Selective isolation and identification of arginine degrading bacteria; the optimized arginine deaminase production by Enterobacter sp. sgn1 as a new source of this potentially anti-tumor enzyme

Abstract

Since certain tumor cells are auxotrophic for arginine, depletion of the extracellular arginine by means of arginine degrading enzymes might be exploited to target such tumors. Among the arginine degrading enzymes, arginine deaminase has attracted more attention as a potential anti-cancer agent for arginine-auxotrophic tumors. In order to find some new sources for arginine degrading enzymes, this study was designed to screen bacterial species, applying a simple and convenient procedure, using a selective medium and Nessler's reagent test. The characterization of the isolated samples was carried out using 16S ribosomal DNA gene sequence analysis, which were further identified as Enterobacter sp., Bacillus sp., Erwinia sp., Oceanomonas sp., Acinetobacter sp., Cronobacter sp. Enterobacter sp. sgn1 was further studied as the arginine deiminase producing bacteria, by investigating the effect of some factors on enzyme production (using Minitab software and measuring the amount of citrulline as the product of ADI enzyme). According to our results; the arginine deiminase production and activity of Enterobacter sp. sgn1 were affected by: temperature, the concentration of glucose and Mg+ ion. Moreover, the phylogenetic tree was constructed using Mega 6 software and it was observed that among the isolated species, Bacillus species are very close to Mycoplasma arginini.