Enrichment of potential degrading bacteria accelerates removal of tetracyclines and their epimers from cow manure biochar amended soil

Abstract

The excessive usage of tetracyclines in animal husbandry and aquaculture invariably leads to deterioration of the microbial quality of nearby soils. We previously reported the accelerated removal of tetracyclines and their intermediates from the cow manure biochar amended soil (CMB). However, little is known about the underlying changes in the microbial community that mediate the accelerated removal of tetracyclines from the CMB. Here, we compared the concentration of parent tetracyclines along with their intermediates, microbial biomass, and microbial (fungal and bacterial) community in CMB and the control soil (CK) on the day of 1, 5, 10, 20, 30, 45, and 60. The biochar amendment accelerated the removal of tetracyclines and their epimers from the soil. Bacterial community composition varied between the CMB and CK. The relative abundance and richness of the bacteria that correlated with the degradation of tetracyclines and their epimers was significantly higher in the CMB as compared to the CK. Specifically, the CMB had a more intricate network of the degrading bacteria with the three keystone genera viz. Acidothermus sp., Sphingomonas sp., and Blastococcus sp., whereas, the CK had a simple network with Sphingomonas sp. as the keystone genus. Overall, the biochar amendment accelerated the removal of tetracyclines and their epimers through the enrichment of potential tetracycline degrading bacteria in the soil; thus, it can be applied for the in situ remediation of soils contaminated with tetracyclines.

Keywords: Cow manure biochar; Potential degraders; Removal; Tetracyclines.