Kinetic study of fermentative biosurfactant production by Lactobacillus strains

Screening of biosurfactant-producing ability of four Lactobacillus strains was performed, being shown that for all the tested strains biosurfactant production occurred mainly in the first 4 h. The Lactobacillus strains showed zones of clearing in the blood agar with a diameter <1 cm. The minimum surface tension value of the fermentation broth achieved was 39.5 mN/m for Lactobacillus pentosus CECT-4023 that represents a reduction in the surface tension of 10.5 mN/m comparing with the control. Time courses of glucose, biomass and biosurfactant were modeled according to reported models. Using MRS broth (Man, Rogosa & Sharpe medium for lactobacilli strains) as culture medium, the values estimated by the modeling of biosurfactant were Pmax = 1.6 g of biosurfactant/L and rp/X = 0.091 g/(L h), for Lactobacillus casei CECT-5275, Pmax = 1.7 g/L and rp/X = 0.217 g/(L h) for Lactobacillus rhamnosus CECT-288, Pmax = 1.7 g/L and rp/X = 0.069 g/(L h) for L. pentosus CECT-4023 and Pmax = 1.8 g/L and rp/X = 0.090 g/(L h) for Lactobacillus coryniformis subsp. torquens CECT-25600. Pmax is the maximum concentration of biosurfactant (g/L), and Pr is the ratio between the initial volumetric rate of product formation (rp) and the initial product concentration P0 (g/L). Using whey as production medium, the values estimated by the modeling of biosurfactant for L. pentosus CECT-4023 were Pmax = 1.4 g of biosurfactant/L and rp/X = 0.093 g/(L h). In conclusion, the results obtained for L. pentosus CECT-4023 showed that this is a strong biosurfactant producer strain and that cheese whey can be used as an alternative medium for biosurfactant production

Modeling of biosurfactant production by Lactobacillus Strains

Screening of biosurfactant-producing ability of three Lactobacillus strains was performed, being shown that, for all the tested strains, biosurfactant production is occurring mainly in the first 7 hours. All strains reduced 8 mN/m the surface tension of the fermentation broth at the end of fermentation and lysed blood agar with scores ranging between (++) corresponding to complete hemolysis with a diameter < 1 cm. Time courses of lactose, biomass and biosurfactant were modeled according to reported models, assuming product inhibition. Using optimized MRS broth as culture medium, the values estimated by the modeling of biosurfactant were P_max = 1.4 g of biosurfactant/L and rp/X = 0.137g/L.hˉ¹ for Lactobacillus casei CECT-5275, P_max = 1.5 g/L and rp/X = 0.145g/L.hˉ¹ for Lactobacillus rhamnosus CECT-288 and P_max = 1.5 g/L and rp/X = 0.089 g/L.hˉ¹ for Lactobacillus pentosus CECT-4023. Using whey as production medium, the values obtained for Lactobacillus rhamnosus CECT-288 were P_max = 1.3 g of biosurfactant/L and rp/X = 0.078 g/L.hˉ¹. In conclusion, the results obtained showed that whey can be used as an alternative medium for biosurfactant production by Lactobacillus strains

Light with tunable non-Markovian phase imprint

We introduce a simple and flexible method to generate spatially non-Markovian light with tunable coherence properties in one and two dimensions. The unusual behavior of this light is demonstrated experimentally by probing the far field and recording its diffraction pattern after a double slit: In both cases we observe instead of a central intensity maximum a line or cross shaped dark region, whose width and profile depend on the non-Markovian coherence properties. Since these properties can be controlled and easily reproduced in experiment, the presented approach lends itself to serve as a testbed to gain a deeper understanding of non-Markovian processes

On the Use of KPCA to Extract Artifacts in One-Dimensional Biomedical Signals

Kernel principal component analysis(KPCA) is a nonlinear projective technique that can be applied to decompose multi-dimensional signals and extract informative features as well as reduce any noise contributions. In this work we extend KPCA to extract and remove artifact-related contributions as well as noise from one-dimensional signal recordings. We introduce an embedding step which transforms the one-dimensional signal into a multi-dimensional vector. The latter is decomposed in feature space to extract artifact related contaminations. We further address the preimage problem and propose an initialization procedure to the fixed-point algorithm which renders it more efficient. Finally we apply KPCA to extract dominant Electrooculogram (EOG) artifacts contaminating Electroencephalogram (EEG) recordings in a frontal channel.info:eu-repo/semantics/publishedVersio

