Recovery of phenolic compounds from wine lees using green processing: Identifying target molecules and assessing membrane ultrafiltration performance.

Winery wastes are rich in polyphenols with high added value to be used in cosmetics, pharmaceuticals, and food products. This work aims at recovering and purifying the polyphenolic fraction occurring in the malolactic fermentation lees generated during the production of Albariño wines. Phenolic acids, flavonoids, and related compounds were recovered from this oenological waste by green liquid extraction using water as the solvent. The resulting extract solution was microfiltered to remove microparticles and further treated by ultrafiltration (UF) using membranes of 30 kDa and 5 kDa molecular weight cut-offs (MWCOs). The feed sample and the filtrate and retentate solutions from each membrane system were analyzed by reversed-phase liquid chromatography (HPLC) with UV and mass spectrometric (MS) detection. The most abundant polyphenols in the extracts were identified and quantified, namely: caftaric acid with a concentration of 200 µg g-1 and trans-coutaric acid, cis-coutaric acid, gallic acid, and astilbin with concentrations between 15 and 40 µg g-1. Other minor phenolic acids and flavanols were also found. The UF process using the 30 kDa membrane did not modify the extract composition, but filtration through the 5 kDa poly-acrylonitrile membrane elicited a decrease in polyphenolic content. Hence, the 30 kDa membrane was recommended to further pre-process the extracts. The combined extraction and purification process presented here is environmentally friendly and demonstrates that malolactic fermentation lees of Albariño wines are a valuable source of phenolic compounds, especially phenolic acids.

A green approach to phenolic compounds recovery from olive mill and winery wastes.

The aim of this study was to evaluate the recovery of phenolic compounds from olive mill and winery wastes by conventional solid-liquid extraction (SLE) using water as the extraction solvent. The studied variables were extraction time (5-15 min), temperature (25-90 °C), solid-to-liquid ratio (1:10-1:100 (kg/L)), pH (3-10) and application of multiple extractions (1-3). The extraction efficiency was evaluated in terms of total phenolic content (TPC), determined by high performance liquid chromatography (HPLC-UV), but also from the recovery of some representative phenolic compounds. The optimized conditions were one extraction step, 10 min, 25 °C, 1:30 (kg/L), pH 5 for olive pomace, and one extraction step, 10 min, 70 °C, 1:100 (kg/L), pH 5 for winery residues. The extraction method is simple and suitable for scaling-up in industry, and the aqueous extracts are fully compatible with further purification schemes based on the use of membranes or resins. The optimized technique was applied to a set of different representative residues from olive mill and winery industries, to assess their suitability as sources for phenolic compounds recovery. The phenolic content in the extracts was evaluated by chromatographic analysis and by the Folin-Ciocalteu assay (FC). Furthermore, the antioxidant capacity was determined by 2,2-azinobis-3-etilbenzotiazolina-6-sulfonat (ABTS), 2,-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Because of their high contents in phenolic compounds and great antioxidant capacity, olive pomace and lees filters were identified as especially suited sources for phenolic compounds recovery.

Cometabolic removal of organic micropollutants by enriched nitrite-dependent anaerobic methane oxidizing cultures.

The innovative and recently discovered n-damo process, based on anaerobic methane oxidation with nitrite, was developed in a membrane-based bioreactor and evaluated in terms of organic micropollutants (OMPs) removal. The main singularity of this study consisted in the evaluation of organic micropollutants (OMPs) removal in the biological reactor. A strategy consisting on progressively increasing the nitrogen loading rate in order to increase the specific denitrification activity was followed to check if the selected OMPs were co-metabolically biotransformed. Significant nitrite removal rate (24.1 mg N L-1 d-1) was achieved after only 30 days of operation. A maximum specific removal of 186.3 mg N gVSS-1 d-1 was obtained at the end of the operation, which is one of the highest previously reported. A successfully n-damo bacteria enrichment was achieved, being Candidatus Methylomirabilis the predominant bacteria during the whole operation attaining a maximum relative abundance of about 40 %. The natural hormones (E1 and E2) were completely removed in the bioreactor. The specific removal rates of erythromycin (ERY), fluoxetine (FLX), roxithromycin (ROX) and sulfamethoxazole (SMX) were successfully correlated with the specific nitrite removal rates, suggesting a co-metabolic biotransformation.

