| Congresso Brasileiro de Microbiologia 2023 | Resumo: 603-3 | ||||
Resumo:The bacteria Brevundimonas sp., Burkolderia sp. and Sphingomonas sp. are bacilli often found in biological wastewater treatment plants ⟨WWTPs⟩. There is an infinite variety of organic micropollutants ⟨OMPs⟩ present in sewage that reach treatment plants or directly to receiving water bodies, which can cause negative impacts on the microbiota. Among these microcontaminants, antibiotics, anti-inflammatory drugs, and parabens can be cited, which are frequently detected and generally not completely removed in WWTPs. This work sought to evaluate the impact of phamaceuticals ⟨sulfamethoxazole − SMX, naproxen − NPX, diclofenac − DCF, ibuprofen − IBU⟩ and parabens ⟨methylparaben − MPB, and propylparaben − PPB⟩ on microorganisms present in the sludge of sewage treatment plants. Initially, the bacterial inocula ⟨Brevundimonas sp., Burkolderia sp. and Sphingomonas sp. ⟩ were acclimatized at 30 ºC in lab−made sewage, filtered at 0.45 μm, composed of ⟨values in mg⁄L ⟩: sucrose ⟨211⟩, starch ⟨221⟩, beef extract ⟨530⟩, NaHCO3 ⟨600⟩ KH2PO4 ⟨30⟩, NaCl ⟨125⟩, CaCl2.2H2O ⟨18⟩, MgCl2.6H2O ⟨28⟩. After reached the exponential growth of these cultures, they were transferred to tubes containing the aforementioned OMPs at a concentration of 100 μg ⁄L. A control without microorganisms was performed to evaluate the abiotic degradation of the compounds, and a control without micropollutants was performed to evaluate bacterial growth without the interference of the chemicals. The incubation time was one week at a mesophilic temperature of 30ºC, with the absorbance read at 600 nm. An aliquot of samples for OMPs analysis were removed from the tubes, centrifuged and diluted to enable detection in the reading range of the LC−MS/MS system. In addition to these assays, glycerol ⟨GOH⟩ was tested as a cosubstrate for growth of microorganisms and the possibility of evaluating heterotrophic cometabolism in the OMPs biodegradation. Considering the removal without GOH, significant biodegradation is reached only for parabens ⟨MPB −81% and PPB− 88%⟩ driven by Burkolderia sp. For the other compounds −IBU, NPX, DCF and SMX, biodegradation was slight ⟨10% to 20%⟩ for Brevundimonas sp. and Burkolderia sp. For Sphingomonas sp., a significant effect of glycerol as a metabolic cosubstrate was observed for the biodegradation of all evaluated compounds ⟨60% to 100%⟩, whereas for the other microorganisms this positive effect was not noticed. It can be concluded that the OMPs evaluated in this study ⟨ IBU, NPX, DCF, SMX, MPB, PPB⟩ do not represent an inhibitory effect on the microorganisms evaluated for the studied concentration. Nonetheless, the removal of these compounds was quite limited, with only parabens being effectively biodegraded by Burkolderia sp. Glycerol proved to be a great carbon source to be supplemented in biological sewage treatment systems containing Sphingomonas sp. to enhance the biodegradation of the aforementioned OMPs.
Palavras-chave: antibiotic, anti-inflammatory drugs, organic micropollutants, microbial inhibition, wastewater Agência de fomento: SÃO PAULO RESEARCH FOUNDATION (FAPESP) | |||||