Some slime-forming heterofermentative species of the genus Lactobacillus

Lactobacillus coprophilus subsp. confusus (NCDO 1586) and 18 other strains of slime-forming heterofermentative lactobacilli obtained from diverse sources are considered to form a new species on the basis of their physiological characteristics and similarities of their pyruvate reductases and lactate dehydrogenases. It is suggested that these strains should be named Lactobacillus confusus (Holzapfel & Kandler) comb. nov. (L. coprophilus subsp. confusus Holzapfel & Kandler), reasons being given. The type strain is NCDO 1586 (NCIB 9311, ATCC 10881). Strains of Lactobacillus vermiforme and Lactobacillus viridescens also form slime. However, L. vermiforme was readily separated from the other two by the criteria used. Although physiological characteristics separated L. viridescens from L. confusus, a relationship between these two species and also between them and the leuconostocs was indicated by the properties of the pyruvate reductases and lactate dehydrogenases. The slime produced by all species was found to be a glucan, probably a dextran, containing primarily alpha-1-6-glycosidic linkages.