Genera Leuconostoc, Oenococcus and Weissella
- PDF / 911,122 Bytes
- 53 Pages / 539 x 751 pts Page_size
- 12 Downloads / 182 Views
CHAPTER 1.2.9 areneG
, cot sonocueL
succoconeO
dna
a l l es s i W e
Genera Leuconostoc, Oenococcus and Weissella JOHANNA BJÖ RKROTH AND WILHELM HOLZAPFEL
Introduction The genera Leuconostoc, Oenococcus and Weissella—typical lactic acid bacteria (LAB)—genoand phenotypically most closely resemble the genus Lactobacillus in that all representatives are Gram-positive, catalase-negative, and facultatively anaerobic. The genus Weissella in fact harbors two different morphological types: the rods (formerly the “atypical” heterofermentative lactobacilli) and the ovoid-shaped cocci (typical also of the leuconostocs, Oenococcus and streptococci) Weissella paramesenteroides and Weissella hellenica. However, a third ovoid-shaped Weissella species (Weissella thailandensis), isolated from fermented fish in Thailand, has recently been described (Tanasupawat et al., 2000). Together with Pediococcus, these genera share physiological relatedness and have in fact already at an earlier stage been considered to be phylogenetically “intermixed” (Stackebrandt and Teuber, 1988). Leuconostoc paramesenteroides was shown to form a natural phylogenetic group with the former lactobacilli Lactobacillus confusus, Lactobacillus halotolerans, Lactobacillus kandleri, Lactobacillus minor and Lactobacillus viridescens, on the basis both of comparative 16S rRNA sequence analysis (Yang and Woese, 1989) and 23S rRNA similarity mapping (Schillinger et al., 1989). These species have now been reclassified as Weissella spp. (Collins et al., 1993), while Leuconostoc oenos has been assigned to the new genus Oenococcus (Dicks et al., 1995c). The major physiological features for species of the genera Leuconostoc, Oenococcus and Weissella are presented in Table 1. Physiological characteristics such as the absence of arginine deiminase, and the production of predominantly D(–)-lactate from glucose, are shared by all Leuconostoc species and Oenococcus, and thus far, only by the ovoid-shaped weissellas (W. paramesenteroides, W. hellenica and W. thailandensis). Among the rod-shaped weissellas, arginine-dihydrolase is absent only in Weissella viridescens and in a few obligately heterofermentative lactobacilli (Lactobacillus oris, Lactobacillus vaccinostercus, Lactobacillus san-
franciscensis and Lactobacillus fructosus; Hammer and Vogel, 1995). Likewise, only some heterofermentative lactobacilli, which do not exhibit the typical peptidoglycan interpeptide bridge (D-isoasparagine) of lactobacilli, have been transferred from the genus Lactobacillus to Weissella. However, Lactobacillus suebicus, with the diaminopimelic acid (m-A2pm) peptidoglycan type, Lactobacillus vaccinostercus (mA2pm), Lactobacillus sanfranciscensis (Lys-Ala), and Lactobacillus fructosus (Lys-Ala) remain in the genus Lactobacillus. Presently, the genus Leuconostoc comprises 10 species, with 3 subspecies recognized for Leuconostoc mesenteroides. The genus Weissella comprises 8 species; a ninth species (Weissella cibaria) has been proposed for strains isolated from Malaysian foods and clinical samp
Data Loading...
