Breeding And Characteristics Analysis Of Potassium Xanthate-degrading Bacterial Strain At High PH

Potassium xanthate, with its molecular formula ROCSSK, is one of the organic flotation reagents used frequently in sulfide mine flotation.This paper first studied domesticating and screening potassium xanthate-degradation strains from flotation wastewaters of refined zinc mineral, refined lead mineral and refined sulfide mineral, which containing potassium xanthate, when pH is 10.0.And we studied the characteristics in structure and appearance of the strains. Then we examined the optimization of biodegradation conditions and explored the mechanism of aniline float biodegradation by strain Zn1.The conditions include pH value, temperature, shaker ratation, quantity of bacterial consortium, concentration of substrate, Na⁺ and K⁺ ,etc. At last we studied the effect of biodegradation on actual wastewater by the strains. This paper provides academic sustains on biodegrading flotation wastewater for Nanjing Xinyang Mine Company.Three bacterial strains were isolated from flotation wastewater, which could grow with potassium xanthate as the sole source of carbon and energy,were respectively christened Zn1, Zn2 and S1. Among those bacterial consortium, the colony of Zn1 is light yellow while deepen as the culturing time goes, glossy and short-bacilliform with gibbosity on the solid culture medium of beef extract, and is gram-negative, short-bacilliform and non-flagella; while Zn2 is aqua while deepen as the culturing time goes, glossy and rotundity with gibbosity, gram-negative; and S1 is ivory , and deepen as the culturing time goes, also glossy, bacilliform with gibbosity and gram-negative. According to the analysis about the shape characteristics of colony or individual and other morphological characters, we guessed the three strains all belong to pseudomonas.Among the three strains, strain Zn1 was the most active in degrading potassium xanthate, therefore, further studies focused on this strain, and also studied the mixed consortium of the three strains in this paper. For the strain Zn1, the optimum pH is 10.0, temperature is 30°C, the shaking speed is 120r/min, and the bacterial consortium is 10% (volume percent). The disposal effect of potassium xanthate with low concentration by strain Zn1 is better, when the concentration of potassium xanthate is 100mg/L, 45.37% of potassium xanthate was degraded and 32.38% of COD_Cr were removed. The results also showed that condign concentration of the Na⁺ ion, about 5g/L, can enhance the strain be able to endure alkali. Adding the glucose at the concentration of 0.2g/L could greatly improve degrading efficiency. At the same experiment condition, the mixed consortium of the three strains with Zn1 occupy 60% is better to biodegrade. The optimal scale is Zn1:Zn2:S1=3:1:1.Finally, ultraviolet spectrophotometry and COD_Cr determination presumed the degradative pathway of potassium xanthate by strain Zn1.