关键词: 高密度培养, 反馈流加, 米根霉, L-乳酸

Abstract:

Production of L-lactic acid was investigated by high density fed-batch fermentation of Rhizopus oryzae As3.819. The optimum culture conditions in shaking flask were as follows: inoculation size 5%, inoculation age 24 h, medium volume in flask 40% and mass glucose to ammonium sulfate ratio 20:1. Higher density of Rhizopus oryzae As3.819 cell was obtained through glucose feedback feeding method in a 15-L fermentor, and the cell dry weight was up to 18.45 g/L. The L-lactic acid yield reached a stable level, 2.25 g/L·h after 5 repeated semi-continuous fermentations, which was higher 82.9% than that of batch fermentation, and the cell dry weight was increased by 92.9% .

Key words: high density fed-batch cultivation, feedback feeding, Rhizopus oryzae, L-lactic acid