Fouling control of submerged and side-stream membrane bioreactors based on the statistical analysis of mid-term assays

The response surface methodology has been applied to study reversible and irreversible fouling rates caused by anaerobic sludge in membrane bioreactors, with the aim of controlling membrane fouling by adjusting filtration conditions. The challenge of obtaining statistically significant results of long-term fouling by means of mid-term assays has been addressed. The individual and combined effects of the filtration flux, backwashing intensity, gas sparging and crossflow velocity on membrane fouling, were analyzed in two types of membranes: an external tubular membrane and a submerged hollow fiber membrane. In the external membrane, the reversible fouling rate was as low as 0.27 ± 0.10 mbar/min, depending mainly on the filtration flux and gas sparging. However, the principal control parameter of the irreversible fouling rate was the crossflow velocity, reaching 2.12 ± 1.75 1012 m−2 in terms of increase of resistance per cubic meter filtered by square meter of membrane. In the submerged membrane, the irreversible fouling rate was quite lower, 0.78 ± 0.40 mbar/d, despite the reversible fouling rate was higher, 1.26 ± 0.42 mbar/min. In this case, the irreversible fouling depended mainly on the backwashing frequency despite the reversible fouling was more affected by the filtration flux and gas sparging. Hence, the approach used to control the reversible fouling rate does not involve mitigating irreversible fouling on both submerged and external membranes. This study provides a methodological basis for the selection of site-specific operating conditions, under which sustainable operation of membrane bioreactors could be achieved.TCUE 2018–2020 cofounded by European Regional Development Fund (ERDF) and Junta de Castilla y León (Spain) and the inestimable collaboration of Campofrío Frescos and Grupo Ecoalia

Kinetic study of the semi-continuous extraction/hydrolysis of the protein and polysaccharide fraction of the industrial solid residue from red macroalgae by subcritical water

The valorization of the underexploited solid residue after agar extraction from red marine algae was studied by subcritical water treatment. Experiments were carried out in two different semi-continuous fix-bed reactor configurations at 185 ºC at different subcritical water residence times. The use of a by-pass section allowed to heat the water previous contact to the biomass, avoiding the exposure of the sample to high temperatures during the heating procedure and reducing the formation of degradation products. Higher hydrolysis yields were obtained for the protein fraction (reaching 96.1%) than for the carbohydrate fraction (reaching 45.7%, 11.3%, 27.5% and 57.6% for galactans, glucans, arabinans and uronic acids, respectively). With the decrease of the residence time, by increasing the flow rate, higher initial hydrolysis rates were obtained due to enhancing diffusion of the hydrolysis products into the bulk solution. It was determined a similar dependence of the initial hydrolysis rates on the residence time for the carbohydrate oligomers and total protein fraction, but the release of free amino acids was less dependent on increasing flow rate due to higher diffusion coefficients for small molecules.Agencia Estatal de Investigación (Spain) [grant number PID2019–104950RB-I00 / AEI / 10.13039/501100011033], the Junta de Castilla y León (JCyL) and the European Regional Development Fund (ERDF) [grant numbers BU301P18 and BU050P20] E. Trigueros and P. Alonso-Riaño predoctoral contracts were funded by the JCyL and the European Social Fund (ESF) by ORDEN EDU/574/2018, de 28 de mayo and ORDEN EDU/556/2019, de 5 de junio, respectively. The C. I. K. Diop contract was funded by the European Commission, Horizon 2020 program through the Marie-Curie Individual Fellowship (H2020-MSCA-IF-2019), with regards to the ALGWAS-BIOR project (Grant agreement number 898804)

Recovery of the protein fraction with high antioxidant activity from red seaweed industrial solid residue after agar extraction by subcritical water treatment

