ciim lactic acid; M.L. gen. noun acidi lactici of lactic acid. Original description supplemented by naaterial from Shimwell (Jour. Inst. Brew- ing, 5i (N.S. 45), 1948, 103). Cocci, 0.6 to 1.0 micron in diameter, oc- curring singly, in pairs and tetrads or even in short chains. Gram-positive. Gelatin colonies: Small; no liquefaction. Gelatin streak: Growth grayish white, moist, iridescent, thin; smooth edges. Gelatin stab: Growth along stab; white, leafy surface growth. Growth in unhopped wort but not in beer. Produces much acid from maltose and wort. Cultures that do not produce acid from maltose are regarded by some (see Shimwell, loc. cit.) as forming a distinct species as they produce slight or no acid in unhopped wort. Catalase-negative. Optimum temperature, 41° C. Killed in a short time at 60° C. Source: Isolated from spoiled mash. Habitat: Found in mash and unhopped wort. Genus IV. Leuconostoc van Tieghem, emend. Hucker and Pederson, 1930.* (Van Tieghem, Ann. Sci. Nat., 6, S6r. 7, 1878, 170; Betacoccus Orla-Jensen, The Lactic Acid Bacteria. Mem. Acad. Sci. Danemark, Sec. d. Sci., 5, S6r. 8, 1919, 146; Hucker and Pederson, New York Agr. Exp. Sta. Tech. Bui. 167, 1930, 66.) Leu.co.nos'toc. Gr. leucus clear, light; M.L. neut.n. Nostoc algal generic name; M.L. neut.n. Leuconostoc colorless Nostoc. Cells normally spherical. Under certain conditions, such as in acid fruits and vegetables, the cells may lengthen and become pointed or even elongated into a rod. Certain types grow with a characteristic slime formation in sucrose media. Grow on ordinary culture media, but growth is enhanced by the addition of yeast, tomato or other vegetable extracts. Gen- erally, a limited amount of acid is produced, consisting of lactic and acetic acids; alcohol is also formed, and about one-fourth of the fermented glucose is changed to CO2 . Levo rotatory lactic acid is always produced, and sometimes dextro rotatory lactic acid also. Milk is rarely curdled. Fructose is reduced to mannitol. Found in milk and in plant juices. The type species is Leuconostoc mesenter aides (Cienkowski) Van Tieghem. Key to the species of genus Leuconostoc. I. Acid from sucrose. A. Acid from pentoses. 1. Leuconostoc mesenteroides. B. No acid from pentoses. 2. Leuconostoc dextranicum. II. No acid from sucrose. 3. Leuconostoc citrovorum. 1. Leuconostoc mesenteroides (Cien- kowski, 1878) van Tieghem, 1878. {Asco- coccus mesenteroides Cienkowski, Arb. d. Naturf. Gesellsch. a. d. Univ. a. Charkoff, 1878, 12; van Tieghem, Ann. Sci. Nat., 6, S^r. 7, 1878, 170.) me.sen.te.ro.i'des. Gr. noun mesen- terium the mesentery; Gr. noun eidus form. shape; M.L. adj. mesenteroides mesentery- like. Spheres, 0.9 to 1.2 microns in diameter, occurring in pairs and short or long chains. In sucrose solutions the chains are usually surrounded by a thick, gelatinous, colorless membrane consisting of dextran. Gram- positive.
- Revised by Prof. G. J. Hucker and Prof. Carl S. Pederson, New York State Experiment
Station, Geneva, New York, September, 1938; further revision, December, 1943, and Au- gust, 1954.
