title: Direct production of ethanol from neoagarobiose using recombinant yeast that secretes α-neoagarooligosaccharide hydrolase.
abstract: An α-neoagarooligosaccharide hydrolase, AgaNash, was purified from Cellvibrio sp. OA-2007, which utilizes agarose as a substrate. The agaNash gene, which encodes AgaNash, was obtained by comparing the N-terminal amino acid sequence of AgaNash with that deduced from the nucleotide sequence of the full-length OA-2007 genome. The agaNash gene combined with the Saccharomyces cerevisiae signal peptide α-mating factor was transformed into the YPH499 strain of S. cerevisiae to generate YPH499/pTEF-MF-agaNash, and the recombinant yeast was confirmed to produce AgaNash, though it was mainly retained within the recombinant cell. To enhance AgaNash secretion from the cell, the signal peptide was replaced with a combination of the signal peptide and a threonine- and serine-rich tract (T-S region) of the S. diastaticus STA1 gene. The new recombinant yeast, YPH499/pTEF-STA1SP-agaNash, was demonstrated to secrete AgaNash and hydrolyze neoagarobiose with an efficiency of as high as 84%, thereby producing galactose, which is a fermentable sugar for the yeast, and ethanol, at concentrations of up to 1.8 g/L, directly from neoagarobiose.
authors.affiliation: Department of International Development Engineering, Graduate School of Engineering, Tokyo Institute of Technology, 2-12-1 I4-2 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
authors.lastname: Syazni
authors.affiliation: Department of Environmental Sciences, School of Food, Agricultural and Environmental Sciences, Miyagi University, 2-2-1 Hatadate, Taihaku-ku, Sendai City, Miyagi 982-0215, Japan.
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Yanagisawa
authors.affiliation: School of Environmental Science and Engineering, Kochi University of Technology, 185 Miyanokuchi, Kami City, Kochi 782-8502, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kasuu
authors.affiliation: School of Environmental Science and Engineering, Kochi University of Technology, 185 Miyanokuchi, Kami City, Kochi 782-8502, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Ariga
authors.affiliation: Department of International Development Engineering, Graduate School of Engineering, Tokyo Institute of Technology, 2-12-1 I4-2 Ookayama, Meguro-ku, Tokyo 152-8550, Japan. Electronic address: nakasaki@ide.titech.ac.jp.
authors.forename: Kiyohiko
authors.initials: K
authors.lastname: Nakasaki
mesh_terms: D056804:Biofuels; D020633:Cellvibrio / Q000201:enzymology / Q000235:genetics; D003001:Cloning, Molecular; D004187:Disaccharides / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D005690:Galactose / Q000378:metabolism; D005798:Genes, Bacterial; D006026:Glycoside Hydrolases / Q000235:genetics / Q000378:metabolism*; D000072235:Mating Factor / Q000235:genetics; D021382:Protein Sorting Signals / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism
chemical_list: D056804:Biofuels; D004187:Disaccharides; D021382:Protein Sorting Signals; D011994:Recombinant Proteins; D000431:Ethanol; C068544:neoagarobiose; D000072235:Mating Factor; D006026:Glycoside Hydrolases; C090400:alpha-neoagarooligosaccharide hydrolase; D005690:Galactose
keywords: Bioethanol; Cellvibrio sp. OA-2007; Neoagarooligosaccharide; Saccharomyces cerevisiae; α-NAOS hydrolase