As the typical brown alage, Sargassum fulvellum contains a large amount of the carbohydrate, it can be used to produce bioethanol after pretreatment. The overall goal of this work was to develop a saccharification method for the production of bioethanol using Sargassum fulvellum. A two-step hydrolysis method including acid hydrolysis (first stage) and enzyme hydrolysis ( second stage) was carried out to optimize the condition for the saccharification of sargassum. Results displayed that the acid hydrolysis efficiency of first stage was 31. 05% ±0. 32% (w/w dry bio-mass) of the reducing sugar under optimum conditions of feed content 6% (w/v) , 1.5% (v/v) sulfuric acid, 120t and 40min. After enzyme hydrolysis of second stage, the efficiency of the saccharification was increased by 9. 68% under optimum conditions of feed content 5% (w/v) , alginate lyase concentration 0.0025% (w/v) and reaction time 2h. The reducing sugar yields from Sargassum fulvellum using a two-stage hydrolysis method was 38% ~40% ( w/w dry biomass) , which reached 89% of the theoretical yields. The hydrolyzate derived from Sargassum fulvellum by a two-stage hydrolysis was employed for conversion to ethanol by industrial Saccharomyces cerevisiae R1 -11. The highest ethanol yield was 91. 9 g/kg dry biomass.%马尾藻是典型的大型褐藻,含有大量的碳水化合物,通过糖化处理后能够用于生物乙醇的发酵生产.研究了马尾藻的两步水解方法,优化了两步水解法中酸水解和酶水解的最适水解条件.试验发现在料液比为6％(w/v),H2SO4浓度1.5％(v/v),时间40 min,温度为120℃的水解条件下马尾藻的第1步酸水解效率可以达到(31.05±0.32)％ (w/w).进一步用海藻酸盐裂解酶进行第2步水解,最适水解条件:料液比5％(w/v)、酶用量0.0025％ (w/v)、时间2h,第2步酶水解后马尾藻的水解效率可以在第1步水解的基础上提高9.68％(w/w).最终两步法的总水解效率可以达到38％ ～40％ (w/w),达到理论产量的89％.用工业酿酒酵母R1-11对水解液进行发酵实验,在未优化发酵条件的情况下每千克马尾藻生产乙醇60.75 g,当水解液补充1％(w/v)(NH4)2SO4时乙醇的产量可以达到每千克马尾藻生产乙醇91.9 g.
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