Phenotypic and Molecular Identification of Bifidobacterium sp. Isolated from Infants Feces

Abstract

One hundred fecal samples from clinically less than one month old infants was collected for isolation of bifidobacterium sp. , and these samples was cultured on two different selective media for this bacteria De Mann, Rogosa and Sharpe (MRS) agar and Liver Cysteine Lactose (LCL) agar media . Identification of this bacteria was obtained by morphological characteristic, microscopic feature, biochemical tests, Fructose-6-phosphate phosphoketolase (F6PPK) activity assay and molecular identification by used genus-specific primer . And also detection and amplification of xfp gene was achieved by PCR technique and specific primer with a product size 249 bp . Gene expression of xfp was measured by detection of F6PPK enzyme in crude extract of bifidobacteria . Different conditions from pH, temperature, incubation period, and culture media was used to optimization of condition for production of F6PPK enzyme from bifidobacteria. The result revealed that pH 7 was optimum pH for growth and production of enzyme while 30 Cº was optimum temperature for production of F6PPK enzyme and its reach to maximal production after 18 hr of incubation .