The investigation of media components for optimal metabolite production of Aspergillus terreus ATCC 20542

Abstract

PurposeThis study aimed to assess the effect of nitrogen, salt and pre-culture conditions on the production of lovastatin in A. terreus ATCC 20542. MethodsDifferent combinations of nitrogen sources, salts and pre-culture combinations were applied in the fermentation media and lovastatin yield was analysed chromatographically. ResultThe exclusion of MnSO4 ·5H2O, CuSO4·5H2O and FeCl3·6H2O were shown to significantly improve lovastatin production (282%), while KH2PO4, MgSO4·7H2O, and NaCl and ZnSO4·7H2O were indispensable for good lovastatin production. Simple nitrogen source (ammonia) was unfavourable for morphology, growth and lovastatin production. In contrast, yeast extract (complex nitrogen source) produced the highest lovastatin yield (25.52 mg/L), while powdered soybean favoured the production of co-metabolites ((+)-geodin and sulochrin). Intermediate lactose: yeast extract (5:4) ratio produced the optimal lovastatin yield (12.33 mg/L) during pre-culture, while high (5:2) or low (5:6) lactose to yeast extract ratio produced significantly lower lovastatin yield (7.98 mg/L and 9.12 mg/L, respectively). High spore concentration, up to 107 spores/L was shown to be beneficial for lovastatin, but not for co-metabolite production, while higher spore age was shown to be beneficial for all of its metabolites. ConclusionThe findings from these investigations could be used for future cultivation of A. terreus in the production of desired metabolites.