西藏开菲尔粒(俗称藏灵菇)是由多种乳酸菌(间或少量醋酸菌)和酵母菌共生而成一种外形酷似菜花的白色或乳黄色团状聚合体,是目前已知的唯一可用于酸奶制作的天然野生菌种资源。采用扫描电镜、分离培养、26S rRNA基因测序与序列分析、荧光原位杂交(FISH)相结合的技术方法,对西藏开菲尔粒中的酵母菌进行了分离培养、鉴定和形态观察。结果显示:西藏开菲尔粒中酵母菌多为球形(2.0~5.0μm)或椭圆形(1.0~3.0×2.0~4.0μm);从西藏开菲尔粒中分离出的16株酵母菌分属于酿酒酵母属(Saccharomyces)、克鲁维酵母属(Kluyveromyces)、亚罗酵母属(Yarrowia)这3个属中的4个种,其中3株是酿酒酵母菌(Saccharomyces cerevisiae),8株为马克斯克鲁维酵母菌(Kluyveromyces marxianus),3株为解脂亚罗酵母菌(Yarrowia lipolytica)。
Tibetan kefir grains (TKGs), the so-called Tibetan mushroom, contain a variety of microorganisms, e. g. , lactic acid bacteria, yeasts, and occasionally acetic acid bacteria, in a white or milky viscous matrix. In the present study, the cuhurable yeasts in TKGs were isolated, identified and characterized mainly based on scanning electron microscopy, 26S rRNA gene cloning and sequencing, phylogenetic analysis, and fluorescence in situ hybridization (FISH). The results showed most of yeasts in TKGs were spherical (2.0 - 5.0 μm) or oval ( 1.0 - 3.0 × 2.0 - 4.0 μm). The yeasts were observed present on the outer and inner surfaces of TKGs and were less in numbers compared with bacteria. Totally, sixteen yeast strains were identified, which belonged to three genera-Saccharomyces, Kluyveromyces and Yarrowia, and were grouped to four species of S. cerevisiae ( 3 strains ) , Saccharomyces sp. ( 2 strains ) , K. rnarxianus ( 8 strains) and Y. lipolytica (3 strains).