Screening and characterization of yeasts for xylitol production
Screening and characterization of yeasts for xylitol production
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DOI：
10.1111/j.1365-2672.2006.02994.x
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发表时间：
2006-11-01
影响因子：
4
通讯作者：
Jiang, N.
中科院分区：
文献类型：
--
作者：
Guo, C.;Zhao, C.;Jiang, N.
目的：为了发现具有工业应用潜力的新型天然木糖醇生产酵母菌种，方法和结果：以木糖为唯一碳源，在固体和液体筛选培养基上培养了274株酵母菌。根据显著的生长和高度的木糖同化，选择了五个菌株。通过对大亚基rDNA基因（5 '-LSU rDNA）5'端D1/D2结构域的PCR-RFLP和序列分析，确定了它们的系统发育位置。进行酶分析以比较每种菌株中的木糖代谢。季也蒙假丝酵母（Candida guilliermondii）Xu 280和麦芽糖假丝酵母（Candida maltosa）Xu 316在微好氧条件下进行分批发酵，木糖消耗率和木糖醇产量较高。研究了高初始木糖浓度的不同培养基对两株菌木糖醇生物合成的影响。菌株，表现出高水平的木糖醇生产表明这些可能具有潜在的工业应用。研究的意义和影响：微生物物种是重要的木糖醇生产。木糖醇的生产涉及到复杂的代谢调控，包括木糖的转运、关键酶的产生和辅因子的再生。因此，筛选天然存在的利用木糖的微生物是获得具有工业应用的木糖醇生产生物的可行且有效的手段。此外，对所选菌株的研究将有助于更好地了解不同酵母中木糖代谢的调控特性。
Aims: To discover novel naturally occurring xylitol producing yeast species with potential for industrial applications.Methods and Results: Exactly 274 strains were cultivated on both solid and liquid screening medium with xylose as the sole carbon resource. Five strains were selected on the basis of significant growth and high degree of xylose assimilation. Their phylogenetic position was confirmed by the PCR-RFLP and sequence analysis of the D1/D2 domain of the 5' end of the large subunit rDNA gene (5'-LSU rDNA). Enzymatic analysis was conducted to compare xylose metabolism in each strain. Candida guilliermondii Xu280 and Candida maltosa Xu316 were found to have high xylose consumption rates and xylitol yields in the batch fermentation under micro-aerobic condition. The effect of the different media with high initial xylose concentration on biosynthesis of xylitol by both strains was investigated.Conclusions: We have identified Candida spp. strains, which exhibit high levels of xylitol production from xylose suggesting that these may have potential for industrial applications.Significance and Impacts of the Study: Microbial species are of importance for xylitol production. Xylitol production involves complicated metabolic regulation including xylose transport, production of key enzymes and cofactor regeneration. Thus, screening of naturally occurring xylose-utilizing micro-organisms is a viable and effective mean to obtain xylitol producing organisms with industrial application. Moreover, the research on selected strains will contribute to a better understanding of regulatory properties of xylose metabolism in different yeasts.