Thermostable L-Arabinose Isomerase and Process for Preparing D-tagatose thereby

摘要

PURPOSE: A thermophilic L-arabinose isomerase and a method for producing D-tagatose using the isomerase are provided, therefore the D-tagatose can be produced in higher yield at high temperature. CONSTITUTION: A gene encoding the thermophilic L-arabinose isomerase, derived from Thermotoga sp. has the nucleotide sequence of SEQ ID NO: 3. The thermophilic L-arabinose isomerase has the amino acid sequence of SEQ ID NO: 4. A recombinant expression vector pTNAI contains the L-arabinose isomerase gene and has the restriction enzyme map of figure 1. A strain E. coli BL21/DE3(pTNAI)(KCCM-10231) is prepared by transforming E. coli with the expression vector pTNAI. The method for producing D-tagatose comprises the steps of: culturing the transformant E. coli BL21/DE3(pTNAI)(KCCM-10231) and collecting the recombinant L-arabinose isomerase from the cultured medium.