Department of Chemical Biology & Applied Chemistry, College of Engineering, Nihon University, 1 Nakagawara, Tokusada, Tamura-machi, Koriyama, Fukushima, 963-8642, Japan.
Department of Applied Biological Science, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa, 252-0880, Japan.
Appl Biochem Biotechnol. 2019 Mar;187(3):994-1010. doi: 10.1007/s12010-018-2864-6. Epub 2018 Aug 23.
The cellulosome is a supramolecular multienzyme complex formed via species-specific interactions between the cohesin modules of scaffoldin proteins and the dockerin modules of a wide variety of polysaccharide-degrading enzymes. Here, we report a comparative analysis of cellulosomes prepared from the thermophilic anaerobic bacteria Clostridium (Ruminiclostridium) clariflavum DSM 19732 and Clostridium (Ruminiclostridium) thermocellum ATCC 27405 grown on delignified rice straw. The results indicate that the isolated C. clariflavum cellulosome exhibits lower activity for insoluble cellulosic substrates and higher activity for hemicellulosic substrates, especially for xylan, compared to the isolated C. thermocellum cellulosome. The C. clariflavum cellulosome was separated into large and small complexes by size exclusion chromatography, and the high xylanase activity of the intact complex is mainly attributed to the small complex. Furthermore, both C. clariflavum and C. thermocellum cellulosomes efficiently converted delignified rice straw into soluble sugars with different compositions, whereas a mixture of these cellulosomes exhibited essentially no synergy for the saccharification of delignified rice straw. This is the first study to report that isolated C. clariflavum cellulosomes exhibit greater xylanase activity than isolated C. thermocellum cellulosomes. We also report the effect of a combination of intact cellulosome complexes isolated from different species on the saccharification of plant biomass.
纤连蛋白体是一种超分子多酶复合物，通过支架蛋白的黏合模块与各种多糖降解酶的 dockerin 模块之间的种特异性相互作用而形成。在这里，我们报告了从嗜热厌氧细菌 Clostridium (Ruminiclostridium) clariflavum DSM 19732 和 Clostridium (Ruminiclostridium) thermocellum ATCC 27405 制备的纤连蛋白体的比较分析，这些细菌是在木质素去除的水稻秸秆上生长的。结果表明，与分离的 C. thermocellum 纤连蛋白体相比，分离的 C. clariflavum 纤连蛋白体对不溶性纤维素底物的活性较低，对木质素去除的水稻秸秆的半纤维素底物，特别是木聚糖的活性较高。C. clariflavum 纤连蛋白体通过排阻色谱法分离成大、小复合物，完整复合物具有较高的木聚糖酶活性，主要归因于小复合物。此外，C. clariflavum 和 C. thermocellum 纤连蛋白体都能有效地将木质素去除的水稻秸秆转化为具有不同组成的可溶性糖，而这些纤连蛋白体的混合物对木质素去除的水稻秸秆的糖化基本上没有协同作用。这是首次报道分离的 C. clariflavum 纤连蛋白体比分离的 C. thermocellum 纤连蛋白体具有更高的木聚糖酶活性。我们还报告了不同种属的完整纤连蛋白体复合物组合对植物生物质糖化的影响。
