inetics of Biodegradation of p-Nitrophenol y Different Bacteria

u d o s c t t b Three bacterial species, i.e., Ralstonia sp. SJ98, Arhrobacter protophormiae RKJ100, and Burkholderia ceacia RKJ200, have been examined for their efficiency nd kinetics behavior toward PNP degradation. All the hree bacteria utilized PNP as the sole source of carbon, itrogen, and energy. The rates of radiolabeled U-C]PNP degradation by all the bacteria were higher n the nitrogen-free medium compared to the medium ith nitrogen. The apparent Km values of PNP degradaion by SJ98, RKJ100, and RKJ200 were 0.32, 0.28, and .23 mM, respectively, as determined from the ichaelis–Menten curves. The maximum rates of PNP egradation (Vmax) according to Lineweaver–Burk’s lots were 11.76, 7.81, and 3.84 mmol PNP degraded/ in/mg dry biomass, respectively. The interpretation rawn from the Lineweaver–Burk’s plots showed that he PNP degradation by SJ98 was stimulated by -nitrocatechol and 1,2,4-benzenetriol. Benzoquinone nd hydroquinone inhibited PNP degradation by KJ100 noncompetitively and competitively, respecively, whereas in the case of RKJ200, benzoquinone and ydroquinone inhibited PNP degradation in an uncometitive manner. b-Ketoadipate did not affect the rate of NP degradation in any case. © 2000 Academic Press