Levan-type FOS production using a Bacillus licheniformis endolevanase
Levan-type FOS production using a Bacillus licheniformis endolevanase
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DOI：
10.1016/j.procbio.2014.02.005
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发表时间：
2014-05-01
影响因子：
4.4
通讯作者：
Lopez Munguia, Agustin
中科院分区：
文献类型：
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作者：
Porras-Dominguez, Jaime R.;Avila-Fernandez, Angela;Lopez Munguia, Agustin
在目前的工作中，我们描述了一种酶促生产方法，通过一系列反应获得β 2-6果糖低聚糖（左旋型FOS），其中细菌内旋乙酰化酶应用于由细菌左旋乙酰化酶从蔗糖生产的左旋乙酰化酶。通过生物信息学搜索，从我们自己收集的地衣芽孢杆菌IBt1菌株中分离出一个编码内酯酶的基因，命名为LevBl，并在大肠杆菌中表达。在50 mM pH 6.0的磷酸盐缓冲液中，35℃时，LevB1蛋白的比活性为1.8 U/mg。以150g /L的低分子量levan （8.3 kDa）为底物时，发现了一级动力学行为。经HPAEC-PAD测定，产物为聚合度在2 ~ 8之间的左烷型FOS，反应时间长，主要产物为左烷二糖。当1.0 U/mL的LevB1与100 g/L的枯草芽孢杆菌（Bacillus subtilis）的左旋蔗糖酶（levansucrase）产生的左旋蔗糖酶（levan）反应时，可得97%的左旋型FOS。最后，观察了益生乳酸菌对利末型果寡糖的发酵效果。(C) 2014 Elsevier Ltd.版权所有。
In the present work we describe an enzymatic production method to obtain beta 2-6 fructose oligosaccharides (levan-type FOS) through a sequential reaction in which a bacterial endolevanase is applied to levan produced from sucrose by bacterial levansucrases. A putative gene encoding an endolevanase, designated as LevBl, was identified through a bioinformatics search, isolated from a strain of Bacillus licheniformis IBt1 from our own collection and expressed in Escherichia coli. LevB1 showed a specific activity of 1.8 U/mg protein at 35 C in 50 mM phosphate buffer pH 6.0. A first order kinetic behavior was found when up to 150 g/L of low molecular weight levan (8.3 kDa) was used as the substrate. The product profile was determined by HPAEC-PAD and consisted of levan-type FOS with a polymerization degree between 2 and 8, with levanbiose as the major product after long reaction times. Yields of 97% of levan-type FOS were obtained when 1.0 U/mL of LevB1 reacted with 100 g/L of levan produced by the levansucrase from Bacillus subtilis. Finally, it was observed that levan-type FOS are efficiently fermented by probiotic lactic acid bacteria. (C) 2014 Elsevier Ltd. All rights reserved.