Effect of temperature and additional carbon sources on phenol degradation by an indigenous soil Pseudomonad

Abstract

A new indigenous soil bacterium Pseudomonas sp. growing on phenol and on a mixture of phenol, toluene, o-cresol, naphthalene and 1,2,3-trimethylbenzene (1,2,3-TMB) was isolated and characterized. Phylogenetic analysis suggested its classification to Pseudomonadaceae family and showed 99.8% DNA sequence identity to Pseudomonas pseudoalcaligenes species. The isolate was psychrotroph, with growth temperatures ranging from ca. 0 to 40 degrees C. The GC-MS structural analysis of metabolic products of phenol degradation by this microorganism indicated a possible ortho cleavage pathway for high concentrations (over 200 mg L(-1)) of phenol. Biodegradation rates by this species were found to be three times more effective than those previously reported by other Pseudomonas strains. The effect of temperature on phenol degradation was studied in batch cultures at temperatures ranging from 10 to 40 degrees C and different initial phenol concentrations (up to 500 mg L(-1)). Above 300 mg L(-1) of initial phenol concentration no considerable depletion was recorded at both 10 and 40 degrees C. Maximum degradation rates for phenol were recorded at 30 degrees C. The biodegradation rate of phenol was studied also in the presence of additional carbon sources (o-cresol, toluene, naphthalene, 1,2,3-TMB) at the optimum growth temperature and was found significantly lower by a factor of eight in respect to the strong competitive inhibition between the substrates and the more available sources of carbon and energy. The Haldane equation mu = mum S/(Ks + S + S2/K1) was found to best fit the experimental data at the optimum temperature of 30 degrees C than the Monod equation with kinetic constants mum = 0.27 h(-1), KS = 56.70 mg L(-1), KI = 249.08 mg L(-1).

Assessment of phenol biodegradation capacity of indigenous bacteria isolated from sewage treatment plant

“…This result corroborates with previous report of phenol degradation by Pseudomonas sp. (Polymenakou and Stephanou, 2005) but contradict the findings of Rosa et al (2004) where 30C was optimum for biodegradation of phenol. At elevated temperature exposure than the optimum one, showed decreasing trend in the biodegradation capacity.…”

Evaluation of different phenol hydroxylase-possessing phenol-degrading pseudomonads by kinetic parameters

“…The l max value determined for an ortho pathway possessing Pseudomonas sp. strain in batch experiments was 0.27 h -1 (Polymenakou and Stephanou 2005). Herein it is important to underline that we did not observe differences between the l max values of the mPHstrains possessing either ortho (PC17 and PC30) or meta (PC1, PC18 and CF600) cleavage type, whereas the strains having sPH showed a lower rate of phenol degradation.…”

Aerobic biodegradation kinetics of tannic acid in activated sludge system

“…Thus the relationship between the biodegradation rate of the substrate and temperature can be expressed [32,33] by…”