatment of lignocellulosic feedstock during biofuel production leads to the formation of toxic by-products, such as furfural and 5-hydroxy-2-methylfurfural (HMF), which inhibit the downstream enzymatic hydrolysis and fermentation. An efficient and environment friendly process for removal of these inhibitors is essential. The present study reports the isolation of a bacterium, Bordetella sp. BTIITR, from soil that exhibited capability to selectively degrade furfural and HMF without significant consumption of sugars (1). This substrate priority of Bordetella sp. BTIITR for HMF and furfural makes it a potential organism for biodetoxification of lignocellulosic hydrolysate liquor. The isolated bacterium was able to degrade 100 % of furfural and 80 % of HMF from simulated hydrolysate liquor in 16 h 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 16 h of incubation period. Further, Bordetella sp. BTIITR was immobilized within chitosan beads and the beads were utilized to detoxify the hydrolysate. The immobilized cells were able to degrade 94 % HMF and 100 % furfural in 20 h at pH 8 and 35- 40 ⁰C temperature. The detoxified hydrolysate liquors demonstrated improved fermentation efficiency for production of ethanol as compare to the undetoxified hydrolysate. Isolation of bacteria, characterization, detoxification in free and immobilized forms, and effect on ethanol production will be discussed. This is the first study to report the capability of Bordetella to metabolize the furan derivatives.

Reference: 1. B. Singh, A. Verma, Pooja, P. K. Mandal, S. Datta^*, A Biotechnological Approach for Degradation of Inhibitory Compounds Present in Lignocellulosic Biomass Hydrolysate Liquor Using Bordetella sp. BTIITR, Chem. Eng. J., 328 (2017) 519-526