ISOLATION AND CHARACTERIZATION OF A NOVEL ENDO-BETA-GALACTOFURANOSIDASE FROM BACILLUS SP

A soil bacterium capable of growing on a polysaccharide containing bet a(1 --> 6)galactofuranoside residues derived from the acidic polysacch aride of Fusarium sp, as a carbon source has been isolated, From vario us bacteriological characteristics, the organism was identified as a B acillus sp, The bacterium produced beta-galactofuranosidase inductivel y in the culture media. The most effective inducer for the beta-galact ofuranosidase production was a polysaccharide containing beta(1 --> 5) or beta(1 --> 6)-linked galactofuranoside residues, but gum arabic, g um guar, gum ghati, arabinogalactam, araban, and pectic acid did not i nduce the enzyme, The enzyme had three different molecular weight form s, The low molecular-weight form was purified by a combination of Toyo pearl HW-55 and DEAE-Toyopearl 650S column chromatographies, and prepa rative polyacrylamide gel electrophoresis. The molecular weight of the enzyme was estimated to be 67,000 by SDS-polyacrylamide gel electroph oresis, The enzyme was most active at pH 6 and 37 degrees C, and was s table between pH 4 to 8 at 5 degrees C, The action of the enzyme was i nhibited by the addition of Cd2+, Co2+, Hg2+, Zn2+, iodoacetic acid, a cid EDTA, The purified enzyme cleaved beta(1 --> 5) and beta(1 --> 6)- linked galactofuranosyl chains, Based upon the mode of liberation of g alactofuranosyl residues from pyridylamino-beta(1 --> 6)-linked galact ofuranoside oligomers, the enzyme can be classified as an endo-beta-ga lactofuranosidase that randomly hydrolyzes the linkage.