title: Yeasts from sub-Antarctic region: biodiversity, enzymatic activities and their potential as oleaginous microorganisms.
abstract: Various microbial groups are well known to produce a range of extracellular enzymes and other secondary metabolites. However, the occurrence and importance of investment in such activities have received relatively limited attention in studies of Antarctic soil microbiota. Sixty-one yeasts strains were isolated from King George Island, Antarctica which were characterized physiologically and identified at the molecular level using the D1/D2 region of rDNA. Fifty-eight yeasts (belonging to the genera Cryptococcus, Leucosporidiella, Rhodotorula, Guehomyces, Candida, Metschnikowia and Debaryomyces) were screened for extracellular amylolytic, proteolytic, esterasic, pectinolytic, inulolytic xylanolytic and cellulolytic activities at low and moderate temperatures. Esterase activity was the most common enzymatic activity expressed by the yeast isolates regardless the assay temperature and inulinase was the second most common enzymatic activity. No cellulolytic activity was detected. One yeast identified as Guehomyces pullulans (8E) showed significant activity across six of seven enzymes types tested. Twenty-eight yeast isolates were classified as oleaginous, being the isolate 8E the strain that accumulated the highest levels of saponifiable lipids (42 %).
authors.affiliation: Cátedra de Microbiología, Departamento de Biociencias, Facultad de Química, Universidad de la República, Montevideo, Uruguay.
authors.forename: A
authors.initials: A
authors.lastname: Martinez
authors.affiliation: Research and Development Center for Industrial Fermentations, CINDEFI (CONICET, La Plata, UNLP), Calle 47 y 115 (B1900ASH), La Plata, Argentina.
authors.forename: I
authors.initials: I
authors.lastname: Cavello
authors.affiliation: Cátedra de Microbiología, Departamento de Biociencias, Facultad de Química, Universidad de la República, Montevideo, Uruguay.
authors.forename: G
authors.initials: G
authors.lastname: Garmendia
authors.affiliation: Facultad de Química, Instituto Polo Tecnológico, Universidad de la República, By Pass Ruta 8 s/n, Pando, Canelones, Uruguay.
authors.forename: C
authors.initials: C
authors.lastname: Rufo
authors.affiliation: Research and Development Center for Industrial Fermentations, CINDEFI (CONICET, La Plata, UNLP), Calle 47 y 115 (B1900ASH), La Plata, Argentina.
authors.forename: S
authors.initials: S
authors.lastname: Cavalitto
authors.affiliation: Cátedra de Microbiología, Departamento de Biociencias, Facultad de Química, Universidad de la República, Montevideo, Uruguay. svero@fq.edu.uy.
authors.forename: S
authors.initials: S
authors.lastname: Vero
mesh_terms: D000222:Adaptation, Physiological; D000864:Antarctic Regions; D002480:Cellulase / Q000378:metabolism; D003080:Cold Temperature; D004950:Esterases / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000378:metabolism; D046448:Ice Cover / Q000382:microbiology*; D064307:Microbiota; D012335:RNA, Ribosomal / Q000235:genetics; D012988:Soil Microbiology; D015003:Yeasts / Q000145:classification / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D005656:Fungal Proteins; D012335:RNA, Ribosomal; D004950:Esterases; D006026:Glycoside Hydrolases; D002480:Cellulase; C023086:inulinase
keywords: Bioenergetics; Enzymes; Psychrophiles