Consolidated bioprocessing of highly concentrated jerusalem artichoke tubers for simultaneous saccharification and ethanol fermentation

Abstract

Consolidated bioprocessing (CBP) of Jerusalem artichoke tuber (Jat) for ethanol production is one of the most promising options for an alternate biofuel technology development. The technical barriers include the weak saccharolytic enzyme (inulinase) activity of the fermentation strain, and the well mixing of the high viscous fermentation slurry at the highly concentrated Jat loading. In this study, Saccharomyces cerevisiae DQ1 was found to produce relatively large amount of inulinase for hydrolysis of inulin in Jat, and the helical ribbon stirring bioreactor used provided well mixing performance under the high Jat loading. Even a highly concentrated Jat loading up to 35% (w/w) in the helical ribbon bioreactor for CBP was allowed. The results obtained from this study have demonstrated a feasibility of developing a CBP process technology in the helical ribbon bioreactor for ethanol production at a high yield 128.7 g/L and the theoretical yield 73.5%, respectively. This level of ethanol yield from Jat is relatively higher than others reported so far. The results of this study could provide a practical CBP process technology in the helical ribbon bioreactor for economically sustainable alternate biofuel production using highly concentrated inulin containing biomass feedstock such as Jat, at least 35%.

The prospects of Jerusalem artichoke in functional food ingredients and bioenergy production

“…Under their experimental conditions, these two strains gave 90% and 79.7% of theoretical ethanol yield respectively at 40 °C within 84 h fermentation. Very recently, Guo et al [161] reported an improved CBP process in a helical ribbon stirring bioreactor using mutant yeast, S. cerevisiae DQ1. The ethanol concentration was as high as 128 g/L, which is very promising.…”

Optimizing Acid Hydrolysis of Jerusalem Artichoke-Derived Inulin for Fermentative Butanol Production

“…Yeast strains expressing high levels of inulases have been developed and successfully used for ethanol production from Jerusalem artichoke [31]. However, not very biotransformation can be achieved by inulaseproducing strains.…”

Biofuel production from Jerusalem artichoke tuber inulins: a review

“…Relatively new studies employed the CBP approach for ethanol production using JA tuber flour. In these studies, tubers were washed, cut or chopped in a grinder, dried, and then milled to obtain tuber flour (Yuan et al, 2008;Liu et al, 2011;Guo et al, 2013;Sarchami and Rehmann, 2014;Khatun et al, 2016). In two studies, dried slices (Yuan et al, 2013b) or tuber mash after grinding (Charoensopharat et al, 2015) were the source of inulins.…”

“…This resulting strain JZD-InuMKCP showed highest ethanol productivity of 3.2 g/L/h in 24 h and 2.44 g/L/h in 36 h with 95% theoretical ethanol yield solely fermented on JA tuber flour. Guo et al (2013) used engineered S. cerevisiae DQ1 for CBP at optimum conditions of 30°C and pH 5.5. The optimum activity of the inulinase from this strain was at 50-55°C and pH 5.0.…”