Reciclado del orujo de uva como medio sólido de fermentación para la producción de enzimas hidrolíticas de interés industrial

En la presente tesis se pretende profirndizar en el desarrollo de un nuevo proceso, de bajo impacto medioambiental y de costes muy reducidos, para aprovechar el principal subproducto de la industria vitivinícola: el orujo de uva. Los resultados obtenidos han puesto de manifiesto que mediante la fermentación en estado sólido (FES) del hongo Aspergillus awamori sobre el orujo de uva se secretan las enzimas pectinasas, xilanasas y celulasas. Sin embargo, la composición de este sustrato natural cambia en función de la estación, el tipo de uva, el punto de recolección, las condiciones meteorológicas, etc., de forma que no es posible asegurar productividades enzimáticas reproducibles cuando se utilizan diferentes orujos de uva. Por este motivo, el lavado previo de este residuo, junto con la suplementación con una solución nutritiva y mezcla con cáscaras de naranja, con gran contenido en pectina, celulosa y hemicelulosa, mejoran la producción y la reproducibiidad de la síntesis de las mencionadas enzimas. Por tanto, mediante este trabajo se han producido extractos con un alto contenido en las enzimas pectinasas, xilanasas y celulasas, usando la tecnología de FES sobre mezclas de estos dos residuos agroindustriales. Estos extractos, una vez concentrados y/o purificados, pueden ser utilizados en las industrias de elaboración de zumos y vinos en las etapas de clarificación. Por otra parte, dada la importancia de las variables externas de fermentación sobre la producción enzimática, y ya que los reactores están estrechamente vinculados a¿ su manipulación de estas, en el presente trabajo se seleccionó la configuración de reactor más apropiada y las condiciones óptimas de operación para la síntesis de las mencionadas enzimas por el hongo Aspergillus awamori. Se compararon cuatro configuraciones diferentes de reactor (tres - de fermentación en estado sólido y una de cultivo suspendido) con el propósito de estudiar la influencia de la agitación y la aireación, siendo el reactor de cultivo sumergido y el tambor rotatorio, en primer y segundo lugar, respectivamente, los que proporcionaron las actividades enzimáticas más altas. Se evaluó además la estabilidad de las enzimas exo-poligalacturonasa (un tipo de pectinasa) y xilanasa en los extractos enzimáticos obtenidos por FES, registrando para ambas altas actividades en un amplio rango de p11 y temperatura y en presencia de distintos cationes. Los extractos obtenidos, una vez seleccionado el método más adecuado para su concentración, se emplearon en la clarificación de mostos de uva, obteniéndose mejores rendimientos que con otros extractos comerciales comúnmente utilizados en las bodegas. Además, para mejorar su aplicabilidad, fUeron parcialmente purificados mediante cromatografla de intercambio iónico en columna DEAE-celulosa, mostrando un mayor grado de pureza que los crudos enzhnáticos comerciales

Sugar Beet Pulp as Raw Material for the Production of Bioplastics

The production of bioplastics from renewable materials has gained interest in recent years, due to the large accumulation of non-degradable plastic produced in the environment. Here, sugar beet pulp (SBP) is evaluated as a potential raw material for the production of bioplastics such as polylactic acid (PLA) and polyhydroxyalkanoates (PHAs). SBP is a by-product obtained in the sugar industry after sugar extraction from sugar beet, and it is mainly used for animal feed. It has a varied composition consisting mainly of cellulose, hemicellulose and pectin. Thus, it has been used to produce different value-added products such as methane, hydrogen, pectin, simple sugars, ethanol, lactic acid and succinic acid. This review focuses on the different bioprocesses involved in the production of lactic acid and PHAs, both precursors of bioplastics, from sugars derived from SBP. The review, therefore, describes the pretreatments applied to SBP, the conditions most frequently used for the enzymatic hydrolysis of SBP as well as the fermentation processes to obtain LA and PHAs

Valorization of orange peels exploiting fungal solid-state and lacto-fermentation

