Rugthaworn Prapassorn, Murata Yoshinori, Machida Masashi, Apiwatanapiwat Waraporn, Hirooka Akiko, Thanapase Warunee, Dangjarean Hatairat, Ushiwaka Satoru, Morimitsu Kozo, Kosugi Akihiko, Arai Takamitsu, Vaithanomsat Pilanee
Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki, 305-8686, Japan.
Appl Biochem Biotechnol. 2014 Jul;173(5):1197-208. doi: 10.1007/s12010-014-0906-2. Epub 2014 Apr 30.
In this study, we report the inhibition of Kluyveromyces marxianus TISTR5925 growth and ethanol fermentation in the presence of furan derivatives and weak acids (acetic acid and lactic acid) at high temperatures. Cassava pulp, obtained as the waste from starch processing, was collected from 14 starch factories located in several provinces of Thailand. At a high temperature (42 °C), the cassava pulp hydrolysate from some starch factories strongly inhibited growth and ethanol production of both K. marxianus (strain TISTR5925) and Saccharomyces cerevisiae (strain K3). HPLC detected high levels of lactic acid and acetic acid in the hydrolysates, suggesting that these weak acids impaired the growth of K. marxianus at high temperature. We isolated Trp-requiring mutants that had reduced tolerance to acetic acid compared to the wild-type. This sensitivity to acetic acid was suppressed by supplementation of the medium with tryptophan.
在本研究中，我们报告了在高温下，马克斯克鲁维酵母TISTR5925在呋喃衍生物和弱酸（乙酸和乳酸）存在的情况下生长及乙醇发酵受到抑制。木薯渣作为淀粉加工的废料，取自泰国多个省份的14家淀粉厂。在高温（42℃）下，一些淀粉厂的木薯渣水解产物强烈抑制了马克斯克鲁维酵母（菌株TISTR5925）和酿酒酵母（菌株K3）的生长及乙醇生成。高效液相色谱法检测到水解产物中含有高浓度的乳酸和乙酸，这表明这些弱酸在高温下损害了马克斯克鲁维酵母的生长。我们分离出了与野生型相比对乙酸耐受性降低的色氨酸需求型突变体。通过在培养基中补充色氨酸，这种对乙酸的敏感性得到了抑制。
