Direct micro-electric stimulation alters phenanthrene-degrading metabolic activities of Pseudomonas sp. strain DGYH-12 in modified bioelectrochemical system

Abstract

Bioelectrochemical systems (BESs) have great potential for treating wastewater containing polycyclic aromatic hydrocarbons (PAHs); however, detailed data on cell physiological activities in PAH biodegradation pathways stimulated by BESs are still lacking. In this paper, a novel BES device was assembled to promote the growth of Pseudomonas sp. DGYH-12 in phenanthrene (PHE) degradation. The results showed that in the micro-electric field (0.2 V), cell growth rate and PHE degradation efficiency were 22% and 27.2% higher than biological control without electric stimulation (BC), respectively. The extracellular polymeric substance (EPS) concentration in BES (39.38 mg L−1) was higher than control (33.36 mg L−1); moreover, the membrane permeability and ATPase activities were also enhanced and there existing phthalic acid and salicylic acid metabolic pathways in the strain. The degradation genes nahAc, pcaH, and xylE expression levels were upregulated by micro-electric stimulation. This is the first study to analyze the physiological and metabolic effect of micro-electric stimulation on a PHE-degrading strain in detail and systematically.Electronic supplementary materialThe online version of this article (10.1007/s11356-019-05670-5) contains supplementary material, which is available to authorized users.

Biodegradation of phenanthrene at high concentrations by Acidovoraxsp. JG5 and its functional genomic analysis

“…The metabolic pathways and genes involved in PAH degradation by bacteria have been well studied. [17][18][19] Related functional gene clusters include: nah (e.g., nahAa, nahB), phn (e.g., phn AaAb, phnC), phd (e.g., phdA, phdB), nid (e.g, nidA, nidB), nag (e.g., nagAa, nagB), nar (e.g., narAa, phtA). Metabolites of PHE degradation include dihydroxyphenanthrene, hydroxy-naphthoic acid, phthalic acid, and salicylic acid.…”

Biotechnological processes improved with electric fields: the importance of operational parameters selection

“…For example, research by Jackman et al (1999) has mainly focused on metabolism, and the operational parameters they used (20 mA, 3 V, 200 A m 2 ) were set according to those used in soil remediation. Wang et al (2019), evaluated the degradation of phenanthrene and the growth rate of Pseudomonas sp. using cylindrical graphite electrodes and varying the intensity of the applied electric field (0.1, 0.2 and 0.3 V).…”