title: Optimum production, stability, partial purification and inhibitory spectrum of antimicrobial compounds produced by Pediococcus pentosaceus DI.
abstract: The optimum conditions for production of antimicrobial compounds by Pediococcus pentosaceus DI were studied. The antimicrobial compounds in cell free fermented medium were extracted (methanol-acetone), then tested for inhibitory activity against fourteen bacterial strains and its stability to heating, various pH and proteolytic enzymes. In addition, methanol-acetone extract was partial purified through Sephadex G-100 column and thin-layer chromatography. Production of antimicrobial compounds were maximized when P. pentosaceus DI was grown in lactobacilli MRS containing 0.05% L-cysteine-HCl medium at 30 degrees C for 48 h. The methanol-acetone extract showed relatively broad antimicrobial spectrum including lactic acid bacteria and some spoilage and pathogenic bacteria. Antimicrobial activity of methanol-acetone extract was retained after heating (100 degrees C for 30 min) at pH 2.5 to 6.0 but was lost after treating with several proteolytic enzymes at pH 6.5 and 7.0. Sephadex G-100 column revealed three peaks in methanol-acetone extract. The major peak was eluted at 40 ml and including three fractions, which exhibited inhibitory activity, while the other peaks were principally free from any antimicrobial compounds. Thin-layer chromatography of crude methanol-acetone extract and the three fractions, which exhibited inhibitory activity, showed that there was one main spot with Rf at 0.8.
authors.affiliation: Menofiya University, Faculty of Agriculture, Food Science and Technology Department, ET-32516 Shibin El-Kom, Egypt.
authors.forename: T A
authors.initials: TA
authors.lastname: el-Adawy
mesh_terms: D001419:Bacteria / Q000187:drug effects*; D001430:Bacteriocins / Q000096:biosynthesis* / Q000494:pharmacology; D002855:Chromatography, Thin Layer; D004355:Drug Stability; D005511:Food Handling; D005516:Food Microbiology; D006863:Hydrogen-Ion Concentration; D010376:Pediococcus / Q000378:metabolism*; D013696:Temperature; D013997:Time Factors
chemical_list: D001430:Bacteriocins