| An alkaline lipase producing strain N4-2 is isolated from entrails samples of fish collected from a soda lake in Neimenggu, China and identified as Fusarium. By treatment of infertile incubation and directional inducement on the lipase producing strain, the lipase activity increases by 22.7%, from 66.4 U/ml to 81.5U/ml, in 48h shaking flask. The fermentation medium and condition of enzyme production under flask shaking are investigated. Under the obtained optimum condition, the strain gives a maximum alkaline lipase activity of 605.15U/ml in shaking flask after 52h cultivation when growing in a medium containing(g/l) : olive oil 30, yeast extract 5, (NH4)2SO4 3, MgSO4·7H2O 0.75, CaCl2 0.2,K2HPO4 4 (pH 10.0).A novel surfactant-and oxidation- stable and low-temperature alkaline lipase from Fusarium sp.N4-2 is purified using acetone precipitation and Q-Sepharose ion exchange techniques. The enzyme has a relative molecular weight of 36.8kDa by SDS polyacrylamide gel electrophoresis. The optimum temperature and pH are 30℃and 9.0, respectively. The lipase is stable in a pH range of 8.0-11.0 and in a temperature range of 10℃-50℃and keeps 50% enzyme activity even at 0℃.The Michaelis–Menten kinetic parameters of the lipase (Km and Vmax) are 0.03046 (m mol L -1) and 13.245 (μmol L -1min -1), respectively. The enzyme activity can be strongly activated by several commercial laboratory surfactants (Tween-80, Sodium Cholate) and bleaches (H2O2, sodium hypochlorite), and shows a valuable stability towards them in different concentrations, respectively. The lipase is stable towards 3 proteases: Alcalase, Pro-1 and Protamex. Enzyme activity is increased, by 11.6% and 12.0%, with addition of Mn2+ and Ca2+, respectively.The abstraction of chitosan from the outgrowth of the lipase producing fermentation (mycelium) is studied. After extraction under optimum conditions, the recovery of the chitosan reaches to 8.65%.This alkaline lipase can be used in detergent as an enzyme addition. It can improve the...
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