Original Research Paper
Construction of a direct starch-fermenting industrial strain of
Saccharomyces cerevisiae producing glucoamylase, α-amylase and debranching enzyme
Ji-Hye Kim1, Ha-Ram Kim1, Mi-Hyeon Lim1, Hyun-Mi Ko2, Jong-Eon Chin3, Hwanghee Blaise Lee1, Il-Chul Kim1 and Suk Bai1 
| (1) |
Department of Biological Sciences, College of Natural Sciences, Chonnam National University, Gwangju, 500-757, South Korea |
| (2) |
Dental Science Research Institute, 2nd Stage Brain Korea, School of Dentistry, Chonnam National University, Gwangju, South Korea |
| (3) |
Department of Cosmetology, Dongkang College University, Gwangju, South Korea |
Received: 9 December 2009 Revised: 13 January 2010 Accepted: 14 January 2010 Published online: 4 February 2010
Abstract 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 α-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 δ-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 α-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.
Keywords Amylase -
Aspergillus awamori
-
Debaryomyces occidentalis
- Glucoamylase -
Saccharomyces cerevisiae
- Starch
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