1株南极真菌的鉴定及其分泌色素性质分析

Identification of an Antarctic Fungus and Property Analysis of its Secretory Pigment

从南极土壤中分离得到1株分泌紫红色色素的真菌WNF-15A,通过菌落特征、显微形态观察和ITS序列分析,将其归为地丝霉属(Geomyces)。该菌最适生长温度范围15～20℃,属于嗜冷真菌。其分泌色素为水溶性,在波长533nm处有最大吸收峰。采用反应动力学的方法对色素的热降解进行了研究,其热降解符合Ar-rhenius经验公式,活化能在65.4～81.2kJ/mol之间,温度稳定性相对常用的红曲红色素和甜菜苷色素为一般。pH对色素稳定性影响较小,pH1～10色调不发生变化,pH3～9色素最稳定。在太阳光曝晒下光稳定较差,室内散射光对色素的稳定性影响较小。急性毒性试验测得小鼠的LD_(50)>15000mg/kg,属于无毒级别。该色素可以作为天然食用色素资源开发利用。

A fungus named WNF-15A which secreted a special amaranthine pigment was isolated from soil collected from Antarctic. It was determined as a member of Geomyces based on colony morphologic characteristics, microscopic morphology and the phylogenetic analysis of ITS. And it was a psychrophiles which has optimum growth temperature between 15~20℃. The hydro soluble amaranthine pigment produced by WNF-15A has the maximum absorption at 533 nm. Its thermal degradation dynamics corresponded with Arrhenius empirical formula and the activation energy was 65.4-81.2 kJ/mol, and this pigment has a nearly higher thermostability than monacolin K and betacyanin. Changes of pH had little effect on the stability of the pigment that was most stable under pH3 ~9 condition. Although the pigment was faded quickly when it exposed to sunlight, scattered light was almost ineffective on its stability. This pigment was nontoxic determined by LD50〉15 000 mg/kg observed from mice toxicity test. This pigment could be largely exploited as a natural pigment.