Síntesis enzimàtica d'un aromatitzant

Investigadors del Departament d'Enginyeria Química de la UAB han dut a terme amb èxit la síntesis enzimàtica d'un aromatitzant. Aquesta síntesis permet obtindre compostos aromatitzants "naturals" sense que suposin un cost tan elevat com els compostos extrets directament del producte natural. Els científics, que han sintetitzat enzims que s'utilitzen com a biocatalitzadors per obtenir aromatitzants, també han determinat diferents paràmetres, com la temperatura o la concentració d'enzim, que permetran establir les condicions òptimes per a la producció industrial d'aquests aromatitzant.Investigadores del Departamento de Ingeniería Química de la UAB han llevado a cabo con éxito la síntesis enzimática de un aromatizante. Esta síntesis permite obtener compuestos aromatizantes "naturales" sin que supongan un coste tan elevado como los compuestos extraídos directamente del producto natural. Los científicos, que han sintetizado enzimas que se utilizan como biocatalizadores para obtener aromatizantes, también han determinado los diferentes parámetros, como la temperatura o la concentración de enzima, que permitirán establecer las condiciones óptimas para la producción industrial de estos aromatizantes.Researchers at the Department of Chemical Engineering at UAB have carried out successfully a flavor enzymatic synthesis. This synthesis allows to obtain a "natural" flavor compound without the high cost of the natural product directly extracted compound. Scientists have synthesized enzymes that are used to produce flavors and also have stated the parameters, such as temperature or the concentration of enzyme, that will provide the optimal conditions for the industrial production of these flavorings

Second- and third-generation biodiesel production with immobilised recombinant Rhizopus oryzae lipase : Influence of the support, substrate acidity and bioprocess scale-up

Altres ajuts: Beca del Gobierno Vasco para la formación de investigadores predoctorales PRE_2017_1_0110Altres ajuts: Acord transformatiu CRUE-CSICRhizopus oryzae lipase immobilised onto differently functionalised polymethacrylate (Purolite®) and magnetite superparamagnetic supports was assessed as a catalyst for biodiesel production with pomace oil. The presence of surface hydrocarbon chains increased the operational stability of the biocatalysts supported on Purolite® and superparamagnetic particles up to 9 and 2 times, respectively. By contrast, the presence of functional groups had no effect on the initial transesterification rate, which was twice higher with the lipase immobilised onto Purolite®. Also, functionalising Purolite® with epoxide and octadecyl groups led to the highest biodiesel and volumetric productivity. This biocatalyst with other substrates including makauba, jatropha, waste cooking oil, and microbial oil, led to similar initial reaction rates. However, simply raising substrate acidity from 0.5 to 2% increased the operational stability of the biocatalysts 15 times. A synergistic effect between acyl-acceptor concentration and substrate acidity was observed. The transesterification reaction was successfully scaled up to 50 mL

Constitutive expression in komagataella phaffii of mature rhizopus oryzae lipase jointly with its truncated prosequence improves production and the biocatalyst operational stability

Altres ajuts: Eusko Jaurlaritza/PRE_2017_1_0110Rhizopus oryzae lipase (ROL) containing 28 C-terminal amino acids of the prosequence fused to the N-terminal mature sequence in ROL (proROL) was successfully expressed in the methylotrophic yeast Komagataella phaffii (Pichia pastoris) under the constitutive glyceraldehyde-3-phosphate dehydrogenase promoter (PGAP). Although the sequence encoding the mature lipase (rROL) was also transformed, no clones were obtained after three transformation cycles, which highlights the importance of the truncated prosequence to obtain viable transformed clones. Batch cultures of the K. phaffii strain constitutively expressing proROL scarcely influenced growth rate and exhibited a final activity and volumetric productivity more than six times higher than those obtained with proROL from K. phaffii under the methanol-inducible alcohol oxidase 1 promoter (PAOX1). The previous differences were less marked in fed-batch cultures. N-terminal analysis con-firmed the presence of the 28 amino acids in proROL. In addition, immobilized proROL exhibited increased tolerance of organic solvents and an operational stability 0.25 and 3 times higher than that of immobilized rROL in biodiesel and ethyl butyrate production, respectively. Therefore, the truncated prosequence enables constitutive proROL production, boosts bioprocess performance and provides a more stable biocatalyst in two reactions in which lipases are mostly used at industrial level, esterification (ethyl butyrate) and transesterification (biodiesel)

