Food Research Institute, National Agriculture and Food Research Organization (NARO), 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan.
J Ind Microbiol Biotechnol. 2012 Feb;39(2):307-15. doi: 10.1007/s10295-011-1033-5. Epub 2011 Sep 4.
Yeasts that ferment both hexose and pentose are important for cost-effective ethanol production. We found that the soil yeast strain NY7122 isolated from a blueberry field in Tsukuba (East Japan) could ferment both hexose and pentose (D-xylose and L-arabinose). NY7122 was closely related to Candida subhashii on the basis of the results of molecular identification using the sequence in the D1/D2 domains of 26S rDNA and 5.8S-internal transcribed spacer region. NY7122 produced at least 7.40 and 3.86 g l⁻¹ ethanol from 20 g l⁻¹ D-xylose and L-arabinose within 24 h. NY7122 could produce ethanol from pentose and hexose sugars at 37°C. The highest ethanol productivity of NY7122 was achieved under a low pH condition (pH 3.5). Fermentation of mixed sugars (50 g l⁻¹ glucose, 20 g l⁻¹ D-xylose, and 10 g l⁻¹ L-arabinose) resulted in a maximum ethanol concentration of 27.3 g l⁻¹ for the NY7122 strain versus 25.1 g l⁻¹ for Scheffersomyces stipitis. This is the first study to report that Candida sp. NY7122 from a soil environment could produce ethanol from both D-xylose and L-arabinose.
既能发酵己糖又能发酵戊糖的酵母对于经济高效的乙醇生产很重要。我们发现，从筑波蓝莓田（日本东部）分离出的土壤酵母菌株 NY7122 既能发酵己糖又能发酵戊糖（D-木糖和 L-阿拉伯糖）。基于对 26S rDNA 的 D1/D2 结构域和 5.8S-内部转录间隔区序列的分子鉴定结果，NY7122 与 Candida subhashii 密切相关。NY7122 在 24 小时内可分别从 20 g/L 的 D-木糖和 L-阿拉伯糖中产生至少 7.40 和 3.86 g/L 的乙醇。NY7122 可以在 37°C 下从戊糖和己糖糖中生产乙醇。NY7122 的最高乙醇生产率是在低 pH 条件（pH 3.5）下实现的。混合糖（50 g/L 葡萄糖、20 g/L D-木糖和 10 g/L L-阿拉伯糖）发酵后，NY7122 菌株的最大乙醇浓度为 27.3 g/L，而 Scheffersomyces stipitis 的最大乙醇浓度为 25.1 g/L。这是首次报道土壤环境中的 Candida sp. NY7122 可以从 D-木糖和 L-阿拉伯糖生产乙醇。
