Environmental considerations and bioremediation applications of the metal-, nitrate-, and organohalide-respiring bacterium Trichlorobacter lovleyi (formerly Geobacter lovleyi )

ABSTRACT Trichlorobacter lovleyi (formerly Geobacter lovleyi ) is a gram-negative bacterium that can couple the oxidation of acetate or other small organic acids with the reduction of soluble and insoluble electron acceptors, such as chlorinated solvents, heavy metals, and nitrate. Evidence has shown that T. lovleyi plays a direct role in nitrogen, iron, and carbon cycling, and its versatile metabolism can be leveraged for environmental biotechnology applications. However, the contributions of T. lovleyi to treatment of contaminants at groundwater sites or electron transfer in bioelectrochemical systems have been largely overlooked. This minireview examines the genetic and metabolic features of T. lovleyi for dissimilatory reduction of nitrate to ammonium, extracellular electron, and organohalide-respiration, highlighting unique and conserved features relative to other genera in Geobacterales. We highlight applications of T. lovleyi in bioremediation of contaminated environments and identify knowledge gaps to fully leverage the metabolic potential of this bacterium. We feature T. lovleyi ’s ability to produce the important vitamin B 12 cofactor and the syntrophic partnership it establishes with cobalamin-scavenging, obligate organohalide-respiring bacteria, particularly in environments where the concentration of chlorinated solvents poses toxicity challenges to the groundwater microbiome. We conclude that T. lovleyi has a meaningful, multi-faceted, but often neglected, contribution to groundwater and soil bioremediation. We hope this minireview will prompt researchers and bioremediation practitioners to more closely monitor T. lovleyi during reductive dechlorination enrichment efforts and bioremediation applications at sites contaminated with organohalogens, uranium, or nitrate.