一株产纤维素酶嗜盐真菌的筛选、鉴定及其酶学性质研究

Screening and Identification of a Halophilic Fungi and Its Optimization of Celluase Production

摘要: 本研究从青海茶卡盐湖来源样品中纯化出一批嗜盐真菌，通过刚果红染色法初步筛选可降解纤维素的菌株，利用DNS测定法进一步筛选，获得一株产纤维素酶能力较强的菌株，命名为F33。通过形态观察和ITS rRNA序列比较分析，初步鉴定该菌株为枝孢属(Cladosporium sp.) (GenBank登录号：ON318389)。使用玉米杆作为碳源进行诱导，收集发酵液对其分泌的纤维素酶进行酶学性质研究，发现菌株F33来源纤维素酶最适反应温度为45℃、最适pH为4.0，盐浓度在0~3.0 mol/L时，保持50%以上的相对活性。此外，Mn²⁺对该菌株所产的纤维素酶有较强的促进作用，而化学试剂十二烷基硫酸钠(SDS)对其有明显的抑制作用，在标准条件下测得总酶活力达到0.54 ± 0.03 U/mL。这些性质说明菌株F33所产纤维素酶系具有嗜酸、耐盐的特性，预示着其在食品、饲料、纺织、造纸业等领域有广阔的应用前景。

Abstract: In this study, a batch of halophilic fungi were purified from the samples from the Chaka salt lake in Qinghai, and the degradable cellulose strains were preliminarily screened by Congo red staining, and further screened by DNS assay to obtain a strain with strong cellulase-producing ability F33. Through morphological observation and comparative analysis of ITS rRNA sequences, the strain was preliminarily identified as a Cladosporium sp. (GenBank accession number: ON318389). The use of corn stalks as a carbon source for induction, the collection of fermentation broth and the enzymatic properties of the cellulase secreted by it were found that the optimal reaction temperature of cellulase from F33 source was 45˚C, the optimal pH was 4.0, and there was more than 50% enzyme activity within 0~3.0 mol/L NaCl. In addition, Mn²⁺ has a strong promoting effect on the cellulase produced by this strain, and the chemical reagent sodium lauryl sulfate (SDS) has a significant inhibitory effect on it, and the total enzyme activity measured under standard conditions reaches 0.54 ± 0.03 U/mL. These properties indicate that the cellulase produced by strain F33 has the characteristics of acidophilicity and salt tolerance, indicating that it has broad application prospects in the fields of food, feed, textile, and paper industry.