**Acknowledgements**

of the thermotolerant yeast is favorable to fermentation in a tropical country because it can be performed under temperature-noncontrolled conditions. When a bench-scale fermentation, 2 L of 9% glucose medium, was tested, DMKU 3-1042 produced ethanol equivalent to that under the temperature-controlled condition at 30°C [39]. In a fermenter-scale fermentation

As an additional challenge, distillation-connected fermentation was attempted. Because the saturated vapor pressure of ethanol is 177.8 mbar at 41°C, where a thermotolerant microbe can grow well, ethanol can be collected from the fermenting culture when pressure is reduced to less than the saturated vapor pressure. The system shown in **Figure 5** was constructed and tested, which consists of a fermentation and a distillation tank, the primary and secondary ethanol recovery units, a vacuum pump, and a drain unit. In this system, ethanol is concentrated as the process proceeds from the primary to secondary ethanol recovery units. Due to the set-up of this system, the air in the tank was discharged outside during the vacuum distillation, and some ethanol was trapped in the drain unit. When fermentation with *K. marxianus* DMKU 3-1042 and distillation at 70 mbar and 41°C was applied, about 35 and 60% were recovered in the primary and secondary bottles [39]. The process of the simultaneous fermentation and distillation under a low pressure was continuously repeated three times, with 12% rice-hydrolysate [39]. Similar performance was achieved with a thermo-adopted

That system provides some benefits: (i) microbes avoid exposure to high concentrations of ethanol or acetic acid or strong oxidative stress and (ii) fermentation can be continued during distillation increasing ethanol yields. Although further experiments for its evaluation are required, the system including HTF is expected to be one of next-generation fermentation technologies.

**Figure 5.** Apparatus for fermentation and distillation under a low pressure. This apparatus consists of a fermentation

and distillation tank, primary and secondary recovery bottles, a drain unit, and a vacuum pump.

with 4000 L of 18% sugarcane, 7% ethanol production was achieved [39].

**9.2. Distillation-connected fermentation with thermotolerant yeast**

140 Fuel Ethanol Production from Sugarcane

strain of *Zymomonas mobilis* TISTR548, an ethanologenic bacterium [39].

This work was supported by The Core to Core Program, which was granted by the Japan Society for the Promotion of Science, the National Research Council of Thailand, Ministry of Science and Technology in Vietnam, National Univ. of Laos, Univ. of Brawijaya and Beuth Univ. of Applied Science Berlin, supported by Japan Science and Technology Agency, Ministry of Research, Technology and Higher Education of the Republic of Indonesia, Agricultural Research Development Agency of Thailand and Ministry of Science and Technology of Laos as part of the e-ASIA Joint Research Program (e-ASIA JRP), and partially supported by Advanced Low Carbon Technology Research and Development Program, which was granted by Japan Science and Technology Agency.
