Phialophora Melinii (NFCCI 3617): A Newly Isolated Psychrotolerant Fungus That Produces Enhanced Laccase Under the Influence of Organic Solvents

A psychrotolerant fungus, isolated from decomposing pine needle debris, is investigated for laccase production under the influence of 5 organic solvents. The fungus was identified as Phialophora melinii and was able to grow between 4 to 35 °C (opt. 25 °C) and 2-14 pH (opt. 5-7). In quantitative estimations that were carried out at optimum growth temperature and pH, the fungal laccase was estimated to be 21.0 ± 4.0 U/L. Native PAGE study revealed 35 kDa molecular mass of the fungal laccase. Supplementation of organic solvents namely, methanol, ethanol, acetone, n-propanol and iso-propanol in varying concentrations (0.5%-2.0%, separately), significantly affected the production of fungal laccase. Out of 5 solvents used, n-propanol was found to be the most efficient enhancer of laccase production. n-Propanol (0.5%) resulted in maximum enhancement (7 folds) in laccase production at 18th day of incubation. Methanol, iso-propanol and ethanol were able to enhance laccase production up to 5-6 folds in comparison to control with respect to the varying concentration and incubation length. Age of the fungal culture (incubation days) was observed as an important factor for laccase production. Use of low molecular compounds in enhancing the fungal laccase production may be considered as an eco-friendly approach

Microbial Ecology from the Himalayan Cryosphere Perspective

Cold-adapted microorganisms represent a large fraction of biomass on Earth because of the dominance of low-temperature environments. Extreme cold environments are mainly dependent on microbial activities because this climate restricts higher plants and animals. Himalaya is one of the most important cold environments on Earth as it shares climatic similarities with the polar regions. It includes a wide range of ecosystems, from temperate to extreme cold, distributed along the higher altitudes. These regions are characterized as stressful environments because of the heavy exposure to harmful rays, scarcity of nutrition, and freezing conditions. The microorganisms that colonize these regions are recognized as cold-tolerant (psychrotolerants) or/and cold-loving (psychrophiles) microorganisms. These microorganisms possess several structural and functional adaptations in order to perform normal life processes under the stressful low-temperature environments. Their biological activities maintain the nutrient flux in the environment and contribute to the global biogeochemical cycles. Limited culture-dependent and culture-independent studies have revealed their diversity in community structure and functional potential. Apart from the ecological importance, these microorganisms have been recognized as source of cold-active enzymes and novel bioactive compounds of industrial and biotechnological importance. Being an important part of the cryosphere, Himalaya needs to be explored at different dimensions related to the life of the inhabiting extremophiles. The present review discusses the distinct facts associated with microbial ecology from the Himalayan cryosphere perspective

Simultaneous production of ligninolytic enzymes by a temperature and pH tolerant strain of <i style="mso-bidi-font-style:normal">Aspergillus niger</i> under different cultural conditions

81-86Ligninolytic activity, represented by laccase, lignin peroxidase (LiP) and manganese peroxidase (MnP), of a temperature and pH tolerant strain of Aspergillus niger isolated from a temperate location in the Indian Himalayan Region (IHR), has been studied under different cultural (physico-chemical & nutritional) conditions. In plate assays, the fungus exhibited ligninolytic activity at wide range of temperature (5-45°C) and pH (3.5-9.5). In quantitative estimations, carried out at 15, 25 and 35°C, production of laccase was favoured by low temperature (15°), while production of LiP and MnP were favoured by higher temperatures (25 & 35°C). At optimum growth temperature (25°C), laccase production was the maximum at 7.5 pH. LiP and MnP production was favoured between 7.5 to 9.5, and 5.5 to 9.5 pH, respectively. Amongst nutritional sources, nitrogen sources were recorded as better enhancers for enzyme production, followed by vitamins and carbon sources. Folic acid (0.01%) was also found to be a good enhancer for production of all the three enzymes