Effect of acyl-acceptor stepwise addition strategy using alperujo oil as a substrate in enzymatic biodiesel synthesis

Background: using renewable feedstock sources for biodiesel production seems to be a promising strategy and even more so when enzymatic catalysis with lipases are used. However, it is well known that these enzymes could be inactivated by reaction conditions such as temperature or alcohol concentration. In this work, the effect of temperature and initial water activity (aw) value on immobilised recombinant Rhizopus oryzae lipase (rROL) were studied. Methanolysis and ethanolysis reactions using alperujo oil with three different stepwise addition strategies were employed. - Results: recombinant 1,3-positional selective rROL covalently immobilised on polymethacrylate amino-epoxy activated support showed maximum initial reaction rate at low aw value (0.093). It was found that 30 °C was the optimal temperature in terms of biocatalyst stability during transesterification reactions. Adding alcohol at once, ethanol was clearly a better acyl-acceptor in terms of stability than methanol. Productivity was found to be 2-fold higher when five pulses of ethanol were used instead of methanol. - Conclusions: alperujo oil has great potential as a low cost feedstock for biodiesel production through enzymatic catalysis using a nearly semi-continuous alcohol addition strategy

Lipase-catalysed transesterification : viewpoint of the mechanism and influence of free fatty acids

Grup de Recerca Enginyeria de Bioprocesos i Biocatàlisi AplicadaA series of lipase-catalysed transesterification experiments were carried out to study the effect of the presence of free fatty acids on synthesis reaction rate and the stability of the biocatalyst, and also to elucidate the underlying mechanism, which remains a subject of debate. Based on the results, the reaction rate and biocatalyst stability increased with increasing content in free fatty acids of the reaction mixture. Also, tests carried out with a mixture of triolein and linoleic acid revealed that the transesterification mechanism is a combination of direct alcoholysis of triacylglycerols and a twostep reaction involving hydrolysis of acylglycerols and further esterification of previously released free fatty acids. The time course of triacylglycerols and diacylglycerols revealed that the enzyme is similarly selective for both types of substrate

Rice husk ash as a potential carrier for the immobilization of lipases applied in the enzymatic production of biodiesel

The potential application of rice husk ash (RH26) as support for the immobilization of a recombinant Rhizopus oryzae (rROL) lipase as biocatalyst in the enzymatic biodiesel production using alperujo oil and the comparison with commercial hydrophobic support OD403 (RelOD) has been made. Although the specific activity (UA mg support−1) was around one-half lower in RH26 than in RelOD when they were used as biocatalyst in biodiesel reaction, the normalized initial rate was similar, between 1.6 and 2.4 μmol FAME mL⁻¹ mL⁻¹ UA⁻¹. Thus in terms of biocatalysis performance, rice husk as is an alternative to commercial supports. However, the main problem is the more complex recovery of RH26 for the reutilization compared with commercial ones

HLADH-catalyzed synthesis of β-amino acids, assisted by continuous electrochemical regeneration of NAD+ in a filter press microreactor

This work focuses on the use of electrochemical microreactors, applied to the direct electroregeneration of nicotinamide dinucleotide (NAD+) used in-situ for the enzymatically-assisted oxidation of the β-alanine. Mechanistic and chemical/electrochemical reactor approaches were investigated, to achieve satisfactory conversions (>80%) of the substrate in reasonable (1–2 days) reaction times; no fouling observed of the gold anode. An original method was proposed to limit the complexation effect of the produced β-alanine to the enzyme. Simulations of the overall system were achieved and an estimation of the required kinetic and Michaelis constants was proposed

El impacto sobre los trabajadores de una gestión de recursos humanos socialmente responsable. Un análisis para Catalunya

