Interspecies metabolite transfer and aggregate formation in a co-culture of Dehalococcoides and Sulfurospirillum dehalogenating tetrachloroethene to ethene

Abstract

Microbial communities involving dehalogenating bacteria assist in bioremediation of areas contaminated with chlorinated hydrocarbons. To understand molecular interactions between dehalogenating bacteria, we co-cultured two bacterial species dechlorinating chloroethenes: Sulfurospirillum multivorans, dechlorinating tetrachloroethene (PCE) to cis-1,2-dichloroethene (cDCE) and Dehaloccoides mccartyi strains BTF08 or 195, transforming PCE via cDCE to ethene. The interaction of these bacteria cultivated with lactate as electron donor and PCE as electron acceptor was investigated using growth studies, metabolite analysis, microscopy, isotope fractionation and proteomics. Co-cultures exhibited more than 3-fold higher PCE to ethene dechlorination rates than D. mccartyi pure cultures. S. multivorans provided hydrogen, acetate and the reductive dehalogenase cobamide cofactor to D. mccartyi. While D. mccartyi 195 dechlorinated cDCE in the presence of norpseudo-B12 produced by S. multivorans, cDCE dechlorination by D. mccartyi BTF08 depended on the supply of 5,6-dimethylbenzimidazole for producing functional cobamides. Co-cultures were characterized by the formation of aggregates and electron microscopy revealed an extracellular matrix enabling cell-to-cell contact. D. mccartyi showed an unusual barrel-like morphology, probably dependent on down-regulation of cell division gene expression, as observed in the co-culture proteome. Only the reductive dehalogenases PteA and VcrA were found in the proteomes of D. mccartyi BTF08 during dehalogenation of PCE to ethene.

Bioremediation of trichloroethylene‐polluted groundwater using emulsified castor oil for slow carbon release and acidification control

“…Researchers reported that the following bacteria could dechlorinate TCE under anaerobic conditions: Dehalococcoides (DHC), Geobacter , Sulfurospirillum , Desulfitobacterium , Dehalogenimonas , Desulfovibrio , Dehalobacter , and Desulfomonile (Kruse et al, 2021 ; Puentes Jácome et al, 2019). These bacteria can growth in an organohalide respiration process coupling the reductive dechlorination of TCE (Puentes Jácome et al, 2019).…”

Surface enhanced Raman spectroscopy‐based evaluation of the membrane protein composition of the organohalide‐respiring Sulfurospirillum multivorans

“…[3,4] The PCE reductive dehalogenase converts PCE via trichloroethene to cis-1,2-dichloroethene, which can be further dehalogenated by other bacteria in synthetic co-cultures or coupled anoxic-oxic bioreactors. [5][6][7][8][9] S. multivorans was characterized as a metabolically flexible bacterium, able to use a high number of different electron donors and acceptors, including oxygen. [10,11] Prolonged cultivation of S. multivorans with nitrate or fumarate instead of PCE as electron acceptor leads to the loss of the PCE respiratory chain components.…”