We developed the intensive multiple sequential batch simultaneous saccharification and cultivation of the selected thermotolerant yeast strain for single-step ethanol production. The selection and high-cell-density inoculum production of thermotolerant yeast able to produce ethanol under the optimal conditions for single-step ethanol fermentation has become a necessity. In this study, the newly isolated Kluyveromyces marxianus SS106 could tolerate high temperatures (35–45 °C) and grow under a wide range of pH values (3.0–5.5), which are the optimum conditions of raw cassava starch hydrolyzing enzyme used in single-step ethanol fermentation. The high-cell-density concentration of K. marxianus SS106 was produced by a single batch and an intensive multiple sequential batch process in a 5-L stirred tank bioreactor using the simultaneous saccharification and cultivation (SSC) method. The single SSC process yielded the yeast cell biomass at a concentration of 39.30 g/L with a productivity of 3.28 g/L/h and a specific growth rate of 0.49 h⁻¹. However, the yeast cell density concentration was higher in the intensive multiple sequential batch SSC than in the single batch process. This process yielded yeast cell biomass at concentrations of 36.09–45.82 g/L with productivities of 3.01–3.82 g/L/h and specific growth rates of 0.29–0.44 h⁻¹ in the first six batch cycle. The results suggested that the intensive multiple sequential batch simultaneous saccharification and cultivation of K. marxianus SS106 would be a promising process for high-cell-density yeast production for use as the inoculum in single-step ethanol fermentation. Furthermore, we also experimented with single-step ethanol production from raw cassava starch by K. marxianus SS106 in a 5-L stirred tank fermenter. This produced ethanol at a concentration of 61.72 g/L with a productivity of 0.86 g/L/h.

中文翻译：

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从木薯淀粉中一步发酵乙醇的马氏克鲁维酵母SS106耐热酵母菌株的多批次连续分批糖化和栽培

我们开发了密集的多个连续批次同时糖化和选定的耐热酵母菌株培养用于一步一步乙醇生产。能够在单步乙醇发酵的最佳条件下选择能够生产乙醇的耐热酵母的选择和高细胞密度接种物已成为必需。在这项研究中，新分离的马克斯克鲁维酵母SS106可以耐受高温（35–45°C），并且可以在很宽的pH值范围（3.0–5.5）下生长，这是单个使用的木薯淀粉水解酶的最佳条件。步乙醇发酵。马克斯克鲁维酵母的高细胞密度浓度SS106是通过同时糖化和培养（SSC）方法在5-L搅拌釜生物反应器中通过单批生产和密集的多个连续批生产工艺生产的。单一的SSC工艺产生的酵母细胞生物质浓度为39.30 g / L，生产率为3.28 g / L / h，比生长率为0.49 h ^-1。但是，在密集的多顺序分批SSC中，酵母细胞密度浓度比单批过程中的高。此过程在前六个批处理周期中产生的酵母细胞生物量浓度为36.09-45.82 g / L，生产率为3.01-3.82 g / L / h，比生长率为0.29-0.44 h ^-1。结果表明，密集的连续批量分批同步糖化和栽培沙棘。K. marxianus SS106对于单细胞乙醇发酵中的接种物而言，是生产高细胞密度酵母的有前途的方法。此外，我们还尝试了在5升搅拌罐发酵罐中，由K. marxianus SS106从木薯淀粉原料中一步生产乙醇。这样产生的乙醇浓度为61.72 g / L，生产率为0.86 g / L / h。