Cometabolic Enzymatic Transformation of Organic Micropollutants under Methanogenic Conditions

González-Gil, Lorena; Carballa, Marta; Lema, Juan M.

doi:10.1021/acs.est.6b05549

Cited by 73 publications

(45 citation statements)

References 54 publications

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“…The exception was NPX, which decreased its concentration at higher rates in anaerobic condition. The higher anaerobic degradation rates of NPX, unlike the cases of other NSAIDs, were consistent with previous reports on anaerobic digestion of sewage sludge [5,13,24], although transformation products of NPX have usually been detected after aerobic and anaerobic treatment [25,26]. No anaerobic degradation of CA was observed.…”

Section: Effect Of Soil Type On the Degradationsupporting

confidence: 91%

Aerobic and Anaerobic Biological Degradation of Pharmaceutically Active Compounds in Rice Paddy Soils

2019

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One of the concerns against the use of sewage sludge for agricultural purposes is emerging contaminants contained in sewage sludge. Most of the studies on biological degradation of pharmaceutically active compounds in agricultural land were carried out with water-unsaturated soils under relatively aerobic conditions. In this study, the degradation of pharmaceuticals mainly including non-steroidal anti-inflammatory drugs (NSAIDs) was investigated in Asian rice paddy soils that are flooded in anaerobic condition. The experimental results showed that the concentrations of the target pharmaceuticals excluding the exception of naproxen were poorly decreased in anaerobic condition. On the other hand, the microbial communities of the soils contained the aerobic degraders of clofibric acid and diclofenac, which are generally persistent in biological wastewater treatment. The higher degradation rates in aerobic condition suggest the possibility of enhanced degradation of pharmaceuticals by supplying oxygen with plowing anaerobic rice fields or with drying the field in off-season for farming.

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Section: Effect Of Soil Type On the Degradationsupporting

confidence: 91%

Aerobic and Anaerobic Biological Degradation of Pharmaceutically Active Compounds in Rice Paddy Soils

2019

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“…hydrolases) and intracellular enzymes (i.e. hydrolases, acetate kinase and monooxygenases) have been recently shown to be able to biotransform OMPs in biological wastewater processes (Fernandez-Fontaina et al, 2016;Fischer and Majewsky, 2014;Gonzalez-Gil et al, 2017;Krah et al, 2016). Therefore, we hypothesize that OMPs can be biotransformed in both phases.…”

Section: Biotransformation Phase and Influence Of The Partition Coeffmentioning

confidence: 94%

Role of methanogenesis on the biotransformation of organic micropollutants during anaerobic digestion

González-Gil

Mauricio‐Iglesias

Serrano

et al. 2018

Science of The Total Environment

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Several studies showed that some organic micropollutants (OMPs) are biotransformed during anaerobic digestion (AD). Yet, most of them aim at reporting removal efficiencies instead of understanding the biotransformation process. Indeed, how each of the main AD stages (i.e., hydrolysis, acidogenesis, and methanogenesis) contribute to OMP biotransformation remains unknown. This study focuses on investigating the role of methanogenesis, the most characteristic step of AD, to OMP removal. More specifically, the sorption and the biotransformation of 20 OMPs by methanogenic biomass were analyzed determining their concentrations in both liquid and solid phases. Sorption onto methanogenic biomass displayed a similar behavior as reported for digested sludge. Most of the OMPs were biotransformed to a medium extent (35-70%) and only sulfamethoxazole was completely removed. Comparing these results with those reported for the complete AD process, methanogenesis was proven to play a key role, accounting for more than 50% of the OMP biotransformation (except for roxithromycin) during AD. An increase in the organic loading rate from 1 to 2gCOD/Ld, typical loads employed in sewage sludge anaerobic digesters, did not exert a clear cometabolic effect on the OMPs biotransformation. It is hypothesized that biotransformation occurs in both liquid and solid phases because no link between the partition coefficient (Kd) and the overall biotransformation efficiency was found. These findings allow a better understanding of the OMPs fate under anaerobic conditions, which is necessary to design efficient biological mitigation strategies.

