Metabolism of 2-, 3- and 4-hydroxybenzoates by soil isolatesAlcaligenessp. strain PPH andPseudomonassp. strain PPD

Abstract

Pseudomonas sp. strain PPD and Alcaligenes sp. strain PPH isolated from soil by enrichment culture technique utilize 2-, 3- and 4-hydroxybenzoates as the sole source of carbon and energy. The degradation pathways were elucidated by performing whole-cell O(2) uptake, enzyme activity and induction studies. Depending on the mixture of carbon source and the preculture condition, strain PPH was found to degrade 2-hydroxybenzoate either via the catechol or gentisate route and has both salicylate 1-hydroxylase and salicylate 5-hydroxylase. Strain PPD utilizes 2-hydroxybenzoate via gentisate. Both strains degrade 3- and 4-hydroxybenzoate via gentisate and protocatechuate, respectively. Enzymes were induced by respective hydroxybenzoate. Growth pattern, O(2) uptake and enzyme activity profiles on the mixture of three hydroxybenzoates as a carbon source suggest coutilization by both strains. When 3- or 4-hydroxybenzoate grown culture was used as an inoculum, strain PPH failed to utilize 2-hydroxybenzoate via catechol, indicating the modulation of the metabolic pathways, thus generating metabolic diversity.

Biodegradation of phenanthrene by Pseudomonas sp. strain PPD: purification and characterization of 1-hydroxy-2-naphthoic acid dioxygenase

“…Cells grown on appropriate carbon sources were used to monitor whole-cell O 2 uptake. Rates were measured in the presence of various probable metabolic intermediates at 30 uC using an oxygraph (Hansatech) fitted with a Clark-type electrode as described previously (Deveryshetty et al, 2007).…”

“…Cells were harvested by centrifugation, washed twice with Tris/HCl (50 mM, pH 7.5), and cell-free extract was prepared as described previously (Deveryshetty et al, 2007). 1-HNDO activity was monitored spectrophotometrically (Perkin Elmer Lambda 35) by measuring the rate of product formation as the increase in absorbance at 300 nm.…”

“…Pseudomonas sp. strain PPD can utilize phenanthrene, hydroxybenzoic acids (o-, m-and p-) and phthalic acid isomers (o-, m-and p-) as the sole source of carbon and energy (Deveryshetty et al, 2007;Vamsee-Krishna et al, 2006). Here, we report the metabolic pathway for degradation of phenanthrene in Pseudomonas sp.…”

“…Several bacterial species capable of degrading phenanthrene have been reported (Phale et al, 2007). The metabolic pathway is initiated by a ring-hydroxylating dioxygenase to yield cis-3,4-dihydroxy-3,4-dihydrophenanthrene, which is subsequently metabolized to 1-hydroxy-2-naphthoic acid (1-H2NA).…”

Bacterial degradation of phthalate isomers and their esters

“…Pseudomonas sp. strain PPD also metabolizes phenanthrene via phthalate [23]. Phenanthrene grown PPD cells did not show O 2 uptake on phthalate and 3,4-DHB, while phthalate grown cells showed considerable O 2 uptake on both phthalate and 3,4-DHB.…”