BackgroundOrange peels can serve as a cost-effective raw material for the production of lactic acid. Indeed, given their high concentration of carbohydrates and low content of lignin, they represent an important source of fermentable sugars, recoverable after a hydrolytic step. ResultsIn the present article, the fermented solid, obtained after 5 days of Aspergillus awamori growth, was used as the only source of enzymes, mainly composed of xylanase (40.6 IU g(-1) of dried washed orange peels) and exo-polygalacturonase (16.3 IU g(-1) of dried washed orange peels) activities. After the hydrolysis, the highest concentration of reducing sugars (24.4 g L-1) was achieved with 20% fermented and 80% non-fermented orange peels. The hydrolysate was fermented with three lactic acid bacteria strains (Lacticaseibacillus casei 2246 and 2240 and Lacticaseibacillus rhamnosus 1019) which demonstrated good growth ability. The yeast extract supplementation increased the lactic acid production rate and yield. Overall, L. casei 2246 produced the highest concentration of lactic acid in mono-culture. ConclusionTo the best of our knowledge this is the first study exploiting orange peels as low-cost raw material for the production of lactic acid avoiding the employment of commercial enzymes. The enzymes necessary for the hydrolyses were directly produced during A. awamori fermentation and the reducing sugars obtained were fermented for lactic acid production. Despite this preliminary work carried out to study the feasibility of this approach, the concentrations of reducing sugars and lactic acid produced were encouraging, leaving open the possibility of other studies for the optimization of the strategy proposed here. (c) 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. Keyword

Conversion of Exhausted Sugar Beet Pulp into Fermentable Sugars from a Biorefinery Approach

In this study, the production of a hydrolysate rich in fermentable sugars, which could be used as a generic microbial culture medium, was carried out by using exhausted sugar beet pulp pellets (ESBPPs) as raw material. For this purpose, the hydrolysis was performed through the direct addition of the fermented ESBPPs obtained by fungal solid-state fermentation (SSF) as an enzyme source. By directly using this fermented solid, the stages for enzyme extraction and purification were avoided. The effects of temperature, fermented to fresh solid ratio, supplementation of fermented ESBPP with commercial cellulase, and the use of high-solid fed-batch enzymatic hydrolysis were studied to obtain the maximum reducing sugar (RS) concentration and productivity. The highest RS concentration and productivity, 127.3 g.L-1 and 24.3 g.L-1.h(-1) respectively, were obtained at 50 degrees C and with an initial supplementation of 2.17 U of Celluclast (R) per gram of dried solid in fed-batch mode. This process was carried out with a liquid to solid ratio of 4.3 mL.g(-1) solid, by adding 15 g of fermented solid and 13.75 g of fresh solid at the beginning of the hydrolysis, and then the same amount of fresh solid 3 times every 2.5 h. By this procedure, ESBPP can be used to produce a generic microbial feedstock, which contains a high concentration of monosaccharides

Maladaptive use of ICT in adolescence: Profiles, supervision and technological stress

ICT use during adolescence is now commonplace. Its power of attraction and the vulnerable condition of adolescents are giving rise to growing concern, aggravated by the imminent consequences of such synergy. In order to deepen understanding of this relationship, the following research objectives were formulated: a) Analyze the frequency of ICT use; b) Examine family supervision; c) Identify stress associated with the use of ICTs; d) Establish profiles of ICT use. The sample consisted of 1,101 adolescents of 10 educational centers in Southeastern Spain. A descriptive analysis was performed and contingency tables, Chi Square, Cramer V, hierarchical cluster analysis and one-factor ANOVA were used. The results show that more than 60% of adolescents use ICTs without supervision and that 1 out of 3 feel stressed in the absence of the Internet. In addition, statistically significant relationships were found between the frequency of ICT use and stress, as well as with family supervision. A solution of three groups or profiles of use was obtained. 45% of the subjects display maladaptive use or signs of it. The study concludes by stressing that the relationship between adolescents and ICTs is far from ideal and warns of the urgent need to train adolescents and parents in the responsible use of ICTs

