Taxonomic characterization, adaptation strategies and biotechnological potential of cryophilic yeasts from ice cores of Midre Lovénbreen glacier, Svalbard, Arctic.
Ten strains of cryophilic yeast were studied from glacier ice cores of Svalbard, Arctic. The ice melt samples contained about 3×10(3) - 1×10(4) colony forming unit (CFUs) per ml. Sequence analysis of the isolates, using D1/D2 domain identified five species of yeasts: Cryptococcus adeliensis (MLB-18 JX192655), Cryptococcus albidosimilis (MLB-19 JX192656), Cryptococcus saitoi (MLB-22 JX192659), Rhodosporidium lusitaniae (MLB-20 JX192657), and Rhodotorula mucilaginosa (MLB-27 JX192664). Effect of temperature on growth of these isolates was studied. The strains are able to grow at temperatures ranging between 1 and 20°C. Screening of the cultures for amylase, cellulase, protease, lipase, urease and catalase activity were carried out indicating varying amounts of enzyme production at different temperatures. Characterization of lipase in strain Cryptococcus sp. MLB-24 was performed. Fatty acid methyl ester (FAME) analysis of the cultures grown at four different temperatures (1, 4, 15, and 20°C) was also done. Decrease in temperature was reported to cause increase in concentration of unsaturated fatty acids. High amount of oleic acid accumulated with increase in temperature. These fatty acids possibly help the strains to survive in glacial ice core cold environment. The extracellular and intracellular filtrate of the cultures showed negative antifreeze protein (AFP) activity. The observations indicate that probably the isolates in the present undertaking adapt to low temperatures, by enzyme and PUFA secretion rather than by antifreeze protein secretion.
Department of Biological Sciences, Birla Institute of Technology and Science, Pilani-K.K. Birla Goa Campus, Zuarinagar, Goa, India. purnimabitsgoa@gmail.com
Purnima
P
Singh
Masaharu
M
Tsuji
Shiv Mohan
SM
Singh
Utpal
U
Roy
Tamotsu
T
Hoshino
D000064:Acclimatization; D001110:Arctic Regions; D003080:Cold Temperature; D004271:DNA, Fungal / Q000032:analysis / Q000235:genetics; D005227:Fatty Acids / Q000378:metabolism; D046448:Ice Cover / Q000382:microbiology*; D007218:Industrial Microbiology; D008049:Lipase / Q000378:metabolism; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D015003:Yeasts / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology*
D004271:DNA, Fungal; D005227:Fatty Acids; D008049:Lipase