A new decentralized biological treatment process based on activated carbon targeting organic micropollutant removal from hospital wastewaters.

Although hospital wastewaters (HWWs) are usually discharged in urban sewage systems, their separate treatment has several benefits, such as the specific treatment of potential toxics as well as avoidance of further dilutions. In this work, an integrated industrial pilot plant (2200 L) corresponding to the technology SeMPAC® is proposed and validated for such purpose. The process consists of a sequential batch reactor (SBR) connected to an external submerged microfiltration membrane, in which powdered activated carbon (PAC) is directly added into the biological reactor to enhance the removal of the organic micropollutants (OMPs). The combination of different redox conditions in the SBR, as well as the operation at long sludge retention times (SRTs) and high biomass concentrations favored OMP biotransformation in the SBR, being their final removal efficiencies enhanced clearly after PAC addition, especially for the recalcitrant compounds. A periodical renewal of the adsorbent is necessary to overcome its gradual saturation. The main operational conditions were influenced by (i) the recalcitrant OMP carbamazepine, which defines the PAC dosage; (ii) the easily degradable OMP ibuprofen, which can be used to optimize the duration of the aerobic cycle; and (iii) the denitrification efficiency, which defines the correct time length of the anoxic period.

Olive Mill and Winery Wastes as Viable Sources of Bioactive Compounds: A Study on Polyphenols Recovery.

In this study, the recovery of polyphenols from olive oil mill and winery waste was investigated. The performance of ultrasound assisted extraction (UAE), microwave assisted extraction (MAE), and pressurized liquid extraction (PLE) was assessed using ethanol-water mixtures, which are compatible with food, nutraceutical, and cosmetic applications. The extraction efficiency from olive pomace and lees samples was evaluated in terms of total polyphenol content (TPC), determined by high performance liquid chromatography (HPLC) and Folin-Ciocalteu assay. The effect of solvent composition, temperature, and time was analyzed by response surface methodology. Ethanol:water 50:50 (v/v) was found to be a suitable solvent mixture for both kinds of samples and all three extraction techniques. The performance of the extraction techniques was evaluated, under optimal experimental conditions, with a set of different representative samples of residues from olive oil and wine production. Overall, the best extraction efficiency for olive pomace residues was provided by MAE (ethanol:water 50:50 (v/v), 90 °C, 5 min), and for wine residues by PLE (ethanol:water 50:50 (v/v), 100 °C, 5 min, 1 cycle). However, the results provided by UAE (ethanol:water 50:50 (v/v), 30 min) were also suitable. Considering not only extraction performance, but also investment and operational costs, UAE is proposed for a future scaling up evaluation. Regarding olive pomace as a source for natural phenolic antioxidants, olive variety and climatic conditions should be taken into account, since both influence TPC in the extracts, while for winery residues, lees from red wines are more suitable than those from white wines.

Inhibition of biomass activity in the via nitrite nitrogen removal processes by veterinary pharmaceuticals.

The inhibitory effect of two veterinary pharmaceuticals was studied for different types of biomass involved in via nitrite nitrogen removal processes. Batch tests were conducted to determine the inhibition level of acetaminophen (PAR) and doxycycline (DOX) on the activity of short-cut nitrifying, denitrifying and anoxic ammonium oxidation (anammox) biomass and phosphorus accumulating organisms (PAOs). All biomass types were affected by PAR and DOX, with anammox being the most sensitive bacteria. DOX inhibited more the biomass treating high strength nitrogenous effluents (HSNE) than low strength nitrogenous effluents (LSNE). The phosphorus uptake inhibition under anoxic conditions was lower than 25% in the presence of PAR up to 400 mg L(-1). The same DOX concentration inhibited anoxic phosphorus uptake more than 65% for biomass treating LSNE and HSNE. Heterotrophic denitrifying bacteria seem to be more robust at high DOX and PAR concentrations than anammox. Both veterinary products inactivated ammonium oxidizing, Accumulibacter phosphatis and denitrifying bacteria.