KHOUKHI FAIZA, SALIMA KEBOUCHE, NACER EDDINE DJELALI, MOHAMED LAMINE GANA THE APPLICATION OF ENZYMOLOGICAL TECHNIQUES FOR DETERMINATION OF THE INHIBITOR ACTIVITY OF BIO ENZYM EXTRACTED FROM SEAWATER BACTERIA PSEUDOMONAS AEROGENOSA TO FIGHT BIOCORROSION OF CARBON STEEL The paper presents a studies for the development of new corrosion inhibitors by biotechnological way applicable to many areas of petroleum industry including, characterization of protective films on carbon steel and biocorrosion inhibition. Our research is oriented towards the isolation of new strains of bacteria from the sea waters of the Mediterranean region that have power (inhibitory and/or bactericidal that blocks the growth of sulfate-reducing bacteria responsible for microbiologically influenced by production of Pyocyanin (1 hydroxyphenazin) or 5-methylphenazin-1-one. Our first objective was to isolate the population of Pseudomonas Aerugenosa on a specific medium, characterization gram, then fermentation in a nutrient broth. The second objective of this study is evaluation of corrosion rate by weight loss method with injecting different dose of the crude enzyme extract CEE containing the methylphenazine (Pyocyanin). An efficacy test was performed on test kit vials containing the specific culture medium with the SRB contaminated with industrial injection water from SONAHESS region. The total disappearance of the SRB is 40% of CEE by blocking their metabolism in the growth phase confirms the efficiency of treatment.