Optimisation of ethanol fermentation of Jerusalem artichoke tuber juice using simple technology for a decentralised and sustainable ethanol production

•Partial inulin hydrolysis was performed by a juice treatment prior to fermentation.•Inulinases exhibited activity during fermentation, after optimal treatments.•Higher inulinase dose and energy are required for autumn juice than for winter ones.•Almost 90% of the theoretical maximum ethanol yield was achieved.•8200 L ethanol ha− 1 could be obtained from Jerusalem artichoke tubers.

Ethanol production from Jerusalem artichoke was optimised using simple technology according to tuber harvest date. The optimal treatment for winter juice was the addition of 0.25 mL L − 1 of a commercial inulinase (17 U g− 1) and a juice heating at 52.5 °C for 60 min before the beginning of the fermentation. For autumn juice, the optimal treatment was a previous heating at 80 °C for 15 min followed by the addition of 0.75 mL L− 1 of the inulinase at 60 °C kept for 120 min, prior to the fermentation. Ethanol yields of 0.458 and 0.454 g g − 1 were obtained with autumn juice and winter ones, respectively. Fermentation was conducted at 30 °C by Saccharomyces cerevisiae. These results could be useful for a staggered and decentralised ethanol production from a low-requirement crop which does not interfere with the food chain.