外源添加乙酸对酿酒酵母(Saccharomyces cerevisiae)产2,3-丁二醇影响初探

Acetic Acid Addition: Effects on the Production of 2,3-butanediol by Saccharomyces cerevisiae

为验证乙酸作为信号分子的作用,本研究分别将酿酒酵母(Saccharomyces cerevisiae)W141上清液(对照组)、W141-07 (△aldh6)上清液及1.5 g/L乙酸添加至对数生长期的W141发酵液中,检测2,3-BD产量、乙酰乳酸合成酶(ILV2)及2,3-丁二醇脱氢酶(BDH1)酶活。结果表明:当添加1.5 g/L乙酸时,2,3-BD产量、ILV2和BDH1酶活性均达到最高,分别为3.01±0.04 g/L、1.41±0.03 U/mg和0.12±0.002 U/mg,且较其余两组相比差异极显著(P<0.01)。同时,测定3组条件下ilv2(24 h)和bdh1(60 h)基因的表达情况时发现,添加W141-07上清液后,ilv2和bdh1基因的表达量分别下调了31.6%和25.0%;而添加1.5 g/L乙酸后,ilv2和bdh1的表达量均发生上调,分别是对照组的4.38及1.24倍。表明乙酸可作为信号分子驱动相关基因的表达,进而提高2,3-BD产量。

To verify the role of acetic acid as a signal molecule, the supernatant of Saccharomyces cerevisiae W141(the control group) and W141-07(△aldh6), as well as 1.5 g/L acetic acid were added into S. cerevisiae W141 fermentation broth at the logarithmic phase. The content of 2,3-butanediol(2,3-BD), the activity of acetolactate synthase(ILV2) and 2,3-BD dehydrogenase(BDH1) were detected. The results showed that under the condition of 1.5 g/L acetic acid, the content of 2,3-BD, the ILV2 and BDH1 enzyme activities reached the highest value, which were 3.01±0.04 g/L, 1.41±0.03 U/mg and 0.12±0.002 U/mg, respectively. The acetic acid addition group was significantly higher than those of supernatant addition groups(P<0.01). At the same time,the expressions of ilv2(24 h) and bdh1(60 h) genes under the three conditions were determined. After adding W141-07 supernatant, the expression levels of ilv2 and bdh1 genes were down-regulated by 31.6% and25.0%, respectively. After adding acetic acid with a final concentration 1.5 g/L, the expression levels of ilv2 and bdh1 were up-regulated, which were 4.38 and 1.24 times that of the control, respectively. These results indicate that acetic acid can act as a signal molecule to drive the expression of related genes, thus to improve 2,3-BD production.