Changhae Institute of Cassava and Ethanol Research, Changhae Ethanol Co., Jeonju 561-203, Republic of Korea.
Bioprocess Biosyst Eng. 2013 May;36(5):547-54. doi: 10.1007/s00449-012-0810-5. Epub 2012 Aug 21.
In this study, an ethanol fermentation waste (EFW) was characterized for use as an alternative to yeast extract for bulk fermentation processes. EFW generated from a commercial plant in which ethanol is produced from cassava/rice/wheat/barley starch mixtures using Saccharomyces cerevisiae was used for lactic acid production by Lactobacillus paracasei. The effects of temperature, pH, and duration on the autolysis of an ethanol fermentation broth (EFB) were also investigated. The distilled EFW (DEFW) contained significant amounts of soluble proteins (2.91 g/l), nitrogen (0.47 g/l), and amino acids (24.1 mg/l). The autolysis of the EFB under optimum conditions released twice as much amino acids than in the DEFW. Batch fermentation in the DEFW increased the final lactic acid concentration, overall lactic acid productivity, and lactic acid yield on glucose by 17, 41, and 14 %, respectively, in comparison with those from comparable fermentation in a lactobacillus growth medium (LGM) that contained 2 g/l yeast extract. Furthermore, the overall lactic acid productivity in the autolyzed then distilled EFW (ADEFW) was 80 and 27 % higher than in the LGM and DEFW, respectively.
在这项研究中，利用从以木薯/大米/小麦/大麦淀粉混合物为原料利用酿酒酵母生产乙醇的商业工厂中产生的乙醇发酵废物（EFW），通过副干酪乳杆菌进行乳酸生产。还研究了温度、pH 和时间对乙醇发酵液（EFB）自溶的影响。经蒸馏的 EFW（DEFW）含有大量的可溶性蛋白质（2.91 g/l）、氮（0.47 g/l）和氨基酸（24.1 mg/l）。在最佳条件下，EFB 的自溶释放出的氨基酸是 DEFw 的两倍。与在含有 2 g/l 酵母提取物的副干酪乳杆菌生长培养基（LGM）中进行的可比发酵相比，在 DEFw 中进行分批发酵可分别将最终乳酸浓度、总乳酸生产率和葡萄糖产酸率提高 17%、41%和 14%。此外，在自溶然后蒸馏的 EFW（ADEFW）中的总乳酸生产率分别比在 LGM 和 DEFw 中高 80%和 27%。
