CREATION OF HIGH ARGININE PRODUCING STRAIN OF SYNECHOCYSTIS SP. PCC 6803 BY UV MUTAGENESIS

Arginine has been widely used in medicine and food industry. Synechocystis sp. PCC 6803, a unicellular cyanobacterium, synthesize amino acids and other compounds using nitrate or nitrite as the nitrogen source. In flue gases released by industrial production, NO_x (nitrogen oxides) can react with water to form nitrate and nitrite, which can be utilized by cyanobacteria. Hence, creating high arginine producing strain of Synechocystis sp. PCC 6803 has a strong application prospects, in denitrification of industrial flue gases. This study reported the successful creation of a high arginine producing strain #13807-111-55 of Synechocystis sp. PCC 6803 by 0.8 g/L D-arginine and 0.2 g/L 6-azaruacil resistant mutants with UV mutagenesis. Compared with the parent strain #13807, extracellular arginine production per OD₇₃₀ of #13807-111-55 increased 62.3-fold, reaching (0.76±0.1) mg/(L·OD₇₃₀). Total arginine production per OD₇₃₀ of #13807-111-55 increased about 6.0-fold, reaching (0.82±0.08) mg/(L·OD₇₃₀). Extracellular arginine production per OD₇₃₀ of the mutant was significantly higher than that of intracellular, showing that the strain was the arginine-secreting mutant with strong production potential.