Aerobic Energy Expenditure and Intensity Prediction During a Specific Circuit Weight Training: a Pilot Study

During circuit weight training (CWT), workloads, index of intensity as well as estimation of energy expenditure (EE) have been under estimated. The aim of this study was to describe and evaluate physiological variables and gender related differences, including intensity prediction and EE, during CWT at different intensities. Twenty six subjects were assessed in a CWT, fourteen men and twelve women. The CWT program was performed at six different intensities, 40%, 50%, 60%, 70%, 80% and 85% of 15RM. Seven exercises made up the circuit: sitting bench press, leg press, lat pull down, shoulder press, hamstring curl, biceps curl, and triceps cable push downs. A polar heart rate monitor and a portable metabolic system were used to measure heart rate (HR), intensity measured relative to the HR reserve, cardiorespiratory variables, EE and EE relative to muscle mass (EEMM). Differences between genders were observed at the following variables: HR, intensity measured relative to the HR reserve (in percentage), VO2, VCO2, VE, RER, aerobic EE and EEMM. The EE was significantly higher in men during the six intensities, but differences did not exist for EEMM from 70% to 85%. In addition HR, load and body weight were used to predict intensity and two gender specific equations were obtained for men and women [I (%) = 57.265 + 0.512HR - 0.696HRmax + 1.035 Loadavg + 0.188 Body Weight (R2=0.92; SEE=4.9%) for men; I (%) = 4.036 + 0.412HR% + 1.667 Loadavg (R2=0.79; SEE=7.7%) for women]. Thus, we conclude that gender related differences are present during CWT for EE, even when expressed relative to muscle mass, in addition HR, work load and body weight can estimate the intensity during CWT

Maladaptive use of ICT in adolescence: Profiles, supervision and technological stress

El uso de las TIC durante la adolescencia es un hecho normalizado en la actualidad. Su poder de atracción y la condición de vulnerabilidad de los púberes están suscitando una creciente preocupación, agravada por las consecuencias inminentes de tal sinergia. Con la finalidad de profundizar en esta relación, se formulan los siguientes objetivos de investigación: a) Analizar la frecuencia de uso de las TIC; b) Examinar la supervisión familiar; c) Identificar estrés asociado al uso de las TIC; d) Establecer perfiles de uso de las TIC. La muestra estuvo compuesta por 1.101 adolescentes de 10 centros educativos del Sureste Español. Se realizó un análisis descriptivo y se emplearon tablas de contingencia, Chi Cuadrado, V de Cramer, análisis de clúster jerárquico y ANOVA de un factor. Los resultados arrojan que más del 60% de los adolescentes usa las TIC sin supervisión y que uno de cada tres se siente estresado ante la ausencia de Internet. Además, se encontraron relaciones estadísticamente significativas entre la frecuencia de uso de las TIC y el estrés, así como con la supervisión familiar. Se obtuvo una solución de tres grupos o perfiles de uso. El 45% de los sujetos tiene un uso desadaptado o indicios del mismo. Se concluye subrayando que la relación entre adolescentes y TIC dista mucho de la deseada y se alerta de la imperiosa necesidad de formar a adolescentes y a progenitores en el uso responsable de las TICICT use during adolescence is now commonplace. Its power of attraction and the vulnerable condition of adolescents are giving rise to growing concern, aggravated by the imminent consequences of such synergy. In order to deepen understanding of this relationship, the following research objectives were formulated: a) Analyze the frequency of ICT use; b) Examine family supervision; c) Identify stress associated with the use of ICTs; d) Establish profiles of ICT use. The sample consisted of 1,101 adolescents of 10 educational centers in Southeastern Spain. A descriptive analysis was performed and contingency tables, Chi Square, Cramer V, hierarchical cluster analysis and one-factor ANOVA were used. The results show that more than 60% of adolescents use ICTs without supervision and that 1 out of 3 feel stressed in the absence of the Internet. In addition, statistically significant relationships were found between the frequency of ICT use and stress, as well as with family supervision. A solution of three groups or profiles of use was obtained. 45% of the subjects display maladaptive use or signs of it. The study concludes by stressing that the relationship between adolescents and ICTs is far from ideal and warns of the urgent need to train adolescents and parents in the responsible use of ICT

