Résumé
Corn oil was the best lipid substrate for lipase activity, dry weight of cell and total cell nitrogen of R. japonicum 61 A 76, whereas olive oil gave maximum lipase production for R. japonicum 311 b 136. The optimum concentration of corn and olive oils added to the production medium was 0.2% [V/V] for R. japonicum 61 A 76 and 311 b 136. DL- Aspartic acid and L-glutamic acid were the best nitrogen sources for biosynthesis of lipase, dry biomass and total nitrogen content of both J. Japonicum strains. Addition of glycine, L-cystine and DL-serine to the production medium caused a decrease in the above traits for R. japonicum 61 A 76, whereas other amino acids such as DL-serine, L- histidine HCL, DL-alaninen and L-tyrosine exhibited an inhibitory effect on lipase production and other characters for R. Japonicum 311 b 136. However, organic nitrogen sources [urea and peptone] are generally more available than inorganic nitrogen sources [ammonium nitrate and calcium nitrate] for production of lipase by both strains of R. Japonicum. The paper throws some light on R. Japonicum not only for N2 fixation but also for lipase production