Biodegradation and metabolic pathway of sulfamethoxazole by Pseudomonas psychrophila HA-4, a newly isolated cold-adapted sulfamethoxazole-degrading bacterium

Abstract

Sulfamethoxazole is a common antibiotic that is frequently detected in wastewater and surface water. This study investigated the biodegradation and metabolic pathway of sulfamethoxazole by Pseudomonas psychrophila HA-4, a cold-adapted bacterium. Strain HA-4, which uses sulfamethoxazole as its sole source of carbon and energy, was isolated at a low temperature (10 °C) and identified as P. psychrophila by physico-biochemical characterization and 16S rRNA gene sequence analysis. Strain HA-4 removed sulfamethoxazole at temperatures ranging from 5.0 °C to 30 °C, with the maximal removal rate at 10 °C. The maximal removal rate of sulfamethoxazole by strain HA-4 was 34.30 % after 192 h at 10 °C. The highest percentage of unsaturated fatty acid was determined to be 23.03 % at 10 °C, which adheres to the characteristic for cold-adapted psychrophiles and psychrotrophs. At low concentrations of sulfamethoxazole, the growth kinetics correlated well with the Haldane model. The single-substrate parameter values of sulfamethoxazole on cell growth were determined to be μ max = 0.01 h(-1), K s = 20.91 mg/l and K i = 170.60 mg/l. Additionally, the major intermediates from sulfamethoxazole biodegradation by strain HA-4, including aniline, 3-amino-5-methylisoxazole, 4-aminothiophenol and sulfanilamide, were identified by GC-MS and high-resolution mass spectrometry (HR-MS) analysis. The results demonstrate that strain HA-4 has the potential to degrade sulfamethoxazole at low temperatures.

Biodegradation of sulfamethoxazole and other sulfonamides by Achromobacter denitrificans PR1

“…Furthermore, it is unknown whether strain BR3 shares with strain PR1 the capacity to tolerate concentrations of SMX as high as 10 mM, while maintaining the biodegradative ability, and if SMX is degraded with the concomitant accumulation of 3A5MI. Indeed, inhibition of degradation when the initial SMX concentration was higher than 0.55 mM was reported for P. psychrophila HA-4 [23]. The fact that independent studies led to the isolation of Achromobacter strains able to degrade sulfonamides suggested that this property could be a characteristic of the genus.…”

“…and Rhodococcus sp. [21][22][23]. Also a versatile peroxidase from the ligninolytic fungus Bjerkandera adusta showed SMX breakdown activity [32].…”

“…Indeed, several bacterial strains capable of degrading sulfonamide antibiotics were isolated from activated sludge [21][22][23]30]. However, the extent of removal of SMX during wastewater treatment varies consider-ably (0-100%) [2].…”

“…The first examples were reported for members of the genus Rhodococcus, which were able to co-metabolize SMX with glucose in axenic culture [19,20]. Later, other organisms, all enriched from activated sludge, belonging to the genera Achromobacter, Ralstonia, Pseudomonas, Brevundimonas, Variovorax, Rhodococcus, and Microbacterium were reported as capable of degrading SMX [21][22][23]. The diversity and distribution of SMX biodegradation in wastewater environments is still a major question, since this property has been detected in distantly related phylogenetic lineages and geographic regions.…”

Isolation of Bacterial Endophytes from Phalaris arundinacea and their Potential in Diclofenac and Sulfamethoxazole Degradation

“…Some studies have reported on the microbial removal of SMX and DCF. Jiang et al (2014) described the strain Pseudomonas psychrophila HA-4, which was able to remove 34.30% of 100 mg/l of SMX at 10°C after 192 h of incubation. Aissaoui et al (2017) demonstrated that strains identified as Pseudomonas sp.…”