Consolidated Bioprocess for Bioethanol Production from Lignocellulosic Biomass Using Clostridium thermocellum DSM 1237

A consolidated bioprocessing (CBP) using Clostridium thermocellum DSM 1237 for bioethanol production in anaerobic bottles and a 3-L fermenter from biomass was investigated. The effects of key operational parameters including different carbon sources, temperature, and substrates on the metabolic performance of the strain were firstly evaluated. It was found that ethanol yield reached 0.60 g/L with a cell biomass of 0.80 g/g at the optimal temperature of 60 degrees C with 0.5% (w/v) cellobiose. Further experiments indicated that sugarcane bagasse (SCB) could be utilized to efficiently culture this strain. Ethanol yield reached 0.68 g/L (65.8% of theoretical yield) from alkali-pretreated SCB. In the subsequent 3-L fermenter trial, the maximum ethanol 0.86 g/L (83.3% of theoretical yield) was achieved, with enzymes enriched in both cellulase and xylanase. The CBP provided enzymes on-site and integrated hydrolysis and fermentation in one-step, which might be an effective approach for economic bioethanol production.