Lovastatin Producing Strain Of Aspergillus Terreus Mutation Screening Methods And Fermentation Conditions

As a main lovastatin-producing fungi, the wild strain of Aspergillus terreus produces lower lovastatin, however, limiting its industrial production greatly. In this paper, an efficient and easy biological screening method based on the sensitivity to lovastatin of Neurospora crassa was built to deal with the mutant strain rudely by UV mutation. A high-level strain was screened in the shaking flask culture incorporating with TLC and HPLC. A comparison between this two methods also was originally discussed while identifying dyeing using bromophenol blue as the better treatment of TLC, and offering a kind of simple, practical, fast and economical determination qualitatively and quantitatively.An primary optimization for medium composition in shake flask showed the best carbon source, nitrogen source and its best ratio. The results demonstrate glycerol as the best carbon source, yeast extracts and soybean meal as the best organic nitrogen source, NH4H2PO4 as the best inorganic nitrogen source. A lower ratio can promote lovastatin production in lower original concentration of carbon source while increasing its ratio in higher level can also result in it. A 448 mg/mL end yields of lovastatin was obtained along with the best C/N ratio in 2.5 and the original carbon source in 50g/L.The effects of culture volume and incubating quantity on mycelium formation and lovastatin production in shaking flask was researched. The experimental data suggested higher spore density would form larger quantity mycelium possessing lower diameters and well-proportioned profiles which could produce high-level lovastatin. A 2+10 7spore/mL suspensions supplied a satisfied result and a 15-20% culture volume in shaking flask of 500mL-scale can also result in a better effect wherein a lower culture volume was suitable. These all testified the importance of aeration to synthesis of end-product.The dynamics of mycelium growth and end-product formation in the lovastatin production by Aspergillus terreus strain was studied in the 2L fermentor based on its batch culture results. At the same time, the batch fermenting dynamics model of lovastatin was also built and the model parameters were subsequently estimated, which indicated to the experimental results better.