Open Journal of Applied Sciences, 2017, 7, 83-97 http://www.scirp.org/journal/ojapps ISSN Online: 2165-3925 ISSN Print: 2165-3917 DOI: 10.4236/ojapps.2017.73008 March 15, 2017 Characterization and Optimization of Bacteriocin from Lactobacillus plantarum Isolated from Fermented Beef (Shermout) Mona E. Elyass 1,2 , M. T. Shigidi 3 , Idress Hamad Attitalla 2* , Ahmed A. Mahdi 2,4* 1 Commission for Biotechnology and Genetic Engineering, National Center for Research, Khartoum, Sudan 2 Department of Microbiology, Faculty of Science, Omar Mukhtar University, El Beida, Libya 3 Department of Microbiology, Faculty of Veterinary Science, University of Khartoum, Khartoum, Sudan 4 Department of Agricultural Biotechnology, Faculty of Agriculture, University of Khartoum, Khartoum, Sudan Abstract Many lactic acid bacteria (LAB) were isolated from “Shermout”, a popular Sudanese fermented beef product intended for long storage. An isolate that demonstrated significant antibacterial activity was identified as Lactobacillus plantarum PM4 based on phenotypic, physiological and biochemical charac- teristics and carbohydrate utilization patterns. The inhibitory activity of the partially purified bacteriocin was completely arrested by the proteolytic en- zymes proteinase-k and pepsin but not by α-amylase, asserting its proteina- ceous nature. The activity was not due to H 2 O 2 as similar inhibition was ob- tained by cell-free supernatant (CFS) produced under anaerobic conditions. The bacteriocin showed a molecular weight in the range of 3 - 5 kDa and had a bactericidal mode of action. No significant reduction in activity was ob- served on heating to 60˚C for 60 min, but activity was lost on heating to 100˚C or autoclaving. Highest inhibitory activity was at pH 5.5 and there was appreciable reduction in activity at pH 3, 7 or 9. There was no drop in activity at -80˚C or -20˚C up to four weeks of storage. However, at 4˚C and 35˚C, a gradual decline in activity was observed. Lb. plantarum PM4 exhibited bacte- ricidal activity against Staphylococcus aureus, Bacillus subtilis, Enterococcus faecalis, Escherichia coli ATCC25922, Klebsiella pneumoniae and Proteus vulgaris. Bacteriocin production generally coincided with the phase of maxi- mum growth and the best combination for maximum production of inhibi- tory activity was at pH 5.5 for 48 h whether incubated at 25˚C, 30˚C or 37˚C. Lb. plantarum PM4 showed promise as a starter culture in the fermentation of preserved meat products. How to cite this paper: Elyass, M.E., Shi- gidi, M.T., Attitalla, I.H. and Mahdi, A.A. (2017) Characterization and Optimization of Bacteriocin from Lactobacillus plantarum Isolated from Fermented Beef (Shermout). Open Journal of Applied Sciences, 7, 83-97. https://doi.org/10.4236/ojapps.2017.73008 Received: January 27, 2017 Accepted: March 12, 2017 Published: March 15, 2017 Copyright © 2017 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY 4.0). http://creativecommons.org/licenses/by/4.0/ Open Access