Simultaneous acetone-butanol-ethanol fermentation, gas stripping, and full-cell-catalyzed esterification for effective production of butyl oleate.

ABSTRACT

In this study, aiming to improve the economic feasibility of acetone-butanol-ethanol (ABE) fermentation process, generate valuable products and extend the product chain, esterification catalyzed by Candida sp. 99-125 cells was hybrid with the ABE fermentation-gas-stripping integration system. The gas-stripping condensate that contained concentrated ABE products was directly used for esterification without the participation of toxic organic solvents. Full-cell catalysis temperature and the cell dosage rate on oleate production were evaluated and optimized in the esterification process. Under the optimized conditions (35 °C, 8% of cells), ~ 68% of butyl oleate and ~ 12% of ethyl oleate were obtained after 4 h of esterification. The Candida sp. 99-125 cells were able to be reused for at least four cycles. The novel cascade process showed environmental benefits, which also showed promising in improving the economic feasibility of the conventional ABE fermentation process.