Valorisation of fungal hydrolysates of exhausted sugar beet pulp for lactic acid production

BACKGROUND Exhausted sugar beet pulp pellets (ESBPP) were used as raw material for lactic acid (LA) fermentation. The enzymatic hydrolysis of ESBPP was performed with the solid obtained after the fungal solid-state fermentation of ESBPP as a source of hydrolytic enzymes. Subsequently, a medium rich in glucose and arabinose was obtained, which was used to produce LA by fermentation. For LA production, two Lactobacillus strains were assayed and the effects of the supplementation of the hydrolysate with a nitrogen source and the mode of pH regulation of the fermentation were investigated. Moreover, a kinetic model for LA fermentation by Lactobacillus plantarum of ESBPP hydrolysates was developed. RESULTS L. plantarum produced a LA concentration 34% higher than that produced by L. casei. The highest LA concentration (30 g L−1) was obtained with L. plantarum when the hydrolysate was supplemented with 5 g L−1 yeast extract and the pH was controlled with CaCO3. The concentration of acetic acid differed depending on the concentration of CaCO3 added, producing its maximum value with 27 g L−1 CaCO3. The proposed kinetic model was able to predict the evolution of substrates and products depending on the variation of the pH in the hydrolysate, according to the amount of CaCO3 added. CONCLUSIONS ESBPP can be valorised to produce LA. A pure LA stream or a mixture of LA and acetic acid, depending on the pH control method of the fermentation, can be produced. Thus, this control is of great interest depending on the destination of the effluent

Rugulopteryx okamurae: Effect of hydrothermal acid pretreatment on the saccharification process

The biological invasion caused by the invasive macroalga Rugulopteryx okamurae is causing increasing concern in southern Europe. To reduce its impact, this brown alga can be treated from a biorefinery approach. In this study, the macroalga is used as raw material to obtain fermentable sugars, which can be converted into high-value-added products. The alga was exposed to hydrothermal and hydrothermal acid pretreatment and the pretreated biomass was used for enzymatic hydrolysis, achieving a hydrolysate with a reducing sugar concentration of almost 25 g/L (49.2% more than with non-pretreated alga). In addition, the combined severity factor was calculated to identify the best pretreatment conditions, finding the optimum in those pretreatments performed with 0.2 N HCl concentration and 15 min reaction time. Based on the results, it would be interesting to carry out new studies using the saccharified medium obtained under optimal conditions to obtain value-added compounds by fermentation

Influence of gold nanoparticles size for photocatalytic NO oxidation in low loading Au/TiO2 catalysts

Gold nanoparticles (AuNPs) supported on TiO2 are one of the most investigated photocat-alysts, however, the positive effect of AuNPs size reduction on Au/TiO2 activity is clear for conventional catalysis, but this relationship not strictly happens in photocatalysis. The present work investigates how small changes in the lower size range of AuNPs can affect the Au/TiO2 photoactivity in order to maximize the performance of photocatalysts with low metal loadings (<1 wt%). Precipitation-deposition methods and a speciation-controlled incipient wetness impregnation (ScIWI) method have been employed for preparing Au/TiO2 photocatalysts that exhibited a NOx elimination capacity significantly higher than pristine TiO2. Comparing the photocatalysts, ScIWI method achieved the highest gold dispersion and Au-TiO2 contact perimeter providing the most active photocatalysts, confirming the positive effect of AuNPs size reduction in the average sizes around 2 nm. In addition, on the basis of the results obtained, it has been proposed that the adsorption of nitrogen oxides species on gold has a relevant role on the NO photooxidation process.(c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)