Characteristics and selection of cultures of photosynthetic purple non-sulphur bacteria as a potential 5-aminolevulinic acid producers.

Wild strains of purple non-sulphur bacteria: Rhodospirillum rubrum B-6505, Rhodopseudomonas palustris B-6506, Rhodobacter capsulatus B-6508 and Rhodobacter spheroides B-6509 were studied as 5-ALA (5 aminolevulinic acid) producers. Selected strains were subjected to mutagenesis with N-methyl-N-nitro-N-nitrosoguanidine to obtain a strain with high 5-ALA producing capacity. After mutagenesis 19 stable mutant strains were selected from Rhodobacter capsulatus B-6508 and Rhodobacter sphaeroides B-6509. On the basis of obtained results, mutant strain of Rhodobacter capsulatus B-6508 has shown the highest potential for 5-ALA production. The most favorable conditions for growth and 5-ALA production by mutant strain R. capsulatus B-6508 were observed in media composed of glutamate and malate, light at 2000 Lux, microaerophilic conditions and temperature of 28 °C. In these conditions, the highest 5-ALA concentration (179 mg/L) was detected together with the highest bacterial physiological activity. The prolongation of mutant strain R. capsulatus B-6508 cultivation time after glycine, succinate and levulinic acid addition is related to the reduction of 5-ALA concentrations (e.g. 124.5 mg/L after 48 h and 89.5 mg/L after 72 hours). In the light/aerobic conditions R. capsulatus B-6508 produced only 58.1 mg/L of 5 ALA. Furthermore, in dark conditions even lower biomass and 5-ALA concentrations were observed during R. capsulatus B-6508 cultivation. [ABSTRACT FROM AUTHOR]