the bacterium is inoculated into a culture medium containing about 1 to 10 inulin as a carbon source and subjected to shaking culture the medium may also contain a nitrogen source such as for example soybean flour wheat germ corn steep liquor cotton seed meal meat extract peptone yeast extract ammonium sulfate sodium nitrate or urea and optionally mineral salts capable of releasing sodium potassium calcium magnesium cobalt chloride phosphate sulfate and other ions preferably the temperature is in the range of 20 to 37 u00b0 c and the time period is in the range of 12 to 40 hours in the shaking culture the resultant culture is centrifuged to remove bacteria and the supernatant is heat treated to inactivate the enzyme after concentration the material is chromatographed for example on an active carbon column after elution of fructose by distilled water elution is effected by 5 aqueous ethanolic solution dfa iii produced during this fractionation is then concentrated to dryness when such an inulin lytic enzyme as described above is employed in the reaction the culture obtained by the above described procedures is first centrifuged to remove bacteria to the filtrate 65 saturated ammonium sulfate solution is added to salt out and the resulting precipitate is collected by centrifugation suspended into a small amount of water and dialyzed to produce a.