Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo 657-8501, Japan.
Appl Microbiol Biotechnol. 2010 Jun;87(1):109-15. doi: 10.1007/s00253-010-2487-5. Epub 2010 Feb 24.
We successfully demonstrated batch ethanol fermentation repeated ten times from raw starch with high ethanol productivity. We constructed a yeast diploid strain coexpressing the maltose transporter AGT1, alpha-amylase, and glucoamylase. The introduction of AGT1 allows maltose and maltotriose fermentation as well as the improvement of amylase activities. We also found that alpha-amylase activity during fermentation was retained by the addition of 10 mM calcium ion and that the highest alpha-amylase activity was 9.26 U/ml during repeated fermentation. The highest ethanol productivity was 2.22 g/l/h at the fourth batch, and after ten cycles, ethanol productivity of more than 1.43 g/l/h was retained, as was alpha-amylase activity at 6.43 U/ml.
我们成功地展示了从生淀粉进行十批次的高乙醇生产力的批量乙醇发酵。我们构建了一个共表达麦芽糖转运蛋白 AGT1、α-淀粉酶和葡萄糖淀粉酶的酵母二倍体菌株。AGT1 的引入允许麦芽糖和麦芽三糖发酵，并提高了淀粉酶的活性。我们还发现，在发酵过程中添加 10mM 钙离子可以保留α-淀粉酶的活性，并且在重复发酵过程中最高的α-淀粉酶活性为 9.26U/ml。第四次批量发酵的最高乙醇生产力为 2.22g/l/h，经过十次循环后，乙醇生产力仍保持在 1.43g/l/h 以上，α-淀粉酶的活性也保持在 6.43U/ml。
