Study On Stabilizatation Of Inulinase Produced By Penicillium Sp.B01

Inulin is a kind of poly-fructose be connected by β-2-1-gycosidec bond. It has a gluctose in its reducing end. Many compositae are rich in inulinase, such as Jerusalem artichoke. The main ingredient of Jerusalem artichoke is inulin. It accounts70%-80%in its dry weight. Because its strong adaptability and high yield, Jerusalem artichoke is usually used to make high fructose syrup and fuel alcohol. Inulinase is a kind of catalyst with high efficiency in the course of enzymatic hydrolysis of inulin. It is mainly extracted from Saccharomyces, Aspergillus niger and Penicillium. As a functional food additives, fructose not only can be a bifidus factor in intestinal flora but also can reduce the content of cholesterol in human’s body. So it is welcomed by the producers and consumers.We used Penicillum sp.BO1as a research material which was selected from863test base in Laizhou, Shandong province. In order to improve the stability of the inulinase, protective test, immobilized enzyme and immobilized cells were studied on the activity of inulinase production. The results were showed as follows:1) Through the single factor test, the results showed that polyethylene glycol, sorbitol, calcium chloride and glycerol were good for the stability of the inulinase. Ethnol and potassium sorbate were bad for the stabilinase of the inulinase. Through the orthogonal test, the optimum combination of the four ingridents were obtained. It was polyethylene glycol2%, glycerol5%, sorbitol1g.L-1, calcium chloride2.4%.2) Embedding method using sodium alginate as a carrier were studied. It showed that the activity of the immobilized inulinase reached its maximum and the mechnical strength was best when the concentrations of sodium alginate and CaCl2were4%and1%respectively. When the enzyme was less dosage, the immbolization efficiency was higher. The optimum pH of the reaction of both free enzyme and immbolized inulinase was4.5. The activity of immbolized inulinase was higher than the free enzyme in the pH range from4to6.5. The optimum temperature of both were55℃. There was little change in the enzyme activity when the temperature ranged from35℃to55℃. The temperature adaptability of the immbolized inulinase was better than that of free enzyme when the temperature ranged from55℃to75℃. The relatively enzyme activity was58.2%after repeating use7times of the immbolized inulinase. The immbolized inulinase was valuable in industrial production because of the low cost and the high utilization.3) Compared the four ways of immobilized cells, we concluded that sodium alginate embedding method was relatively better than the other three methods. When the sodium alginate density was2%, and the mycelia content was10g/100mL, the enzyme recovery could reach47.22%. In the staility of pH, temperature experiment in embedding method, we found that the suitable pH was drifted to acid part compared with the free cells. The suitable denitity of the substrate was4%. In the stability of storage, the immobilized cells still have activity after48h. Penicillium sp B01had s short fermentation time, and easy cultivation. In general, it is a good material to research the immobilization cells.