Preparation And Characteristics Of Microcapsule Immobilizing Atrazine Degrading Enzyme

In the global scope, atrazine has become an important agricultural pollutant which haveseriously break the ecological balance, especially in black soil region of Northeast China. That’s notonly because the harm caused by atrazine on black soil environment,but also for the extremely coldarea of northeast which limit the microbial degradation. This paper based on immobilized atrazinedegrading enzyme materials, using the microcapsule preparation process, investigating thecharacteristics of microcapsule immobilizing atrazine degrading enzymes, such as the structure ofmicrocapsules, the physical properties of microcapsules, degradation rate of microcapsuleimmobilizing atrazine degrading enzyme, safety performance and so on, to provide scientific basisfor a reasonable and efficient method of degrading of pollutants, which not bring secondaryenvironmental pollution. The main conclusions are as following:Using microscopy, scanning electron microscopy, atomic force microscopy and specificsurface area analyzer instrument micro capsule to observe the microcapsules with differentmaterials. Observation results show that: the addition of divalent cobalt metal ions can significantlyimprove the mechanical strength of microcapsules; and the addition of sodiumcarboxymethylcellulose improves the uniformity of alginate-chitosan material, at the same timethe inner have a phenomenon of porous film phenomenon, through the BET analysis，the pore sizedistribution of the microcapsule can entrap the size of atrazine degrading enzyme at70KD.We also from the extreme temperature at4degree centigrade,reuse times, repeated use ofstorage stability, with the goal of atrazine degradation rate to study the characteristics ofmicrocapsule immobilizing atrazine degrading enzyme. The results show that, the optimized threekinds of microcapsule immobilizing atrazine degrading enzymes under the orthogonal test in28dremained the ability of degradation rate at45%which was greatly improved compared with freeenzyme of10%, at the same time the repeated use times was improved with five,and also maintainthe atrazine degradation rate of45%and have a storage time of28d.We studied the dynamic changes of microbial biomass carbon, nitrogen and phosphorus in thecondition of atrazine-contaminated soil with microcapsule immobilized enzyme using thechloroform fumigation extraction method. The results showed that, comparing with the controlgroup, in the whole experiment process of the addition of microcapsule immobilizing atrazine degrading enzyme can reduce the effect of atrazine treatment on microbial activity in black soil,which indicates that immobilized enzyme has ability of degrading of atrazine.Analysis of soil of atrazine degradation rate and the dynamic changes of soil bacterial diversityThe results showed that at28d the immobilized enzyme degradation of atrazine rate was higherthan70%, while under the free enzyme and the blank control treatment was kept at30%and15%,respectively.The immobilized enzyme can achieve the objective of degradation of atrazinewith stable and efficient.We also analysis the DGGE map and similarity, in the repair process, thedominant species of free enzyme, immobilized enzyme and blank control soil almost showed nochange,each samples have no difference in bacterial diversity. Combinate with the high atrazineremoval concentration of atrazine-contaminated soil, we know that this method with immobilizedenzyme can realize high ecological safety.In short, microcapsule immobilizing atrazine degrading enzyme was prepared in this study, theproperties of microcapsule was greatly improved by adding sodium carboxymethylcellulose anddivalent cobalt metal,make the immobilization of atrazine degradation enzyme into reality. Themicrocapsule immobilizing atrazine degrading enzyme also solve the problem of atrazinedegradation in cold are at4degree centigrade,without disturbing the soil microbial community. Sothat the the microcapsule immobilized atrazine degrading enzyme can degrade atrazine,with thecharacteristics of better repeatability, storage stability and ecological safety than the free enzyme.