Antimicrobial Activity of Nisin Immobilized onto Membrane
A. KRASTANOV1, A. CRAPISI2, A. LANTE2 and P. SPETTOLI2
1 Higher Institute of Food Industry, Dept. Biotechnology, BG-4002 Plovdiv, Bulgaria
2 University of Padova, Dept. Biotechnology, 35020 Legnaro (PD), ItalyAbstract
KRASTANOV, A., A. CRAPISI, A. LANTE and P. SPETTOLI, 2000. Antimicrobial activity of nisin immobilized onto membrane. Bulg. J. Agric. Sci., 6: 333-337
The efficiency of the antimicrobial peptide nisin was examined against Lactobacillus brevis in a free and immobilized form. 74 IU nisin per 1 ml cell culture totally inhibit cell growth after 24 hours at pH 3.5 and after 48 hours at pH 5.5. The antimicrobial activity of nisin was studied after its adsorption to polyethersulfonic membrane in spiral UF-module. Maximum adsorption level was observed when using 0.4 mg/ml nisin solution for immobilization. The immobilized nisin completely inhibits growth of L. brevis when culture is treated prior to log-phase. The quantity of survival cells depends on suspension flow rate. Results indicated that immobilized nisin can be used to control malolactic fermentation and may have potential for use as a food grade antimicrobial agent on food contact surfaces.
Key words: nisin, immobilization, malolactic fermentation