Bioenergy recovery from olive mill effluent in a hybrid reactor

An anaerobic hybrid reactor was tested in the treatment of raw olive mill effluent (OME)without water dilution, chemical correction and any pretreatment. A feeding strategy was applied by increasing progressively the OME volume fraction from 8% to 83% in the feed mixture combined with an OME complementary substrate (piggery effluent). A biogas production of 3.16 m3 m-3 d-1 was achieved at an organic loading rate of COD at 7.1 kg m-3 d-1, when the highest fraction of OME was added to the influent (volume fraction of 83%; COD concentration fraction of about 94%). At these conditions, the degradation of olive mill effluent occurred without any inhibition. The reactor was capable to digest an acid influent (pH = 4.7), revealing a high buffering capacity. The increase of influent phenols concentration from 0.87 kg m-3 to 2.31 kg m-3 did not influence the reactor removal capacity (phenolic fraction removal from 51% to 61%). Biomass acclimation to OME was accomplished by using a feeding strategy based on effluents complementarity. Furthermore, it was demonstrated that the hybrid digester was able to recover after an accidental overload, and the packing material on the top of the unit prevented excessive loss of biomass. Comparatively to the classic configuration digesters, the hybrid digester is an effective alternative to maximize bioenergy recovery from OME

Anaerobic digestion of OMW : intermittent feeding strategy and LCFA oxidation profile

ManuscriptAn intermittent feeding strategy was applied to the anaerobic treatment of raw olive mill wastewater (OMW). Two reactors were operated under influent concentrations of 5 to 50 g COD L-1. Two and one batch (feed-less) periods were applied to reactor R1 and R2, respectively, operating in continuous thenceforth. It was demonstrated that the intermittent feeding of OMW improved the mineralization of accumulated Long Chain Fatty Acids (LCFA) inside the reactor. Nevertheless, LCFA accumulated again when the organic loading rate was increased from 2 to 3 and 5 kg COD m-3 d-1. The profiles of LCFA, obtained with OMW digestion, were different from previous studies with synthetic effluents. At the beginning of reactors operation, oleate was the main LCFA compound (~50%) followed by palmitate. Afterwards, a shift in the LCFA pattern accumulation was noticed for both reactors. At periods with higher OMW concentrations (30-50 g COD L-1, 3-5 kg COD m-3 d-1) palmitate was the main LCFA accumulated with 69% at R1 and 54% at R2. For real oily wastewaters, a periodically batch period could be a practical solution to maintain low values of LCFA inside the reactor. The addition of a nitrogen source was essential to enhance the methane yield

Strategies for lipids and phenolics degradation in the anaerobic treatment of olive mill wastewater

Strategies are proposed for the anaerobic treatment of lipid and phenolic-rich effluents, specifically the raw olive mill wastewater (OMW). Two reactors were operated under OMW influent concentrations from 5 to 48 g COD L-1 and Hydraulic Retention Time between 10 and 5 days. An intermittent feeding was applied whenever the reactors showed a severe decay in the methane yield. This strategy improved the mineralization of oleate and palmitate, which were the main accumulated Long Chain Fatty Acids (LCFA), and also promoted the removal of resilient phenolic compounds, reaching remarkable removal efficiencies of 60% and 81% for two parallel reactors at the end of a feed-less period. A maximum biogas production of 1.4 m3 m-3 d-1 at an Organic Loading Rate of 4.8 kg COD m-3 d-1 was obtained. Patterns of individual LCFA oxidation during the OMW anaerobic digestion are presented and discussed for the first time. The supplementation of a nitrogen source boosted immediately the methane yield from 21 and 18 to 76 and 93% in both reactors. The typical problems of sludge flotation and washout during the anaerobic treatment of this oily wastewater were overcome by biomass retention, according to the Inverted Anaerobic Sludge Blanket (IASB) reactor concepts. This work demonstrates that it is possible to avoid a previous detoxification step by implementing adequate operational strategies to the anaerobic treatment of OMW.The authors acknowledge the financial support of the “Fundação para a Ciência e a Tecnologia”, FCT/MCTES, through the project PTDC/ENR/69755/2006 and also through the grants given to Marta Gonçalves SFRH/BD/40746/2007 and José Carlos Costa SFRH/BDP/ 48962 /2008. The authors thank Tânia Ferreira for the help in LCFA analysis and Ana Cavaleiro for her scientific support

Peptide fraction identification by SE-HPLC and LC-MS/MS analysis of the body mucus from Portugal coastal fish Halobatrachus didactylus

The mucus covers the fish's body, working as a protective barrier. Besides physical protection, mucus provides molecules that protect the fish from pathogens damaging. 1,2These include antimicrobial peptides secreted in the mucus, which play an essential role in defense against microbial pathogens since these belong to the innate immune system2,3. In this study, two adult Halobatrachus didactylus individuals were captured from the wild in Sesimbra. Then, mucus collection was performed by scraping the dorsal-lateral body of the fish with a sponge. Our objective was the identification of new peptides with bioactive potential in mucus samples by chromatography analysis. Size exclusion high-performance liquid chromatography (SE-HPLC) analysis performed on mucus samples from the two individuals revealed a similar profile with an intense highlight peak which resulted in a distribution of about 775 Dalton. With interest in that peak, the two mucus samples were pooled for fractionation by SEC. The resulting fraction was analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify the most probable peptide sequences. Identification from databases did not provide reliable results, indicating a lack of information on the matrix analyzed. We resorted to de novo sequencing with good results using PEAKS Studio software. Five identified peptides were selected according to their bioactivities predicted in silico. Furthermore, the five identified peptides were synthesized, and the molecular size was validated by SE-HPLC analysis. Overall, this chromatographic approach enabled the identification of promising peptides, which bioactivities will be evaluated in vitro in future work.info:eu-repo/semantics/publishedVersio

