It is necessary to avoid the inhibitory activity unrelated to bacteriocin.Hence, neutralization of cell free supernatants to pH 7 is mandatory and then filtration by millipore. From this CFS , spotting on soft agar seeded with sensitive strains is the second step; bacteriocins are active against the closely related species to the producer strains. Once inhibition zones are detected, precipitation of bacteriocin by ammonium sulphate is necessary followed by dialysis against suitable buffer pH 6.5.Then techniques of HPLC and GC-MS are needed.

Dear Amenu,

1- Bacteria growth under anaerobic conditions.

2-remover the bacteria cell by centrifuge 5000 rpm for 20 mn and filtration by millpore filter .

3-The cell free supernatants just 7 is testing against some bacterial test by using walls in agar .

Kindly check this link

Optimization of bacteriocin production by Lactobacillus sp ...

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3679972/

Study Bacteriocin Production and Optimization Using New ...

The optimization of culture conditions for bacteriocin production areas showed that ... broth (pH 7.0) for 48 h at 30˚C. For extraction of bacte-.

https://www.researchgate.net/publication/271288133_Study_Bacteriocin_Production_and_Optimization_Using_New_Isolates_of_Lactobacillus_spp_Isolated_from_Some_Dairy_Products_under_Different_Culture_Conditions

Optimization for the maximum bacteriocin ... - SpringerLink

https://link.springer.com/article/10.1007/s10068-012-0085-2

Bacteriocin can be produced from promising isolate. Bacteriocin from fermented broth was extracted by solvent extraction and antibacterial activity was determined against selected test microorganisms of both Gram positive and Gram negative groups.

https://www.researchgate.net/publication/236629121_ISOLATION_AND_EXTRACTION_OF_BACTERIOCINS_FROM_LACTIC_ACID_BACTERIA_ISOLATED_FROM_RAW_MILK_SAMPLES