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Efficient isopropanol-butanol (IB) fermentation of rice straw hydrolysate by a newly isolated Clostridium beijerinckii strain C-01

Dalal, Jyotsana, Das, Mriganko, Joy, Sam, Yama, Mohan, Rawat, Jaya
Biomass and bioenergy 2019 v.127 pp. 105292
Clostridium beijerinckii, ammonia, batch fermentation, biofuels, butanol, ethanol, glucose, hydrolysates, hydrolysis, isopropyl alcohol, rice straw, solvents, sulfuric acid, xylose
In the present study, a Clostridium beijerinckii strain capable of producing Isopropanol-Butanol (IB) was isolated from gram grain. Batch fermentation of un-detoxified sulfuric acid pretreated rice straw (RS) hydrolysate (SARSH) with this strain resulted in the production of 6.6g L−1 acetone-free Isopropanol-Butanol (IB), of which butanol was 4.9 g L−1. Fermentation of hydrolysate obtained after ammonia pretreated enzyme hydrolysed RS resulted in the production of 8.5 g L−1 of acetone-free IB, giving a yield of 0.34 g g−1. IB production from fermentation of 30 g L−1 glucose and 30 g L−1 xylose was 10 and 8.6 g L−1, respectively, showing an equal and efficient utilization of both glucose and xylose. The total solvent yield from glucose and xylose was 0.36 and 0.32 g g−1 respectively. During fermentation mostly butanol (7.0 g L−1) and isopropanol (2.0 g L−1) were produced as biosolvents with negligible amounts of ethanol (0.1 g L−1). Since isopropanol can be used as a fuel additive, the mixture of isopropanol and butanol (IB) can be directly used as a biofuel.