Bioconversion of d-galactose to d-tagatose: continuous packed bed reaction with an immobilized thermostable L-arabinose isomerase and efficient purification by selective microbial degradation
Bioconversion of d-galactose to d-tagatose: continuous packed bed reaction with an immobilized thermostable L-arabinose isomerase and efficient purification by selective microbial degradation
复制标题
d-半乳糖生物转化为 d-塔格糖：与固定化热稳定性 L-阿拉伯糖异构酶进行连续填充床反应，并通过选择性微生物降解进行有效纯化
DOI：
10.1007/s00253-011-3638-z
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发表时间：
2012-02-01
影响因子：
5
通讯作者：
Wang, Peng
中科院分区：
文献类型：
--
作者：
Liang, Min;Chen, Min;Wang, Peng
The continuous enzymatic conversion of d-galactose to d-tagatose with an immobilized thermostable l-arabinose isomerase in packed-bed reactor and a novel method for d-tagatose purification were studied. l-arabinose isomerase from Thermoanaerobacter mathranii (TMAI) was recombinantly overexpressed and immobilized in calcium alginate. The effects of pH and temperature on d-tagatose production reaction catalyzed by free and immobilized TMAI were investigated. The optimal condition for free enzyme was pH 8.0, 60A degrees C, 5 mM MnCl2. However, that for immobilized enzyme was pH 7.5, 75A degrees C, 5 mM MnCl2. In addition, the catalytic activity of immobilized enzyme at high temperature and low pH was significantly improved compared with free enzyme. The optimum reaction yield with immobilized TMAI increased by four percentage points to 43.9% compared with that of free TMAI. The highest productivity of 10 g/L h was achieved with the yield of 23.3%. Continuous production was performed at 70A degrees C; after 168 h, the reaction yield was still above 30%. The resultant syrup was then incubated with Saccharomyces cerevisiae L1 cells. The selective degradation of d-galactose was achieved, obtaining d-tagatose with the purity above 95%. The established production and separation methods further potentiate the industrial production of d-tagatose via bioconversion and biopurification processes.
