Cross-Feeding between Members of Thauera spp. and Rhodococcus spp. Drives Quinoline-Denitrifying Degradation in a Hypoxic Bioreactor

Abstract

We experimentally verified that the second most abundant taxon, Rhodococcus , played a role in degrading quinoline to 2-hydroxyquinoline, while the most abundant taxon, Thauera , degraded 2-hydroxyquinoline. Metabolites from Thauera further served to provide metabolites for Rhodococcus . Hence, an ecological guild composed of two isolates was assembled, revealing the different roles that keystone organisms play in the microbial community. This report, to the best of our knowledge, is the first on cross-feeding between the initial quinoline degrader and a second bacterium. Specifically, the quinoline degrader ( Rhodococcus ) did not benefit metabolically from quinoline degradation to 2-hydroxyquinoline but instead benefited from the metabolites produced by the second bacterium ( Thauera ) when Thauera degraded the 2-hydroxyquinoline. These results could be a significant step forward in the elucidation of the microbial mechanism underlying quinoline-denitrifying degradation.