Bioremediation of petroleum-contaminated soils: mathematical modelling as a tool for the simulation of alternative strategies

POCI-01-0145-FEDER-016575; ERC Grant n.º 323009; UID/BIO/04469/2013; POCI -01-0145-FEDER-006684; NORTE-01-0145-FEDER-000004; FCOMP-01-0124- FEDER-027462; SFRH/BPD/80528/2011info:eu-repo/semantics/publishedVersio

Effects of dissolved organic matter and nitrification on biodegradation of pharmaceuticals in aerobic enrichment cultures

Natural dissolved organic matter (DOM) and nitrification can play an important role in biodegradation of pharmaceutically active compounds (PhACs) in aerobic zones of constructed wetlands (CWs). This study used an enrichment culture originating from CW sediment to study the effect of DOM and nitrification on aerobic biodegradation of seven PhACs. The enriched culture degraded caffeine (CAF), metoprolol (MET), naproxen (NAP), and ibuprofen (IBP) with a consistent biodegradability order of CAF > MET > NAP > IBP. Biodegradation of propranolol, carbamazepine, and diclofenac was insignificant (<15%). CAF biodegradation was inhibited by the easily biodegradable DOM. Conversely, DOM enhanced biodegradation of MET, NAP, and IBP, potentially by contributing more biomass capable of degrading PhACs. Nitrification enhanced biodegradation of NAP and IBP and mineralization of the PhAC mixture as well as less biodegradable DOM, which may result from co-metabolism of ammonia oxidizing bacteria or enhanced heterotrophic microbial activity under nitrification. MET biodegradation was inhibited in the presence of nitrification. DOM and nitrification effects on PhAC biodegradation in CWs gained from this study can be used in strategies to improve CW operation, namely: designing hydraulic retention times based on the biodegradability order of specific PhACs; applying DOM amendment; and introducing consistent ammonium streams to increase removal of PhACs of interest

Unraveling who is who in methanogenic oil degradation

2015 Gulf of Mexico Oil Spill and Ecosystem ConferenceMethanogenesis from hydrocarbons is a potentially important component of attenuation in water and sediments impacted by oil spills. The largest fraction of crude oil consists of aliphatic hydrocarbons (AHC). Current knowledge on key microorganisms degrading alkenes is scarce and is a central question addressed in our research. A methanogenic hexadecene (Hxd)-degrading consortium was obtained from laboratory microcosms inoculated with anaerobic granular sludge, and characterized by 16S rRNA gene amplification, cloning and sequencing. We have learned by community analysis that the present bacteria belong mainly to Syntrophaceae and Synergistaceae families. A Syntrophus-like microorganism (96% similarity at genera level) is possibly involved in Hxd degradation. Known methanogens utilizing acetate and H2/CO2 were identified, namely Methanosaeta-, Methanobacterium- and Methanolinea-related microorganisms, and were likely the syntrophic partners in Hxd degradation. With these results we find hints for similar pathways involved in alkenes and alkanes biodegradation. For alkanes, complete degradation to methane can occur through syntrophic interactions between bacteria and methanogens. This is the first time that an alkene-degrading methanogenic mixed community is characterized. Novel microorganisms involved in AHC degradation could be identified. This information is useful for understanding who is doing what, and at what rate. It can be used for innovative biotechnological solutions for deep contaminated sites clean-up.info:eu-repo/semantics/publishedVersio

Effect of ultra-high-density polyethylene microplastic on the sorption and biodegradation of organic micropollutants

Microplastics and organic micropollutants are two emerging contaminants that interact with each other in environmental and engineered systems. Sorption of organic micropollutants, such as pharmaceuticals, pesticides and industrial compounds, to microplastics can modify their bioavailability and biodegradation. The present study investigated the capacity of ultra-high density polyethylene particles (125 µm in diameter), before and after aging, to sorb 21 organic micropollutants at different environmentally relevant concentration. Furthermore, the biodegradation of these organic micropollutants by a biofilm microbial community growing on the microplastic surface was compared with the biodegradation by a microbial community originating from activated sludge. Among all tested organic micropollutants, propranolol (70%), trimethoprim (25%) and sotalol (15%) were sorbed in the presence of polyethylene particles. Growth of a biofilm on the polyethylene particles had a beneficial effect on the sorption of bromoxynil, caffeine and chloridazon and on the biodegradation of irbesartan, atenolol and benzotriazole. On the other hand, the biofilm limited the sorption of trimethoprim, propranolol, sotalol and benzotriazole and the biodegradation of 2,4-D. These results showed that ultra-high density polyethylene particles can affect both in a positive and negative way for the abiotic and biotic removal of organic micropollutants in wastewater. This project highlights the need for further investigation regarding the interaction between microplastics and organic micropollutants in the aquatic environment

Addition of co-substrates stimulates hexadecene conversion to methane by an enriched microbial consortium

