Dye decolourization, humic substances degradation and guajacol oxidation by yeasts from Isla 25 de mayo, Antarctica

HIPÓLITO F. PAJOT; JOSÉ I ROVATI; FIGUEROA, LUCÍA INÉS CASTELLANOS DE; WALTER MAC CORMAK

Madyson

Congreso; International Congress on Yeasts ICY 2012; 2012

International Commission on Yeasts

The biotechnological potential of psychrophilic or psychrotolerant yeasts is closely related to the ability of these yeasts to survive and to grow at low temperatures, producing cold active enzymes. Dye decolourization by white rot fungi (WRF) or their ligninolytic enzymes has been widely studied over last years. On the other hand, yeasts have been successfully applied to treat industrial effluents. However, the ecology of dye-degrading yeasts is still poorly understood. Oligotrophic yeasts tend to have comparatively lower growth rates and to assimilate a broader substrate spectrum than copiotrophic yeasts. In this work, a diluted media (YM 1/10) was employed in yeast isolation from Isla 25 de Mayo, Antarctica. Plant, wood and soil samples were processed within the first 24 hs of being aseptically collected. Sixty four yeasts were isolated comprising both: asco- and basidiomycetous yeasts. Isolates were assayed, on agar plates, for textile dye decolourization, humic substances degradation and guaiacol oxidation an incubated at 15ºC for up to 2 weeks. Humic substances degradation ability showed to be the most abundant one, being present on 52% isolates. Dye decolourization and guaiacol oxidation were scarcer (33% and 25% isolates respectively). Dye decolourization showed to be associated with humic substances degradation (p<0.05) but not with guaiacol oxidation (p>0.1) pointing to a non-conventional oxidative decolourization mechanism. Present results demonstrate that cold adapted yeasts could be used in designing biodecolourization processes at relatively low temperatures, thus allowing a significant cost reduction in industrial effluent´s treatment.