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“…Changing the oxygen conditions can influence the redox potential of the cell, hence, resulting in endogenous ROS production. As previously described, the oxygen free radicals can act as co-substrates for the synthesis of oxidoreductases (peroxidases, laccases and cytochromes) while fortuitously oxidising nearby organic substrates (53, 56). For example, the synthesised lignin peroxidases are high redox peroxidases which use activated molecular oxygen (such as superoxides and hydrogen peroxides) for the hydroxylation and cleavage of aromatic rings (57–59).…”

Section: Discussionmentioning

confidence: 95%

“…For example, the synthesised lignin peroxidases are high redox peroxidases which use activated molecular oxygen (such as superoxides and hydrogen peroxides) for the hydroxylation and cleavage of aromatic rings (57–59). We suggest that non-specific oxidoreductases such as peroxidases, cytochrome P450 and laccases in the DO perturbed cultures are metabolising OMPs in the presence of energy molecules (NADH or NAD + ) produced during cellular metabolism operated by different oxygen regulatory systems (53).…”

Section: Discussionmentioning

confidence: 99%

“…The capability of synthesised oxidoreductases for OMP biotransformation across different functional groups including carboxylic compounds (NPX and IBP), hydroxyl compounds (TT) and other functional groups (SMX, CBZ and ATZ) is demonstrated by their transformation in the DO perturbed cultures (53, 60, 61). The active haem and copper centres of peroxidases and laccases and their reactivity with the evaluated OMPs (having relatively small sizes being comprised of 1-2 benzene rings) explains their significant biotransformation.…”

Section: Discussionmentioning

confidence: 99%

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Induction of microbial oxidative stress as a new strategy to enhance the enzymatic degradation of organic micropollutants in wastewater

Bains

Perez-Garcia

Lear

et al. 2019

Preprint

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15Organic micropollutants (OMPs) are pervasive anthropogenic contaminants of fresh and 16 marine waters with known potential to adversely affect aquatic life (e.g. endocrine disruption). 17Their ubiquitous environmental occurrence is primarily attributed to wastewater treatment 18 plant discharges following their incomplete removal by common biological treatment 19 processes. This study assesses a new strategy for promoting the degradation of six model OMPs 20 (i.e. sulfamethoxazole, carbamazepine, tylosin, atrazine, naproxen and ibuprofen) by 21 stimulating microbial oxidoreductase production to counter the effects of oxidative stress 22 caused by oxygen perturbation. Microbial cultures from dairy farm wastewater were exposed 23 to a cyclical ON-OFF perturbations of oxygen supply, ranging from 0.16 to 2 cycles per hour 24 (i.e. 2, 1, 0.5, 0.25 and 0.16 cycles/hour), in laboratory bioreactors. The activity and relative 25 abundances of microbial oxidoreductases (such as peroxidases, cytochromes P450) were 26 upregulated by oxygen perturbation. In comparison to controls subjected to constant oxygen 27 levels, OMP concentrations in perturbed cultures decreased by 70±9% (mean ± SD). A 28 distance-based linear model confirmed strong positive correlations between the relative 29 abundance of the bacterial families, Rhodocyclaceae, Syntrophaceae and 30 Syntrophobacteraceae, and oxygen perturbations. Our results confirm that intentional 31 perturbation of oxygen supply to induce microbial oxidative stress can improve OMP removal 32 efficiencies in wastewater treatment bioreactors. 33 Microbial communities | Oxidoreductase activity | Bioreactor aeration regime | Wastewater 34 OMPs removal 35 36 37 38 39 40 41 42 43 44 45 Significance 46 47Oxygen concentration is a critical control variable for biological processes in conventional 48 wastewater treatment systems. We provide a simple approach that could be used in existing 49 wastewater treatment infrastructure to enhance removals of otherwise persistent OMPs by 50 exploiting oxidative stress responses of microbes. Our study illustrates the ability of fluctuating 51 oxygen conditions to affect microbial activity and polulation by upregulating oxidoreductases 52 linked to the removal of organic micropollutants. The incorporation of inexpensive and easy to 53 implement dissolved oxygen supply strategies for more efficient OMPs biotransformation 54 provides a realistic approach to improving the treatment performance of biological processes. 56Because of their resistance to conventional wastewater treatment and environmental 60 persistence as complex mixtures, these organic micropollutants (OMPs) present risks of 61 adverse ecological impact to biota via direct toxicity and endocrine disruption (4-6). For 62 example, occurrence of the herbicide, atrazine, even at concentrations below 6 µg/L in 63 receiving waters, caused behavioural changes in the zebrafish, Brachydanio rerio, such as a 64 preference for dark habitats and alterations in swimming due to failure of its nervou...

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Cometabolic Enzymatic Transformation of Organic Micropollutants under Methanogenic Conditions

Cited by 73 publications

References 54 publications

Aerobic and Anaerobic Biological Degradation of Pharmaceutically Active Compounds in Rice Paddy Soils

Aerobic and Anaerobic Biological Degradation of Pharmaceutically Active Compounds in Rice Paddy Soils

Role of methanogenesis on the biotransformation of organic micropollutants during anaerobic digestion

Induction of microbial oxidative stress as a new strategy to enhance the enzymatic degradation of organic micropollutants in wastewater

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