Ethyl lactate biosynthesis by the cascade of the aerobic process and the anaerobic process with corn stover

Ethyl lactate was produced with corn stover as a carbon source by a cascade bioprocess without adding any enzymes. Immobilized Aspergillus niger and Saccharomyces cerevisiae was co-cultivated in a modified gas lift bioreactor. Cellulase from Aspergillus niger was 8.05 U/mL in the gas lift bioreactor. The fermentation broth was transferred into an anaerobic fermenter, in which the immobilized Saccharomyces cerevisiae and Lactobacillus rhamnosus was cultivated. The maximum esterase activities were over 5005 U/mL and the ethyl lactate yield was over 8.76 g/L during five repeated batches. Without adding any cellulase and esterase, ethyl lactate production was achieved during five repeated batches by the cascade of the aerobic process and the anaerobic process with the lignocellulose as a carbon source. Graphical abstract