Document Type : Narrative Review
Department of Biological Science, Faculty of Science, University of Kurdistan, Sanandaj, Kurdistan, Iran. Nanobiotechnology Department, Faculty of Innovative Science and Technology, Razi University, Kermanshah, Iran.
Nanobiotechnology Laboratory, Department of Biotechnology, SGB Amravati University, Amravati-444 602, Maharashtra, India Department of Microbiology, Nicolaus Copernicus University, 87-100 Toruń, Poland
Pharmacology and Molecular Chemistry Laboratory, Department of Chemical Biology, Regional University of Cariri, CEP 63105-000, Crato, Ceara, Brazil
A plethora of natural metabolites has been identified as antimicrobial and antioxidant agents. Pathogenic and spoilage microorganisms can be inhibited by antimicrobial agents produced by lactic acid bacteria (LAB) via strong antagonistic activity toward them. These bacteria can synthesize bioactive metabolites such as bacteriocins, reutericyclin, reuterin, hydrogen peroxide, carbon dioxide, acetoin, diacetyl, ethanol, acetaldehyde, and organic acids (acetic and lactic acid) as antimicrobial agents. Both Gram-negative and Gram-positive pathogenic bacteria have shown different levels of sensitivity towards these materials. In addition, chelating ferrous ions as well as degrading cholesterol and nitrite have been found for LAB as its main antioxidant activity. These bacteria may be isolated from fermented foods including stinky tofu, corn noodle, chili sauce, glutinous rice dough, meat, vegetable, yogurt, sauerkraut, cultured butter, cheese, cocoa, and potherb mustard pickles. These bacteria can be employed to produce minicells and SimCells in nanosized drug delivery systems to load a range of different chemotherapeutic drugs as a new technology that is functionalized by specific ligands to active targeting tumor cells with minimum toxicity against healthy cells. Moreover, LAB is able to synthesize various types of organic and inorganic nanomaterials as nano-bioreactors.
- Cell suspension and cell-free supernatants are two main sources of LAB with antimicrobial activity.
- LAB can produce antimicrobial metabolites such as bacteriocins and organic acids (acetic and lactic acid), which can hinder Gram-negative and Gram-positive pathogenic bacteria.
- LAB can be enriched by selenium to increase antibacterial effects on Gram-negative and Gram-positive bacteria.
- Heterofermentative bacteria have biochemical pathways involving enzymes as flavoprotein oxidases and catalyze that increase antimicrobial activity.
- LAB has ability to produce functionalized minicells and SimCells by specific ligands to encapsulating various anticancer agents.
- LAB also can be employed to as bioreactors synthesis of nanomaterials as reducing and stabilizing agents.