| The immobilizations of papain using covalent and chemical crosslinking method on the nano-modified ceramic particles have been studied. Ceramic particles are activated by hydrochloric acid,KH-570 and glutaraldehyde before being used as the carrier of the immobilized enzyme.The effects of the surface modification on immobilized enzymes activities are discussed. The optimum conditions were as follows: concentration of hydrochloric acid was 0.20 mol.L-1 ,KH-570 was 0.392%,activating with 0.25% glutaraldehyde. In this condition ,the recovery ratio of activity of immobilized enzyme was 7.16%,the relative activity was 9.90%.The effects of the immobilized conditions on immobilized enzymes activities are discussed, such as time,temperature and pH of the immobilized reaction and amount of papain were studied. The optimum conditions for immobilization were as follows: the ratio of enzyme and carrier was 5ml/g, immobilizing for 12h,at 30℃and pH7.2. In this condition ,the recovery ratio of activity of immobilized enzyme was 7.45%,the relative activity was 11.42%.The characters of these immobilized papain were also studied and compared with native papain, such as the optimum pH, the optimum temperature,the stabilities of the immobilized enzyme of the thermostability ,the stored stabilityand the operational stability.When the low concentrate wastewater is diposed,in conditions of definite hydraulic loading the HRT 6 h,the process of biofilm colonization in AF can be completed in 7days by using immobilized papain and the special anaerobes, the COD removal efficencies are 71.6%,but 10days by using common sludge and ceramic particles , the COD removal efficencies are 50.7%.9days by using immobilized papain and common sludge, the COD removal efficencies are 56.6%.Kinetics experiments reveal that the degeration rate of COD in AF is first-grade reaction to its concentration .when the COD of wastewater is 412mg/L using immobilized papain and the special anaerobes. the experiential equation is... |
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