Study On Highly Synthetic 1,3 - Glyceride Diester From Aspergillus Niger GZUF36

The purpose of this subject is to deeply study the disintegration of glycerol to generate 1, 3-DAG. Aspergillus niger GZUF36 fermentation conditions for enzyme production was optimized, the best cultivate conditions: Cultivate time was 72 h, inoculated quantity was 3%, 40 mL liquid in the 250 mL triangle bottled, temperature was 28 ℃, the speed was 180 r/min. In the best condition, the receiving rate of 1, 3- DAG was 23.865%, the selectivity rate of 1, 3- DAG was 82.955%.In order to better adapt to the industrialized production, 5L fermentation tank was selected for fermentation in the laboratory, discovered that when the fermentation tank culture was 96 h, the yield and selectivity of 1, 3- DAG was maximum, respectively 25.300% and 82.018%.Then studied the water activity of glycerin and triglyceride catalytic glycerin solution response law of the preparation of 1, 3- DAG, discovered that at aw = 0.528, the yield of 1, 3-DAG and selectivity of 1, 3- DAG were 25.822% and 84.037% respectively. Next, study reaction system water activity control methods of 1, 3- DAG yield and selectivity of 1, 3- DAG, found that added salt hydrate of aw = 0.58 separately into the whole-cell lipase enzyme powder and the reaction system respectively, to balance the effect of 3 days, 1, 3- DAG yield and selectivity of 1, 3- DAG were 26.100% and 83.056% respectively. Then whole-cell lipase powder was balanced by aw = 0.528 saturated salt, the reaction system was pre-equilibrated by aw = 0.58 salt hydrate,the catalytic performance of an enzyme can be further improved.To eliminate the adverse health effects caused by substrate viscosity, first of all, different adsorption material, molecular sieve, the activated charcoal, bamboo charcoal fiber, sponge and macroporous adsorption resin(AB- 8, D101, HPD750, NKA- 9 and NKA- II) was chose, the yield of 1, 3- DAG, and the influence of the selectivity of 1, 3- DAG, and examined the best adsorption affects the quality of material. Found that the molecular sieve on the substrate to eliminate the effect of viscosity was best, and when its volume was 0.3 g, the highest yield and selectivity of 1, 3- DAG was 30.070% and 83.617% respectively. And then studied the AB- 8, D101, HPD750, NKA- 9 and NKA II five kinds of macroporous adsorption resin for 1, 3- DAG yield and selectivity of 1, 3- DAG regularity. The result was that AB 8 macroporous adsorption resin on the reduction of substrate viscous effect was best, and when its volume was 0.3 g, the yield and selectivity of 1, 3- DAG was the highest, at 30.097% and 83.902% respectively. In order to better reduce the viscosity and the side effects of the reaction substrates, selected the time gradient increase substrate method to eliminate the substrate adhesive.Results showed that three times add substrate was the best result, 1, 3- DAG yield and selectivity were 27.529% and 85.004% respectively.In order to better adapted to the industrialized production, polyurethane foam particles was used as immobilized carrier, the Aspergillus Niger GAUF36 was immobilized and enzyme fermentation produced in the same time. First we studied the immobilization methods, found by seed cultivation, seed liquid added to the fermentation medium containing polyurethane particles in the way best result, the 1, 3- DAG yield and selectivity were 26.023% and 83.940% respectively.Then the immobilized carrier polyurethane foam particle size was studied, and found that when the polyurethane foam particles size of 5 mm x 5 mm x 5 mm, 1, 3- DAG yield and selectivity was the highest, at 27.303% and 83.638% respectively. In order to increase the stability of immobilized cells, found after glutaraldehyde pretreatment of immobilized cells into the reaction system, the r 1, 3- DAG in the highest yield and selectivity of 1, 3- DAG, were 28.407% and 84.354%, respectively. Finally, the whole-cell lipase immobilized cells and free reuse was investigated, the results show that the immobilized cells of repeated utilization ratio was higher than that of free whole-cell lipase, immobilized cells so more can adapt to the industrialized production.