A study on 3-mercaptopyruvate sulphurtransferase (3-MST) produced under submerged fermentation by <i>Pseudomonas putida</i> KT12440 isolated from an industrial effluent

Abstract

Effluents from an Iron and Steel company were collected, the cyanide level was determined and screening for cyanide degrading bacterial isolates on modified Bushnell Haas agar media was done. The amount of cyanide present in the industrial effluent was 1.06 mg/L. The 16S rRNA gene sequencing identified Pseudomonas putida KT12440 as the isolate with highest activity for 3-MST production. The cell growth was optimal at 30 h incubation time and a decrease in cell growth was observed with the increase of incubation time after the optimum. The highest 3-MST production was observed when mannitol was used as the sole carbon source while fructose is the least source of carbon. Casein showed the highest production for 3-MST when used as an alternative nitrogen source while NH₄NO₃ was the least. The optimal pH for 3-MST production was 9.0 and a sharp decrease in the enzyme production was observed thereafter. The incubation temperature for the production of 3-MST in the culture medium peaked at 30ºC and a sharp decline in temperature was observed afterward. The bacterial isolate screened in this study showed degradation potential that can be harnessed to remediate effluents containing cyanide.

 Keywords: Cyanide, Industrial Effluent, Pseudomonas putida KT12440, 3-MST