title: A New Isolation and Evaluation Method for Marine-Derived Yeast spp. with Potential Applications in Industrial Biotechnology.
abstract: Yeasts that are present in marine environments have evolved to survive hostile environments that are characterized by high exogenous salt content, high concentrations of inhibitory compounds, and low soluble carbon and nitrogen levels. Therefore, yeasts isolated from marine environments could have interesting characteristics for industrial applications. However, the application of marine yeast in research or industry is currently very limited owing to the lack of a suitable isolation method. Current methods for isolation suffer from fungal interference and/or low number of yeast isolates. In this paper, an efficient and non-laborious isolation method has been developed and successfully isolated large numbers of yeasts without bacterial or fungal growth. The new method includes a three-cycle enrichment step followed by an isolation step and a confirmation step. Using this method, 116 marine yeast strains were isolated from 14 marine samples collected in the UK, Egypt, and the USA. These strains were further evaluated for the utilization of fermentable sugars (glucose, xylose, mannitol, and galactose) using a phenotypic microarray assay. Seventeen strains with higher sugar utilization capacity than the reference terrestrial yeastSaccharomyces cerevisiaeNCYC 2592 were selected for identification by sequencing of the ITS and D1/D2 domains. These strains belonged to six species:S. cerevisiae,Candida tropicalis,Candida viswanathii,Wickerhamomyces anomalus,Candida glabrata, andPichia kudriavzevii. The ability of these strains for improved sugar utilization using seawater-based media was confirmed and, therefore, they could potentially be utilized in fermentations using marine biomass in seawater media, particularly for the production of bioethanol and other biochemical products.
authors.affiliation: Division of Food Sciences, School of Biosciences, University of Nottingham, Nottingham LE12 5RD, UK.|School of Applied Sciences, University of Huddersfield, Huddersfield HD1 3DH, UK.|Department of Microbiology, Faculty of Agriculture, Cairo University, Giza 12613, Egypt.
authors.forename: Abdelrahman Saleh
authors.initials: AS
authors.lastname: Zaky
authors.affiliation: Division of Food Sciences, School of Biosciences, University of Nottingham, Nottingham LE12 5RD, UK.
authors.forename: Darren
authors.initials: D
authors.lastname: Greetham
authors.affiliation: Centre for Genetic Architecture of Complex Traits, Department of Genetics, University of Leicester, Leicester LE1 7RH, UK.
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Louis
authors.affiliation: Division of Food Sciences, School of Biosciences, University of Nottingham, Nottingham LE12 5RD, UK.
authors.forename: Greg A
authors.initials: GA
authors.lastname: Tucker
authors.affiliation: Division of Food Sciences, School of Biosciences, University of Nottingham, Nottingham LE12 5RD, UK.|School of Applied Sciences, University of Huddersfield, Huddersfield HD1 3DH, UK.
authors.forename: Chenyu
authors.initials: C
authors.lastname: Du
mesh_terms: D000431:Ethanol / Q000378:metabolism; D005285:Fermentation; D007218:Industrial Microbiology; D008828:Microbiological Techniques / Q000379:methods*; D012623:Seawater / Q000382:microbiology*; D014994:Xylose / Q000378:metabolism; D015003:Yeasts / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D000431:Ethanol; D014994:Xylose
keywords: Marine yeast; fermentation; identification; phenotypic microarray; screening; seawater