六堡茶中“金花”菌的生物学特性

Biological Characteristics of Jinhua Fungus from Liupao Tea

微生物对六堡茶的品质形成有重要影响,以"金花"菌普遍茂盛品质为佳。"金花"生长具有随机性,因此,难以控制六堡茶中金花的数量。本研究对从六堡茶分离出的一株金花菌株LB-1雪黄散囊菌(Eurotium niveoglaucum)的形态学与生理特性进行研究,力图掌握其发花规律。结果表明,该菌株的形态学表现为,大量黄色菌丝,有隔;闭囊壳缠绕在具饰菌丝网中,破碎释放子囊孢子;分生孢子头结构呈疏松放射形,其末端会出现泡囊状的顶囊,分生孢子梗较长,壁光滑,顶囊烧瓶形,产孢结构单层;分生孢子椭圆形,少数近球形。菌株LB-1生长周期呈"S"形,其生长适宜温度为25℃、pH值为6.1。菌株LB-1在不同碳源的培养基中以蔗糖和葡萄糖为碳源的培养基菌丝生长良好,其中蔗糖浓度为20%时生长最佳。NaCl浓度为5%时菌株LB-1生长良好。菌株LB-1在不同氮源的培养基中以牛肉膏、蛋白胨、酵母膏为碳源的培养基菌丝生长最佳。

The quality formation of Liupao Tea is greatly influenced by the microbe, with the flourishing of ＂Jinhua＂ fungus as a symbol of high quality. The random growth of the strain of ＂Jinhua＂ fungus makes it difficult to control the quantity of ＂Jinhua＂ fungus from Liupao Tea. A strain LB-1 was separated from Liupao Tea from Guangxi, which was identified as Eurotium niveoglaucum. The morphological and the physiological properties of this strain were investigated to master the growth regularity of ＂Jinhua＂ fungus. The results show that the strain LB-1 contains a large quantity of septate yellow mycelium.The cleistotheeia, which is surrounded by a dense network of septate hyphae, will release ascospores when it is broken. Conidial head displays a loose and radial structure while acrosomal vesicle appears at the terminal. Conidiophores is long, with smooth walls, as well as a flask shape and uniseriate acrosomal vesicle. Conidia were almost oval, with few spherical. The growth curve of ＂Jinhua＂ fungus stain LB-1 shows the shape of ＂S＂, with a preference temperature of 25 ~C and pH value of 6.1. Among different culture media, the strain LB-1 grew well in the culture medium with sucrose and glucose as its carbon source, with an optimum sucrose concentration of 20%. The optimum concentration of NaC1 was 5%. Besides, among different nitrogen sources, the strain LB-1 grew the best with beef extract, peptone and yeast extract.