Abstract

SCREENING OF PSYCHROTROPHIC FUNGI FOR BIOACTIVE MOLECULES

Devipriya R. Majumder*, Gauri Yadre and Nilofar Shaikh

Abstract

Organisms adapted to extreme cold environments which have successfully evolved genotypic and/or phenotypic features, to overcome the negative effects of low temperatures are known as psychrophilic organisms which have potential applications in a broad range of industrial, agricultural and medical processes. The ability of psychrophiles to survive and proliferate at low temperatures implies that they have adapted to key barriers like lack of water availability, optimum temperature for growth, appropriate density for mycelial growth, etc. inherent to permanently cold environments. Major part on the earth like polar, Alpine and Antarctica continent consist of cold areas, hence study of psychrophilic/psychrotolerant microorganism becomes important. Modernized lifestyle makes it important to study cold-adapted fungi as they are predominantly present in food at refrigeration temperature. The present study was conducted to determine the ability of psychrotrophic fungi to synthesize enzyme and secondary metabolite which shows antifungal and antibacterial activity. They were isolated from garden soil, contaminated pineapple syrup and preserved petri-plates under refrigeration temperature. Isolates viz: GSND1, GSND2, GSND3 produced pectinase which has greater commercial application, in fruit juice industry, while GSND1 produced cellulase which also has great industrial application, in textile, detergent, biofuel production industries, etc. Therefore, cellulase and pectinase and were partially purified by ammonium sulphate precipitation method, dialysed and SDS- PAGE were performed. The specific activity of pectinase purified extract of three isolates were 0.23U/ml, 1.52U/ml, and 0.36U/ml respectively, while that of cellulase activity GSND1was 4.25U/ml. And the molecular weights of the pectinase and cellulase enzymes were determined as approximately 27kDa,27kDa, 28kDa and 53kDa respectively. The antifungal activity of GSND1 was determined against Candida albicans -hospital isolate while antibacterial activity was determined against Staphylococcus aureus ATCC6358P, Escherichia coli NCIM 2065as per NCCLS/CLSI guidelines. The secondary metabolite showing antibacterial activity was characterized using Thin Layer Chromatography (TLC) method, UV absorption spectrum and its spectroscopic characteristics were investigated using FTIR. This analysis indicates UV absorption spectra at 330nm characterizing aromatic organic group and Infra-red (IR) spectrum showed absorption at 3353.6cm-1 indicates amine groups and absorption at 2111.67 cm-1 and 1634.38 cm-1 indicates alkaline/nitrile and alkene group respectively. The Minimum Inhibition Concentration (MIC) of the metabolite was determined at 8.33×10-4 μg/ml.The excellent enzymatic potential and antibacterial properties of the facultative psychrophilic fungi may find various industrial and pharmaceutical applications, respectively.

Keywords: Psychrotrophic fungi, cellulase, pectinase, secondary metabolite, Staphylococcus aureus ATCC6358P, Escherichia coli NCIM 2065, Candida albicans.