Bioactive potential and chromatographic characterization of body mucus from Portugal coastal fish halobatrachus didactylus

The body mucus in fish provides a stable physical or chemical barrier against invading pathogens. In mucus, antimicrobial peptides are secreted as a response to immunestimulation. Studies have shown antimicrobial activity against multidrug­resistant pathogens and low toxicity to eukaryotic cells. Previously, body mucus from five captive Halobatrachus didactylus individuals was collected. We aim to explore the mucus studying molecules with bioactive potential. Size exclusion high­performance liquid chromatography (SE­HPLC) analyses were performed on the five body mucus samples showing a similar molecular size distribution with a maximum peak of ca. 800 Da. These five mucus samples were pooled to assess the following bioactivities: antioxidant (ABTS and ORAC), antimicrobial (minimal inhibitory concentration), andcytotoxicity (Caco­2 and HaCaT human cell lines). The protein content in the mucus, determined by the bicinchoninic acid methodology, was 16836 ± 1020 µg BSA/mL. The antioxidant activity resulted in 268 ± 11 µmol TE/g mucus protein for ABTS and 306 ± 11 µmol TE/g mucus protein for ORAC. The antibacterial activity was assessed against five pathogenic bacteria: Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella enterica, Staphylococcus aureus, within minimal inhibitory concentrations of 421 to 105 µg mucus protein/mL. Moreover, the mucus showed non­cytotoxic for Caco­2 cells in concentrations between 196 to 25 µg mucus protein/mL, while it showed cytotoxicity for HaCaT cells. In the future, liquid chromatography­tandem mass spectrometry (LC­MS/MS) analysis will be performed to determine the molecules behind these bioactivities, namely antimicrobial peptides.info:eu-repo/semantics/publishedVersio

First bioactive characterization of the skin mucus from Portugal coastal fish Halobatrachus didactylus

info:eu-repo/semantics/publishedVersio

Determination of ascorbic acid and acetylsalicylic acid in commercial preparations using an electronic tongue

The electronic tongue is a multi-sensors system used to identify the basic standards of taste, such as sweet, salty, sour and bitter, at levels not detectable by humans. Although the main purpose of electronic tongue is the qualitative analysis, the quantitative analysis of substances in a liquid matrix is also possible, having been the subject of these preliminary studies the application of electronic tongue to pharmaceutical products. In this way, the aim of the current study was the quantitative analysis of ascorbic acid (AA) and acetylsalicylic acid (ASA) in several commercial preparations using an electronic tongue. For that, solutions of standard compounds or of commercial preparations contain ascorbic acid and acetylsalicylic acid were analizes by an electronic tongue. The obtained data were using to determine the concentrations of the solutions thought através do multiple linear regression method. The preliminary tests showed that it is possible to quantify the ascorbic acid in effervescent formulations of vitamin C, using the predictor model obtained by multiple linear regression. In the case of acetylsalicylic acid it was verified that the matrix of the analgesics or antipyretics drugs significantly affect the signs of the electronic tongue. The electronic tongue can be used determined ascorbic acid in effervescent formulations while it is necessary developed more selective sensors to acetylsalicylic acid in order to improve the predictive power of electronic tongue quantification of this compound

Bioaccessibility of novel bioactive peptides from the body mucus of the Lusitanian Toadfish Halobatrachus didactylus using an in vitro digestion model

The bioprospection of marine resources for drug discovery is receiving increasing attention (1). Adverse marine environmental conditions lead organisms to develop a collection of bioactive molecules for survival (1). Mucus, acting as a first line of defense against pathogens (2), is known to protect fish from the surrounding environment. Our previous studies have already demonstrated the bioactive potential of body mucus from the Lusitanian toadfish Halobatrachus didactylus. We performed LC-MS/MS to identify potential peptides within the mucus peptide fraction, selecting them based on in silico predictions of their bioactivities. It was important to assess the capacity of our bioactive peptides to resist the gastrointestinal tract and cross the intestinal epithelial barrier, thereby confirming their possible applicability as health potentiators (3). In this study, two peptides coded HdLPN (sequence PFPGPLPN) and HdVLPN (sequence VYPFPGPLPN) were submitted to an in vitro digestion model using the protocol INFOGEST 2.0. The digested content from the dialysis process after gastrointestinal simulation, both permeate and retentate using 3.5 kDa membranes, were evaluated in vitro for their antioxidant activity through ORAC assay, and the permeate for antihypertensive potential through inhibition of angiotensin-converting enzyme (iACE). The antioxidant activity of the two digested peptides, in both permeate and retentate forms, was comparable to the control (which utilized water in place of peptides); similar results were obtained for their antihypertensive activity in the permeate form. The results for both bioactivities showed no significant differences when comparing the digested peptides' retentate and permeate forms with control. This suggests that the enzymatic hydrolysis occurring during digestion degrades the bioactivity of these peptides, as they exhibited antioxidant activity prior to digestion (HdLPN 0.20±0.02 µmol Eq. Trolox/ mg peptide and HdVLPN 1.51±0.07 µmol Eq. Trolox/ mg peptide), and there was no subsequent activation or potentiation related to antihypertensive activity, which was also absent before digestion. This research primarily focused on evaluating how digestion affects bioactive peptides derived from the mucus of H. didactylus. However, comprehensive analysis, including mass spectrometry, is essential to fully understand the impact of digestion on the hydrolysis of these peptides. A forthcoming study could explore biocompatible materials for safe delivery methods of peptides, e.g. encapsulation, enabling them to withstand gastrointestinal digestion and effectively reach target organs to exert their intended bioactivity (3).info:eu-repo/semantics/publishedVersio