Biostimulation of Indigenous Microbial Communities for Anaerobic Transformation of Pentachlorophenol in Paddy Soils of Southern China

Abstract

This study explored biostimulation mechanisms with an electron donor and a shuttle for accelerating pentachlorophenol (PCP) transformation in iron-rich soils. The results indicated that indigenous microbial communities are important for PCP transformation in soils. Biostimulation of indigenous microbial communities by the addition of lactate and anthraquinone-2,6-disulfonate (AQDS) led to the enhanced rates of PCP dechlorination by the dechlorinating-and ironreducing bacteria in soils. The electrochemical studies using cyclic voltammograms and microbial current measurements confirmed the high reduction potential and the large amount of electrons generated under biostimulation conditions, which were responsible for the higher rates of PCP transformation. After biostimulation treatments by the additions of lactate and/or AQDS during PCP dechlorination processes, microbial community analysis by the terminal restriction fragment length polymorphism (T-RFLP) method showed the abundance terminal restricted fragments (T-RFs), an indicator of bacterial abundance, which represents the dechlorinating-and iron-reducing bacteria, suggesting their critical roles in PCP dechlorination in soils.

The key microorganisms for anaerobic degradation of pentachlorophenol in paddy soil as revealed by stable isotope probing

“…Lactate, which acted as the electron donor, was important for microorganism metabolism and consequently accelerates microbial PCP degradation in paddy soils under anaerobic conditions. Our previous study also suggested that the microbial community structure can even be changed after biostimulation by the additions of lactate [65].…”

Shifts in indigenous microbial communities during the anaerobic degradation of pentachlorophenol in upland and paddy soils from southern China

“…The filtrate was collected for highperformance liquid chromatography (HPLC) analysis of the PCP concentration. Details of the HPLC analysis are provided elsewhere (Lan et al 2008;Chen et al 2012;Wang et al 2012;Tong et al 2014).…”

“…Essentially, in the anaerobic environment, PCP degradation is a microbial dechlorinated respiration process, during which the chlorinated compounds serve as terminal electron acceptors (Saia et al 2007;Payne et al 2011). In our previous study, Chen et al (2012) revealed that the dechlorinated products of degradation of PCP are 2,3,5,6-tetrachlorophenol (TeCP) and 2,3,5-trichlorophenol (TCP), and Tong et al (2014) also found the similar intermediates in dechlorination of PCP. According to these reports, PCP is expected to be dechlorinated under anaerobic conditions by microbes at the ortho-position (Bouchard et al 1996;Field and Sierra-Alvarez 2008).…”

“…Yoshida et al (2007) enriched a microbial community from paddy soil that degraded PCP, and the structure of the microbial community was characterized by fluorescence in situ hybridization and PCR-DGGE (denaturing gradient gel electrophoresis). Chen et al (2012) used the terminal restriction fragment length polymorphism (T-RFLP) method to study the anaerobic degradation of PCP by indigenous microorganisms in paddy soils collected from typical sites in southern China. Furthermore, DNA-based stable isotope probing (SIP) was applied to explore the key microorganisms responsible for PCP mineralization in paddy soils (Tong et al 2015;Li et al 2015).…”

Spatial and temporal variations in pentachlorophenol dissipation at the aerobic–anaerobic interfaces of flooded paddy soils

“…It is relatively persistent, where it undergoes slow natural dissipation, by e.g. adsorption, volatilization, leaching and biodegradation (He et al, 2007;Chen et al, 2012;Puglisi et al, 2009). The main process leading to the dissipation of pesticide residues in soil is biological degradation, caused by the activities of soil microorganisms (RodriguezCruz et al, 2006;Vryzas et al, 2012).…”