Yield evaluation of enzyme hydrolysis and dark fermentation of the brown seaweed Rugulopteryx okamurae hydrothermally pretreated by microwave irradiation

Microwave irradiation has been applied to solubilise the organic matter from the invasive seaweed Rugulopterix okamurae as pretreatment for two conventional biological processes: enzyme hydrolysis (EH) for obtaining reducing sugars (RS) and dark fermentation (DF) for obtaining volatile fatty acids (VFAs). As operational conditions for the microwave pretreatment, temperature and time has been tested between 120 and 220 °C and 5–20 min respectively. The maximum solubilisation yield in terms of DOC (26%) through the microwave pretreatment was registered at 220 °C at 20 min. However, the maximum concentration for RS (1.8 g/L) was obtained at 200 °C at 20 min due to the decomposition of monomeric sugars at high temperature and the total polyphenols (TP) were above 0.25 g/L (where inhibition in dark fermentation begins to be noticiable) at 180 °C. When the pretreated biomass was used for the EH the maximum accumulated RS production was 160 mg-RS/g-biomass, at 220 °C which was a 35% better than the RS production for non-pretreated biomass. In the case of the DF tests, the maximum yield of VFAs obtained with the pretreated biomass was 46.3 mg/g-biomass at 220 °C while the maximum hydrogen yield was obtained at 200 °C (6.6 mL-H2/g-biomass) due to the high level of TP (1.1 g/L) of pretreated biomass at 220 °C. Despite of this toxic effect, the VFAs production at 220 °C was 93% higher than in the non-pretreated biomass

Preliminary Study of Enological Potential and Volatile Compounds of Tintilla de Rota Somatic Variant Grown in a Warm Climate

In an enological market notable for its use of universal varieties, the enological potential of the somatic variant Tintilla de Rota has been studied in a warm climate area from where it originates and has been compared with three universal cultivars and with a reference cultivar in Spain. It has been found that Tintilla de Rota is a grapevine cultivar that can adapt easily to the area where it has been grown traditionally, achieving adequate pH and acidity values while maintaining a moderate sugar content compared to the other varieties studied. Additionally, it has shown high anthocyanin content. In terms of aromatic composition, it has exhibited a content equal to or even higher than the other varieties analyzed in this study in most of the aromatic families studied, with a higher content of compounds such as 1-octanol, benzyl alcohol and citronellol, which can lead to wines with an interesting and distinguished aromatic profile. All these facts confirm the interest in the use of this cultivar and the importance of recovering and enhancing the value of autochthonous cultivars as opposed to other so-called universal varieties

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

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

Creation of Immersive Resources Based on Virtual Reality for Dissemination and Teaching in Chemical Engineering

Chemical Engineering is a complex discipline that is mainly applied to the industrial context, which makes it difficult to approach real equipment and systems in the classroom to students. Nevertheless, Information and Communication Technologies (ICTs) are particularly useful to encourage active and autonomous learning, normally associated with deeper levels of engagement and understanding of the subjects taught. In this way, several studies have demonstrated that immersion has the potential to increase learning experiences and improve creativity and engagement, Virtual Reality (VR) being a remarkable example. In this context, we created and shared with students two immersive resources based on VR: (a) a laboratory 360 degrees video tour, which was used to disseminate the Chemical Engineering Degree in an Open Door Days organized for high school students; and (b) an experiential learning tool integrated with Moodle, which was available previously to face-to-face practical lessons of the subject Separation Operations. In both cases, the feedback from the participant students was positive. High school students increased their interest in Chemical Engineering Degree after viewing the 360 degrees video, meanwhile undergraduate students found the immersive tool useful in the subsequent performance of real practical activities. From the perspective of professors, creation of these resources required purchase of equipment, time and effort, but they were highly valued as a tool for disseminating and supporting teaching, being an initial starting point for the creation of more enhanced VR-based materials

Détermination de la charge polluante et nature des déchets dans les chais d'élaboration des vins

On suit, pendant une campagne, dans différents secteurs d'un chai de la zone de JEREZ, l'évolution de la charge polluante des rejets. Les eaux résiduaires ne diffèrent que très légèrement de celles d'autres chais. Les taux maxima de pouvoir contaminant se situent pendant les vendanges et le processus de stabilisation par le froid. Par rapport à d'autres industries du secteur agro-alimentaire, la charge contaminante des déchets des chais d'élaboration des vins est faible. Un recyclage des rejets est impossible du fait de leur faible concentration et de l'irrégularité avec laquelle ils sont produits. +++ During a complete season, for different parts of a cellar in JEREZ area, the evolution of waste water pollution has been observed. Waste water is only slightly different from the ones coming from other cellars. Maximum contamination occurs during harvest and cold stabilisation. Compared to other food processing industries, cellar waste contamination is low. A recycling of those waste waters is impossible due to their low concentration and irregular production

Feasibility of exhausted sugar beet pulp as raw material for lactic acid production

Exhausted sugar beet pulp pellets (ESBPP), a sugar industry by-product generated after sugar extraction in the sugar production process, have been used as a raw material for lactic acid (LA) production via hydrolysis and fermentation by Lactobacillus casei. The present study proposes simultaneous saccharification and fermentation (SSF) of ESBPP to design a more cost-effective process. The effects of pH control, nutrient supplementation and solid addition in fed-batch SSF on lactic acid production were investigated. RESULTS The highest LA concentration (26.88 g L–1) was reached in fed-batch SSF at a solid/liquid loading of 0.2 g mL–1, with pH control (by adding 30 g L–1 CaCO3 to the medium) and nutrient supplementation (by adding 20 mL of MRS medium per 100 mL of buffer). Under these conditions, a maximum productivity of 0.63 g L−1 h−1 was achieved, 2.7 times higher than that of the control experiment (SSF inoculated at time 0 h). However, a slightly lower LA yield was obtained, revealing the need for an increasing dose of enzymes at high solid-loading SSF. CONCLUSION An efficient fed-batch SSF strategy with pH control and MRS supplementation is described in the present study, attaining higher LA productivity compared to separate hydrolysis and fermentation and SSF