Kinetics of p-nitrophenol degradation by Pseudomonas pseudomallei wild and mutant strains.

Pseudomonas pseudomallei EBN-10 strain, previously isolated from a local pharmaceutical industry's wastewater, was spontaneously adapted to higher p-nitrophenol (PNP) levels, which then was subjected to gamma ray-induced mutagenesis; the efficient isolates hence obtained were designated as EBN-11 and EBN-12, respectively. EBN-12 mutant strain could completely mineralize PNP (100 mg/L) on the minimal media in 24 h while, the parent strain utilized only 6% of it. Addition of glucose as co-substrate further increased the PNP degradation rate; however, phenol inclusion inhibited the degradation process. Ammonium sulphate was experienced as the best of the nitrogen sources used by EBN-12 mutant strain, while degrading PNP.