Miyagawa H.,Kirishima Shuzo Co. |
Miyagawa H.,Kumamoto University |
Tang Y.-Q.,Peking University |
Morimura S.,Kumamoto University |
And 5 more authors.
Journal of the Institute of Brewing | Year: 2011
In traditional shochu production with a long-term repetition of sashimoto, the activity of yeast cells decreases, generally resulting in bacterial contamination problems. In this study, a pilot scale study was carried out to demonstrate a technique developed with a laboratory scale test, which improved the activity of the yeast in the first-stage fermentation and the possibility of reuse of stillage for the fermentation to reduce the quantity of stillage from the distillation by 50%. The yeast cells were activated by aeration and stirring for several hours after sashimoto. The yeast cells maintained a high activity level during the entire test period. The ethanol concentration of the second-stage fermented mash was improved and an ethanol concentration of more than 17.5% (v/v) was achieved when stillage was reused in place of water for the fermentation. Comparing the flavour compounds of shochu produced by the traditional process with the long-term repetition of sashimoto, 0.2 ppm of furfural was detected in the shochu produced from the stillage reuse process. No other significant differences were found in the concentrations of the low-, middle- and high-boiling flavour compounds examined, nor in the concentrations of isoamyl acetate and β- phenethyl acetate, which are desired flavour compounds in shochu. © 2011 The Institute of Brewing & Distilling.
Kobayashi T.,Kumamoto University |
Kobayashi T.,Kirishima Shuzo Co. |
Tang Y.,University of Sichuan |
Urakami T.,Kumamoto University |
And 3 more authors.
Journal of Environmental Sciences (China) | Year: 2014
Sweet potato shochu is a traditional Japanese spirit produced mainly in the South Kyushu area in Japan. The amount of stillage reaches approximately 8 × 105 tons per year. Wastewater mainly containing stillage from the production of sweet potato-shochu was treated thermophilically in a full-scale treatment plant using fixed-bed reactors (8 reactors × 283 m3). Following the addition of Ni2+ and Co2+, the reactors have been stably operated for six years at a high chemical oxygen demand (COD) loading rate of 14 kg/(m3·day). Analysis of coenzyme content and microbial communities indicated that similar microbial communities were present in the liquid phase and on the fiber carriers installed in reactors. Bacteria in the phyla Firmicutes as well as Bacteroidetes were dominant bacteria, and Methanosarcina thermophila as well as Methanothermobacter crinale were dominant methanogens in the reactors. This study reveals that stillage from sweet potato-shochu production can be treated effectively in a full-scale fixed-bed reactor under thermophilic conditions with the help of Ni2+ and Co2+. The high diversity of bacterial community and the coexistence of both aceticlastic and hydrogenotrophic methanogens contributed to the excellent fermentation performance. © 2014 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.