Characterization of pure cultures isolated from sulfamethoxazole-acclimated activated sludge with respect to taxonomic identification and sulfamethoxazole biodegradation potentialReport as inadecuate




Characterization of pure cultures isolated from sulfamethoxazole-acclimated activated sludge with respect to taxonomic identification and sulfamethoxazole biodegradation potential - Download this document for free, or read online. Document in PDF available to download.

BMC Microbiology

, 13:276

Applied microbiology

Abstract

BackgroundSulfamethoxazole SMX, sulfonamide antibiotic biodegradation by activated sludge communities ASC is still only partly understood. The present work is focusing on nine different bacteria species capable of SMX biodegradation that were isolated from SMX-acclimated ASC.

ResultsInitially 110 pure cultures, isolated from activated sludge, were screened by UV-absorbance measurements UV-AM for their SMX biodegradation potential. Identification via almost complete 16S rRNA gene sequencing revealed five Pseudomonas spp., one Brevundimonas sp., one Variovorax sp. and two Microbacterium spp

Thus seven species belonged to the phylum Proteobacteria and two to Actinobacteria. These cultures were subsequently incubated in media containing 10 mg L SMX and different concentrations of carbon sodium-acetate and nitrogen ammonium-nitrate. Different biodegradation patterns were revealed with respect to media composition and bacterial species. Biodegradation, validated by LC-UV measurements to verify UV-AM, occurred very fast with 2.5 mg L d SMX being biodegraded in all pure cultures in, for UV-AM modified, R2A-UV medium under aerobic conditions and room temperature. However, reduced and different biodegradation rates were observed for setups with SMX provided as co-substrate together with a carbon-nitrogen source at a ratio of DOC:N – 33:1 with rates ranging from 1.25 to 2.5 mg L d.

ConclusionsMedia containing only SMX as carbon and nitrogen source proved the organisms’ ability to use SMX as sole nutrient source where biodegradation rates decreased to 1.0 – 1.7 mg L d. The different taxonomically identified species showed specific biodegradation rates and behaviours at various nutrient conditions. Readily degradable energy sources seem to be crucial for efficient SMX biodegradation.

KeywordsBatch setups Wastewater treatment plants Xenobiotics UV-absorbance Pharmaceuticals Phylogenetic analyses Sulfamethoxazole Electronic supplementary materialThe online version of this article doi:10.1186-1471-2180-13-276 contains supplementary material, which is available to authorized users.

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Author: Bastian Herzog - Hilde Lemmer - Harald Horn - Elisabeth Müller

Source: https://link.springer.com/



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