Graduate School, Khon Kaen University, Khon Kaen, 40002, Thailand.
Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen, 40002, Thailand.
J Biotechnol. 2021 May 20;332:1-10. doi: 10.1016/j.jbiotec.2021.03.012. Epub 2021 Mar 16.
A stirred tank bioreactor (STR) coupled with two column bioreactors (CRs) was used for ethanol production from sweet sorghum stem juice by Saccharomyces cerevisiae SSJ01KKU in a very high gravity fermentation. The effects of the medium circulation rate between the STR and CRs (2.6 and 5.2 mL/min, corresponding to 25 and 50 % of the S. cerevisiae specific growth rate), the starting time of medium circulation (0 and 4 h) and cell inoculation were investigated. The results showed that a medium circulation rate of 5.2 mL/min, starting the medium circulation at the beginning of fermentation (0 h) with cell inoculation into the STR only were appropriate conditions for ethanol production. This yielded an average ethanol concentration (P) of 120.96 g/L and ethanol productivity (Q) of 2.52 g/L⋅h. When a repeated-batch (RB) ethanol fermentation in the STR coupled with CR was carried out using a drain and fill technique at different volumes (75 and 90 %, referenced as RB1 and RB2, respectively), it was found that at least eight successive cycles could be operated under both RB1 and RB2. The average P and Q for RB1 and RB2 were not significantly different. However, the average total ethanol production rate in RB2 (3.25 g/h) over the eight cycles was significantly higher than that of RB1 (2.60 g/h).
采用搅拌式生物反应器（STR）与两个塔式生物反应器（CR）耦联，利用酿酒酵母 SSJ01KKU 从甜高粱秸秆汁中进行高浓度发酵生产乙醇。考察了 STR 与 CR 之间的培养基循环速率（2.6 和 5.2 mL/min，分别对应于酿酒酵母比生长速率的 25%和 50%）、培养基循环开始时间（0 和 4 h）和细胞接种量对乙醇生产的影响。结果表明，以 5.2 mL/min 的培养基循环速率、在发酵开始时（0 h）开始培养基循环并仅将细胞接种到 STR 中是适合乙醇生产的条件。在此条件下，平均乙醇浓度（P）为 120.96 g/L，乙醇生产率（Q）为 2.52 g/L⋅h。采用排空和填充技术在不同体积（75%和 90%，分别表示为 RB1 和 RB2）下在 STR 中进行重复批次（RB）乙醇发酵时，发现 RB1 和 RB2 均可运行至少 8 个连续循环。RB1 和 RB2 的平均 P 和 Q 没有显著差异。然而，RB2（3.25 g/h）在 8 个循环中的平均总乙醇生产速率明显高于 RB1（2.60 g/h）。
