High cell density culture of baker's yeast FX-2 based on pH-stat coupling with respiratory quotient.

摘要: The high cell density culture of baker's yeast FX-2 was investigated in a 50 L(A) automatic bioreactor. Herein, it found firstly that the Crabtree effect clearly existed batch fermentation with higher glucose content, then critical initial content range (≤2.00 g L-1 ) reasonably ascertained to effectively avoid effect. In next fed-batch fermentations different strategies, second strategy (maintain ethanol concentration lower than 0.10% and pH around 4.80) confirmed be more beneficial growth first (keep reducing sugar not 2.00 control steady Carbon/Nitrogen ratio 3.05:1.00). After that, one optimal 4.80 keep respiratory quotient 0.90-1.00) constructed further enhance yield. Under an strategy, four schemes aim achieving pH-stat were compared, extract instead other alkaline materials selected as better regulator. As result, 148.37 dry weight, 38.25 × 108 mL-1 living cells, 8.24  h-1 productivity harvested, which respectively elevated 23.74%, 135.38%, 24.47% compared obtained under traditional scheme (regulate ammonia); meanwhile, maximum oxygen uptake rate carbon dioxide excretion both 250.00 mmol L-1  min-1 .