ICBM-3 - 3rd International Conference on Biogas MicrobiologyLinear olefins with 16 to 18 carbon atoms are frequently used as hydrophobic groups in oil soluble surfactants and as lubricating fluids. The production of olefins in petrochemical plants generates olefin contaminated wastewater that can be treated anaerobically in methanogenic bioreactors, coupling degradation to energy recovery. However, this conversion is generally slow, due to olefins ́ insolubility in water and poor bioavailability for microorganisms. Addition of an easy degradable carbon source may enhance the growth of hydrocarbon degrading methanogenic communities. In this study, hexadecene degradation by a methanogenic enrichment was stimulated by addition of yeast extract (0.5 g·L-1), lactate (4.5 mmol·L-1) or crotonate (4.5 mmol·L-1) as co-substrates. After stimulation with yeast extract or lactate, the microbial communities were able to convert hexadecene to methane 5 and 2.5 times faster, respectively, than non-stimulated cultures. Hexadecene conversion to methane was not enhanced by crotonate addition. Further incubations with fermented yeast extract did not improve methane production from hexadecene, which suggests that the positive stimulatory effect of yeast extract was due to the extra carbon source and not to the supply of essential co-factors. The microbial community composition of the hexadecene degrading enrichments was studied by 16S rRNA sequencing. Bacteria from the Chloroflexi, Firmicutes, Proteobacteria(Deltaproteobacteria), Spirochaetes, Synergistetes and Thermotogaephyla were identified, with Syntrophobacterales, Spirochaetales and Synergistales as the most abundant orders. Hydrogenotrophic methanogens predominated over acetoclastic methanogens. Currently the isolation and identification of key microbial players involved in hexadecene degradation are ongoing. This study can be useful for improving the treatment of olefin contaminated wastewater using methanogenic conditionsinfo:eu-repo/semantics/publishedVersio

Multi-walled carbon nanotubes enhance methanogenesis from diverse organic compounds in anaerobic sludge and river sediments

Conductive nanomaterials affect anaerobic digestion (AD) processes usually by improving methane production. Nevertheless, their effect on anaerobic communities, and particularly on specific trophic groups such as syntrophic bacteria or methanogens, is not extensively reported. In this work, we evaluate the effect of multi-walled carbon nanotubes (MWCNT) on the activity of two different anaerobic microbial communities: an anaerobic sludge and a river sediment. Methane production by anaerobic sludge was assessed in the presence of different MWCNT concentrations, with direct methanogenic substrates (acetate, hydrogen) and with typical syntrophic substrates (ethanol, butyrate). MWCNT accelerated the initial specific methane production rate (SMPR) from all compounds, with a more pronounced effect on the assays with acetate and butyrate, i.e., 2.1 and 2.6 times, respectively. In the incubations with hydrogen and ethanol, SMPR increased 1.1 and 1.2 times. Experiments with the river sediment were performed in the presence of MWCNT and MWCNT impregnated with 2% iron (MWCNT-Fe). Cumulative methane production was 10.2 and 4.5 times higher in the assays with MWCNT-Fe and MWCNT, respectively, than in the assays without MWCNT. This shows the high potential of MWCNT toward bioenergy production, in waste/wastewater treatment or ex situ bioremediation in anaerobic digesters.This research was funded by the Portuguese Foundation for Science and Technology(FCT) under the scope of project MORE (POCI-01-0145-FEDER-016575), of the strategic funding of UIDB/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020-Programa Operacional Regional do Norte, as well as FCT/MCTES trough national funds (PIDDAC) and Base Funding-UIDB/50020/20 of the Associate Laboratory LSRE-LCM-funded by national funds rough FCT/MCTES (PIDDAC). Research of O.S.G.P.S. was funded by FCT under the Scientific Employment Stimulus-Institutional Call EECINST/00049/2018.info:eu-repo/semantics/publishedVersio

Opinion paper about organic trace pollutants in wastewater: Toxicity assessment in a European perspective

This opinion paper focuses on the role of eco- toxicological tools in the assessment of possible impacts of emerging contaminants on the aquatic ecosystem, hence, on human health. Indeed, organic trace pollutants present in raw and treated wastewater are the pivot targets: a multidisciplinary approach allows defining the basic principles for managing this issue, from setting a proper monitoring campaign up to evaluating the optimal process treatment. Giving hints on trace pollutants fate and behavior, attention is focused on the choice of the bioassay( s), by analyzing the meaning of possible biological answers. Data interpretation and exploitation are detailed with the final goal of providing criteria in order to be able to select the best-targeted treatment options. The manuscript deals with conventional and innovative analytical approaches for assessing toxicity, by reviewing laboratory and field assays ; illustrative real scale and laboratory applications integrate and exemplify the proposed approach

Aerobic nonylphenol degradation and nitro-nonylphenol formation by microbial cultures from sediments

Nonylphenol (NP) is an estrogenic pollutant which is widely present in the aquatic environment. Biodegradation of NP can reduce the toxicological risk. In this study, aerobic biodegradation of NP in river sediment was investigated. The sediment used for the microcosm experiments was aged polluted with NP. The biodegradation of NP in the sediment occurred within 8 days with a lag phase of 2 days at 30°C. During the biodegradation, nitro-nonylphenol metabolites were formed, which were further degraded to unknown compounds. The attached nitro-group originated from the ammonium in the medium. Five subsequent transfers were performed from original sediment and yielded a final stable population. In this NP-degrading culture, the microorganisms possibly involved in the biotransformation of NP to nitro-nonylphenol were related to ammonium-oxidizing bacteria. Besides the degradation of NP via nitro-nonylphenol, bacteria related to phenol-degrading species, which degrade phenol via ring cleavage, are abundantly present