title: Selection of stress-tolerant yeasts for simultaneous saccharification and fermentation (SSF) of very high gravity (VHG) potato mash to ethanol.
abstract: 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.
authors: National Food Research Institute, National Agriculture and Food Research Organization (NARO), 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan.
authors: Takashi
authors: T
authors: Watanabe
authors: Sathaporn
authors: S
authors: Srichuwong
authors: Mitsuhiro
authors: M
authors: Arakane
authors: Seiji
authors: S
authors: Tamiya
authors: Masaru
authors: M
authors: Yoshinaga
authors: Itsuki
authors: I
authors: Watanabe
authors: Mami
authors: M
authors: Yamamoto
authors: Akira
authors: A
authors: Ando
authors: Ken
authors: K
authors: Tokuyasu
authors: Toshihide
authors: T
authors: Nakamura
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects; D050260:Carbohydrate Metabolism / Q000187:drug effects; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation / Q000187:drug effects / Q000502:physiology*; D005947:Glucose / Q000494:pharmacology; D018471:Hypergravity; D011198:Solanum tuberosum / Q000187:drug effects / Q000378:metabolism*; D013312:Stress, Physiological / Q000187:drug effects; D013696:Temperature; D013997:Time Factors; D015003:Yeasts / Q000187:drug effects / Q000254:growth & development / Q000302:isolation & purification*
chemical_list: D000431:Ethanol; D005947:Glucose