Characterization of lactic acid bacteria isolated from poultry farms in Senegal

Abstract

The group that includes the lactic acid bacteria is one of the most diverse groups of bacteria known and these organisms have been characterized extensively by using different techniques. In this study, thirty lactic acid bacterial strains were isolated from soils chicken faeces and feathers. A total of nineteen isolates were obtained and by sequential screening for catalase activity and Gram-staining, eight were
determined to be LAB out of which six were established to be homofermentative by the gel plug test. Five isolates were identified by use of the API 50CHL kit and four Lactobacilli strains and one
Lactococci strain were selected to study their growth and lactic acid production profiles in a time course experiment. The Lactobacilli strains, both isolated from faeces, produced higher amounts of
cells and lactic acid from soils as compared to the lactococci strain isolated from feathers. L (+)-lactic acid is the only optical isomer for use in pharmaceutical and food industries because is only adapted to
assimilate this form. The optical isomers of lactic acid were examined by L (+) and D (-) lactate dehydrogenase kit. Lactobacilli strains produced combination of both optical isomers of lactic acid.
Among them, Lactobacillus casei subsp. casei produced the low amount of D (-)-lactic (2%). The optimum rates of glucose for lactic acid production by Lactobacillus strains were 180 and 120 g/l for
Lactobacillus plantarum and Lactobacillus paraplantarum, respectively.