Department of Biological Sciences, College of Natural Sciences, Chonnam National University, Gwangju, 500-757, South Korea.
Biotechnol Lett. 2010 May;32(5):713-9. doi: 10.1007/s10529-010-0212-1. Epub 2010 Feb 4.
To develop a strain of Saccharomyces cerevisiae that produces ethanol directly from starch, two integrative vectors were constructed to allow the simultaneous multiple integration of the Aspergillus awamori glucoamylase gene (GA1) and the Debaryomyces occidentalis alpha-amylase gene (AMY) and glucoamylase with debranching activity gene (GAM1) into the chromosomes of an industrial strain of S. cerevisiae. The GA1 and AMY genes were constitutively expressed under the ADC1 promoter in S. cerevisiae using the double delta-integration system. The GAM1 gene was constitutively expressed under the corresponding promoter using the double 18S rDNA-integration system. The recombinant industrial strain secreting biologically active alpha-amylase, glucoamylase and debranching enzyme was able to ferment starch to ethanol in a single step. The new strain produced 8% (v/v) ethanol (62.8 g l(-1)) from 20% (w/v) soluble starch after 2 days, fermentation.
为了开发一株能够直接利用淀粉生产乙醇的酿酒酵母菌株，构建了两个整合载体，以允许同时将曲霉菌葡糖淀粉酶基因（GA1）和德巴利酵母α-淀粉酶基因（AMY）以及具有脱支酶活性的葡糖淀粉酶基因（GAM1）整合到工业酿酒酵母菌株的染色体上。在酿酒酵母中，GA1 和 AMY 基因在 ADC1 启动子的控制下表达，使用双δ-整合系统。GAM1 基因在相应的启动子下表达，使用双 18S rDNA 整合系统。分泌具有生物活性的α-淀粉酶、葡糖淀粉酶和脱支酶的重组工业菌株能够在一步发酵中利用淀粉生产乙醇。新菌株在 2 天发酵后，能够从 20%（w/v）可溶性淀粉中生产 8%（v/v）乙醇（62.8 g l(-1)）。
