| Summary: | Cold adapted yeasts from soil samples from King George Island and Tierra del Fuego province were evaluated for their potential to produce extracellular pectinases. Pectinolytic yeasts were previously identified by 26S rDNA (D1/D2 domain) sequencing and phylogenetic analyses. Among 103 isolates, only eight showed pectinolytic activity at 20ºC, and only four -strains e9.2, 4.6, 5.9 and 8E- were capable to produce pectinolytic activity at 8ºC. Strain 8E identified as Guehomyces pullulans and the strains e9.2 and 5.9 identified as Cystofilobasidium infirmominiatum and Cryptoccocus adeliensis were selected for enzyme production under submerged fermentation. All the strains were capable to grow in presence of lemon peel. C. adeliensis 5.9 produced the highest enzyme activity at 24 h (4.8 U/ml) while C. infirmominiatum e9.2 and G. pullulans 8E showed considerable activity at 45 h (3.9 U/ml and 2.83 U/ml, respectively). It could be seen that at 10ºC enzyme/s remained active. Besides polygalacturonase (PGase), presence of other pectin-degrading enzymes in the culture supernatants was investigated. None of the strains produce neither pectin or pectate lyase activity nor rhamnogalacturonan hydrolase activity. Regarding pectin esterase activity, it was only produced by G. pullulans (0.022 U/ml). All the strains produced enzymatic pools that showed higher activity against highly esterified pectin than against pectin with 63% methoxyl. This behavior could be attributed to the presence of polymethylgalacturonase activity (PMGase) in its supernatant. β- glucosidase activity was detected in all supernatants. This is the first report on the capacity of these species to produce pectinases. Inulinase activity was detected in G. pullulans and C. infirmominiatum supernatants, while xylanase and cellulase activities were only detected in G. pullulans supernatants. Centro de Investigación y Desarrollo en Fermentaciones Industriales
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