Insights into interactions between vanadium (V) bio-reduction and pentachlorophenol dechlorination in synthetic groundwater

Abstract

Aquifer co-contamination by vanadium (V) and pentachlorophenol (PCP) involves complicated biogeochemical processes that remain poorly understood, particularly from the perspective of microbial metabolism. Batch experiment results demonstrated that V(V) and PCP could be competitively bio-reduced, with 96.0 ± 1.8% of V(V) and 43.4 ± 4.6% of PCP removed during 7 d operation. V(V) was bio-transformed to vanadium (IV), which could precipitate naturally under circumneutral conditions, facilitating the removal of up to 78.2 ± 3.1% dissolved total V. The PCP reductive dechlorination products were mainly 2,4,6-trichlorophenol and 4-monochlorophenol with lower toxicity. High-throughput 16S rRNA gene sequencing indicated that Pseudomonas, Soehngenia, and Anaerolinea might be responsible for the two bio-transformations, with detected functional genes of nirS and cprA. Extracellular reduction by cytochrome c and intracellular conversion by nicotinamide adenine dinucleotide (NADH) occurred for both V(V) and PCP. Extracellular proteins in microbial-secreted extracellular polymeric substances (EPS) might also be involved in these enzymatic bioprocesses. EPS could protect microbial cells through V(V) binding by the chemically reactive carboxyl (COO-), and hydroxyl (-OH) groups. These findings elucidate the metabolic processes during anaerobic V(V) and PCP biotransformation, advance understanding of their biogeochemical fates, and provide a foundation on which to develop novel strategies for remediation of co-contaminated aquifers.

Microbially-Enhanced Vanadium Mining and Bioremediation Under Micro- and Mars Gravity on the International Space Station

“…One element with strong industrial interest is vanadium, a metal that can be extracted from minerals and other materials using microorganisms ( Mishra et al, 2007 ; Mirazimi et al, 2015 ; Dong et al, 2019 ) and can be immobilized by microbial reduction in bioremediation schemes ( Mirazimi et al, 2015 ; Zhang et al, 2019a , b ). This element is used in ferrous and non-ferrous (including nickel, titanium, aluminum, and chromium) alloys to enhance hardness, tensile strength and fatigue resistance ( Moskalyk and Alfantazi, 2003 ).…”

Exploring the Potential of Antibiotic Production From Rare Actinobacteria by Whole-Genome Sequencing and Guided MS/MS Analysis

“…Based on the genome mining results, MS screening was used to look for the predicted secondary metabolites, particularly antibiotics, of the M. aurantiaca sp.01 under laboratory conditions. In general, HPLC can accurately and efficiently separate and quantify each component in a mixture; it does involve tedious development of an appropriate analytical method suitable for an unknown (or a partly known) sample (Zhang et al, 2019a). MS analysis, coupled with MS/MS, is efficient and reliable in identifying unknown compounds without the need for a specific method development, which is more suitable for the present study to rapidly identify the compounds from fermentation products.…”

Taisui TS-2007S, a Large Microbial Mat Discovered in Soil in China

“…Extracellular polymeric substance plays an important role in protecting cells (Zhang et al, 2019b(Zhang et al, , 2020 and generates the framework of bacterial mats (Krüger et al, 2008). The bacteria and archaea harbored in TS-2007S possessed many genes associated with EPS formation, protein-degrading enzyme, and phosphomonoesterase, but few genes encoding polysaccharide or oligosaccharide-degrading enzyme.…”