High solid loading and multiple-fed simultaneous saccharification and co-fermentation (mf-SSCF) of rice straw for high titer ethanol production at low cost. (December 2021) - Sharma, Sumit
Abstract: Efficient ethanol production using dilute acid pretreated rice straw was investigated in multiple-fed simultaneous saccharification and co-fermentation (mf-SSCF) for producing high titer ethanol at a low cost. The mf-SSCF was performed at very high solid loading (29.5% w/v) by multiple feeding of dilute acid pretreated rice straw without any detoxification, solid-liquid separation, and sterilization. After 72 h, an ethanol titer of 68.72 g L −1 was attained with higher ethanol yield (0.42 g g −1 ) and productivity (0.95 g L −1 h −1 ). Only magnesium sulfate (6 g L −1 ) was added as nutrient component and aqueous ammonia was used for pH adjustment of pretreated slurry to 5, which also provides ammonium ions as a nitrogen source for yeast during ethanol fermentation. Almost no water was added in the mf-SSCF process; therefore, higher ethanol titer (8.7 % v/v) was achieved, which further reduce distillation, water input, and treatment cost. These results suggest that the mf-SSCF process has great potential for the production of high titer ethanol on a commercial scale due to the consolidation and simplification of the process at a low cost. Highlights: Pretreated biomass used without detoxification and sterilization. Aqueous ammonia plays a dual role: pH adjuster and nitrogen source. Only MgSO4 supplemented as nutrient. Almost no water addition in the process after pretreatment. High titer, yield, and productivity of 2G ethanol at lower CAPEX and OPEX.