Characterization, probiotic assessment and viability of Bifidobacterium asteroides Bif21 and Lactobacillus paracasei. subsp. paracasei Lb49 strains, isolated from Algerian honeybee’s gut and infant faeces, in fermented camel milk

Abstract

The genus Bifidobacterium and Lactobacillus are part of the microbiote of the gastrointestinal tract in human and animal. Certain members of these genera are beneficial to human health and are used as probiotic agents. Camel milk, in addition to its nutritional value, possesses incontestable therapeutic potential against several diseases. These important benefits prompted us to conduct this present research with the aim to firstly, charaterize tow indigenous strains and to screen their probiotic attributes and, secondly, evaluate their viability in camel milk during cold storage. Phenotypic and genotypic identification showed that strain Lb49 belongs to Lactbacillus paracasei. subsp. Paracasei, and the strain Bif21 belongs to Bifidobacterium asteroides. The study showed the safety aspect of the two identified strains, high resistance towards bile (SR> 71%), lysozyme (SR> 81%), low to moderate auto-aggregation (10.9-44.4%) and hydrophobicity (23.4-41.9) as well as antimicrobial activity against the tested pathogens with the highest scores recorded by the strain Lb49. When exposed to low pH conditions, only the strain Lb49 exhibited high tolerance with SR> 77%. Regarding the strain’s viability in camel milk, they maintained an excellent viability (93.5-100.5 %) after 15 days storage at 4° C. The characteristics demonstrated by Lb49 enable it to be used as a potential probiotic as well as Bif21 strain, as far as protection is provided for their survival by filling their intolerance to acidic stress using an adequate technique. Moreover, camel milk guaranteed excellent viability for the studied strains thanks to its physicochemical composition, acting as a good medium for nutrition and transport of probiotics.