Biofilms based on polysaccharides and bioactive agents are currently used for the coating, protection and extension of the shelf life of foods. In the present study, a biofilm was elaborated from chitosan extracted from residues of shrimp shell (Cryphiops caementarius) and Muña oil (Minthostachys mollis). Chitin was initially obtained from shrimp shell by lactic acid fermentation; After that, the deacetylation process of chitin to chitosan was carried out, obtaining a degree of deacetylation of 80.84% and a yield of 58.5% (p/p); the presence of chitosan obtained was corroborated by FTIR analysis. The Muña oil was extracted by steam distillation, obtaining a yield of 0.48% (v/p). For the evaluation of the antimicrobial effect, biofilms were made with different concentrations of oil (1–3%). The antimicrobial activity against the bacterial strain Escherichia coli showed an inhibition halo of 29.5 mm and by means of the T- Student analysis it was determined that the 3% concentration has a greater effect against chitosan. In conclusion, it is possible to elaborate a biofilm from shrimp residues and Muña oil as a potential coating for the food industry.