Search

The Hindu Kush, Karakoram, and Himalaya (HKKH) range is called the third pole of the world due to heavy ice storage. Passu Glacier is one of the HKKH range glaciers in Pakistan. In the present study, Passu glacier is explored geochemically, recovered psychrophilic fungi, and screened for their biotechnological applications. Geochemistry of the glacial samples revealed a high amount of dissolved free amino acids (tyrosine and adenosine), major ions (acetate, Ca2+ and Mg2+), and heavy metals (Fe, Cr and Zn). A total of 27 isolated fungi belonged to 13 genera including Antrodia, Beauveria, Cladosporium, DothideomycetesFontanospora, Mrakia, Penicillium, Phoma, Pleosporales, Pseudeurotium, Pseudogymnoascus, Sporobolomyces and Trichoderma with the abundance of Penicillium followed by Mrakia. The majority of isolated fungi grew well at a wide range of temperature (4–37°C), while some grew at 45°C as well, pH 1–13 and in the presence of 2–26% of NaCl. Many isolates inhibited the growth of tested bacteria and fungi. The activity of Fontanospora sp. LP5 was quite promising. The study isolates also produced commercially important extracellular enzymes. The strain Sporobolomyces ruberrimus LP6 produced 6 different types of enzymes such as amylase, cellulase, deoxyribonuclease, lipase, phosphatase and protease. This study reports first-ever geochemical analysis and fungal diversity possessing the potential of producing a wide range of antimicrobial metabolites and extracellular enzymes from Passu glacier. [ABSTRACT FROM AUTHOR]

Psychrophilic fungi are a critical biotic component in cold deserts that serves a central role in nutrient recycling and biogeochemical cycles. Despite their ecological significance, culture-independent studies on psychrophilic mycobiome are limited. In the present study, the fungal diversity patterns across the Drass, an Indian cold desert in the Himalaya, were indexed by targeted amplicon pyrosequencing (ITS). In the Drass dataset, Ascomycota was represented by 92 genera, while 22 genera represented Basidiomycota. The most abundant genus was Conocybe (20.46%). Most of the identified genera were reported in the literature to be prolific extracellular hydrolytic enzyme producers. To identify whether the Drass fungal assemblages share similarities to other cold deserts, these were further compared to Antarctic and Arctic cold deserts. Comparative analysis across the three cold deserts indicated the dominance of Dikarya (Ascomycota and Basidiomycota). The observed alpha diversity, Shannon index as well as Pielou's evenness was highest in the Antarctic followed by Drass and Arctic datasets. The genera Malassezia, Preussia, Pseudogymnoascus, Cadophora, Geopora, Monodictys, Tetracladium, Titaea, Mortierella, and Cladosporium were common to all the cold deserts. Furthermore, Conocybe was represented predominantly in Drass. Interestingly, the genus Conocybe has not been previously reported from any other studies on Antarctic or Arctic biomes. To the best of our knowledge, this is the first fungal metagenome study in Drass soil. Our analysis shows that despite the similarities of low temperature among the cold deserts, a significant differential abundance of fungal communities prevails in the global cold deserts. [ABSTRACT FROM AUTHOR]

A psychrotolerant yeast strain Mrakia robertii A2‐3 isolated from cryoconites of Hamtah glacier, Himalaya, India was investigated for the production of cold‐tolerant endoglucanase. Optimum endoglucanase production was found at 15°C with an initial pH of 5.5, and potent inducers were 1% wt/vol of xylose and KNO3 and 0.1% wt/vol of NaCl. Under optimum conditions, the enzyme production was 1.81‐fold higher than the unoptimized conditions. Crude enzyme was partially purified by ammonium sulfate precipitation followed by dialysis. The enzyme was purified to 2.53‐fold and the yield was 6.03% with specific activity of 17.38 U/mg and molecular weight ~57 kDa. The Km and Vmax values of the partially purified enzyme were found to be 1.57 mg/ml and 142.85 U/mg, respectively. The characterization study revealed that the best temperature was 15°C for activity and stability. Furthermore, the enzyme showed the highest activity at pH 11.0 and was stable at pH 6.0. Fe2+, Mn2+, Na2+, Cu2+, Co2+, Ca2+ proved to be activators of endoglucanase. Ethylenediamine tetraacetic acid showed very low effect on the enzyme activity whereas it was active with Tween‐80 and sodium deoxycholate. The present study successfully produced a cold‐active endoglucanase with novel properties making it promising as a biocatalyst for industrial processes. [ABSTRACT FROM AUTHOR]

Abstract: Microbial cold-active α-amylases offer various economical and ecological benefits through energy savings by overcoming the heating requirements and also provide large biotechnological potentials. The objective of present study was to isolate new cold-adapted bacterial strains for production of cold-active α-amylases and their production optimization. Out of 30 cold-active α-amylase producing bacteria, isolated from soil of Gangotri glacier, Western Himalaya, India, two potential isolates, designated as GA2 and GA6, were selected for enzyme production. The α-amylase production was found maximum at 20°C and pH 9 after 120h incubation for GA2; and 20°C and pH 10 after 96h incubation for GA6. Among the carbon sources, lactose and glycerol was most suitable for GA2 and GA6, respectively. However, yeast extract and ammonium acetate was found best as nitrogen source by GA2 and GA6, respectively. Out of two potential isolates, maximum enzyme production (5870units) was achieved with GA2 followed by GA6 (4746units). GA2 was resistant to penicillin (10μg) among tested antibiotics and as per plasmid curing results, amylase production was a plasmid mediated characteristic. The phylogenetic analysis revealed that GA2 and GA6 have highest homology with Microbacterium foliorum (99%) and Bacillus cereus (98%), respectively. This was the first report on cold-active α-amylase production by M. foliorum strain GA2 and B. cereus strain GA6, also their 16S rRNA sequences assigned an accession number HQ832574 and HQ832575, respectively from NCBI. [Copyright &y& Elsevier]

Abstract: A psychrophilic bacterium producing cold-active lipase upon growth at low temperature was isolated from the soil samples of Gangotri glacier and identified as Microbacterium luteolum. The bacterial strain produced maximum lipase at 15°C, at a pH of 8.0. Beef extract served as the best organic nitrogen source and ammonium nitrate as inorganic for maximum lipase production. Castor oil served as an inducer and glucose served as an additional carbon source for production of cold-active lipase. Ferric chloride as additional mineral salt in the medium, highly influenced the lipase production with an activity of 8.01Uml−1. The cold-active lipase was purified to 35.64-fold by DEAE-cellulose column chromatography. It showed maximum activity at 5°C and thermostability up to 35°C. The purified lipase was stable between pH 5 and 9 and the optimal pH for enzymatic hydrolysis was 8.0. Lipase activity was stimulated in presence of all the solvents (5%) tested except with acetonitrile. Lipase activity was inhibited in presence of Mn2+, Cu2+, and Hg2+; whereas Fe+, Na+ did not have any inhibitory effect on the enzyme activity. The purified lipase was stable in the presence of SDS; however, EDTA and dithiothreitol inhibited enzyme activity. Presence of Ca2+ along with inhibitors stabilized lipase activity. The cold active lipase thus exhibiting activity and stability at a low temperature and alkaline pH appears to be practically useful in industrial applications especially in detergent formulations. [Copyright &y& Elsevier]