LAUSR

Abstract During biofuel production, acid pretreatment of lignocellulosic feedstock leads to 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. Earlier, we reported a bacterium, Bordetella sp. BTIITR, which exhibited capability to selectively degrade HMF and furfural from lignocellulosic hydrolysate liquor without significant consumption of sugars. In the present study, Bordetella sp. BTIITR was immobilized within chitosan beads and the beads were utilized to detoxify hydrolysate liquors. The immobilized cells were able to degrade 93% HMF + 100% furfural and 86% HMF + 100% furfural in 20 h at pH 8 and temperature of 40 °C from simulated and sugarcane bagasse hydrolysate liquors, respectively. Immobilized cells were able to detoxify lignocellulosic hydrolysate liquor at broader range of operating pH, temperature and inhibitor concentration as compare to the free cells. Further, the immobilized cells were successfully reused for seven consecutive cycles of operations with nearly constant degradation efficiency. To the best of our knowledge, this is the first report on successful utilization of the immobilized cells for biodetoxification of lignocellulosic hydrolysate liquor to improve bioethanol production.