Screening of L(+) lactic acid-producing local cocci from Iran and identification of superior strains

Since L() lactic acid is catalyzed in the body, this compound is used in food, medicine and pharmaceutical industries. Several microorganisms are involved in the production of L() lactic acid. In this study Cocci were screened for production of L() lactic acid. In the first stage, 63 strains of cocci were screened for production of lactic acid by titration method. In the second stage, through superior strains of the first stage, final superior strains were selected by enzymatic method. These strains produce L()lactic acid purely that have identified by hydrocarbons fermentation. Then DNA extraction and amplification of the gene 16SrRNA of them was performed. After sequencing of PCR products and comparing them with the existing data in the database of NCBI, final superior strains were identified. The rates of Lactic acid production by local strains were observed very different. In the First stage, seven strains with 24-27.25 mg/g lactic acid production were selected and were evaluated by enzymatic method. Strains that produced 3.35, 3.05, 2.97 mg/g L() lactic acid were reported as superior strains. One Superior strains was identified as Staphylococcus pasteuri and others were identified as Enterococcus faecium. The sequences of 16SrRNA of superior strains were registered in National center for Biotechnology Information (NCBI) with accession numbers, Kj508199, Kj508200 and Kf735653. Superior strains are suitable for production of pure L() lactic acid so they could introduce to related industries after optimization process.