Action of bacteriocin from Lactobacillus casei spp. Rhamnosus (SN 11) against pathogenic bacteria

Nitinat Kumthavee, M.Sc. Student in Biotech., PSU.
Suganya Chanthachum, D. of Food Tech., F. of Agro-Industry, PSU.
Aran H-Kittikun, Asst. Prof., D. of Industrial Biotech., F. of Agro-Industry, PSU.
Corresponding e-mail : csuganya@ratree.psu.ac.th

Grant : Graduate School, PSU.
Presented : The 12th Annual Meeting of the Thai Society for Biotechnology "Biotechnology : Impacts & Trends" Kanchanaburi, Thailand, 1-3 Novermber, 2000
Key words : bacteriocin, Lactobacillus casei ssp. rhamnosus, Escherichia coli, Listeria murrayi, Staphylococcus aureus

Lactobacillus casei ssp. rhamnosus (SN 11), isolated from fermented fish was used to produce bacteriocin. Escherichia coli, Listeria murrayi and Staphylococcus aureus were used as indicator organisms for Lactobacillus bacteriocin. When Lactobacillus casei was mixed with individual indi-cator microorganism. Inhibition percentage of 50-62.96, 64-79.4 and 53.53-64.71 were observed for E. coli, L. murrayi and S. aureus respectively. Bacteriocin of Lactobacillus casei was partialy purified by centrifugation, ultrafiltration and two steps of ammonium sulfate precipitation. Minimum Inhibi-tory Concentration (MIC) of bacteriocin for E. coli and S. aureus was 80 Au/ml by using agar well diffusion method and on L. murrayi was 150 Au/ml by using spot on lawn method. The bacteriocin is bacteriostatic.

Further investigation for mode of action of bacteriocin will be performed.

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