Efecte antimicrobià de formulacions netejadores de interès industrial en cèl·lules en suspensió i biopel·lícules

Las biopelículas son una fuente de contaminación de difícil eliminación debido a su resistencia a los procedimientos de limpieza y de higiene convencionales. En este trabajo se ha evaluado las propiedades antimicrobianas a temperatura ambiente de tensioactivos de interés industrial en la formulación de detergentes. En primer lugar se estudió la capacidad de adhesión de la levadura Yarrowia lipolytica y del moho Aspergillus niger a superficies de espuma de poliuretano y de vidrio, así como su habilidad para formar biopelículas bajo diferentes condiciones de cultivo. Las biopelículas más estables fueron tratadas a temperatura ambiente con una mezcla de un alquilpoliglucósido y un alcohol graso etoxilado, y con un ácido alquil éter carboxílico. Los resultados experimentales mostraron que células formando parte de biopelículas eran más resistentes al tratamiento desinfectante que células libres en suspensión del mismo microorganismo. Aunque las soluciones de tensioactivos ensayadas fueron poco eficaces contra biopelículas, mostraron un gran efecto inhibidor sobre células en disolución. Además inhiben la formación de nuevas biopelículas. Por lo tanto, los buenos efectos antimicrobianos de estos tensioactivos ecológicos a temperatura ambiente podrían proporcionarles un interés potencial en procedimientos de limpieza a baja temperatura.Biofilms are a challenging source of contamination due to their resistance to conventional cleaning and hygiene procedures. In this work, we assessed the antimicrobial properties at room temperature of surfactants of industrial interest in detergent formulation. The adhesion abilities of the yeast Yarrowia lipolytica and the mould Aspergillus niger to polyurethane foam and glass surfaces and their ability to develop as biofilm was firstly studied under different culture conditions. The most stable biofilms were then treated at room temperature with a mixture of an alkylpolyglucoside and an ethoxylated fatty alcohol, and with an ether carboxylate. Experimental results illustrated that surface-attached cells were more resistant to disinfectant treatment than cells of the same microorganism grown in suspension. Although the assayed surfactant solutions hardly removed attached biofilms, they showed a great inhibitory effect on free-living cells. What is more, biofilms did not grow during treatments. Therefore, the good antimicrobial effects of these ecological surfactants at room temperature could provide them a potential interest in low-temperature cleaning in place procedures.Les biopel·lícules son una font de contaminació de difícil eliminació degut a la seva resistència als procediments de neteja i higiene convencionals. En aquest treball s’han avaluat les propietats antimicrobianes a temperatura ambient de tensioactius d’interès industrial en la formulació de detergents. En primer lloc es va estudiar la capacitat d’adhesió del llevat Yarrowia lipolytica i de la floridura Aspergillus niger a superfícies d’espuma de poliuretà i de vidre, així com la seva habilitat per a formar biopel·lícules sota diferents condicions de cultiu. Les biopel•lícules més estables van ser tractades a temperatura ambient amb una barreja d’un alquilpoliglucósid i un alcohol gras etoxilat, i amb un àcid alquil èter carboxílic. Els resultats experimentals mostren que cèl·lules formant part de biopel ·lícules eren mes resistents al tractament desinfectant que cèl·lules lliures en suspensió del mateix microorganisme, encara que les solucions de tensioactius assajades van ser poc eficaces contra biopel·lícules, mostrant un gran efecte inhibidor sobre cèl·lules en dissolució. A més inhibeixen la formació de noves biopel·lícules. Per tant, els bons efectes antimicrobians d’aquests tensioactius ecològics a temperatura ambient podrien proporcionar-lis un interès potencial en procediments de neteja a baixa temperatura

Antimicrobial effect of cleaning formulations of industrial interest on free-living cells and biofilms

Biofilms are a challenging source of contamination due to their resistance to conventional cleaning and hygiene procedures. In this work, we assessed the antimicrobial properties at room temperature of surfactants of industrial interest in detergent formulation. The adhesion abilities of the yeast Yarrowia lipolytica and the mould Aspergillus niger to polyurethane foam and glass surfaces and their ability to develop as biofilm was firstly studied under different culture conditions. The most stable biofilms were then treated at room temperature with a mixture of an alkylpolyglucoside and an ethoxylated fatty alcohol, and with an ether carboxylate. Experimental results illustrated that surface-attached cells were more resistant to disinfectant treatment than cells of the same microorganism grown in suspension. Although the assayed surfactant solutionshardly removed attached biofilms, they showed a greatinhibitory effect on free-living cells. What is more, biofilmsdid not grow during treatments. Therefore, the good antimicrobial effects of these ecological surfactants at roomtemperature could provide them a potential interest inlow-temperature cleaning in place procedures

