| At present, the air purifying filter is the most economical, effective and the safest defend equipment for purifying air,and its performance primarily rests with filtration material which determines the biosafety of air purifying directly.Even if filtration material of the high efficiency air filter may ensure to remove 100% of various dusts and bio-particles,but because the conventional filtration material have no capability of sterilization and self-purified,so filtration material of the conventional air filter will become a hotbed on which various fungi,bacteria,mildew,virus and other micro- organism propagate flourishingly, as a result,which will result in serious secondary contamination.The main objective of this study was to set a stable organic net with no effect on original physical performance of the air filtration material under enzyme immobilized conditions to obtain the air filtration material which is capable of directly killing or otherwise control of air-borne microorganisms.Here,the hen egg white lysozyme and marine low temperature lysozyme were respectively immobilized by covalent binding and by the self-assembly technique on the surface of the air filtration material comprising chemically functionalized glass fiber. The influence of important parameters in immobilization process,namely immobilization time,temperature,buffer system pH,enzyme concentration on immobilized lysozyme activity are investigated.And at the same time,wind resistance of filtrate material and its efficiency in removing dust and microorganism were tested.Lastly, antimicrobial efficiency of immobilized enzyme filtration material was estimated by qualitative and quantitative analysis. Experimental results was showed below:1.In immobilization process, the pretreatment steps were more serious influence factors for ensuring original physical performance of glass fibre filtrtion material, a longer time than 6h immersion in toluene solution of silane coupling agent will lead to a certain extent rupture of glass fibre. To rinse silanized filter material using toluene thoroughly was also a key step for ensuring original physical performance of glass fibre filtration material. The optimum immobilized conditions were: silanization time 6h, glutaraldehyde activation time 6h,lysozyme coupling time 9h,enzyme concentration0.05g/ml, lysozyme coupling tempreture 4-10*C, buffer system pH7.2.Under optimum immobilization conditions, the retention of the specific activity of the immobilized lysozyme was as high as 48% of the free lysozyme.3.Under dry conditions,immobilized lysozyme could be deposited for longer time. At 4*C and 25 "C,the immobilized lysozyme activity retained more than 80% in 10 months,and immobilizedl lysozyme showed consistent thermic stability,.But in PBS buffer solution.immobilized lysozyme was easy to deactivate.At 4*C,only 30% of immobilized lysozyme activity can be retained in 3 months.And at 25*C,immobilized lysozyme almost deactivated completely in 3 months.4.Under optimum conditions,lysozyme immobilization process nearly had no influence on original filtration efficiency of the filtration material, namely the filtration material with immobilized lysozyme retained consistent filtration efficiency with the filtration material without being immobilized lysozyme.But wind consistence of the filtration material increased, especially to I model filtration material.5.SEM imaging showed that immobilized lysozyme could destroy bacterial cell wall and kill them under the gas condition. The quantitative results showed that antimicrobial efficiency of the immobilized lysozyme by covalent binding is 95.3%,92.2% and 94.1% in 0.3h,2h and 5h respectively.while those results of the self-assembly technique is 96.2%, 83.9% and 70.7% respectively.
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