Relationship to other species : This species is apparently similar to Lactobacillus del- brueckii but has a lower optimum tempera- ture. Source: Isolated from compressed yeast and from fermenting milk. Habitat: Dairy and plant products. 11. Laclobacillus plantaruni (Orla- Jensen, 1919) Holland, 1920. (Streptobac- teriurn plantarum Orla-Jensen, The Lactic Acid Bacteria, Copenhagen, 1919, 174; Hol- land, Jour. Bact., 5, 1920, 225.) Probable synonyms: Lactobacillus pento- sus Fred, Peterson and Anderson, Jour. Biol. Chem., 48, 1921, 410; Lactobacillus arabinosus Fred, Peterson and Anderson, loc. cit. plan.ta'rum. L. fem.n. planta a sprout; M.L. planta a plant; M.L. gen. pi. noun plan- tarum of plants. Description from Orla-Jensen supple- mented b}^ material from Pederson (Jour. Bact., SI, 1936, 217). Rods, ordinarily 0.7 to 1.0 by 3.0 to 8.0 microns, occurring singly or in short chains, with rounded ends. Under favorable growth conditions these organisms tend to be short rods. Under adverse conditions they tend to be longer; for example, in tomato juice agar at 45° C. (Pederson, N. Y. Agr. Exp. Sta. Tech. Bull. 150, 1929). In fermenting vegetables, the organisms tend to become longer as the acidity becomes greater. The organisms are usually longer in milk than in broths. Differences in morphology are well illustrated by Orla-Jensen. Non-motile. A motile strain of this organism has been described bj' Harrison and Hansen (Jour. Bact., 59, 1950, 444). Gram-positive. Gelatin-yeast extract-glucose stab: Fili- form growth. No liquefaction. Agar slant: Growth, if any, is very faint. Broth: Turbid, clearing after a few days. A few strains flocculate. Litmus milk: Acid, usually coagulated. The majoritj' of strains produce acid from glucose, fructose, mannose, galactose, arabi- nose, sucrose, maltose, lactose, raffinose, salicin and, to a lesser extent, from sorbitol, mannitol, dextrin, glycerol and xylose. Rhamnose, starch and inulin usually not fermented. Lactic acid (usually optically inactive), with only small quantities of acetic acid and carbon dioxide, is produced in the fer- mentation of hexose sugars. Acetic and lactic acids are produced from the pentoses Produces up to 1.2 per cent acid in broth. Nitrites not produced from nitrates in ordinary broth. In special media, some strains produce nitrites from nitrates (Cos- tilow and Humphreys, Science, 121, 1955, 168). Microaerophilic. Temperature relations: Optimum, 30° C. Minimum, 10° C. Maximum, 40° C. Thermal death point, 65° to 75° C. for 15 minutes. Salt tolerance: Usually grows in salt up to 5.5 per cent. Relationship to other species : This species is the optically inactive lactic acid-produc- ing rod from fermenting materials but is closely related to Lactobacillus casei. It ferments sucrose and maltose as readily as lactose. Comments: Breed and Pederson (Jour. Bact., 36, 1938, 667; also see New York Agr. Exp. Sta. Tech. Bull. 259, 1941, 15 pp.) have described a chromogenic variety of this species which causes rusty spots in cheese. Source: Isolated from cheese, butter, kefir, feces, fermenting potatoes, beets, corn, chard, bread dough, sauerkraut, cu- cumber pickles, tomato pickles, cauliflower pickles and spoiled tomato products. Habitat: Widely distributed in nature, particularly in fermenting plant and animal products. 12. Lactobacillvis pastorianus (van Laer, 1892) Bergey et al., 1923. (Saccharo- bacillus pastorianus van Laer, Contributions k I'Histoire des Ferments des Hydrates de Carbone. M6m. Acad. Royale de Belgique, 47, 1892, 5; Bergey et al., Manual, 1st ed., 1923, 246.) pas.tor.i.an'us. L. mas.n. pastor a shep- herd, the Latin rendition of Pasteur; M.L. adj. pastorianus pertaining to Pasteur; named for Louis Pasteur, French chemist and bacteriologist. Description supplemented by material from Henneberg (Cent. f. Bakt., II Abt., 8, 1902, 184), Shimwell (Jour. Inst. Brewing,
