National Food Research Institute, National Agriculture and Food Research Organization (NARO), 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan.
Bioresour Technol. 2010 Dec;101(24):9710-4. doi: 10.1016/j.biortech.2010.07.079. Epub 2010 Jul 24.
Highly concentrated bioethanol production requires less volume in fermentation tanks and conserves distillery energy. We screened osmotolerant yeasts from a collection of 1699 yeast strains at our institute and found that three strains, NFRI3062, NFRI3213, and NFRI3225, were candidates for use in bioethanol production. All of these strains belonged to Saccharomyces cerevisiae. NFRI3062 produced 15.0% (w/v) of ethanol from YPD medium containing 35% glucose cultivated at 30 degrees C for 60 h, while S. cerevisiae NBRC0224, which has previously been reported suitable for ethanol production, only produced 13.0% (w/v). The thermotolerances of NFRI3213 and NFRI3225 were also superior to those of NBRC0224 and NFRI3062. We also demonstrated the simultaneous saccharification and fermentation (SSF) of very high gravity (VHG) potato mash and sweet-potato mash. NFRI3225 produced ethanol from potato mash at the fastest rate and in the highest volume (13.7% (w/v)) among the tested strains. The maximum productivity and ethanol yields were 9.1g/L/h and 92.3%, respectively. Although the potato mash was not sterilized, bacterial contamination was not observed. This may have been due to the growth inhibition of bacteria by the rapid glucose consumption and ethanol production of NFRI3225 during the VHG-SSF process.
高浓度生物乙醇生产需要在发酵罐中使用较少的体积，并节省酿酒厂的能源。我们从我们研究所的 1699 株酵母菌株中筛选出耐渗透压酵母，并发现三株酵母 NFRI3062、NFRI3213 和 NFRI3225 可作为生物乙醇生产的候选菌株。这些菌株均属于酿酒酵母。NFRI3062 在 30℃下用含有 35%葡萄糖的 YPD 培养基培养 60 小时，可产生 15.0%（w/v）的乙醇，而之前报道适用于乙醇生产的 S. cerevisiae NBRC0224 仅能产生 13.0%（w/v）的乙醇。NFRI3213 和 NFRI3225 的耐热性也优于 NBRC0224 和 NFRI3062。我们还证明了高浓度（VHG）马铃薯浆和甘薯浆的同步糖化和发酵（SSF）。在测试的菌株中，NFRI3225 从马铃薯浆中以最快的速度和最高的体积（13.7%（w/v））生产乙醇。最大生产力和乙醇产率分别为 9.1g/L/h 和 92.3%。尽管马铃薯浆没有经过消毒，但没有观察到细菌污染。这可能是由于 NFRI3225 在 VHG-SSF 过程中快速消耗葡萄糖和生产乙醇，从而抑制了细菌的生长。
