Optimization Of The Conditions For Phospholipase A₂ Production With Streptomyces Lividans And Enzymic Hydrolysis Of Oil Residual

Phosphatide is a general term of lipid contained phosphoras group, it has been widely applied in the field of food, medicine, cosmetics, leather ang point. Because the water affinity of the ordinary phosphatide isnt perfect, its application has been restriccited. In order to improve the water affinity of phosphatide it must be modified. The methods of modification include physical modification, chemical modification and enzyme modification. Becouse the former two methods have problems of safety, so they hadn t been gradually adopted any more. Enzyme modification is adopted in this test, it turns groups of fatty acid into lysophospholipids. Whereas, groups come from phosphatide molecule of phospholipase division. Compared with ordinary phosphatide, lysophospholipides had been bettered clearly in the aspects of emulsion.The aim of study is to make phospholipase with PLA₂ prolific vaccines constructed by the teacher Li, and hydrolyzed oil residual by phospholipase. To creat the best conditions of violaceoraber and phosphatide of oil residual, the solid foundation of experiment laboratory for the industrial production of lysophospholipids has been laid already. The specific information and the results are following:1. By the fermeatation of PLA2 prolific vaccine, the phospholipase A₂ will be made,also the forming of cultural medium and fermentation conditions have been bettered. Composition of fermented cultural medium(g/L):soybeen meal 5.0, wheat bran 5.0, NaNO₃ 5.0, CaCO₃ 1.0. The optimal shaking fiask fermentation condition: The initiation pH7.5, cultural temperature 30°C, the rotation speed of shaking the bed is 180r/min, inoculation volume 7%,80mL cultural medium per 250mL taper bottle. After inoculation 48h enzyme vitality has been improved to 0.54IU/mL from 0.43IU/mL, before inoculation increased by 26%. Meantime, the preliminary enlarged experiment has been done in the 10L fermentator. When the optimal quantity of inoculation is 7%, the initiation pH7.5, ventilation 0.5m³/h, 50r/min, 30°C fermentation, 24h PLA2 vitality reach the peak of 0.55IU/mL.2. During the enzyme modification research , the enzyme from the fomentation was used to hydrolyze oil residual. The best hydrolyzed craft condition of oil residual phosphatide: base concentration 20%, reaction temperature 50°C the initiation pH8.0, the concentraction of Ca²⁺ 0.3% .3. Under best condition of hydrolysed lysophospholipids are made, and measure abilities of lysophosphlipids: 251mL oil/g phosphatide, is about five times more than the ordinary phosphatide. For different pH, in different temperature, the emulsion stability of lysophospholids is better than that of the ordinary phosphatide.