镉诱导抗镉茎点霉产生水溶性红色素

Water-soluble Red Pigment from Cadmium-resistant Phoma Induced by Cadmium

筛选纯化出一株在含镉培养基中能分泌水溶性红色素的抗镉丝状真菌KGM01。ID序列测定与系统发育分析显示它与草茎点霉聚类在一个进化枝,表明菌株KGM01是一种茎点霉,ID序列在GenBank中的登录号为KF675768。它的生长温度范围为20~30℃（最适25~28℃）,能耐受0.001~0.005 mol/L硝酸镉。在含硝酸镉（0.001~0.005 mol/L）察氏培养液振荡培养时,大部分镉离子被菌丝体吸附,同时镉诱导该菌株产生水溶性红色素。可通过“氯仿-无水乙醇分步沉淀/离心法”制备红色素粗提液,红色素的紫外-可见光谱特征吸收峰为458 nm。红色素在低温暗室中稳定期长,在强酸、强碱、高热和强日照下不稳定。菌株KGM01有潜力开发成镉污染的生物监测菌物。

A cadmium-resistant fungal isolate KGM01 was characterized by producing water-soluble red pigment （WSRP） on medium containing cadmium. ID sequence and phylogenetic analysis results suggested the strain KGM01 was closely related to Phoma herbarum, which indicated the isolate is a member of genus Phoma, with GenBank accession number of the ID sequence as KF675768. For the strain KGM01, growth occurred at 20-30 ~C（optimum at 25~28 ~C） and in mediums containing 0.001-0.005 mol/L cadmium nitrate. When shaking cultured in the liquid Czapek＇s mediums containing 0.001- 0.005 mol/L cadmium, most of the cadmium ions were biosorbed off by the hyphae, and a WSRP induced by cadmium secreted in the broth. The preparation of WSRP crude solution was obtained by chloroform-absolute alcohol fractional precipitation and centrifugation method. The characteristic ultraviolet-visible absorption peak of the red pigment was at 458 nm. The red pigment has long stable phase under a low temperature condition in dark, and it is unstable in the strong acid or base, in intense sunshine or at high temperature. The strain KGM01 has a potential to be developed as a biomonitor for cadmium pollution.