Enhanced production of Lovastatin by filamentous fungi through solid state fermentation

Abstract

Lovastatin is a natural competitive inhibitor of 3-hydroxy-3-methyl glutaryl coenzyme-A (HMG-CoA) reductase and inhibits specifically rate limiting step in cholesterol biosynthesis. Further, lovastatin in comparison with synthetic drugs has no well-reported side effects. Four pure isolated filamentous fungal strains including Aspergillus niger IBL, Aspergillus terreus FFCBP-1053, Aspergillus flavus PML and Aspergillus nidulans FFCBP-014 have been cultured by solid state fermentation (SSF) using rice straw as substrate for the synthesis of lovastatin. After selecting Aspergillus terreus FFCBP-1053 as the best producer of lovastatin, various selected physical parameters including pH, temperature, inoculums size and moisture content were optimized through response surface methodology (RSM) under center composite design (CCD) for lovastatin hyper production. Maximum lovastatin production of 2070±91.5 was predicted by the quadratic model in the medium having moisture content 70% and pH 4.5 at 35°C which was verified experimentally to be 2140±93.25µg/g DW of FM (microgram/gram dry weight of fermentation medium), significantly (P<0.05) high as compared to un-optimized conditions while it was noted that lovastatin production is independent on inoculum size (P>0.05) measured by spectrophotometer at 245 nm against standard. It was determined that optimized conditions for the hyper-production of lovastatin from fungal sources have a significant effect.