Benassi Vivian Machado, de Lucas Rosymar Coutinho, Jorge João Atílio, Polizeli Maria de Lourdes Teixeira de Moraes
Departamento de Bioquímica e Imunologia Faculdade de Medicina de Ribeirão Preto Universidade de São Paulo Ribeirão PretoSP Brazil Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.
Departamento de Biologia Faculdade de Filosofia Ciências e Letras de Ribeirão Preto Universidade de São Paulo Ribeirão PretoSP Brazil Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.
Braz J Microbiol. 2015 Mar 4;45(4):1459-67. doi: 10.1590/s1517-83822014000400042. eCollection 2014.
Plant cell wall is mainly composed by cellulose, hemicellulose and lignin. The heterogeneous structure and composition of the hemicellulose are key impediments to its depolymerization and subsequent use in fermentation processes. Thus, this study aimed to perform a screening of thermophilic and thermotolerant filamentous fungi collected from different regions of the São Paulo state, and analyze the production of β-xylosidase and arabinanase at different temperatures. These enzymes are important to cell wall degradation and synthesis of end products as xylose and arabinose, respectively, which are significant sugars to fermentation and ethanol production. A total of 12 fungal species were analyzed and 9 of them grew at 45 °C, suggesting a thermophilic or thermotolerant character. Additionally Aspergillus thermomutatus anamorph of Neosartorya and A. parasiticus grew at 50 °C. Aspergillus niger and Aspergillus thermomutatus were the filamentous fungi with the most expressive production of β-xylosidase and arabinanase, respectively. In general for most of the tested microorganisms, β-xylosidase and arabinanase activities from mycelial extract (intracellular form) were higher in cultures grown at high temperatures (35-40 °C), while the correspondent extracellular activities were favorably secreted from cultures at 30 °C. This study contributes to catalogue isolated fungi of the state of São Paulo, and these findings could be promising sources for thermophilic and thermotolerant microorganisms, which are industrially important due to their enzymes.
植物细胞壁主要由纤维素、半纤维素和木质素组成。半纤维素的异质结构和组成是其解聚以及后续用于发酵过程的关键障碍。因此，本研究旨在对从圣保罗州不同地区收集的嗜热和耐热丝状真菌进行筛选，并分析不同温度下β-木糖苷酶和阿拉伯糖苷酶的产生情况。这些酶分别对细胞壁降解以及木糖和阿拉伯糖等终产物的合成很重要，而木糖和阿拉伯糖是发酵和乙醇生产中的重要糖类。总共分析了12种真菌，其中9种能在45℃下生长，表明具有嗜热或耐热特性。此外，新萨托菌的嗜热突变曲霉无性型和寄生曲霉能在50℃下生长。黑曲霉和嗜热突变曲霉分别是β-木糖苷酶和阿拉伯糖苷酶产量最高的丝状真菌。总体而言，对于大多数测试微生物，菌丝体提取物（细胞内形式）中的β-木糖苷酶和阿拉伯糖苷酶活性在高温（35 - 40℃）培养的菌株中较高，而相应的细胞外活性则在30℃培养的菌株中分泌良好。本研究有助于对圣保罗州分离出的真菌进行编目分类，这些发现可能成为嗜热和耐热微生物的有前景来源，因其所含的酶在工业上具有重要意义。
