It is estimated that more than three quarters of the Earth＇s biosphere is in perennially cold environments. Despite the extreme environmental conditions of desiccation and freezing, microbes can colonize these habita...It is estimated that more than three quarters of the Earth＇s biosphere is in perennially cold environments. Despite the extreme environmental conditions of desiccation and freezing, microbes can colonize these habitats through the adaptation of metabolic functions and the synthesis of structurally adapted enzymes. Enzymes within psychrophilic microbes exhibit high specific activity at low and moderate temperature, with low thermostability. In this study we used a classic microbiological approach to isolate Antarctic bacteria with cellulolytic, lipolytic, and ligninolytic activities. From 15 different environmental samples, we generated a collection of approximately 800 bacterial isolates that could grow on R2A or Marine medium at 4℃. This collection was then screened for the presence of the three types of activity at 4℃. We found that 47.7% of the isolates displayed lipolytic activity, 10.2% had cellulase/xylanase activity, and 7.7% showed guaiacol oxidase activity. Of these, 10% displayed two different types of activity, while 0.25% displayed all three types of activity. Our results indicate that cold environments represent outstanding resources for bioprospecting and the study of enzymatic adaptation.展开更多
基金the Antarctic Institute of Uruguay (IAU) Research Projects 2012-2014the National Agency for Innovation and Investigation (ANII) INI_X_2012_1_4201 for partial financial support
文摘It is estimated that more than three quarters of the Earth＇s biosphere is in perennially cold environments. Despite the extreme environmental conditions of desiccation and freezing, microbes can colonize these habitats through the adaptation of metabolic functions and the synthesis of structurally adapted enzymes. Enzymes within psychrophilic microbes exhibit high specific activity at low and moderate temperature, with low thermostability. In this study we used a classic microbiological approach to isolate Antarctic bacteria with cellulolytic, lipolytic, and ligninolytic activities. From 15 different environmental samples, we generated a collection of approximately 800 bacterial isolates that could grow on R2A or Marine medium at 4℃. This collection was then screened for the presence of the three types of activity at 4℃. We found that 47.7% of the isolates displayed lipolytic activity, 10.2% had cellulase/xylanase activity, and 7.7% showed guaiacol oxidase activity. Of these, 10% displayed two different types of activity, while 0.25% displayed all three types of activity. Our results indicate that cold environments represent outstanding resources for bioprospecting and the study of enzymatic adaptation.
