The Role of Extracellular Polymeric Substances in Micropollutant Removal

Melo, A. R. B.; Quintelas, C.; Ferreira, E. C.; Mesquita, D. P.

doi:10.3389/fceng.2022.778469

Cited by 18 publications

(3 citation statements)

References 102 publications

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“…The formation of granules and granule-like aggregates is known to depend significantly on the synthesis of extracellular polymer substances (EPSs), which play important roles in biofilms and a key role in the aggregation of activated sludge (Liu et al, 2010;Karygianni Melo et al, 2022). According to our observations, bacterial cells in the aggregates were embedded in the EPS matrix, which bound the cells together.…”

Section: Spontaneous Formation Of Granule-like Aggregatesmentioning

confidence: 50%

New insight into the granule formation in the reactor for enhanced biological phosphorus removal

Pelevina,

Gruzdev,

Berestovskaya

et al. 2023

Front. Microbiol.

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While granulated activated sludge exhibits high productivity, the processes of granule formation are incompletely studied. The processes of granule formation and succession of communities were investigated in a laboratory sequencing batch reactor (SBR) under conditions for enhanced biological phosphorus removal (EBPR) using microbiological and molecular techniques. Active consumption of acetate, primarily by the phosphate-accumulating organisms (PAO), commenced at day 150 of cultivation. This was indicated by the high ratio of molar P-released/acetate uptake (0.73–0.77 P-mol/C-mol), characteristic of PAO. During this period, two types of granule-like aggregates formed spontaneously out of the activated sludge flocs. The aggregates differed in morphology and microbial taxonomic composition. While both aggregate types contained phosphorus-enriched bacterial cells, PAO prevailed in those of morphotype I, and glycogen-accumulating organisms (GAOs) were predominant in the aggregates of morphotype II. After 250 days, the elimination of the morphotype II aggregates from the reactor was observed. The subsequent selection of the community was associated with the development of the morphotype I aggregates, in which the relative abundance of PAO increased significantly, resulting in higher efficiency of phosphorus removal. Metagenomic analysis revealed a predominance of the organisms closely related to Candidatus Accumulibacter IС and IIС and of Ca. Accumulibacter IIB among the PAO. Based on the content of the genes of the key metabolic pathways, the genomes of potential PAO belonging to the genera Amaricoccus, Azonexus, Thauera, Zoogloea, Pinisolibacter, and Siculibacillus were selected. The patterns of physicochemical processes and the microbiome structure associated with granule formation and succession of the microbial communities were revealed.

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Section: Spontaneous Formation Of Granule-like Aggregatesmentioning

confidence: 50%

New insight into the granule formation in the reactor for enhanced biological phosphorus removal

Pelevina,

Gruzdev,

Berestovskaya

et al. 2023

Front. Microbiol.

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“…The limited effect of S-metolachlor on photoautotrophic groups could be linked to the periphyton matrix that is composed by extracellular polymeric substances (EPS) which may represent up to 90% of the dry mass (Flemming and Wingender, 2010). The EPS matrix has several functional groups allowing for the sorption of nutrients and xenobiotics, but can also form a protective layer for the bio lm cells against substances such as pesticides (Melo et al, 2022). The universal decrease in periphyton biomass that we observed over time is likely due to the age of the periphyton in our experiment.…”

Section: Effects Of Herbicides On Photoautotrophs Biomassmentioning

confidence: 99%

Effects of atrazine and S-metolachlor on stream periphyton taxonomic and fatty acid compositions

Malbezin,

Morin,

Lavoie

2024

Ecotoxicology

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Extensive pesticide use for agriculture diffusely pollutes aquatic ecosystems through leaching and runoff events and has the potential to negatively affect non-target organisms. Atrazine and S-metolachlor are two widely used herbicides often detected in high concentrations in rivers that drain nearby agricultural lands. To determine the effects of these two herbicides on river ecosystems, we conducted a 14-day laboratory experiment to expose river periphyton to a wide range of atrazine and S-metolachlor concentrations. The response of periphyton was evaluated using ecologically relevant endpoints including chlorophyll a uorescence and fatty acids composition. Results showed that atrazine disrupted photoautotroph biomass measured by chlorophyll a uorescence. Both herbicides caused dissimilarities in fatty acid pro les between control and high exposure concentrations, but S-metolachlor had a stronger effect than atrazine on the observe increase or reduction in saturated fatty acids (SFAs) and very long chain fatty acids (VLCFAs). Our study demonstrates that two commonly used herbicides, atrazine and S-metolachlor, can negatively affect the composition and fatty acid pro les of stream periphyton, thereby altering the nutritional quality of this resource for primary consumers.

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“…Figure 8 illustrates the various mechanisms employed by microorganisms for the elimination of HMs, including detoxification, biosorption, degradation, mineralization, and transformation from highly toxic to low toxic forms [ 122 , 123 ]. Furthermore, it has been suggested that the utilization of fungi and bacteria may have a potential role in the bioremediation of HM, as depicted in Table 3 [ 124 , 125 , 126 , 127 , 128 , 129 , 130 , 131 , 132 , 133 , 134 , 135 , 136 , 137 , 138 , 139 , 140 ].…”

Section: Bioremediation: Interaction Of Microorganisms With Hmsmentioning

confidence: 99%

Toxicity of Heavy Metals and Recent Advances in Their Removal: A Review

Abd Elnabi,

Elkaliny,

Elyazied

et al. 2023

Toxics

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Natural and anthropogenic sources of metals in the ecosystem are perpetually increasing; consequently, heavy metal (HM) accumulation has become a major environmental concern. Human exposure to HMs has increased dramatically due to the industrial activities of the 20th century. Mercury, arsenic lead, chrome, and cadmium have been the most prevalent HMs that have caused human toxicity. Poisonings can be acute or chronic following exposure via water, air, or food. The bioaccumulation of these HMs results in a variety of toxic effects on various tissues and organs. Comparing the mechanisms of action reveals that these metals induce toxicity via similar pathways, including the production of reactive oxygen species, the inactivation of enzymes, and oxidative stress. The conventional techniques employed for the elimination of HMs are deemed inadequate when the HM concentration is less than 100 mg/L. In addition, these methods exhibit certain limitations, including the production of secondary pollutants, a high demand for energy and chemicals, and reduced cost-effectiveness. As a result, the employment of microbial bioremediation for the purpose of HM detoxification has emerged as a viable solution, given that microorganisms, including fungi and bacteria, exhibit superior biosorption and bio-accumulation capabilities. This review deals with HM uptake and toxicity mechanisms associated with HMs, and will increase our knowledge on their toxic effects on the body organs, leading to better management of metal poisoning. This review aims to enhance comprehension and offer sources for the judicious selection of microbial remediation technology for the detoxification of HMs. Microbial-based solutions that are sustainable could potentially offer crucial and cost-effective methods for reducing the toxicity of HMs.

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The Role of Extracellular Polymeric Substances in Micropollutant Removal

Cited by 18 publications

References 102 publications

New insight into the granule formation in the reactor for enhanced biological phosphorus removal

New insight into the granule formation in the reactor for enhanced biological phosphorus removal

Effects of atrazine and S-metolachlor on stream periphyton taxonomic and fatty acid compositions

Toxicity of Heavy Metals and Recent Advances in Their Removal: A Review

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