APPLICATION OF PLACKETT-BURMAN DESIGN TO EVALUATE SIGNIFICANT MEDIA COMPONENTS AND GROWTH CONDITIONS ON BACTERIOCIN PRODUCTION BY Lactobacilli
Utilization of Lactobacilli for the production of novel antimicrobial small peptides called bacteriocins is gaining more research interest day by day due to its probable applicability in therapeutics and food biopreservation. In this study the Lactobacilli were isolated from dairy and kitchen waste samples using MRS agar. Isolated colonies were screened for production of bacteriocin by agar well diffusion method using E. coli NCIM 2345, S. aureus NCIM 2125, B. subtilis NCIM 2113 and, P. aerogenosa NCIM 2945 as indicator organisms. Out of all bacteriocin producers from kitchen and dairy waste samples, RC1 and MC1 were identified as maximum bacteriocin producers on the basis of maximum cumulative zone of inhibition shown by them. These isolates were used further for identification of significant media components and culture conditions influencing their bacteriocin production capacity using Plackett-Burman design. Five chemical variables of MRS medium viz., peptone, yeast extract, meat extract, glucose, MgSo4 and three physical variables viz., pH, temperature, incubation period were selected for twelve runs matrix. Matrix design and statistical analysis of results was done by using Minitab-16 statistical software. From the analysis for RC1, peptone, glucose and incubation period were found to be having lowest p –value (i.e. significant) while for MC1, meat extract, glucose and pH were found to be having lowest p – value (i.e. significant)