Xylose reductase activity in Debaryomyces hansenii UFV-170 cultivated in semi-synthetic medium and cotton husk hemicellulose hydrolyzate
Xylose reductase activity in Debaryomyces hansenii UFV-170 cultivated in semi-synthetic medium and cotton husk hemicellulose hydrolyzate
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DOI：
10.1007/s00449-009-0299-8
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发表时间：
2009-01
影响因子：
3.8
通讯作者：
F. C. Sampaio;J. T. Faria;J. Coimbra;Flávia M. Lopes Passos;A. Converti;L. A. Minin
中科院分区：
文献类型：
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作者：
F. C. Sampaio;J. T. Faria;J. Coimbra;Flávia M. Lopes Passos;A. Converti;L. A. Minin
为了开发一种新的木糖-木糖醇转化酶，需要对木糖还原酶（XR）的调控有更深入的了解。为此，在含三种醛己糖（d-葡萄糖、d-半乳糖和甘露糖）、一种酮己糖（d-果糖）、一种酮戊糖（d-木糖）、三种醛己糖（d-阿拉伯糖、l-阿拉伯糖和核糖）、三种二糖（麦芽糖、乳糖和蔗糖）和一种戊醇（木糖醇）的半合成培养基中培养了一株具有木糖醇生产潜力的汉斯德巴氏菌（UFV-170）。在乳糖、d-甘露糖、d-葡萄糖和半乳糖的培养基上，细胞的生长速率最高，为0.58 ~ 0.61 h−1。XR比活性最高（0.24 U mg−1）的细胞提取液中生长在木糖和收获在固定生长阶段。当生长在棉花壳半纤维素水解物上时，细胞的XR活性比在半合成培养基上高5到7倍。
To develop a new enzymatic xylose-to-xylitol conversion, deeper knowledge on the regulation of xylose reductase (XR) is needed. To this purpose, a new strain ofDebaryomyces hansenii(UFV-170), which proved a promising xylitol producer, was cultivated in semi-synthetic media containing different carbon sources, specifically three aldo-hexoses (d-glucose,d-galactose andd-mannose), a keto-hexose (d-fructose), a keto-pentose (d-xylose), three aldo-pentoses (d-arabinose,l-arabinose andd-ribose), three disaccharides (maltose, lactose and sucrose) and a pentitol (xylitol). The best substrate was lactose on which cell concentration reached about 20 g l−1dry weight (DW), while the highest specific growth rates (0.58–0.61 h−1) were detected on lactose,d-mannose,d-glucose andd-galactose. The highest specific activity of XR (0.24 U mg−1) was obtained in raw extracts of cells grown ond-xylose and harvested in the stationary growth phase. When grown on cotton husk hemicellulose hydrolyzates, cells exhibited XR activities five to seven times higher than on semi-synthetic media.