In this work valorization of the underexploited industrial solid residue generated after agar extraction from Gelidium sesquipedale was studied by using subcritical water in a semicontinuous fix-bed reactor. First, a complete characterization of this by-product was carried out, determining up to 21%(w/w) of protein content (for a nitrogen factor of 4.9) with high content of essential amino acids, 37% (w/w) of carbohydrate fraction and high amount of ash, 22% (w/w). The effect of temperature, in the range from 129 to 200 °C, and flow rate, in the range from 2 to 6 mL min−1, on protein and carbon fraction extraction/hydrolysiswas studied.At constant flow rate of 2 mL min−1, a maximum in the protein extraction was achieved at 185 °C. Higher temperatures led to degradation of protein or its hydrolysis products. Free amino acids release followed the same trend as the protein fraction. The most temperature sensitive amino acids, as determined by gas chromatography (EZ:faast Phenomenex), were serine and aspartic and glutamic acids. As a consequence, the selectivity towards non-polar amino acids increased by working at high severity factors. A Pearson correlation between antioxidant capacity of the collected extracts with the bioactive compounds determined in the extracts (total polyphenolic compounds –TPC-, peptides and free amino acids) was established, being stronger for TPC. The ash content in the solid residue after treatment steadily increased with temperature due to non-solubilization being possible its application in agriculture as fertilizers.Agencia Estatal de Investigación [grant number PID2019-104950RB-I00 / AEI / https://doi.org/10.13039/501100011033] and the Junta de Castilla y León (JCyL) and the European Regional Development Fund (ERDF) [grant number BU301P18 and BU050P20

Subcritical water fractionation of proteins and free amino acids from Brewer’s Spent Grain (BSG)

Póster presentado en: 1er Encuentro Ibérico de Fluidos Supercríticos/1º Encontro Ibérico de Fluidos Supercríticos. 2020, 18-19 de febrero, Santiago de CompostelaBrewer’s spent grain (BSG) has been traditionally used only in animal feed despite its high nutritional value, with a protein content of ~20% in dry weight basis [1]. This work is part of a wider project for a complete biomass valorization by using pressurized fluids, namely SC-CO2 to recover the lipophilic fraction and water. In this work we proposed the use of subcritical water at 50 bar and 4 ml/min in a semicontinuous reactor at different temperatures (125 to 185ºC) to extract and hydrolyze BSG proteins. Figure1 shows protein and amino acid values on SubCW extracts accumulated after 240 minutes of extraction. The highest protein content, 15.6 g/100g BSG, dry, was obtained at 185ºC. On the other hand, the highest free amino acid content in extracts, 77 μmol aa/g BSG, dry, was achieved at 160ºC due to amino acid decomposition at this operation conditions. This trend has been also observed in the literature for SCWF of oyster at 150 ºC [2]. Free amino acid formed during BSG protein hydrolysis in SubCW are listed in Table 1 together with the amino acid composition of the BSG protein fraction. Results appears to show a trend related to the hydrophobicity of each group of amino acid since an increase in temperature improves the yield of aliphatic amino acids extraction, while the highest yield for charged amino acids, was reached at 145ºC, and neutral amino acids with a polar side chain, had the highest yield at 160ºC. This agrees with the fact that aliphatic amino acids are stable at higher temperatures. The decrease of water polarity with temperature may favor the affinity for these amino acids due to their hydrophobic character. In addition, small aliphatic amino acids are formed during the decomposition of the other amino acids [3]. BSG offers a great potential as raw material to obtain protein hydrolyzates and amino acids due to its high protein content (~20%) and the elevated rate of EAA. Despite different amino acids has found to be a key parameter on the yield obtained for each amino acid as function of operating temperature. Results obtained in this work suggest that SCWF of BSG is able to recover and hydrolyze BSG proteins.JCyl and ERDF for financial support of project BU301P18. To Hiperbaric, S.A. for financial support of Project BIOLIGNO

Recovery of proteins and free amino acids from Gelidium Sesquipedale alga residue by subcritical water extraction (SWE)