Silica micro-and nanoparticles reduce the toxicity of surfactant solutions

In this work, the toxicity of hydrophilic fumed silica microand nanoparticles of various sizes (7 nm, 12 nm, and 50 μm) was evaluated using the luminescent bacteria Vibrio fischeri. In addition, the toxicity of an anionic surfactant solution (ether carboxylic acid), a nonionic surfactant solution (alkyl polyglucoside), and a binary (1:1) mixture of these solutions all containing these silica particles was evaluated. Furthermore, this work discusses the adsorption of surfactants onto particle surfaces and evaluates the effects of silica particles on the surface tension and critical micellar concentration (CMC) of these anionic and nonionic surfactants. It was determined that silica particles can be considered as non-toxic and that silica particles reduce the toxicity of surfactant solutions. Nevertheless, the toxicity reduction depends on the ionic character of the surfactants. Differences can be explained by the different adsorption behavior of surfactants onto the particle surface, which is weaker for nonionic surfactants than for anionic surfactants. Regarding the effects on surface tension, it was found that silica particles increased the surface activity of anionic surfactants and considerably reduced their CMC, whereas in the case of nonionic surfactants, the effects were reversed

Characterization of the ozone effect over an α-amylase from Bacillus licheniformis

Starch usually soils industrial process equipment, hence demanding specific washing procedures to ensure optimal products and reliable process performance. α-Amylases have been included in detergent formulations to hydrolyse starch making easier its elimination. Ozone is frequently used as disinfectant but could also help to remove the starchy soils improving the cleaning process. To study the effect of ozone on the enzyme, the ozonation of an α-amylase from Bacillus licheniformis at pH 7.5 and 25°C was carried out. Enzyme activity assays showed that the relative α-amylase activity after ozonation decreased with increasing ozone/enzyme molar ratio exponentially. On the other hand, the ozone concentration after the reaction was negligible as some enzymatic activity remained, being the ozone consumption fast due to the high reaction kinetics of aromatic and sulfur-containing amino acids residues of the enzyme. The UV and MALDI-TOF mass spectra confirmed the oxidation of these amino acids, while the peptide bonds were unaffected. Therefore the loss of the α-amylase activity observed would be caused by the oxidation of amino acids residues directly involved in the hydrolysis mechanism such as tyrosine and histidine and/or by denaturation of the enzyme upon amino acid residues oxidation.Grupos de Investigación RNM332 y TEP21

Modification of the activity of an a-amylase from Bacillus licheniformis by several surfactants

The influence of different commercial surfactants on the enzymatic activity of a commercial α-amylase from Bacillus licheniformis (Termamyl 300 L) has been studied. As non-ionic surfactants, alkyl polyglycosides (Glucopon® 215, Glucopon® 600 and Glucopon® 650) were studied, as were fatty alcohol ethoxylates (Findet 1214N/23 and Findet 10/15), and nonyl phenol ethoxylate (Findet 9Q/21.5NF). Also, an anionic surfactant, linear alkyl benzene sulfonate (LAS) was assayed. In general, none of the non-ionic surfactants studied, except Findet 10/15, vary substantially the enzymatic activity. Findet 10/15 has the strongest hydrophobic character and reduces the enzymatic activity more significantly the greater its concentration. Regarding LAS, this surfactant significantly depressed enzymatic activity, presumably due to the electrostatic interactions caused by its anionic character.Fellowship awarded to Juan Francisco Martínez Gallegos by Spanish Ministry of Science and Education, FPU fellowships program

Insights into the optimisation of the Clean-In-Place technique: Cleaning, disinfection, and reduced environmental impact using ozone-based formulations

Chemical and food industries are focusing on reducing the economic and environmental impact of cleaning operations. This study aims to analyse the use of alkaline ozonated formulations to remove starch adhering to stainless steel surfaces, improving disinfection of mature biofilms with Listeria and Pseudomonas, and reducing the environmental impact of wastewater. Three key cleaning parameters have been analysed in a lab-simulated Clean-In-Place system (CIP): temperature (20−60 °C), time (20−120 min), and cleaning formulations containing ozone and surfactant (linear alkylbenzene sulfonate, alkylpolyglucoside, fatty ethoxylated alcohol, lauramine oxide) were assayed. Higher temperature, time, and ozone concentration improved starch removal and disinfection of the stainless-steel surfaces, as well as the environmental impact of cleaning wastewater. Therefore, ozone-based CIP protocols could provide new opportunities to achieve cleaner, greener, and safer industries by intensifying cleaning, disinfection, and wastewater treatment in one step, saving operational costs compared to conventional CIP techniques.Grupos de Investigación RNM332 y TEP21

Extracción líquido-líquido en columna de gotas

Se determina el equilibrio y cinética de transferencia de materia en diversos sistemas agua-ácido orgánico-bencenoUniv. Granada, Facultad de Ciencias. Leída el 28-03-8

The Unified Scientometric Model. Fractality and transfractality

A Unified Scientometric Model has been developed on the basis of seven principles: the actornetwork principle, the translation principle, the spatial principle, the quantativity principle, the composition principle, the centre-periphery or nucleation principle, and the unified principle of cumulative advantages. The paradigm of the fractal model has been expanded by introducing the concept of fractality index and transfractality. In this work, as the first demonstration of the power of the model proposed, all the bibliometric laws known and all their mathematical expressions are deduced, both the structural distributions (Zipf, Bradford and Lotka) as well as the Price's Law of the exponential growth of science and Brookes' and Avramescu's Laws of ageing