title: Consolidated bioprocessing of starchy substrates into ethanol by industrial Saccharomyces cerevisiae strains secreting fungal amylases.
abstract: 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 Saccharomyces cerevisiae strain suitable for industrial bioethanol production was developed in this study. Codon-optimized variants of the Thermomyces lanuginosus glucoamylase (TLG1) and Saccharomycopsis fibuligera α-amylase (SFA1) genes were δ-integrated into two S. cerevisiae 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.
authors: Department of Agronomy Food Natural resources Animals and Environment (DAFNAE), Università di Padova, Agripolis, Viale dell'Università 16, 35020, Legnaro (PD), Italy.
authors: Lorenzo
authors: L
authors: Favaro
authors: Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa.
authors: Marko J
authors: MJ
authors: Viktor
authors: Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa.
authors: Shaunita H
authors: SH
authors: Rose
authors: Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa.
authors: Marinda
authors: M
authors: Viljoen-Bloom
authors: Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa.
authors: Willem H
authors: WH
authors: van Zyl
authors: Department of Agronomy Food Natural resources Animals and Environment (DAFNAE), Università di Padova, Agripolis, Viale dell'Università 16, 35020, Legnaro (PD), Italy. marina.basaglia@unipd.it.
authors: Marina
authors: M
authors: Basaglia
authors: Department of Agronomy Food Natural resources Animals and Environment (DAFNAE), Università di Padova, Agripolis, Viale dell'Università 16, 35020, Legnaro (PD), Italy.
authors: Lorenzo
authors: L
authors: Cagnin
authors: Department of Agronomy Food Natural resources Animals and Environment (DAFNAE), Università di Padova, Agripolis, Viale dell'Università 16, 35020, Legnaro (PD), Italy.
authors: Sergio
authors: S
authors: Casella
mesh_terms: D000681:Amylases / Q000378:metabolism*; D056804:Biofuels; D018533:Biomass; D001709:Biotechnology; D003001:Cloning, Molecular; D003062:Codon; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D005656:Fungal Proteins / Q000378:metabolism*; D007218:Industrial Microbiology; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D045868:Sorghum; D013213:Starch / Q000378:metabolism*; D000066889:Triticale
chemical_list: D056804:Biofuels; D003062:Codon; D005656:Fungal Proteins; D000431:Ethanol; D013213:Starch; D000681:Amylases
keywords: codon optimization; consolidated bioprocessing (CBP); industrial yeast; raw starch; sorghum; triticale