Biodegradation of thiocyanate using co-culture of Klebsiella pneumoniae and Ralstonia sp.

Abstract

Thiocyanate-degrading microbial co-culture was isolated from thiocyanate-contaminated site and tested for thiocyanate degradation potential and thiocyanate-toxicity tolerance and identified as Klebsiella pneumoniae and Ralstonia sp. by 16S rDNA sequencing. The co-culture was able to degrade thiocyanate with degradation rate of 500 mg L(-1)d(-1) at 2,500 mg L(-1) thiocyanate concentration at pH 6.0 and 37 degrees C following thiocyanate hydrolase pathway. The Haldane kinetic model elucidates the growth and thiocyanate biodegradation kinetics of the co-culture with Ki value of 1,876 mg L(-1). The thiocyanate biodegradation kinetics was not affected by the additional supply of glucose. The very high activities of thiocyanate hydrolase, cyanide oxygenase, and cytochrome P-450 content during growth on thiocyanate were observed, showing the induction mechanism.