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Li X, Huang C, Xu CQ, Tan YL, Luo YD, Zou K, Li JH, Deng ZS, Zheng Z, Ye H, Zhang XL, Zheng N. High cell density culture of baker's yeast FX-2 based on pH-stat coupling with respiratory quotient. Biotechnol Appl Biochem 2019; 66:389-397. [PMID: 30715749 DOI: 10.1002/bab.1735] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 02/01/2019] [Indexed: 11/08/2022]
Abstract
The high cell density culture of baker's yeast FX-2 was investigated in a 50 L(A) automatic bioreactor. Herein, it was found firstly that the Crabtree effect clearly existed in batch fermentation with higher glucose content, then the critical initial glucose content range (≤2.00 g L-1 ) was reasonably ascertained to effectively avoid Crabtree effect. In the next fed-batch fermentations with different strategies, the second strategy (maintain ethanol concentration lower than 0.10% and pH around 4.80) was confirmed to be more beneficial to yeast growth than the first strategy (keep reducing sugar not more than 2.00 g L-1 and control steady Carbon/Nitrogen ratio 3.05:1.00). After that, one optimal control strategy (maintain pH around 4.80 and keep respiratory quotient in the range of 0.90-1.00) was constructed to further enhance cell yield. Under an optimal control strategy, four schemes with the aim of achieving pH-stat were compared, and yeast extract instead of other alkaline materials was selected as a better regulator. As a result, 148.37 g L-1 dry cell weight, 38.25 × 108 mL-1 living cells, and 8.24 g L-1 h-1 productivity were harvested, which respectively elevated 23.74%, 135.38%, and 24.47% compared to that obtained under the traditional scheme (regulate pH with ammonia); meanwhile, the maximum oxygen uptake rate and carbon dioxide excretion rate were both more than 250.00 mmol L-1 min-1 .
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Affiliation(s)
- Xiao Li
- Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang, China.,Angel Yeast Co., Ltd., Yichang, China
| | - Cong Huang
- Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang, China
| | - Chao-Qun Xu
- Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang, China
| | - Ya-Li Tan
- Angel Yeast Co., Ltd., Yichang, China
| | - Yu-Di Luo
- Angel Yeast Co., Ltd., Yichang, China
| | - Kun Zou
- Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang, China
| | | | - Zhang-Shuang Deng
- Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang, China
| | | | - Han Ye
- Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang, China
| | - Xiao-Long Zhang
- Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang, China
| | - Nian Zheng
- Angel Yeast (Yili) Co., Ltd., Yining, China
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