Rapid screening of statin- producing filamentous fungi.

CABRAL M E; FIGUEROA L I C; SIÑERIZ F; FARIÑA J I

Denver, USA

Congreso; Annual Meeting and Exhibition 2007 of the Society for Industrial Microbiology (SIM); 2007

Society for Industrial Microbiology

Hypercholesterolemia is an important risk factor in coronary artery disease, the main cause of morbidity, especially in developed counties. Statins, a class of fungal secondary metabolites, can inhibit the de novo synthesis of endogenous cholesterol. The hypocholesterolemic activity of lovastatin and its analogs is based on the competitive inhibition of HMG-CoA reductase, which catalyzes the rate limiting step of cholesterol biosynthesis. This study was aimed at the methods optimization for the detection of statins production in solid and liquid cultures of filamentous fungi. Two hundred thirty filamentous fungi isolated from Las Yungas (Tucumán, Argentina) were screened. All isolates were cultivated for 14 days at 20°C on lactose-yeast extract agar medium. Statins extraction from cultures was performed using ethyl acetate by two different methods: glass beads disruption or freeze-thawing. The organic phase was recovered by centrifugation. Presence of lovastatin or analogs in the obtained extracts was simultaneously evaluated by thin layer chormatography (TLC) and a bioassay with Candida albicans and Sacharomyces cerevisiae. Stock solutions of statins (lovastatin, mevastatin, pravastatin, rosuvastatin and atorvastatin) were prepared using pharmaceutical tablets, which were treated as the cultures for statins extraction. For the bioassay, growth inhibitory effect of statins on Candida albicans and S. cerevisiae was tested on solid medium. Statin-containing extracts from fungal cultures could be obtained from both glass-bead and freeze-thaw methodologies. These extracts were useful for subsequent screening steps, either for TLC detection or the yeast bioassays. The optimization of the proposed methods allowed detecting potential statin-producers with high sensitivity and results were readily available. Protocols would be particularly useful at the time of selecting statin-producers and also, for the online monitoring of statin production during liquid cultures.