Anaerobic degradation of phenanthrene by a newly isolated humus-reducing bacterium, Pseudomonas aeruginosa strain PAH-1

Abstract

Purpose The anaerobic degradation of polycyclic aromatic hydrocarbons (PAHs) has great significance to PAHs' natural attenuation in contaminated sites. Previous studies mainly focused on anaerobic PAH degradation by mixed cultures with nitrate, sulfate, or Fe(III) oxides as electron acceptors, and the roles of pure cultures in the process was rarely reported. The aim of this paper is to isolate a pure culture that is capable of degrading phenanthrene anaerobically with anthraquinone-2,6-disulphonate (AQDS) as the sole electron acceptor and evaluate its environmental functions. Materials and methods A strain of pure culture was isolated from anodic solution of a microbial fuel cell via enrichment procedure with phenanthrene and AQDS under anaerobic conditions. Using the single colony isolation technique, a distinct colony was obtained and identified by the phenotypic and phylogenetic analysis. Its ability to reduce AQDS and degrade phenanthrene was conducted in serum bottles by standard anaerobic techniques (purged with 80% N 2 −20% CO 2 ). The concentration of AH 2 QDS and fructose was quantified by UV-vis spectrophotometer at 450 and 210 nm, respectively. Cells number was determined by direct plate counting on aerobic LB agar medium. The concentration of phenanthrene was determined using HPLC. Results and discussion Strain PAH-1 was identified as Pseudomonas aeruginosa. It could oxidize fructose or glucose to reduce AQDS and can support microbial growth by conserving energy from fructose to AQDS. It has the ability to degrade phenanthrene directly with AQDS as the sole electron acceptor (46.5% removal), and the microbial process may be AQDS dependent. The addition of small organic substances (fructose) could enhance the anaerobic biodegradation of phenanthrene from 46.5% to 56.7%. The anaerobic degradation of phenanthrene fits the pseudo-firstorder kinetics, giving the rate constants of 0.0233/day (R 2 =0.934) and 0.0328/day (R 2 =0.933) for non-fructose set and fructose set, respectively. Conclusions We successfully isolated a facultative anaerobe, P. aeruginosa strain PAH-1. This study was the first paper reporting that a pure culture (strain PAH-1) has the ability to anaerobically degrade phenanthrene with AQDS as the sole electron acceptor. The finding also explores the environmental significance of the Pseudomonas genus.

Generation of Renewable Power from Biodegradation of Anthracene in a Microbial Fuel Cell Reactor Using Different Bacterial Inocula

“…Similar observations were made by Huang et al (2011) (Nasseri et al, 2010;Ma et al, 2011). Ma et al (2011) successively isolated P. aeruginosa strain PAH-1 that had the ability to anaerobically degrade phenanthrene with anthraquinone−2, 6−disulfonate as the sole electron acceptor, the authors reported 56.7% phenanthrene removal in the presence of a co-substrate, fructose. Pseudomonas species have also been found in MFC anodes and can be classified as electrochemically active bacteria (Logan, 2008).…”

“…The inoculum AS+PP has attained the highest values at all. It might be result of that anaerobic sludge has consortium of bacteria possess diversity of enzymes as well as, Pseudomonas species have been reported by several authors to have a potential to degrade PAHs compounds (Nasseri et al, 2010;Ma et al, 2011).…”

Isolation of phenazine 1,6-di-carboxylic acid from Pseudomonas aeruginosa strain HRW.1-S3 and its role in biofilm-mediated crude oil degradation and cytotoxicity against bacterial and cancer cells

“…The isolation of this relatively rare compound PDC differs with previous report (Mentel et al 2009) on its origin being strictly anaerobic as Mentel et al suggested that in the presence of dissolved molecular oxygen, the rapid enzymatic decarboxylation of PDC takes place leading to the formation of only phenazine 1-carboxylic acid, rather than the phenazine 1, 6-di-carboxylic acid (PDC). Thus, PA HRW.1-S3 is a new strain closest to P. aeruginosa strain Pyr41 (Ma et al 2011) which produces PDC as a major secondary metabolite during its growth in presence of crude oil as carbon source.…”

Enhanced biodegradation of phenanthrene using different inoculum types in a microbial fuel cell

“…Pseudomonas species have been reported by several authors to have a potential to degrade PAHs compounds . Ma et al.…”

“…Pseudomonas species have been reported by several authors to have a potential to degrade PAHs compounds [28,29]. Ma et al [28] successively isolated P. aeruginosa strain PAH-1 that had the ability to anaerobically degrade phenanthrene with anthraquinone−2, 6−disulfonate as the sole electron acceptor. The authors reported 56.7% phenanthrene removal in the presence of a co-substrate, fructose.…”