Chitosan is extracted from crab shells. Gelatin is procured from Qualigens fine chemicals, Mumbai, India. Ethylene glycol is procured from Central drug House, Mumbai.
Microorganisms
Four bacteria were tested for the evaluation of antimicrobial activity of films. These include two gram positive bacteria (Bacillus subtilis, Staphylococus aureus) and two gram negative bacteria ( Eschericia col, Pseudomonas aeruginosa) obtained from NCL, Pune. These were maintained in nutrient agar media.
Extraction of chitosan from crab shells
Crab shells were washed thoroughly to remove sand and other impurities and dried well. These were soaked in 5% sodium hydroxide solution, in 3N hydrochloric acid solution overnight for deproteinization and to remove calcium carbonate. The shells were treated with acetone for discoloration and dried. The resultant chitin was de acetylated to give chitosan and washed and dried after confirmation of complete deacetylation[20]