Trabajo presentado en: 1er Encuentro Ibérico de Fluidos Supercríticos/1º Encontro Ibérico de Fluidos Supercríticos. 2020, 18-19 de febrero, Santiago de CompostelaGelidium sesquipedale is a red alga that provides the best raw material to obtain the highest quality agar in the spanish agar industry [1]. Industrial process generates a residue that is usually discarded; however, this by-product still contains important amounts of different valuable compounds, such as structural carbohydrates, bioactive compounds and proteins. To valorize by-product supplied by Hispanagar company (Burgos), subcritical water extraction (SWE) is a promising green technology since water presents unique properties as solvent [2]. This work is focused on the valorization of the protein fraction to produce free amino acids and to extract and hydrolyze protein into small peptides. A semi-continuous reactor has been used to perform the extraction, and protein fraction hydrolysis was studied at different temperatures (125, 140, 155, 170, 185, 200ºC), times, and solvent flow rate (2 and 6 mL/min). Total protein content in alga residue was 20.11±1.53% in which it was determined free amino acids, among which VAL, LEU, ILE, PHE, LYS and HIS are majority (Table 1), being total essential amino acids found 10.50±0.16%, whereas non-essential amino acids like GLY, PRO and GLU+GLN represent 4.57±0.06% Protein extraction grows with increasing temperature at constant flow, reaching a maximum at 200ºC. Moreover, when flow and temperature are increased, protein recovery shows the highest and fastest extraction because of its less residence time, what makes able to get a marked extraction yield improvement (Fig. 1). Amino acids extraction follows a similar trend than proteins: an increasing extraction up to a maximum at 185ºC when flow rate is 2 ml/min, but lower than 6 ml/min. Greatest extraction was found for ALA, GLY, SER and the mixture of ASN+ASP; also for MET, TYR and GLU+GLN mixture, with lower but remarkable yield (Table 1). At constant flow rate, maximum extraction is reached at 185ºC for all amino acids determined, decreasing at 200ºC. Nevertheless, flow rate increasing makes 200ºC extraction much higher, about all for GLU+GLN mixture, LYS, HIS, TYR, PRO, LEU and MET (Fig. 2). This agrees with other studies carried out with fish protein and amino acids standard [3,4]. Moreover, it has been noted than amino acids extraction presents a similar behaviour according to its properties: basic amino acids extraction remains practically constant, whereas than neutral and acid, hydrophobic and sulfur amino acids extraction increase when temperature raises. SWE is a useful technique to extract bioactive compounds. Parameters as temperature or solvent flow rate have much influence on the protein and amino acids extraction yield. All of this makes SWE an interesting alternative to conventional treatments.JCyL and ERDF for financial support of project BU301P18. To Hiperbaric, S.A. for financial support of Project BIOLIGNO. To JCyL and ESF for the predoctoral contracts of E. Trigueros and P. Alonso-Riaño an

Microcellular polymer films based on cross-linked 1-vinyl-2-pyrrolidone and methyl methacrylate

A series of cross-linked copolymer films based on 1-vinyl-2-pyrrolidone and methyl methacrylate were produced using different poly(ethylene glycol) dimethacrylates as cross-linking agents. The average molecular mass of the cross-linking agent was varied, then allowing the foaming process using supercritical CO2 (ScCO2), obtaining microcellular films with different cellular structures as a function of the molecular mass of the cross-linking agent. The chemical structure, swelling behavior, CO2 uptake and cellular morphology of the materials were studied. Finally, the influence of the different cross-linking agents in the mechanical properties was also evaluated by measuring the tensile properties of the microcellular films.Fondo Europeo de Desarrollo Regional (FEDER) and the Spanish Agencia Estatal de Investigación (AEI) (MAT2017-84501-R

Sensory polymeric foams as a tool for improving sensing performance of sensory polymers

Microcellular sensory polymers prepared from solid sensory polymeric films were tested in an aqueous Hg(II) detection process to analyze their sensory behavior. First, solid acrylic-based polymeric films of 100 µm thickness were obtained via radical copolymerization process. Secondly, dithizone sensoring motifs were anchored in a simple five-step route, obtaining handleable colorimetric sensory films. To create the microporous structure, films were foamed in a ScCO2 batch process, carried out at 350 bar and 60 °C, resulting in homogeneous morphologies with cell sizes around 5 µm. The comparative behavior of the solid and foamed sensory films was tested in the detection of mercury in pure water media at 2.2 pH, resulting in a reduction of the response time (RT) around 25% and limits of detection and quantification (LOD and LOQ) four times lower when using foamed films, due to the increase of the specific surface associated to the microcellular structure.Fondo Europeo de Desarrollo Regional) and both the Spanish Agencia Estatal de Investigación (MAT2017-84501-R) and the Consejeria de Educación-Junta de Castilla y León (BU306P18

Sostenibilidad curricular de titulaciones universitarias: un proyecto del Grupo SAC-UBU para conocer la percepción del alumnado de la Facultad de Ciencias

Póster presentado en: VIII Jornadas de Innovación Docente de la UBU, Burgos, 5 de abril de 2016, organizadas por el Instituto de Formación e Innovación Educativa-IFIE de la Universidad de Burgo

Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE

Combined search for the quarks of a sequential fourth generation

Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about +/- 20 GeV. These results significantly reduce the allowed parameter space for a fourth generation of fermions.Comment: Replaced with published version. Added journal reference and DO