New generation biofuel: continuous acidogenesis of sucrose-raffinose mixture simulating vinasse is promoted by γ-alumina pellets

Abstract

BackgroundThis investigation comprises a contribution on the production of a new generation biofuel using the industrial liquid waste of bioethanol distilleries, known as vinasse. This study focuses on the exploitation of vinasse as an acidogenesis substrate for volatile fatty acids and simultaneous ethanol production. These products can be used for ester production, which is the new generation biofuel. Therefore, the aims of the present study are (i) to examine any promotional effect of γ-alumina on acidogenesis of a sucrose-raffinose mixture simulating vinasse, (ii) to study the operational stability of the continuous acidogenesis of sucrose and raffinose and subsequently of vinasse, and (iii) to determine the volatile fatty acid chemical composition and ethanol formation.ResultsBatch acidogenesis of sucrose and raffinose mixtures showed that γ-alumina promoted fermentation leading to an increase in the volatile fatty acid yield factor from 40% to 95% compared to free cells. The application of the system in continuous mode for more than 3 months showed that the continuous volatile fatty acid productivity obtained was higher than 7 g/L/day. Lactic acid was the predominant acid when sucrose and raffinose were used while butyric acid in the case of vinasse. The highest volatile fatty acid concentration reached was 19 g/L for vinasse.ConclusionsA promoting effect of γ-alumina in acidogenic fermentation of sucrose-raffinose and vinasse is reported. Continuous acidogenesis of sucrose-raffinose mixtures and vinasse using γ-alumina with immobilized cells showed high operational stability (more than 3 months). These findings result in easy scale up of the process that will produce a high annual added value of $11,000,000 in a daily bioethanol production plant of 50,000 L.

Towards multi-purpose biorefinery platforms for the valorisation of red grape pomace: production of polyphenols, volatile fatty acids, polyhydroxyalkanoates and biogas

“…The final VFAs concentration was comparable to that reported in a study where vinasse was used for VFAs production (19 g L -1 of total VFAs) 26 . Furthermore, comparable VFAs overall concentration was obtained when the same process was carried out using non-dephenolised GP as the substrate (about 23 g L -1…”

Economic evaluation of technology for a new generation biofuel production using wastes

“…Here, the substantial simultaneous ethanol formation along with OAs in the case of acidogenesis of pure carbohydrates in the presence of promoters, also has to be highlighted (Syngiridis et al, 2013, Lappa et al, 2015a, 2015b. However, ethanol formation in the case of the raw materials (vinasse, whey and cellulose) was very low.…”

“…Previous studies have reported the simultaneous production of OAs and ethanol during anaerobic acidogenesis of synthetic media containing glucose (Ren et al, 1997;Syngiridis et al, 2013Syngiridis et al, , 2014. Furthermore, very good OAs productivities were obtained during acidogenesis of vinasse, the main liquid waste of the ethanol industry (Lappa et al, 2015a(Lappa et al, , 2015b.…”

“…The promoting effect of these carriers was also proved in the acidogenesis of wastes such as vinasse (Lappa et al, 2015a(Lappa et al, , 2015b. However, the above studies include only published results on acidogenic fermentations of synthetic, simple carbohydrate media as well as of vinasse at laboratory scale (Table 1).…”

Acidogenesis of cellulosic hydrolysates for new generation biofuels

“…Experiments in comparison to free cells systems showed that g-alumina promoted the simultaneous production of acetic acid and ethanol. The promoting effect of porous materials, like g-alumina pellets, in methane [67] alcoholic [68] and acidogenic fermentations [69] is known. The simultaneous production of VFAs and ethanol is of high technological importance since they can be used in esterification reactions to produce ethyl esters of low molecular weight.…”