IDENTIFICATION OF MICROORGANISMS ISOLATED FROM ACTIVATED SLUDGE; APPLICATIONS ON FOOD INDUSTRY

The activated sludge, from effluent treatment systems, is usually used as fertilizer for food crops. Nevertheless, some bacteria of activated sludge can contaminate vegetables and fruits, causing the spreading of diseases. On the other hand, other microorganisms from activated sludge can be for production of biomolecules (high-added value molecules). The aim of this study was the isolation and identification of bacteria that were isolated from activated sludge, and then prospect their application and implication on food industry. The microorganisms were identified by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) using the MALDI Biotyper CA System software (Bruker Daltonics, Germany). This technique is, relatively, a new method that allows a fast and reliable identification of microorganisms. The main bacteria identified were: Bacillus cereus, Escherichia coli, Kosakonia cowanii, and B. thuringiensis. B. cereus is generally associated with food poisoning due to its resistant endospores that can survive high cooking temperatures. Nevertheless, some of their strains can be used for the production of α-amylase and proteases. E. coli is a well-known pathogen associated to gastroenteritis. Nevertheless, E. coli can also be applied for the production of hydrogen and ethanol, mannitol among others. K. cowanii is also a human pathogen, however, it can be used for the production of exopolysaccharides. B. thuringiensis can used for the production of phospholipases. Therefore, mass spectrometry proved to be a good technique for fast and reliable identification of microorganisms from activated sludge. The isolated and identified microorganisms can be applied in a wide range of food industry process.