Biopolymeric matrices for structural and functional stabilization of bacteriophages

In the recent past years, bacteriophage research has experienced a renaissance due to their potential application in the pharmaceutical field, especially with the increase of bacterial resistance to antibiotics and the possibility to take part in new methods of early detection and diagnosis of bacterial infections. In that context, the structural and functional stabilization of bacteriophages using biopolymeric microporous hydrogels represents a promising research focus with a broad potential biomedical/ biopharmaceutical application. The scope of this work was to develop biopolymeric non-toxic phage-hydrogels of agar and sodium alginate, obtained at neutral pH and mild polymerization conditions, in order to offer adequate characteristics to the maintenance of phage’s lytic activity. Disc-like phage-hydrogels were prepared, with a phage and polymer concentration of 1.3x108 PFU/ml and 1.5% (w/v), respectively. Regarding the alginate hydrogels, CaCO3 (22.5 mM) and GDL (48 mM) were also included in the formulation. Agar hydrogels were prepared naturally by jellification, as a function of temperature lowering, and alginate hydrogels were prepared by internal gelation. The matrices were inoculated with a suspension of susceptible (host) bacteria and incubated at 37 ºC for 24h. Observation of bacterial lawn’s lysis demonstrated that bacteriophages kept their lytic activity, being the method of physical entrapment able to promote their stabilization. Cryo-SEM analysis revealed that both types of phage-hydrogels present interconnective microporous network, which guaranties a facilitated access of the phages to the bacteria, ensuring an efficient lysis of the host bacteria present in the surface of the hydrogels.The developed hydrogels also present appropriate physical and chemical properties for a wider variety of applications in the field of pharmaceutical sciences, such as controlled release of (macro)molecules, cell immobilization and 3D support for tissue regeneration

The effect of bovine milk lactoferrin on human breast cancer cell lines

The evidence that biologically active food components are key environmental factors affecting the incidence of many chronic diseases is overwhelming. However, the full extent of such components in our diet is unknown, as well as our understanding of their mechanisms of action. Beyond their interaction with the gut and intestinal immune functions, more benefits are being tested for whey proteins such as lactoferrin, namely as anti-cancer agents. Lactoferrin is an iron-binding protein that has been reported to inhibit several types of cancer. In the present work, the effects of bovine milk lactoferrin on human breast cancer HS578T and T47D cells were studied. The cells were either untreated or submitted to lactoferrin concentrations ranging from 0. 125 to 125 μM. Lactoferrin decreased 47% and 54% the cell viability of HS578T and T47D, respectively, and increased apoptosis about twofold for both cell lines. Proliferation rates decreased between 40.3 and 63.9% for HS578T and T47D, respectively. T47D cell migration decreased in the presence of the protein. Although the mechanisms of action have still not been unrevealed, the results gathered in this work suggest that lactoferrin interferes with some of the most important steps involved in cancer development.(undefined

Agro-industrial wastewater treatment with Acacia dealbata coagulation/flocculation and photo-fenton-based processes

The removal of dissolved organic carbon (DOC) and total polyphenols (TPh) from agro-industrial wastewater was evaluated via the application of coagulation–flocculation–decantation (CFD) and Fenton-based processes. For the CFD process, an organic coagulant based on Acacia dealbata Link. leaf powder (LP) was applied. The results showed that the application of the LP at pH 3.0, with an LP:DOC ratio of 0.5:1 (w/w), achieved a high removal of turbidity, total suspended solids (TSS), and volatile suspended solids (VSS) of 84.7, 79.1, and 76.6%, respectively. The CFD sludge was recycled as fertilizer in plant culture (germination index ≥ 80%). Afterwards, the direct application of Fenton-based processes to raw WW was assessed. The Fenton-based processes (UV/Fenton, UV/Fenton-like, and heterogeneous UV/Fenton) showed high energy efficiency and a cost of 1.29, 1.31 and 1.82 €/g/L DOC removal, respectively. The combination of both processes showed the near complete removal of TPh and DOC after 240 min of reaction time, with high energy efficiency. In accordance with the results obtained, the combination of CFD with Fenton-based processes achieves the legal limits for the disposal of water into the environment, thus allowing the water to be recycled for irrigation.Fundação para a Ciência e a Tecnologia | Ref. UIDB/00616/2020Fundação para a Ciência e a Tecnologia | Ref. UI/BD/150847/2020CCRN - Comissão de Coordenação da Região Norte | Ref. NORTE-01-0145-FEDER-00004

