| Amino-dithiophosphate (C6H5NH2PSSH) is an important industrial chemical which is used as the collector of lead zinc sulfide minerals flotation.It is the main refractory pollutant in floatation wastewater which contains high concentration of flotation reagents and metal ions, it would cause a large damage to ecological environment around the mine. So it is an important issue for mining industry to reduce the emission of floatation wastewater and to minimize the environment pollution of amino-dithiophosphateAFF0039is gram-positive bacilli and100%related to Bacillus vallismortis, which have the ability to degrading the amino-dithiophosphate. In this study, ultraviolet spectrophotometry was used to researched the characteristic of amino-dithiophosphate degradation enzyme which was generated by AFF0039strains, orthogonal designed experiments of four factors, five levels was adopted to optimize the growing condition and enzyme producing condition of AFF0039. HPLC, IC and GC/MS were used to investigate the biodegradation mechanism of amino-dithiophoshpate by AFF0039.The results show as follow:(1)Amino-dithiophosphate degradation enzyme produced by AFF0039was an inducible enzyme, most of which was distributed inside of the cell, a small percentage was outside the cell,the enzyme activity of amino-dithiophosphate degradation enzyme inside the cell was20.24ug·(h·mL)-1, while it was6.01ug·(h·mL)-1outside the cell. The favorable reaction temperature of amino-dithiophosphate degradation enzyme was35℃～40℃, and the favorable reaction pH was4.3～7.0. The relative enzyme activity was more than65%when amino-dithiophosphate degradation enzyme had been stored under4℃for3hours, when the temperature was45degree Celsius, the relative enzyme was decreased to34.7%. The relative enzyme activity was more than85%when amino-dithiophosphate degradation enzyme had been stored at pH4.3～7.0, four degree celsius for3hours, the relative enzyme activity decreased with the increase of pH.(2)Via orthogonal designed experiments, the highest degradation rate of amino-dithiophosphate by AFF0039was98%, the largest amount of protein in AFF0039bacteria liquid was102.93ug/mL, the maximum activity of amino-dithiophosphate degradation enzyme was48.22ug·(h·mL)-1. Temperature, pH and culture time had a significant impact on the growing of AFF0039and the production of degradation enzyme. The favorable growing condition of AFF0039in amino-dithiophosphate liquid was temperature35℃～40℃, pH5～7. The maximum activity of degradation enzyme was generated at temperature40℃,pH6,culture time12h-18h.(3)AFF0039strain have been cultured in300mg/L amino-dithiophosphate liquid for24h,91.35%of amino-dithiophosphate have been biodegraded, while only67.29%of COD have been biodegraded, the concentration of phosphate radical have increased from31.4mg/L to94.4mg/L. Intermediate products were identified by high performance liquid chromatography,ion chromatagraphy, Gas Chromatograph Mass Spectrometer(GC/MS)and ultraviolet spectrophotometry. It’s concluded:dissolved in water, amino-dithiophosphate partly hydrolyzed to yield phosphate radical, aniline and hydrogen sulfide; most of aniline was degraded to catechol, the catechol then was degraded to2-hydroxy diallyl half hyaluronic acid by catechol2,3dioxygenase, finally fully biodegraded via tricaboxylic acid cycle. A small amount of amino-dithiophosphate was converted to phenol, benzoquinone,3-butene amide and Phenol,2,2’-methylenebis[6-(1,1-dimethylethyl)-4-methyl-], all of which were difficult to biodegrade by AFF0039. It was the reason why the biodegradation rate of COD was low when most of animo-dithiophosphate was biodegraded by AFF0039. The process of AFF0039strain degrading the amino-dithiophosphate promoted the generated of phosphate radical, a small amount of which was used as the nutriment for AFF0039growing, so the amount of phosphate radical would increased. |
