An effective bioremediation approach for enhanced microbial degradation of the veterinary antibiotic sulfamethazine in an agricultural soil

Abstract

Background:The veterinary antibiotic Sulfamethazine (SMZ) contaminates soils via manure applications. Like other soil contaminants (herbicides, fungicides, and nematicides), it has to be degraded. The main challenge is that SMZ biodegradation with bacteria is impeded, since SMZ is a bacteriostatic antibiotic, designed to block microbes in their growth. Results:In this study, we enriched the indigenous soil microbial community (including the single strain Microbacterium sp. C448, adapted to SMZ degradation) from a Canadian soil and we present a suitable approach, for soil remediation by inoculating a German soil with this microbial community established on carrier particles, at environmentally relevant concentrations of 1 mg kg. When compared with the isolated SMZ-degrading strain (also obtained from Canada), the microbial community outperformed the mineralization rates of the isolated strain in soil. The negligible soil native SMZ mineralization was successfully increased to 44 and 57 % within 46 days, by the microbial community. The sustainability of this increased SMZ mineralization capacity was proven by the rapid mineralization of a second application of 14 C-SMZ 112 days after the first. Conclusions:The pronounced SMZ mineralization and the high amount of non-extractable 14 C-residues (NER) in the inoculated soil indicate that the NER are mainly of biogenic origin (metabolically fixed 14 C). Therefore, the applied inoculation approach decreased the risk of persistent non-extractable SMZ residues. Together with our former studies, this specific soil inoculation approach was tested for three substances with different physico-chemical properties, indicating that this soil bioremediation technique might also be used for other substances.

FMNH2-dependent monooxygenases initiate catabolism of sulfonamides in Microbacterium sp. strain BR1 subsisting on sulfonamide antibiotics

“…This indicates that the sad cluster as a whole might be mobile with a potential to spread as a resistance determinant. The potential of this cluster to act as a resistance determinant should be kept in mind when testing antibiotic mineralizing strains for bioremediating contaminated soils or waters 44 , 45 . It has recently also been reported by Vila-Costa et al .…”

Application of Erythromycin and/or Raoultella sp. Strain MC3 Alters the Metabolic Activity of Soil Microbial Communities as Revealed by the Community Level Physiological Profiling Approach

“…Higher values of the measured parameters suggest that the introduced bacterial strain had the ability to survive in new conditions and increased the catabolic potential of the microbial community. Many studies on the degradation of pollutants in the soil environment showed synergy between inoculated strains and natural soil microflora, which resulted in the accelerated degradation of pollutants [39][40][41]. However, the lack of any effect of the introduction of bacterial strains into the soil was also observed.…”

Biodiversity, isolation and genome analysis of sulfamethazine-degrading bacteria using high-throughput analysis

“…strain BR1. [52][53][54][55]. They all have the ability of degrading sulfonamides, which can provide a new insight toward sulfonamide biodegradation [56].…”