Optimization of Low-Temperature Lipase Production Conditions and Study on Enzymatic Properties of Aspergillus Niger

In order to obtain the optimum fermentation medium and conditions for extracellular lipase production by Aspergillus Niger, the fermentation conditions of Aspergillus Niger were optimized by single factor and response surface design, the enzymatic properties of the crude enzyme were also studied. The results showed that the optimum fermentation medium was soluble starch ۴%, (NH۴)۲SO۴ ۰.۱%, K۲HPO۴ ۰.۱%, MgSO۴·۷H۲O ۰.۰۵%, peptone ۳%, olive oil ۱.۰۵%, initial pH ۷. The optimal fermentation conditions were ۳۰℃, the sample size was ۲۶ mL/۲۵۰ mL and the shaking speed was ۲۱۳ r/min. The optimized lipase activity was ۱.۵۵ U/mL, which was ۷.۷۵ times of the pre-optimized lipase. It was found that when the pH value of lipase was ۷.۰, the activity of lipase reached its maximum value of ۷۹.۳±۶.۸۲%. When the pH value was between ۶.۰ and ۸.۰, the activity of lipase could be kept above ۶۰% and the stability was good. At the same time, through the study of the temperature stability of lipase, found that the lipase was stable at ۲۵℃- ۳۵℃, its activity could reach more than ۷۰%. When the enzyme activity reaches the maximum (۱۰۷.۶±۹.۵۷%), the temperature was ۳۰℃.

کلیدواژه ها:

Low-temperature lipase ، Conditions of enzyme production ، Enzymological properties ، Orthogonal experiment ، Response surface analysis