Journal of Microbial & Biochemical Technology

Abstract

Screening and Molecular Characterization of Natural Fungal Isolates Producing Lovastatin

Upendra RS, Pratima Khandelwal, Z R Amiri, L Shwetha and Mohammed Ausim S

Aspergillus sp. is known to produce cholesterol reducing drug lovastatin. Limited investigations have been made on screening of high yielding strains from hitherto under-utilized natural sources. With this objective, in the present study, various fungal cultures (130 in number) were isolated from natural sources such as (soil from paddy fields, oyster mushroom beds from the fields and compost) from different regions of interiors of Karnataka and Tamil Nadu of India. All the isolates were identified through standard microbiological methods such as morphological, microscopic methods. These isolates were further cultured for the production of lovastatin through submerged fermentation process (SmF). The extract from each of the isolate was subjected to three replicates of UV spectrophotometry quantification (200-350 nm). Confirmation of the metabolite production was achieved through HPLC and Attenuated total reflectance (ATR-FTIR) chromatography using the drug lovastatin (Biocon Laboratories) as standard. Out of all, nine high lovastatin yielding fungal strains were selected by applying selection pressures. Submerged state fermentation (SmF) extract (lovastatin) of these strains also exhibited the maximum zone of inhibition (≥ 10 mm) against Neurospora crassa (MTCC-790) in bioassay. Fungal strains giving maximum yield of lovastatin were found to be Aspergillus terreus (SSM4) from oyster mushroom bed source that produced a maximum yield of lovastatin (996.6 mg/l) followed by Aspergillus terreus (SSM3) from compost source (900 mg/l), Aspergillus flavus (SSM8) from compost source (643 mg/l). High yielding Aspergillus terreus (SSM4) isolate was characterized by β2 tubulin gene sequencing, confirmed through phylogenetic and molecular evolutionary analyses using MEGA version 5 software. The present study isolated three high lovastatin yielding fungal isolates from natural samples and one of the highest yielding isolate was sequenced and deposited in the MTCC (IMTECH) Chandigarh with issued accession number Aspergillus terreus nhceup 11045.