Low temperature extracellular enzymatic activities in cold adapted yeasts from Patagonia, Argentina

BRIZZIO SILVIA; TURCHETTI BENEDETTA; DE GARCÍA VIRGINIA; LIBKIND DIEGO; BUZZINI PIETRO; GASPARETTI C.; VAN BROOCK MARÍA

Buenos Aires

Congreso; Biolatina, Impacto Socio-Económico de la Biotecnología de Avanzada, VII Feria Congreso Latinoamericano de Biotecnología, III Congreso Argentino de Biotecnología; 2006

Extreme environments are recognized as a source of microorganisms bearing biotechnologically potential features. Cold active enzymes could be used in industrial processes at low temperatures. In this study we investigated the extracellular enzymatic activity (EEA) of ninety-two cold adapted yeast strains isolated from waters of subglacial rivers and lakes in Nahuel Huapi National Park (Argentina). Amylolytic, lipolytic, proteolytic, pectinolytic, chitinolytic and cellulolytic activities were screened in solid media with specific substrates at 4 and 20 ºC. Proteolytic activity of 4 selected strains and lipolytic activity of 3 ones was quantified in cell free supernatans after incubation of liquid cultures at different temperatures (range 4 - 25 ºC) for 1 hour. Over 15 % of strains exhibited simultaneously three or more EEA at 4 °C, whereas more than 63 % exhibited at least two EEA at the same temperature. Most of the 36 Cryptococcus strains and 16 Rhodotorula strains showed the ability to hydrolyze tributyrin at 4 ºC and Tween 80 at 20 ºC. Almost all of 11 Leucosporidiella strains showed proteolytic activity at 4 and 20 ºC. No strains showed chitinolytic or cellulolytic activity in the assay conditions. Cell-free supernatants of selected strains exhibited significantly (P < 0.01) higher protease and lipase activity at temperatures below 10°C. The results of this study indicate that cold-adapted yeasts from extreme unpolluted areas of Patagonia Argentina are potential sources industrially relevant cold-active enzymes. Further studies will focus on improvement of biomass and enzyme yields of selected strains in laboratory conditions.