Simultaneous Saccharification and Fermentation of Sugar Beet Pulp for Efficient Bioethanol Production

Abstract

Sugar beet pulp, a byproduct of sugar beet processing, can be used as a feedstock in second-generation ethanol production. The objective of this study was to investigate the effects of pretreatment, of the dosage of cellulase and hemicellulase enzyme preparations used, and of aeration on the release of fermentable sugars and ethanol yield during simultaneous saccharification and fermentation (SSF) of sugar beet pulp-based worts. Pressure-thermal pretreatment was applied to sugar beet pulp suspended in 2% w/w sulphuric acid solution at a ratio providing 12% dry matter. Enzymatic hydrolysis was conducted using Viscozyme and Ultraflo Max (Novozymes) enzyme preparations (0.015–0.02 mL/g dry matter). Two yeast strains were used for fermentation: Ethanol Red (S. cerevisiae) (1 g/L) and Pichia stipitis (0.5 g/L), applied sequentially. The results show that efficient simultaneous saccharification and fermentation of sugar beet pulp was achieved. A 6 h interval for enzymatic activation between the application of enzyme preparations and inoculation with Ethanol Red further improved the fermentation performance, with the highest ethanol concentration reaching 26.9 ± 1.2 g/L and 86.5 ± 2.1% fermentation efficiency relative to the theoretical yield.

Integrated Bioethanol Fermentation/Anaerobic Digestion for Valorization of Sugar Beet Pulp

“…Effective utilization of sugar beet pulp biomass-derived media presents several challenges. These relate mainly to the specific composition of the carbohydrates and to the fermentation abilities of used microoganisms [3,21,24]. In our study yeast were chosen for use in further experiments based on their assimilation and fermentation abilities ( Table 3).…”

“…Fermentation of sugars other than glucose (galactose, mannose, arabinose, xylose) has been reported after inoculation of sugar beet hydrolyzate (SBH) with Schefersomyces stipitis [3]. However, compared to Saccharomyces cerevisiae, Schefersomyces stipitis is known to be less effective for the production of ethanol.…”

“…As described in an earlier study [43], one ton of the sugar beet pulp subjected to hydrolysis gave 683 dm 3 of the liquid fraction (hydrolyzate), and 320 kg of beet pulp residues. The average specific bioethanol yield from the hydrolyzate was 9 g/dm 3 , giving a total bioethanol volume of 7.78 dm 3 . A residue of bioethanol production is stillage, which represented approximately 68% of the hydrolyzate.…”

“…Around 660 kg of sugar beets are required to produce 100 kg of sugar, with 330 kg of wet pulp and 25 kg of molasses generated as by-products [2]. The pulp mostly contains polymeric saccharides such as cellulose (22-30%), hemicelluloses (24-32%), lignin (1-2%) and pectin (38-62%), which constitute up to 75-85% of the dry matter [3].…”

Changes in Chemical Composition of Plum Distillate during Maturation in the Presence of Oak Chips under Different Conditions

“…HPLC grade water was used as a mobile phase at a fl ow rate of 0.6 mL/min with a sample volume of 20 μL. Prior to analysis, all samples were fi ltered through 0.45-μm PES (polyethersulfone) membranes (29). The recovery studies for the quantifi ed compounds were in the range of 92-107 %.…”