ISOLATION AND CHARACTERIZATION OF ISOMALTULOSE-PRODUCING AND TREHALULOSE-PRODUCING BACTERIA FROM THAILAND SOIL

The bacterial screening to get the strains that produce isomaltulose (palatinose, 6-O-alpha-D-glucopyranosyl-D-fructose) and trehalulose (1-O-alpha-D-glucopyranosyl-D-fructose) from sucrose, were carried out in Thailand. Many samples such as soil, fruits, etc., were obtained mainly from the northeastern area of Thailand. And several strains named MX-2, -4, -10, -11, and -13 were isolated from these samples. These strains, which were facultative anaerobic, gram-negative and rod-shaped bacteria, belonged to the genus Klebsiella: K. planticola (MX-2, -4, -10, and -11), and K. terrigena (MX-13). The strain MX-10 produced isomaltulose and trehalulose from sucrose, and the yields of isomaltulose and trehalulose were 65 and 30% as against sucrose, respectively, when 98% of sucrose was transformed. It is interesting that the trehalulose yields were higher in the reactions by the strain MX-10 than those by Protaminobacter rubrum (9% of trehalulose and 86% of isomaltulose). The results obtained by using immobilized cells of MX-10 were described.