Dual substrate biodegradation of a nonionic surfactant and pentachlorophenol by Sphingomonas chlorophenolica RA2

Abstract

The simultaneous biodegradation of the nonionic surfactant Tween 20 (Tw20) and pentachlorophenol (PCP) by Sphingomonas chlorophenolica sp. Strain RA2 (RA2) was measured. As a sole substrate, Tw20 biodegradation was best described by the Contois kinetic model. During concurrent biodegradation of Tw20 and PCP, the biodegradation rates of Tw20 were not significantly affected by 50 or 100 mg/L PCP, but were significantly inhibited by 500 mg/L PCP. Decreases in cell yield in the presence of PCP suggest that PCP was acting as an uncoupler. Cultures were pre-grown on PCP or Tw20 before degradation of PCP to evaluate enzyme induction effects, and long lags before PCP biodegradation after growth on Tw20 occurred. Although biokinetic models could accurately describe some of the data sets of RA2 growth and Tw20 and PCP degradation, finding a single set of kinetic parameters that predicted all dual substrate tests was not achieved. The complicating factors to modeling PCP and Tw20 interactions are described and may be more widely applicable to the biodegradation of toxic organic compounds in the presence of a biodegradable surfactant.

A dual-substrate steady-state model for biological hydrogen production in an anaerobic hydrogen fermentation process

“…In addition to endogeneous metabolism, the utilization of dual substrates, glucose, and peptone, as complementary substrates was considered in the Model 3. Although the assumption that only one mostlimiting substrate presents during microbial growth holds for many cases, several studies on microorganisms that are simultaneously limited by two or more substrates have been reported (Bielefeldt and Cort, 2005;Machado and Grady, 1989;Neeleman et al, 2001;Lee et al, 1984;Sambanis et al, 1986;Yoon et al, 1977). In this study, the Model 3, dualsubstrate steady-state model, was demonstrated to be superior than the Model 2 in predicting biomass concentration, especially at D < 0.25/h when consumption of peptone and release of ammonia became substantial.…”

Structure and Mechanism of HpcH: A Metal Ion Dependent Class II Aldolase from the Homoprotocatechuate Degradation Pathway of Escherichia coli

“…[1][2][3] One of the longest and best characterized bacterial aromatic catabolic pathways involves the degradation of 4-hydroxyphenylacetic acid (4-HPA) via 3,4-dihydroxyphenylacetic acid (homoprotocatechuate, HPC) to pyruvate and succinic semialdehyde. 4 This Escherichia coli pathway has similarities to the catechol (TOL) meta fission pathway of Pseudomonads.…”

PAH biodegradation in surfactant‐water systems based on the theory of cohesive energy density (CED)

“…This led to the microbial utilization of the non‐ionic surfactant as a carbon or energy source being accelerated. Bielefeldt and Cort found the same phenomenon for pentachlorophenol and non‐ionic surfactant (Tween 20) biodegradation 36. Pentachlorophenol was acting as an uncoupler and allowed the bacteria to utilize Tween 20 during biodegradation.…”