Loading...
Research Project
Untitled
Funder
Authors
Publications
Insights on sulfamethoxazole bio-transformation by environmental proteobacteria isolates
Publication . Reis, Patrícia J. M.; Homem, Vera; Alves, Arminda; Vilar, Vítor J.P.; Manaia, Celia M.; Nunes, Olga C.
Although sulfonamide residues are frequently reported as freshwaters contaminants, information on the ability of native bacteria to modify these synthetic antibiotics is scarce. Our purpose was to investigate the potential of bacteria from different aquatic environments to cleave or transform sulfamethoxazole (SMX) and infer on their ability to reduce the toxicity of this antibiotic. From a collection of about 100 Proteobacteria, 47 strains previously isolated from drinking water, surface water, and wastewater grew in the presence of 200 μMSMX, and were further studied. Out of these, 14 strains, mostly from mineral drinking water, transformed SMX into equimolar amounts of the lesser toxic derivative N4-acetyl-sulfamethoxazole. The highest percentage of SMX transformation was recorded for two strains affiliated to Pseudomonas mandelii. For P. mandelii McBPA4 higher SMX transformation rate and extent were observed in fed-batch (∼8 μMSMX/h, 81%) than in batch conditions (∼5 μMSMX/h, 25%), but similar specific transformation
rates were found in both cultivation modes (∼20 μmolSMX/gcell dry weight/h), indicating the dependence of the process on the microbial load. These results evidence that the capacity to transform synthetic antibiotics may be common among bacteria and highlight the potential of environmental bacteria in attenuating the potential adverse effects of pollution with sulfonamides.
Biodegradation of sulfamethoxazole and other sulfonamides by Achromobacter denitrificans PR1
Publication . Reis, Patrícia J. M.; Reis, Ana C.; Ricken, Benjamin; Kolvenbach, Boris A.; Manaia, Célia M.; Corvini, Philippe F.X.; Nunes, Olga C.
This study aimed to isolate and characterize a microbial culture able to degrade sulfonamides. Sul-famethoxazole (SMX)-degrading microorganisms were enriched from activated sludge and wastewater.The resultant mixed culture was composed of four bacterial strains, out of which only Achromobacterdenitrificans PR1 could degrade SMX. This sulfonamide was used as sole source of carbon, nitrogen andenergy with stoichiometric accumulation of 3-amino-5-methylisoxazole. Strain PR1 was able to removeSMX at a rate of 73.6 ± 9.6 molSMX/gcell dry weighth. This rate more than doubled when a supplement ofamino acids or the other members of the mixed culture were added. Besides SMX, strain PR1 was able todegrade other sulfonamides with anti-microbial activity. Other environmental Achromobacter spp. couldnot degrade SMX, suggesting that this property is not broadly distributed in members of this genus.Further studies are needed to shed additional light on the genetics and enzymology of this process.
Organizational Units
Description
Keywords
Contributors
Funders
Funding agency
Fundação para a Ciência e a Tecnologia
Funding programme
SFRH
Funding Award Number
SFRH/BPD/80834/2011