Influence of Glycine, Succinate, Levulinic Acid and Glutamate Concentrations on Growth of Purple Non-Sulfur Photosynthetic Bacteria and 5-Aminolevulinic Acid Production

Abstract

Purple non-sulfur photosynthetic bacteria (PNSB) and their product 5-aminolevulinic acid (5-ALA) have broad usage in different fields of medicine, agriculture, bioremediation, etc. As demand for aminolevulinic acid is increasing continuously, new bio-processes and new producers of 5-ALA are researched and optimized. Strain of purple non-sulfur bacteria Rhodobacter azotoformans isolated from mineral waters of Armenia is potential producer of 5-aminolevulinic acid. For better optimization of 5-ALA production, set of experiments was conducted in order to determine influence of glycine, succinate, levulinic acid and glutamate on the growth and production of 5-ALA. As addition of mentioned chemical compounds in nutrient media is needed for promotion of 5-ALA production, it was tested what is the optimal concentration of glycine, succinate, levulinic acid and glutamate during cultivation to obtain highest yields. From the results it can be concluded that maximal 5-ALA concentration was achieved in batch cultivation when concentration of glycine was 40 mM, succinate 30 mM, levulinic acid 15 mM and concentration of glutamate 4g/l. Concentration of 5-ALA was in this case 385 mg/L. Addition of glycine only yielded lower concentrations (183.75 mg/L). Concentrations of added glycine and succinate above 40 mM didn't yield higher concentrations of 5-ALA. Increase of glutamate concentration above 4 g/L also doesn't increase 5-ALA yields.