Magnetic Nanomaterials-Based Immobilized Enzyme Of Microcystinase And Property Detection

With the development of industrialization, in recent years, the blue-green algae cells release algal toxin when they are aging, death and rupture. Algal toxin is a kind of liver toxin which is a serious threat to the environment and human healthy, and it can cause cancer. So it is important for us to find a way to degrade algal toxin effectively. One of the most toxic algal toxin is microcystin(MCs).In the laboratory, we succeed in extracting an enzyme called microcystin degrading enzyme(mlrA), which can degrade microcystin. However, the degradation efficiency is not high enough, and storage time is also short. In this paper, we summarize the method of enzyme immobilized, carrier and new technology of enzyme fixed. We attempt to immobilize this kind of enzyme to the nano-materials to overcome these problems. The details are summarized as follows:1) We construct a kind of composite which combine the graphene oxide with magnetic nanoparticles. Then we use the composite to immobilize the microcystin degrading enzyme, which overcome these disadvantages of the free enzyme such as instability, inactivation easily and storage difficultly.In this immobilized system, the graphene oxide have a large specific surface area, which can adsorb the free enzyme as much as possible. Once the paramagnetic materials loaded, the composite material can be separated well from the mixed system. So it is possible to reuse. Experimental results show that the amount of enzyme immobilized on this material reach to nearly 90%. Compared with the free mlrA, the immobilized enzyme is more stable, adaptable. The immobilized enzyme can be recycled and has a long storage time.2) A composite that combined gold nanoparticle with iron oxide microspheres is used for enzyme immobilization and testing. The gold nanoparticles which are synthesized by reducing the tetrachloroauric acid with sodium citrate. This kind of gold nanoparticles are negatively charged, they can adsorb the enzyme by electrostatic adsorption and the effect of coordinate bond. The enzyme can be firmly and easily combined with the composite material.In the process of detecting the immobilized enzyme, we found that the activity of the enzyme in this system is relatively stable at different pH and temperature compared with the free enzyme. After combined with the magnetic material, the immobilized enzymes are not only reproducible but also repeatable.