Studies On Production Conditions And Application Of Tannase From Aspergillus Oryzae

Tannase can cleave the ester bonds and depside bonds of tannin acid , producing gallic acid and glucose, and the ester linkages of the compound in cold tea. Tannase is widely used in tea beverage, beer process, feedstuff, cosmetic, leather industry and so on. currently, the cost of producing tannase is very high, due to the low yield of tannase from the current microorganism strains and the non-optimal conditions for producing tannase. To reduce the production cost and make it to be utilized rapidly in industry, it is meaningful to study the techniques on how to induce high yield of tannase from microorganism.The conditions for tannase production from Asperyillus Oryzae was studied It shows that Revulsant 2 can also induce mycelium to produce tannase, besides Revulsant 1 (tannic acid). In this study, we use a new idea which has not been reported in our country to induce Asperyillus oryzae to produce tannase. That is, eugonic mycelium was first gained on nutrition-rich medium. Then eugonic mycelium was induced to produce tannase on inducement medium containing Revulsant 2. The activity of tannase acquired at this condition is 2.5 times higher than that acquired on the nutrition-rich medium containing Revulsant 2. The optimal inducement condition of this method is that inducement culture medium contains 1.5% Revulsant 2, initial pH is 5.0, culture for 72h under 30℃. The activity of tannase acquired at the optimal inducement condition reach up to 167.4 U per millilitre of fermentation liquid, which is 2.5 times higher than that acquired at the condition containing tannic acid as revulsant.Preliminary study was done on the property of the tannase produced from Asperyillus Oryzae. The results show that the optimal reaction temperature is 42℃, the optimal pH is 6.5, and the tannase is stable in the pH range of 3.0-7.5 and under 50℃.Tannase was immobilized by cross-linking method using chitosan as carrier and glutaraldehyde as crosslinker. After measuring, the rate of enzyme activity reclaim is about 73.86%. The optimal reaction temperature of immobilized tannase is 50℃, 8℃higher than that of dissociative tannase. The optimal reaction pH is 6.0, compare to dissociative ones, it inclined-acidity has floated 0.5 units, and improving the thermo-stability and the pH-stability. The affinity to substrate is katabatic. Using gallic acid as substrate, the half-life of immobilized tannase is 22.68h.