| Xanthdte, with its molecular formula ROCSSK, is an organic flotation reagent used frequently in zinc sulfide mineral (ZnS) flotation. This paper first studied domesticating and screening highly-effective-xanthate-degradation strains from flotation wastewater of refined zinc mineral which containing xanthate, the variation strain has been obtained by the technique of UV-induced which has the special degeneration function under high pH to the xanthate. Then we examined the optimization of biodegradation conditions and explore the mechanism of xanthate biodegradation by strain 2#. The conditions include pH value, temperature, shaker rotation, illumination, heavy mental, concentration of dextrose, quantity of bacterial consortium, etc. At last we studied the effect and mechanism of biodegradation on actual wastewater by the strains. This paper provides academic sustains on biodegrading flotation wastewater for Nanjing Xinyang Mine Company.A bacterial strain 1# was isolated from flotation wastewater, which could grow with xanthate as the sole source of carbon and energy. the molecular structure of the microorganism deoxyribonucleic acid (DNA) form the thymine diatomic bodies by the ultraviolet ray illumination, Creates the duplication mistake, causes the gene mutation, Use ultraviolet-tray irradiate strain 1#, from the ultraviolet-ray illumination time and the lethality effect curve confirm the best illumination time is 50s. After inducement obtains three positive mutation strains (2#, 3#, 4#), the strain 1# can degrade xanthates and the biodegradation rates was 30.4％, but the strain 2# degeneration rate were highest, had achieved 78.1％, which is over 47.7％higher than that. simultaneously the preponderant strain 2# cultivate 1.5h to enter the logarithm vegetal period, after 11h the mycelium arrived the biggest growth quantity, OD had achieved 0.581, explained strain 2# for the best superiority strain, the xanthate degeneration greatly enhanced. The colony of 1# and 2# are bottle green on the solid culture medium of beef extract, because the bacterial strains 1# and 2# are able to produce water-solubility pigment. The strains are gramreaction-negative, rod and nonflagella.The examination of cell growth and degradation characteristics of strain 2# was conducted in the further studies. The result showed that the strain 2# can highly degrade xanthates and the biodegradation rates were above78.1％. In pH is 10.0 definite values, The optimum temperature and shaking speed of xanthate degrading are 30℃and 120r/min, under the illuminationand the bacterial consortium is 10％(volume percent). and when the concentration of xanthate is 100mg/L, 66.2％of CODCr were removed, 82.1％of xanthate were removed. The results showed that the ions of Zn2+,Pb2+both restrain the biodegradation on xanthate, and the latter stronger. Adding the glucose at the concentration of 0.2g/L could greatly enhance degrading efficiency.Ultraviolet spectrophotometry and CODCr determination showed that strains biodegraded xanthate to new CODCr substances.
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