Combined organic coagulants and photocatalytic processes for winery wastewater treatment

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGDue to the consumers demand for quality wines, washing and disinfection operations are necessary in wine productions, leading to the generation of large volumes of winery wastewater (WW) with a high organic content which has the potential to cause irreversible environmental impacts. The aim and novelty of this work is the production of natural organic coagulants (NOCs) to be applied in coagulation-flocculation-decantation (CFD) process. To complement this treatment process, it is also aimed the performed a photo-Fenton process, combining hydrogen peroxide (H2O2) and potassium persulfate (KPS). The Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) showed that NOCs are carbon-based materials with adsorption capacity. Under the best operational conditions, NOCs achieved a turbidity removal between 86.2 and 98.9%, a total suspended solids (TSS) removal ranging between 85.0 and 94.9% and a dissolved organic carbon (DOC) removal ranging between 14.1 and 44.9%. To degrade the DOC present in the WW, different advanced oxidation processes (AOPs) were tested. Results showed that KPS-photo-Fenton, under the best operational conditions [Fe2+] = 2.5 mM, [KPS] = 1.0 mM, pH = 3.0, radiation UV-C mercury lamp (254 nm), agitation 350 rpm, temperature 298 K, reaction time 240 min achieved a DOC removal of 91.2 and 96.8%, with a H2O2 consumption of 156.9 and 199.0 mM, respectively for red and white WW. With application of combined CFD-KPS-photo-Fenton process, it was observed an increase of DOC removal with lower H2O2 consumptions. The energy consumption of the photosystem was evaluated by application of electric energy per mass (EEM). The application of KPS-photo-Fenton process achieved an EEM of 0.308 and 0.0309 kWh/g/L DOC, with a cost of 2.05 and 2.59 €/g/L DOC respectively for red and white WW. The combination of CFD-KPS-photo-Fenton decreased significantly the costs of treatment and the treated wastewater achieved the Portuguese legal values for wastewater discharge. This work shows that NOCs are a promising technology that can be an alternative to traditional metal salts, the combination of sulfate radicals with hydroxyl radicals can achieve high DOC removal and the combination of CFD with KPS-photo-Fenton process can decrease the operational costs.Fundação para a Ciência e a Tecnologia | Ref. UIDB/00616/2020Fundação para a Ciência e a Tecnologia | Ref. UI/BD/150847/202

Biosurfactants: production, applications and future potential

Book of Abstracts of CEB Annual Meeting 2017[Excerpt] Surfactants are one of the most important classes of industrial chemicals in terms of production volume. These compounds exhibit a wide variety of applications in several industries and are present in nearly every product and aspect of our daily life. They can be found in detergents, laundry formulations, household cleaning products, cosmetics, herbicides or pesticides, and are also used in bioremediation, agriculture, food, pharmaceutical, textile, paper or the petroleum industries, among others. Most conventional surfactants available nowadays are derived from non-renewable resources and their use may lead to significant ecological problems due to their toxicity and low biodegradability. In the recent years, an increase in environmental awareness has led to much more interest in the use of renewablebased, biodegradable and more environmentally friendly surfactants. Among them biosurfactants, surface-active compounds synthesized by microorganisms, are attracting a pronounced interest due to their potential advantages over their synthetic counterparts, and to the fact that they could replace some of the synthetics in many environmental and industrial applications. [...]info:eu-repo/semantics/publishedVersio

Carcass and meat quality in light lambs from different fat classes in the EU carcass classification system

Ninety commercial lamb carcasses were analysed according to the four different fat classes in the light lamb European classiffication system. Shoulder fat increased 3%, muscle decreased 2% and bone decreased 1% for each class increase. No signifficant differences were found among fat classes regarding pH, WHC, cooking losses, juiciness, myoglobin content, meat colour measured immediately after cutting (L*, a*, b*), odour intensity or flavour quality. Some differences were found in colour evolution through ageing. Shear force decreased and tenderness and flavour intensity increased with fat class but this effect was only signifficant in the leanest animals