Tannase Study Of The Solid Fermentation Of Aspergillus Niger Production

The full name of Tannase is the tannin ester acid radical hydroltyic enzyme(Tannase,the EC 3.1.1.20),by which ester key and shrink phenol carboxylic key of the gallic acid tannin could be hydrolyzed into the gallic acid and the glucose.The Tannase mainly produced by microbiology was used widely,existing in and outside the cell.At present the Penicillium and the Aspergillus niger are studied more than others.An Aspergillus niger strain producing tannase highly was selected by ultraviolet mutafacient method in this paper.Measurement about the activity of tannase in the solid ferment was studied and establilshed.Optimization of fermentation condition and the culture medium was carried on in this Aspergillus niger strain producing tannase highly through solid ferment,by which enzyme activity was increased.Finally immobility of tannase was also studied.Effectively initial sieve method was used in this study as follow.The tiny tetrabromophenol sulfonphthalein(0.004%) was added into the dull culture medium,Asporgillus niger strain was induced by ultraviolet to select one strain highly producing tannase 92U/mL successfully after the initial selection of strains with color-changing loop by growing of Aspergillus niger whose activity of tannase enhanced more than 1 time.This rebuilding measurement of tannase activity was simple,sensitive,direct and good at duplication.This examination of activity of tannase produced through the solid fermentation outside of the cell had the character of high effectivity and accuracy.Examination performed under the 520nm wave length had successfully avoided wave length of absorption peak of the disturbance material to reduce the error.The set of control tube and blank tube could eliminate influence of the gallic acid and the tannic acid in the thick enzyme fluid.The gallic acid propyl ester as the substrate colored obviously,which was requested lowly in the purity of substrate so that the conventional instrument in the laboratory can carry on the examination.Through the study of tannase produced by sieved Aspergillus niger,the result indicated that the most suitable nitrogen source of tannase was NH₄NO₃,and each 5g culture medium matrix contains 1%NH₄O₃;0.1%NaCl;0.1%MgSO₄;8%gall nuts;bran.the initial moisture content 50%,initial PH6.0,300℃in the temperature as the best condition were gained by the optimization of the single factor of ferment condition,and the activity of tannase could be enhanced highly by adding 8%gall nuts into medium.Thus we knew that the best condition of producing tannase by solid fermentation was 9.5%gall nut content;2.3%nitrogen source recruitment;320C in the temperature.The activity of tannase was 219.4U/mL by the confirmation experiment according to the best fermentation condition.The sea alginic acid sodium had been chose as the carrier of the immobility of tannase by the method of linking - embedding - crossing linking.We studied influence of returns-ration of tannase activity by the density of the glutaric dialdehyde,the time,the temperature,density of the sea alginic acid sodium,the cacl density and the firm time before the crosses linking and density of the glutaric dialdehyde,time and temperature after the crosses linking.Finally we studied partly the nature of tannase immobilized.