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Dehalogenation enzyme is capable of catalyzing a halogen ion of the enzyme released from the halogenated organic compounds . Through ortho halohydrin catalysis , can make the removal of halogen ions ortho halohydrin to form the corresponding epoxy compound . Dehalogenase epoxy compound has been widely used in medicine and other fields , have recently received wide attention . In this experiment, chloroacetic acid as the sole carbon source , 73 strains were screened from soil samples collected across the country . Qualitative detection, using the precipitation reaction of silver nitrate and of 52 strains having different conversion ability , using HPLC and chiral HPLC , the conversion rate of the test strains and enantioselectivity , and further screening , the final choice of strain No. 17 after the study . The fermentation medium of strain 17 carbon source , a nitrogen source , an inducer , an inorganic metal ion , the initial pH value , incubation temperature, incubation time , etc. have been studied . The results showed that the optimum medium composition per liter containing the lactose 8g, the trypsin 6g , chloroacetic 4g Na2HPO43.2g KH2PO41.5g MgSO498mg , CaCl210mg , FeSO41mg , ZnSO40.1mg , incubated at pH 6.5,30 ° C for 35h , 17 No. strains enzyme activity reached the highest value 132.80U/mg . Transformation of strain 17 β-bromo nitrophenethyl alcohol conversion conditions of the substrate concentration , the medium , temperature , time , etc. . The results show that the substrate concentration of 1g / L, a temperature of 35 ℃ conversion substrate 12h , the maximum conversion rate of the substrate can be achieved 90.6% . Existing strains can be β-bromo nitrobenzene ethanol converted to the corresponding epoxy compound , can attempt to extract the reaction of the enzyme with high selectivity but low enantioselectivity .
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