title: A kinetic model for surfactant inhibition of pentachlorophenol biodegradation.
abstract: A kinetic model is used to describe the effect of the nonionic surfactant Tergitol NP-10 (TNP10) on pentachlorophenol (PCP) biodegradation by Sphingomonas chlorophenolica sp. strain RA2. Different initial biomass to initial substrate ratios ranging from 13 to 418 were tested with 23 TNP10 concentrations ranging from 0 to 1500 mg/L. Tests were also conducted at 10 degrees C and 20 degrees C. No PCP biodegradation inhibition was observed at concentrations below the critical micelle concentration (CMC) of 50 mg/L. TNP10 concentrations above 100 to 200 mg/L were increasingly inhibitory to PCP biodegradation rates. This inhibition was best described by the Monod kinetic equation wherein the effect of TNP10 inhibition is reflected in the half-saturation constant (Ks). The value of the Ks increased from between 1.5 and 13.5 mg/L with no surfactant present to 44 to 131 mg/L at 1000 mg/L TNP10. Using a standard competitive inhibition approach, the inhibition constant for TNP10 was approximately 100 mg/L at both 10 degrees C and 20 degrees C.
authors: Cameron-Cole, LLC, Boulder, Colorado, USA.
authors: Todd L
authors: TL
authors: Cort
authors: Angela R
authors: AR
authors: Bielefeldt
mesh_terms: D001673:Biodegradation, Environmental; D007700:Kinetics; D008956:Models, Chemical; D010416:Pentachlorophenol / Q000378:metabolism*; D012989:Soil Pollutants / Q000378:metabolism*; D020578:Sphingomonas / Q000378:metabolism*; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D012989:Soil Pollutants; D013501:Surface-Active Agents; D010416:Pentachlorophenol