Polyphasic identification of a new thermotolerant species of lactic acid bacteria isolated from chicken faeces

Abstract

Two thermotolerant and desiccation tolerant lactic acid bacteria (TDLAB) were pointed out from twenty isolated strains from soils and dried chicken faeces. Samples were collected in poultry farms in the vicinity of Dakar, Senegal (West Africa). The two new isolates were called Sp .4 ( Sp .4=CWBI-B534=LMG7278) and Sp. 20 ( Sp. 20=CWBI-B545=LMG7279). They are Gram-positive, catalase-negative, facultatively anaerobic, non-motile, and non-spore-forming rods. Both produce D/L lactic acid via homofermentative pathway. Growth of the strains occurred between 15°C and 44°C. The optimum temperature for growth was in 30°C-37°C temperature and pH 3-8 range. Desiccation treatment in glycerol showed 30% survival rates. Complex total fatty acid pattern of the strains showed the presence of C 14:0 , C 16:0 , C 16:1 , C 18:0 , C 18:1 , C 18:2 , C 18:3 . SDS-PAGE of total protein of both strains placed them in L. plantarum group. AFLP analysis showed a phylogenetic proximity of the two strains with L. plantarum stricto sensu species. Specific amplified 16s rDNA restriction analysis (ARDRA) of the 16S rDNA gene, however, showed that these thermotolerant strains were not L. plantarum . ITS sequencing revealed that Sp. 20 (LMG 7279) could be classed into Lactobacillus paraplantarum species since the short sequence of ITS showed 95% of similarity with reference species. Polyphasic identification shows that Sp .4, (the type strain is LMG 7278 T ) represent a new species within the genus Lactobacillus with only 88%+/-1 ITS sequence similarity with reference species. For which the name Lactobacillus aminata sp. nov. is proposed. African Journal of Biotechnology Vol. 4 (5), pp. 409-421, 2005