Study On Fermentation Technology Of Lipase With Penicillium Camembert Ii Thom PG-3

The production of Penicillium camembert ii Thom PG-3lipase, which is known for the1,3-regioselectivity on the hydrolysis of triglyciates, were studied, and the techniques for the lipase production were improved. The fermentation medium constitution in which jojoba (one species of natural oil) served as carbon source was optimized using Response Surface Methodology (RSM). However, it was found that the culture were not suitable for large-scale production because of the expensive jojoba. Further research indicated that the lipase production could be considerably satisfying without the involvement of carbon source. Considering both cost and efficiency of the ferment process, the medium composition was optimized without manually introduced carbon source, and the optimum culture conditions were confirmed as (g/L):defatted soybean meal40,(NH4)2HPO41, K2HPO45, tween-601, cultured at28℃,220rpm;230IU/mL enzyme activity was gained in flasks without pH adjustment, and higher enzyme activity (380IU/mL) was observed when1g defatted soybean meal was fed at48h and72h respectively. Scale-up fermentation was carried out in a5L fermentor, and high concentration of the soybean meal was fed at constant rate of120g/L in48-115h. Final enzyme activity reached392IU/mL using this strategy. The culture in the fermentor was conducted under following conditions (g/L):defatted soybean meal40,(NH4)2HPO41, K2HPO45, tween-601, antifoam1, gentamicin sulphate40000u/L, ambient pH.Separation of Penicillium camembert ii Thom PG-3lipase was attempted using precipitation by organic solvents. Herein3equivalents acetone of the broth volume was most favorable for precipitation with crude yield of74.8%and enzyme activity8681IU/mL. Initial studies in the enzyme properties showed that optimum conditions for enzymatic transformation were43℃at pH7.0; the lipase remained stable within pH range from neutral to basic.