Biological Characteristics And Immobilization Of Highly Efficient Degrading Strain2N3of Chlorimuron-ethyl

Chlorimuron-ethyl are widely used in agricultural production by the ultra-efficient, broad-spectrum, low toxicity, and other higher animals safety advantages, but its long residual effect to the environment for human survival and food safety issues create difficulties, this article aims to solve its residue through biological degradation pathway to reduce the potential harm.High efficient degrading bacteria2N3of chlorimuron-ethyl have been screened and did the basic research work in early times. This paper aims to study Biological characteristics and Immobilization of2N3, the data shows that, glucose, which is the optimal carbon source involved in the co-metabolism, is used to promote the degradation of chlorimuron-ethyl in alternate carbon sources, after96h,5ppm Chlorimuron-ethyl is inoculated to the glucose medium, can be degradated completely; sucrose can also be used to maintain basic growth of2N3, but not the best and fastest carbon source of chlorimuron-ethyl degradation. Alternate nitrogen sources, peptone is conducive2N3adapt to adverse environment of chlorimuron-ethyl to make it grow rapidly, but hide degradation of chlorimuron-ethyl by2N3, the presence of other nitrogen sources have no contribution to growth of chlorimuron-ethyl degradation.The tolerance experiment of2N3shows that, within a certain range (5ppm-300ppm), with the increase of chlorimuron-ethyl inversely,2N3optical density values decreases in glucose inorganic salts liquid medium; in another words, concentration of chlorimuron-ethyl impacts the growth of2N3.The2N3s optimal growth of the orthogonal test showed that:in the following environmental conditions:the glucose concentration equals to5%,1%inoculums, sodium chloride0.2%, ventilation (flask volume of culture medium) in a100ml for the most excellent, under the above conditions2N3growth optimum,18h, OD600is up to0.8Reference to immobilization process,we order the concentration of sodium alginate2.5%, calcium chloride solution between1%-4%, with the concentration increases, the degree of immobilization of the ball than the excellent performance; Immobilization initially carried out single factor curing experiments showed that:process refer to the literature so that the calcium chloride concentration of4%sodium alginate solution sector at1.5%-3.5%, compared with the ideal of curing the ball from the shape and hardness; single factor on a trial basis, with the orthogonal design assistant Complete2N3optimal degradation conditions of the five factors and four levels of screening model. With reference to experimental results obtained:the percentage concentration are as follows:2%calcium chloride, sodium alginate1.5%,2N3inoculum12%inorganic salts liquid medium chlorimuron-ethyl concentration of5ppm, the bacterial suspension with chlorinated calcium solution dosing ratio of5:1under the conditions, the inoculated24h, chlorimuron-ethyl theory degradation optimal effect, obtained at the same time curing the degradation of the main factors for the inoculums.Immobilization stability test of2N3showed that the optimal Immobilization conditions: Immobilization bacteria of2N3preserved for76h at temperature (15℃±2℃), sterile, non-evaporative environment, the degradation of chlorimuron-ethyl and fresh Immobilization bacteria ability equal:both adding chlorimuron-ethyl concentration for5ppm inorganic salts liquid medium24hours to complete degradation (100%);2N3Immobilization bacteria0℃±2℃, sterile, non-evaporative environment save168h contrast, the degradation rate of chlorimuron-ethyl with the control (fresh cured bacteria) drawn:the former degradation was only80%of the latter. Storage will reduce the Immobilization bacteria’s activity of2N3. pH of free bacteria and curing bacteria degradation of the performance impact of chlorimuron-ethyl experimental results show that:at the optimum pH (6.5-7.5), both degradation of chlorimuron-ethyl capacity:the degradation rate of free bacteria curing bacteria three times; under extreme pH with pH to reduce both the degradation of chlorimuron-ethyl, the shorter time, excluding the impact of the acidic environment of Immobilization ball the reference chlorimuron:chlorimuron-ethyl hydrolyzed easily under acidic conditions, we can explain the phenomenon. Alkaline environment, free bacteria and Immobilization bacteria in the degradation rate unchanged; observed through appearance:curing bacterial damage rate increase in a more neutral environment.Formed under the optimal conditions for orthogonal design screening curing bacteria and free bacteria in degradation of chlorimuron-ethyl on the performance comparison test that even smaller:the adsorption capacity of sterile solidified ball of chlorimuron-ethyl, ignoring the impact can be drawn:curing bacterial relatively free bacteria show a strong degradation ability, under the same conditions, within24h of curing bacterial inorganic salts liquid medium5ppm chlorimuron-ethyl degradation completely at the same period but free bacteria need96h, showing the efficiency of curing bacterial and security.