Novel thermostable galactose isomerase and tagatose production thereby

PURPOSE: A novel thermostable galactose isomerase and a method for producing tagatose using the same isomerase are provided, therefore the tagatose can be stably produced in higher yield at relatively high temperature, about 55 deg. C. or more. CONSTITUTION: A gene encoding a novel thermostable galactose isomerase has the nucleotide sequence of SEQ ID NO: 1. A gene encoding the novel thermostable galactose isomerase having improved activities has the nucleotide sequence of SEQ ID NO: 6 which has 95% or more of sequence homology with the SEQ ID NO: 1. The method for producing the novel thermostable galactose isomerase comprises the steps of: preparing a recombinant expression vector containing the gene having the nucleotide sequence of SEQ ID NO: 1 or 6; transforming a host cell with the recombinant expression vector; and culturing the transformed cell to produce the thermostable galactose isomerase. The tagatose is produced from galactose by using the thermostable galactose isomerase. 본 발명은 신규한 내열성 갈락토스 이성화효소 및 그를 이용한 타가토스 제조방법에 관한 것으로, 자연계 유전자원으로부터 내열성 및 반응평형이 증대된 갈락토스 이성화효소 유전자를 스크리닝하고, 이를 포함한 발현벡터로 형질전환시킨 미생물을 배양하여 갈락토스 이성화효소를 제조한 후, 상기 제조된 효소를 이용하여 갈락토스로부터 타가토스를 제조한 결과, 상기 이성화효소는 55℃의 고온에서 46-50%의 높은 전환수율로 타가토스를 생성하는 매우 뛰어난 효과가 있었다.