• Applied Biological Chemistry
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• v.35 no.5
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• pp.375-381
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• 1992

An exoinulase-producing bacterium was isolated from soil, and identified as Streptomyces sp. The maximum inulase production was achieved when inulin as carbon source and soybean meal as organic nitrogen source were included in the culture. The exoinulase was considered to be a constitutive enzyme produced not only by inulin but also by soluble starch or glucose. The purified enzyme on DEAE-cellulose and Sephadex G-200 column showed the maximal activity at $pH\;5.5{\sim}6.0$ and $50^{\circ}C$, but lost 65% inulase activity at $50^{\circ}C$ after 1 hour incubation. This exoinulase was activated by $Mn^{+2}$, wherease more that 80% inactivation was observed with $Ag^+$, $Hg^{+2}$ and $Fe^{+3}$. The enzyme was possibly a metalloenzyme in that EDTA and 8-hydroxyquinoline inhibited the enzyme. Km values for inulin (16.51 mM) and sucrose (14.62 mM) were in very close range suggesting mostly equal affinity toward the subatrates. However, the maximum velocity for inulin was 10 times greater than for sucrose.

• Korean Journal of Food Science and Technology
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• v.25 no.6
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• pp.780-786
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• 1993

About 7.7% of the total anaerobic bacteria in pig feces grew with clear zone around the colonies on the agar medium containing inulin as a sole carbon source. Among these bacteria, a strain with the strongest inulin-utilizing activity was isolated and identified as Bacteroides sp. based on its morphological and taxonomical characteristics. The isolate grew well with inulin, fructooligosaccharides or glucose as a sole carbon source, while its growth dropped to 50% of that obtained with glucose when soluble starch or sucrose are used. Since the inulase activity was found only when fructooligosaccharides or inulin was added to the growth medium, but not when glucose, sucrose or soluble starch was applied, the inulase production was considered to be induced by fructooligosaccharides or inulin. The highest inulase activity, 0.42 U/ml was detected with the inulin medium and 0.25 U/ml with fructooligosaccharides medium. The cell growth of the isolated strain increased with the amounts of inulin up to 2%(w/v) and maximum production of inulase was found in the cells fed 1% inulin. The inulase of the isolated Bacteroides sp. showed its maximum activity at pH $7.0{\sim}7.5\;and\;50{\sim}50^{\circ}C$ and was found to be an exoinulase judging by its mode of action.