Metabolic and genomic analysis elucidates strain-level variation inMicrobacterium spp.isolated from chromate contaminated sediment

Abstract

Hexavalent chromium [Cr(VI)] is a soluble carcinogen that has caused widespread contamination of soil and water in many industrial nations. Bacteria have the potential to aid remediation as certain strains can catalyze the reduction of Cr(VI) to insoluble and less toxic Cr(III). Here, we examine Cr(VI) reducing Microbacterium spp. (Cr-K1W, Cr-K20, Cr-K29, and Cr-K32) isolated from contaminated sediment (Seymore, Indiana) and show varying chromate responses despite the isolates’ phylogenetic similarity (i.e., identical 16S rRNA gene sequences). Detailed analysis identified differences based on genomic metabolic potential, growth and general metabolic capabilities, and capacity to resist and reduce Cr(VI). Taken together, the discrepancies between the isolates demonstrate the complexity inter-strain variation can have on microbial physiology and related biogeochemical processes.

Comparative Genomics of Microbacterium Species to Reveal Diversity, Potential for Secondary Metabolites and Heavy Metal Resistance

“…Several studies associated these bacteria to metal contaminated sites. Several Microbacterium strains can survive in heavy metal contaminated environments ( Brown et al, 2012 ; Fidalgo et al, 2016 ), reduce specific metals such as hexavalent chromium ( Henson et al, 2015 ; Fierros-Romero et al, 2016 ; Kumar and Saini, 2019 ) and change the mobility of heavy metals in contaminated soils ( Kuffner et al, 2010 ; Soni et al, 2013 ). Because of these interesting traits, they have already been used in phytoextraction trials for soil decontamination ( Visioli et al, 2015 ).…”

Draft Genome Sequences of Two Bacillus sp. Strains and Four Cellulomonas sp. Strains Isolated from Heavy-Metal-Contaminated Soil

“…Previously, bacteria were isolated from soil at a Department of Transportation site (Seymore, IN) that was contaminated with chromium ( 1 , 2 ). Chromium is a heavy metal and has two naturally occurring oxidation states, Cr(III) and Cr(VI), the latter being more soluble and toxic than the other ( 3 , 4 ).…”

New Plant Growth-Promoting, Chromium-Detoxifying Microbacterium Species Isolated From a Tannery Wastewater: Performance and Genomic Insights

“…In fact, some bacterial strains, like E. coli , use YieF reductase to reduce Cr(VI) into Cr(III). Other species, like Pseudomonas putida , are known for their chromium reduction through the ChrR reductase (Ramirez-Diaz et al, 2008 ; Learman et al, 2011 ; Ahemad and Kibret, 2014 ; Henson et al, 2015 ; Baldiris et al, 2018 ). Otherwise, M. laevaniformans strain OR221 was able to resist some heavy metals, but the annotation of its genome after sequencing suggested the absence of both ChrR and YieF (Brown et al, 2012 ).…”