Novel thermostable galactose isomerase and tagatose production thereby

摘要

Disclosed are novel thermostable galactose isomerases and production of tagatose using the same. A gene encoding a galactose isomerase with improved thermal stability and reaction equilibrium is screened from natural genetic materials. An expression vector into which the gene is inserted is introduced into bacteria which are then cultured to obtain a thermostable galactose isomerase. In the presence of this enzyme, tagatose is produced from galactose in a yield as high as 46-50% at a temperature as high as 55° C.