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Integrated in situ gas stripping–salting-out process for high-titer acetone–butanol–ethanol production from sweet sorghum bagasse

Wen, Hao, Chen, Huidong, Cai, Di, Gong, Peiwen, Zhang, Tao, Wu, Zhichao, Gao, Heting, Li, Zhuangzhuang, Qin, Peiyong, Tan, Tianwei
Biotechnology for biofuels 2018 v.11 no.1 pp. 134
bagasse, biobutanol, biomass, condensates, culture media, dipotassium hydrogen phosphate, distillation, feedstocks, fermentation, process energy, solvents, sweet sorghum, temperature
BACKGROUND: The production of biobutanol from renewable biomass resources is attractive. The energy-intensive separation process and low-titer solvents production are the key constraints on the economy-feasible acetone–butanol–ethanol (ABE) production by fermentation. To decrease energy consumption and increase the solvents concentration, a novel two-stage gas stripping–salting-out system was established for effective ABE separation from the fermentation broth using sweet sorghum bagasse as feedstock. RESULTS: The ABE condensate (143.6 g/L) after gas stripping, the first-stage separation, was recovered and introduced to salting-out process as the second-stage. K₄P₂O₇ and K₂HPO₄ were used, respectively. The effect of saturated salt solution temperature on final ABE concentration was also investigated. The results showed high ABE recovery (99.32%) and ABE concentration (747.58 g/L) when adding saturated K₄P₂O₇ solution at 323.15 K and 3.0 of salting-out factor. On this condition, the energy requirement of the downstream distillation process was 3.72 MJ/kg of ABE. CONCLUSIONS: High-titer cellulosic ABE production was separated from the fermentation broth by the novel two-stage gas stripping–salting-out process. The process was effective, which reduced the downstream process energy requirement significantly.