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 degree C which was verified experimentally to be 2140+/-93.25Mug/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