Optimization of a Wild-Type Mesophilic Clostridium Species That Produces Butanol

Optimization of a wild-type mesophilic Clostridium Species that produces butanol

Fengxue Xin, Sandhi Eko Bramono, and Jianzhong He*

(*Email: jianzhong.he@nus.edu.sg)

The raising energy demands and climate changes have stimulated people to look for sustainable energy.  Among the alternatives, bioenergy generation from sustainable lignocellulosic materials has received elevating attentions in the industries in order to fulfill the increasing energy demands.  However, the low bio-solvents yield remains as a bottleneck, which is tackled in this study by enhancing the performance of an anaerobic microbe – Clostridium species strain BOH3.

Here we report the optimization of a Clostridium species strain BOH3 that is able to ferment simple monosaccharides and polysaccharides to produce biofuels and fatty acids at mesophillic conditions.  From 30g/l of glucose and xylose, batch culture systems of BOH3 were able to produce 4.67g/l and 4.13g/l of biobutanol within 5 days.  Further treatments such as augmented-inoculation improved biobutanol production to 7.05 and 7.41 g/L from glucose and xylose.  Enhancement treatment at high initial butanol concentrations led to 15 -17 g/L of butanol generation from glucose.  Solventogenic activities, together with biohydrogen gas production (2.47 and 1.93 mmol), were also observed for culture BOH3 when cellulose and xylan (10 g each) were used as substrates, suggesting that strain BOH3 has acquired xylanolytic and cellulolytic capabilities and is able to perform fermentation of these complex polysaccharides.  Therefore, the wild-type culture BOH3 is promising in generating biobutanol and biohydrogen from renewable feedstock and has potential to serve as an important biocatalyst in the bioenergy industry.