Ethanol and Volatile Fatty Acid Production from Lignocellulose by Clostridium cellulolyticum

Abstract

Clostridium cellulolyticum is capable of producing glycosyl hydrolase enzymes as well as fermentation products including ethanol and acetate. In this study, the potential of using C. cellulolyticum for ethanol and volatile fatty acid production from straw and grape pomace was examined. For rice straw, the effects of alkaline pretreatment and substrate sterilization prior to fermentation on products yields were also investigated. Effects of alkaline pretreatment and necessity for subsequent washing were tested for two types of grape pomace. For rice straw, the highest ethanol yield was 0.16 g/gVS from the straw pretreated with 10% sodium hydroxide loading at 121°C for 1 hour. Sterilization of the straw prior to fermentation was found to be not significant for ethanol production. Sterilization appeared to decrease native acetogen populations in the rice straw, resulting in lower acetic acid yields. The highest ethanol yield from grape pomace was of 0.09 g/gVS from the pretreated pomace. Pomace type (red or white) and washing were found to be not significant. Ethanol yields by C. cellulolyticum were lower than those from yeast in a simultaneous saccharification and fermentation system, but overall conversion of cellulose and hemicellulose was high, between 68 and 79%.

Simultaneous Production of Cellulase and Reducing Sugar From Alkali-Pretreated Sugarcane Bagasse via Solid State Fermentation

“…However, substantial amount of wastewater is inevitably produced from the washing step, and this incurs extra cost in the wastewater treatment, which is not beneficial in the economical point of view. To improve the cost effectiveness of this process, the alkaline solution could be pressed out from the biomass after pretreatment (Williams et al 2013). Alternatively, the washed water can also be reused after the desired pH adjustment for alkaline pretreatment process.…”

Biotechnological potential of Clostridium butyricum bacteria

“…Reports confirm the existence of numerous representatives bacteria of the genus Clostridium capable of synthesizing xylanases ( Bahl and Dürre, 2001 ; Wang et al , 2011 ; Yung-Chung et al , 2010 ). Metabolic capacity associated with decomposition and fermentation of biomass is particularly important in the production of 2 nd generation biofuels (ethanol from cellulose) ( Maki et al , 2009 ; Williams et al , 2013 ). Sucrose and xylose are used as sources of carbon in the microbiological synthesis of hydrogen by the CGS2 C. butyricum strain ( Yung-Chung et al , 2010 ).…”

Bioprocessing of Waste for Renewable Chemicals and Fuels to Promote Bioeconomy

“…A Brazil-based company called Braskem has patented the anaerobic coproduction of acetic acid along with other high-value materials which seem to greatly improve yield [82]. Pretreated straw and grape pomace comprised 78% cellulose and hemicellulose, which were utilized to produce ethanol and acetic acid [83]. Further, steamtreated lignocellulosic biomass derived from wheat straw, forest residue, switch grass, and sugarcane straw were fermented to acetic acid along with 5-hydroxymethyl furfural Various feedstock rich in carbohydrates have been evaluated to produce both mixed acid and pure AA employing Acetobacter aceti.…”