Consolidated bioprocessing of starchy substrates into ethanol by industrial Saccharomyces cerevisiae strains secreting fungal amylases. Issue 9 (14th July 2015)

• Record Type: Journal Article
• Authors: Favaro, Lorenzo; Viktor, Marko J.; Rose, Shaunita H.; Viljoen‐Bloom, Marinda; van Zyl, Willem H.; Basaglia, Marina; Cagnin, Lorenzo; Casella, Sergio
• Is Part Of: Biotechnology and bioengineering. Volume 112:Issue 9(2015:Sep.)
• Page Start: 1751
• Page End: 1760
• Publication Date: 2015-07-14
• Subjects: Biotechnology -- Periodicals; Bioengineering -- Periodicals; 660.6
• DOI: 10.1002/bit.25591
• Languages: English
• ISSNs: 0006-3592

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <sec id="bit25591-sec-0001" sec-type="section"> <p>The development of a yeast strain that converts raw starch to ethanol in one step (called Consolidated Bioprocessing, CBP) could significantly reduce the commercial costs of starch‐based bioethanol. An efficient amylolytic <italic>Saccharomyces cerevisiae</italic> strain suitable for industrial bioethanol production was developed in this study. Codon‐optimized variants of the <italic>Thermomyces lanuginosus</italic> glucoamylase (<italic>TLG1</italic>) and <italic>Saccharomycopsis fibuligera</italic> α‐amylase (<italic>SFA1</italic>) genes were δ‐integrated into two <italic>S. cerevisiae</italic> yeast with promising industrial traits, i.e., strains M2n and MEL2. The recombinant M2n[TLG1‐SFA1] and MEL2[TLG1‐SFA1] yeast displayed high enzyme activities on soluble and raw starch (up to 8118 and 4461 nkat/g dry cell weight, respectively) and produced about 64 g/L ethanol from 200 g/L raw corn starch in a bioreactor, corresponding to 55% of the theoretical maximum ethanol yield (g of ethanol/g of available glucose equivalent). Their starch‐to‐ethanol conversion efficiencies were even higher on natural sorghum and triticale substrates (62 and 73% of the theoretical yield, respectively). This is the first report of direct ethanol production from natural starchy substrates (without any pre‐treatment or commercial enzyme addition) using industrial yeast strains co‐secreting both a glucoamylase and α‐amylase. Biotechnol. Bioeng. 2015;112: 1751–1760. © 2015 Wiley Periodicals, Inc.</p> </sec> </abstract>