Socially responsible human resource management constitutes the conceptual-theory framework of the thesis. The results obtained from the empirical part show the existence of three clusters inasmuch as the application of socially responsible practices for promoting job quality in the case of Catalonia: the group of workers in “organizations with low-level of social responsibility”; those who work in a environment of “work practices for implication” and the group of workers in a environment oriented to “health and safety at work”. Among the determining factors in applying these practices we can find characteristics of the firms where the employees work as well as personal characteristics and those of the job. The research also shows that, in general, applying socially responsible management in human resources does have positive effects on the worker and therefore creates greater trust in management, increased job satisfaction, less stress at work and a lower intention to quit a job.La gestión de recursos humanos socialmente responsable constituye el marco teórico-conceptual de la tesis. Los resultados obtenidos en la parte empírica muestran la existencia de tres clusters en cuanto a la aplicación de prácticas laborales socialmente responsables para promover la calidad laboral en el caso de Cataluña: el grupo de trabajadores en “organizaciones poco responsables”; aquellos que se encuentran en entornos de “prácticas para la implicación” y el grupo de trabajadores en entornos de “prácticas orientadas hacia la seguridad y salud laboral”. Entre los determinantes de la aplicación de estas prácticas encontramos características de las empresas donde trabajan los empleados, así como características personales y de la ocupación. La investigación también revela que, en general, la aplicación de una gestión de recursos humanos socialmente responsable tiene efectos positivos sobre el trabajador generando una mayor confianza en la dirección, una satisfacción laboral superior, menos estrés laboral y menos intención de dejar el trabajo

Rhizopus oryzae lipase, a promising industrial enzyme : biochemical characteristics, production and biocatalytic applications

Lipases are biocatalysts with a significant potential to enable a shift from current pollutant manufacturing processes to environmentally sustainable approaches. The main reason of this prospect is their catalytic versatility as they carry out several industrially relevant reactions as hydrolysis of fats in water/lipid interface and synthesis reactions in solvent-free or non-aqueous media such as transesterification, interesterification and esterification. Because of the outstanding traits of Rhizopus oryzae lipase (ROL), 1,3-specificity, high enantioselectivity and stability in organic media, its application in energy, food and pharmaceutical industrial sector has been widely studied. Significant advances have been made in the biochemical characterisation of ROL particularly in how its activity and stability are affected by the presence of its prosequence. In addition, native and heterologous production of ROL, the latter in cell factories like Escherichia coli, Saccharomyces cerevisiae and Komagataella phaffii (Pichia pastoris), have been thoroughly described. Therefore, in this review, we summarise the current knowledge about R. oryzae lipase (i) biochemical characteristics, (ii) production strategies and (iii) potential industrial applications

Síntesis enzimàtica d'un aromatitzant

Investigadors del Departament d'Enginyeria Química de la UAB han dut a terme amb èxit la síntesis enzimàtica d'un aromatitzant. Aquesta síntesis permet obtindre compostos aromatitzants "naturals" sense que suposin un cost tan elevat com els compostos extrets directament del producte natural. Els científics, que han sintetitzat enzims que s'utilitzen com a biocatalitzadors per obtenir aromatitzants, també han determinat diferents paràmetres, com la temperatura o la concentració d'enzim, que permetran establir les condicions òptimes per a la producció industrial d'aquests aromatitzant.Investigadores del Departamento de Ingeniería Química de la UAB han llevado a cabo con éxito la síntesis enzimática de un aromatizante. Esta síntesis permite obtener compuestos aromatizantes "naturales" sin que supongan un coste tan elevado como los compuestos extraídos directamente del producto natural. Los científicos, que han sintetizado enzimas que se utilizan como biocatalizadores para obtener aromatizantes, también han determinado los diferentes parámetros, como la temperatura o la concentración de enzima, que permitirán establecer las condiciones óptimas para la producción industrial de estos aromatizantes.Researchers at the Department of Chemical Engineering at UAB have carried out successfully a flavor enzymatic synthesis. This synthesis allows to obtain a "natural" flavor compound without the high cost of the natural product directly extracted compound. Scientists have synthesized enzymes that are used to produce flavors and also have stated the parameters, such as temperature or the concentration of enzyme, that will provide the optimal conditions for the industrial production of these flavorings