Research Area Gene Technology and Applied Biochemistry, Institute of Chemical Engineering, Vienna University of Technology, Wien, Austria.
Appl Microbiol Biotechnol. 2011 Mar;89(6):1665-73. doi: 10.1007/s00253-010-3071-8. Epub 2011 Jan 7.
L-Arabinose is the second most abundant pentose beside D-xylose and is found in the plant polysaccharides, hemicellulose and pectin. The need to find renewable carbon and energy sources has accelerated research to investigate the potential of L-arabinose for the development and production of biofuels and other bioproducts. Fungi produce a number of extracellular arabinanases, including α-L-arabinofuranosidases and endo-arabinanases, to specifically release L-arabinose from the plant polymers. Following uptake of L-arabinose, its intracellular catabolism follows a four-step alternating reduction and oxidation path, which is concluded by a phosphorylation, resulting in D-xylulose 5-phosphate, an intermediate of the pentose phosphate pathway. The genes and encoding enzymes L-arabinose reductase, L-arabinitol dehydrogenase, L-xylulose reductase, xylitol dehydrogenase, and xylulokinase of this pathway were mainly characterized in the two biotechnological important fungi Aspergillus niger and Trichoderma reesei. Analysis of the components of the L-arabinose pathway revealed a number of specific adaptations in the enzymatic and regulatory machinery towards the utilization of L-arabinose. Further genetic and biochemical analysis provided evidence that L-arabinose and the interconnected D-xylose pathway are also involved in the oxidoreductive degradation of the hexose D-galactose.
L-阿拉伯糖是除 D-木糖之外第二丰富的戊糖，存在于植物多糖、半纤维素和果胶中。寻找可再生碳和能源的需求加速了研究，以调查 L-阿拉伯糖在开发和生产生物燃料和其他生物制品方面的潜力。真菌产生许多细胞外阿拉伯聚糖酶，包括α-L-阿拉伯呋喃糖苷酶和内切阿拉伯聚糖酶，专门从植物聚合物中释放 L-阿拉伯糖。L-阿拉伯糖摄取后，其细胞内分解遵循四步交替还原和氧化途径，最后通过磷酸化，生成 D-木酮糖 5-磷酸，这是戊糖磷酸途径的中间产物。该途径的基因和编码酶 L-阿拉伯糖还原酶、L-阿拉伯糖醇脱氢酶、L-木酮糖还原酶、木糖醇脱氢酶和木酮糖激酶主要在两种生物技术上重要的真菌黑曲霉和里氏木霉中得到了描述。对 L-阿拉伯糖途径成分的分析揭示了在利用 L-阿拉伯糖方面，酶和调节机制的许多特定适应性。进一步的遗传和生化分析提供了证据，表明 L-阿拉伯糖和相互连接的 D-木糖途径也参与了己糖 D-半乳糖的氧化还原降解。
