木糖发酵产乙醇丝状真菌的鉴定及发酵特性

Identification and characterization of filamentous fungus during xylose fermentation for ethanol production

针对目前对丝状真菌的木糖发酵研究较少的现状,应用杜氏管发酵法初筛和发酵测定法复筛对不同环境的土壤样品进行菌株的筛选,并采用显微镜观察和18S rRNA序列扩增分析对菌种进行鉴定;用重铬酸钾法对菌株的发酵特性进行研究.结果表明:筛选到一株能发酵木糖的丝状真菌,命名为cs-28;经形态学和生物学鉴定为尖孢镰刀菌(Fusarium oxysporum);它不仅能发酵木糖,同时也能利用葡萄糖、蔗糖和玉米秸秆等多种发酵碳源;其最适氮源为酵母提取物;在温度为30℃、初始pH值为6.0、初始木糖质量浓度为20 g·L-1时乙醇产率最高.该研究结果为木质纤维素原料的生物转化提供新的菌种资源和工艺参数.

At present,yeast is the main microorganism involved in ethanol production using xylose as carbon source.The filamentous fungi have been less studied compared to yeast.Duchenne tube and ethanol yield assay methods were applied to screen different microbes for xylose fermentation.The microorganism producing the highest amount of ethanol was identified by microscopy and 18s rRNA amplification and analysis.Fermentation assays of this microorganism were studied by the Potassium dichromate method.The screening results showed that the organism code named cs-28 was Fusarium oxysporum.It was found that this fungus could ferment xylose,glucose,sucrose and corn stalk to produce ethanol.The optimal nitrogen source was yeast extract.The ethanol production rate was highest at initial pH 6.0 and 30 ℃,when initial xylose concentration was 20 g·L-1.Thus,cs-28 can be used as a new strain for transformation of cellulose materials to ethanol.Moreover,characterization of cs-28 on xylose fermentation can be applied in technological advancement.