Microbial Co-Culture for Dmac Degradation Mediated by Intercellular Nanotubes: Microbial Interaction, Communication Mode, and Degradation Mechanism

Abstract

Co-culture of Rhodococcus ruber HJM-8 and Paracoccus communis YBH-X for N,N-dimethylacetamide (DMAC) degradation was studied. The comparison of DMAC degradation performance in monoculture and co-culture was presented; the removal efficiencies of DMAC and total nitrogen (TN) in co-culture could be improved to 100% and 90.1% respectively, which was attributed to the strain cooperation via parallel and cascaded degradation. The communication mode of co-culture was determined as contact-independent and contact-dependent interactions between microorganisms. Meanwhile, intercellular nanotube was found as a unique contact-dependent interaction, which could be used as a bridge to exchange cytoplasmic molecules, and thus improved material transfer and enhanced cell connection. Besides, a mutual promotion relationship among nanotube generation, extracellular polymeric substances secretion, and electron transfer was presented; and a bidirectional cooperation between HJM-8 and YBH-X was emerged. Finally, the co-culture system was validated for treating an actual wastewater, indicating that 100% DMAC and 68.2% TN could be removed.

Keywords: Co-culture, Biodegradation mechanism, Interaction, Communication mode, Nanotube