Enzymatic production of L-citrulline by Pseudomonas putida

To develop an efficient method for the production of l-citrulline, optimum conditions for the conversion of l-arginine to l-citrulline by microbial l-arginine deiminase and for production of the enzyme were studied. A number of micro-organisms were screened to test their ability to form and accumulate l-citrulline from l-arginine. Pseudomonas putida was selected as the best organism. With this organism, enzyme activity as high as 9.20 units per ml could be produced by a shaking culture at 30 C in a medium containing glucose, ammonium phosphate, l-arginine hydrochloride, yeast extract, peptone, and inorganic salts. Appropriate addition of a surface active agent to the reaction mixture was found to shorten the time required for the conversion. A large amount of l-arginine hydrochloride was converted stoichiometrically to l-citrulline in 62 hr at 37 C. Accumulated l-citrulline was readily isolated in pure form by ordinary procedures with ion-exchange resins. Yields of isolated l-citrulline of over 90.5% from l-arginine hydrochloride were easily attainable.