Lovastatin production from Agrowastes using Aspergillus terreus by Solid state fermentation

摘要

Lovastatin (C24H36O5) is a blood cholesterol lowering drug. It acts by competitively inhibiting the enzyme HMG-CoA which catalyzes the rate limiting step of cholesterol biosynthesis in eukaryotic cells. The major drawback in the submerged fermentation is that its yield is proportional to the biomass, with the high cell density causing the increase of the fermentation broth viscosity and the complexity in stirring and oxygen mass transfer. An alternative strategy for submerged fermentation is the SSF (solid state fermentation) process, which offers a good environment for fungi to grow, therefore high mycelia density and high lovastatin production can be expected. Ability of two strains of Aspergillus terreus (isolate 18 and 76) for production of lovastatin in solid state fermentation (SSF) using wheat bran has been investigated using one-factor approach. pH 6, 30°C incubation temperature, 1g wheat bran, 70% initial moisture content, and 5 days fermentation time, without addition of any other nutrient sources yielded maximum production of lovastatin of 2.58 mg/g dry substrate and 2.5mg/g dry substrate for A. terreus 18 and 76, respectively, using wheat bran as substrate. All the 14 different agrowastes for lovastatin production by the two isolates showed that all the substrates supported significantly varied levels of lovastatin production by the two isolates (P<0.05). Wheat husk supported lovastatin production of 2.91 mg/g and 3.33 mg/g dry substrate by isolate 18 and 7, respectively, without any addition of nutrient supplements.