Isolation、Identification And Degredation Characters Of Malachite Green-Degrading Bacteria M6

A efficient malachite green-degrading strain M6 was isolated from the activated sludge sample collected from wastewater-treating system of a dye manufacturer. It was preliminarily identified as Arthrobacter sp. according to its morphological, physiological and biochemical characters as well as 16S rRNA gene sequence similarity analysis, and designated as M6 (GenBank Accession No. EU874451).The strain was gram-positive, lemon yellow and opaque; colony was round and colony edges was neat. The optimal pH and temperature value for its growth was 7.0 and 30℃The strain was aerobic, and it grew well in the low salt concentration; the optimal medium for the growth of strain M6 was xylose as carbon source and organic nitrogen as nitrogen source. The strain M6 was resistant to spectinomycin. When the strain M6 grew in the fermentation medium, the logarithmic growth phase last from 12-48 h.The malachite green degradation of strain M6 was also researched. Degrading strain M6 could use malachite green as sole carbon source for growth, and might degrade within 12 h in the 20mg/L of malachite green degradation higher than 80%. Biodegradation of malachite green degradation of the optimum temperature was 30℃, overall in acidic conditions on the degradation of malachite green was better. The degradation of malachite green was good both high and low concentrations; and metal ions, like Ni2+, Zn2+, Fe2+ Mn2+, had no significant effect on the degradation of malachite green, but Cu2+, Cd2+, Al3+ inhibited.MG-degrading enzyme was the constitutive expression, and the largest enzyme production was appropriate when the bacteria was cultured to 48-60h.We had established the best reaction-degrading enzyme. Degrading enzyme was stable in pH 4.0-8.0 and temperature 15-50℃. Metal ions,like Al3+, K+, Ag+ could inhibited on enzyme activity...