Present knowledge on the characteristics of dextransucrase and its mode of action is based primarily on the important investigations of Hehre (1941, 1946, 1951) and Hehre and Sugg (1942). Hitherto, a serious impediment to studies of this interesting enzyme has been the difficulty of procuring dextransucrase. Development of further knowledge about it would be greatly facilitated by the availability of culture liquors rich in dextransucrase. The rapid formation of dextransucrase in high yields has been reported in a preliminary note (Koepsell and Tsuchiya, 1952). The present report deals in greater detail with our observations on factors affecting production of dextransucrase from Leuconostoc mesenteroides, strain NRRL B-512.2 However, culture liquors high in activity have been obtained from a large number of the organisms tested. The dextran produced by strain NRRL B-512 in the conventional whole

No abstract

During recent years many new and extended uses have been developed for fungal enzymes. Prominent among these are applications in the fields of food manufacturing, textile processing, and in the manufacture of malt beverages and industrial alcohol. Although certain microorganisms are capable of elaborating amylases when grown under submerged conditions either aerobically (Waldmann, 1942) or anaerobically (Hockenhull and Herbert, 1945), industrial production methods generally involve cultivation on the surface of unagitated liquid or semisolid substrates. Exceptions are the "amylo" process (Owen, 1933) and a modified amylo process (Erb and Hildebrandt, 1946), in which selected strains of Rhizopus or Mucor are grown under submerged, aerobic conditions to saccharify grain mashes prior to alcoholic fermentation. More commonly, as in the production of mold bran (Underkofler, et al., 1939; Boyer and Underkofler, 1945) and bacterial amylases (Beckord et al., 1945, 1946), media are incubated in shallow layers in closed vessels or in open trays. Attempts to adapt these microorganisms to deep tank conditions to produce comparable yields of amylase have been unsuccessful. The submerged culture method of producing amylases would have definite advantages when the product could be employed directly without concentration or purification as, for example, in the alcoholic fermentation of grain and in the manufacture of sugars and dextrins from starch. With these applications in mind a survey was made of a large number of molds to determine their ability to synthesize starch-hydrolyzing enzymes when cultured under submerged conditions. The present report deals with (1) the results of this survey of fungi, (2) the factors affecting the elaboration of amylases by promising strains, and (3) the substitution of mold amylase thus produced for distillers' malt. Pilot plant studies have been conducted with some of the promising strains disclosed herein, and the results of these experiments will be reported at a later date. METHODS Culture survey. The cultures investigated were selected from the culture collection of the Northern Regional Research Laboratory. The basal medium for the survey of cultures was thin stillage obtained from the alcoholic fermentation

Experiments were conducted on a pilot plant scale by utilizing conventional distillery equipment and were designed to supply data on the following points: type and concentration of enzymes produced in submerged fermentation under varying rates of aeration; concentration

COMMUNICATIONS TO THE EDITOR 3265is correct, and if the molecular configuration of the tetramethylplatinum tetramer is unaltered,' yparameters of all platinum positions are determined. Intensities of (OkO) reflections can then be calculated, and are in good agreement with observation (Table I). One could not achieve this agreement if the molecular structure of the tetramer were seriously altered by complexing with benzene.