Isolation and Identification of Antioxidant-producing Marine Bacteria and Medium Optimization

For the research of the natural marine antioxidant, several bacteria were isolated from the coast of Jin-Hae in Korea. Among the marine bacteria studied, strain HJ-14, a gram-negative, motile, strait rod, aerobic, and Na⁺ required bacterium showed high activity of 1,1-diphenyl-2-picrylhydrazyl radical scavenging. The morphological, physiological, and biochemical characteristics of the strain HJ-14 were similar to those of the Alteromonas macleodii ATCC 27126^T. Thus, it was tentatively identified as Alteromonas sp. HJ-14. The compositions of major fatty acids in cell membrane of Alteromonas sp. HJ-14 were C_14:0, C_15:0, C _16:0 and C_{17:1 w8c}, which also suggest that it is affiliated with Alteromonas sp. The optimum culture conditions for production of antioxidant materials with Alteromonas sp. HJ-14 were at 25-37°C and pH 6-8. The optimum conditions for the production of antioxidant for carbon, inorganic nitrogen, and sodium chloride sources were 2.5%(w/v) dextrin, 0.5%(w/v) ammonium sulfate, and 2-6%(w/v) sodium chloride, respectively. The hydroxyl radical scavenging ability of Alteromonas sp. HJ-14 broth was 90.03%, which is higher than ascorbic acid(83.28%) and lower than butylated hydroxyanisole(95.46%) and α-tocopherol(97.17%).