Enhancement of novel extracellular bacteriocin production by media optimization using LAB isolate from meat

Bacteriocins from lactic acid bacteria have been widely studied in recent years; however, there is a little study for explained their chemical compositions. This study was amid to isolate and identification Lactic Acid Bacteria (LAB) from meat in Jeddah - Saudi Arabia on (MRS) medium. Forty isolates of LAB showed antibacterial activities against indicator bacteria Gram negative bacteria K. pneumonia ATCC700603, E.coli ATCC25422, P. aeruginosa, ATCC27583 and Gram positive bacteria S .aureus ATCC25923. Also antibacterial activities was screened by agar well diffusion method, results showed that ten out of 40 (25%) of the tested isolates have activities against all indicator bacteria. Isolates of LAB with the highest antimicrobial effect were identified on the basis of its genetically sequencing. Results revealed that the M8 isolate have 96% identity with Leuconostoc mesentroides and was the highest bacteriocin producer. So it has been selected for the current investigation. The effect of different factors such as (inoculums concentrations, incubation temperature, incubation period, pH and aeration) on the production was studied. The pointed to the best condition for the bacteriocin production of highest amount of bacteriocin was incubation of static culture at 35 °C for 24 hr. and pH 6.2.