摘要
用含木糖为唯一碳源(培养基X)和含葡萄糖及7.6%乙醇(培养基E)的两种富集培养基分别从采自海南热带雨林的56和57份腐木样品中分离到酵母菌67和75株。依据26SrDNA D1/D2区域序列分析并结合形态学特征对这些菌株进行了分类学研究,探讨了该地区腐木上的酵母菌物种多样性及其分布。从分离的142株酵母菌中鉴定出14个属63个种,其中疑似新种25个,占总种数的近40%,说明在热带雨林腐木中尚存在大量酵母菌新分类群有待被发现。从用培养基X和E分离的酵母菌中分别鉴定出7属37种和11属33种,优势属均为假丝酵母属Candida Berkhout和毕赤酵母属Pichia Hansen,但种类组成基本不同。用培养基X富集分离的菌株以Candida quercitrusa S.A.Meyer & Phaff的地理分布最广,用培养基E富集分离的菌株以异常毕赤酵母Pichiaanomala (Hansen) Kurtzman、酿酒酵母Saccharomyces cerevisiae Meyenex Hansen和亚膜毕赤酵母Pichia subpelliculosa Kurtzman分布最广泛。同一样品用两种不同富集培养基分离的菌株大多数属于不同的种,在对比的23份样品中,只从2份样品中分离到了同一个种的菌株。用培养基X和E分离的菌株分别属于可利用木糖和可耐受乙醇的酵母菌,用两种培养基同时分离到的菌株属于具备利用木糖和耐受高浓度乙醇两种能力的菌株。这些酵母菌在木质纤维素物质的生物乙醇转化技术中的应用价值值得进一步研究。
Yeasts in the rotten wood collected from the rainforests of Hainan, a tropical island in southern China, were isolated by using the enrichment medium X containing xylose as the sole source of carbon and medium E containing glucose and 7.6% （v/v） ethanol. A total of 67 yeast strains were isolated from 56 rotten wood samples using medium X and 75 strains were isolated from 57
samples using medium E. After morphological grouping, these strains were identified based on the 26S rDNA D1/D2 domain sequence analysis. A total of 63 species （including 25 proposed new species） belonging to 14 genera were identified from the 147 strains isolated. Thirty seven species belonging to seven genera and 33 species belonging to 11 genera were identified from the yeast strains isolated using media X and E, respectively. Candida Berkhout and Pichia Hansen were the dominant genera identified from the strains isolated using either of the media. However, the species identified from the strains isolated using different media were quite different. Among strains isolated using medium X, Candida quercitrusa S.A. Meyer ＆ Phaff was the most widely distributed species and among the strains isolated using medium E, Pichia anornala （Hansen） Kurtzman, Saccharomyces cerevisiae Meyen ex Hansen and Pichia subpelliculosa Kurtzman were the most widely distributed species. Strains belonging to the same species were only isolated from two of the 23 rotten wood samples compared using different media. The present study suggests that the species diversity of yeasts colonizing rotten wood is quite high and a considerable number of new yeast species remain to be discovered from this habitat. The yeasts isolated using medium X are usually able to utilize xylose and those isolated using medium E are usually able to tolerate ethanol. These strains may be useful in bio-ethanol production from lignocellulose materials.
出处
《菌物学报》
CAS
CSCD
北大核心
2009年第3期354-362,共9页
Mycosystema
基金
国家自然科学基金(No.30470005)
