• Journal of Life Science
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• v.25 no.11
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• pp.1273-1279
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• 2015

Agarase from a novel agar-degrading bacterium isolated from seawater in Namhae at Gyeongsangnamdo province of Korea was characterized. The SH-1 strain was selected from thousands of colonies on Marine agar 2216 media. Almost full 16S rRNA gene sequence of the agarolytic SH-1 strain showed 99% similarity with that of bacteria of Simiduia genus and named as Simiduia sp. SH-1. Agarase production was growth related, and activity was declined from stationary phase. Secreted agarase was prepared from culture media and characterized. It showed maximum activity of 698.6 units/L at pH 7.0 and 30℃ in 20 mM Tris-HCl buffer. Agarase activity decreased as the temperature increased from an optimum of 30℃, with 90% and 75% activity at 40℃ and 50℃, respectively. Agarase was not heat resistant. Slightly lower agarase activity was observed at pH 6.0 than at pH 7.0, without statistical difference, and 80% and 75% activity were observed at pH 5.0 and 8.0, respectively. Neoagarotetraose and neoagarobiose were the main final products of agarose, indicating that it is β-agarase. Simiduia sp. SH-1 and its β-agarase would be useful for the industrial production of neoagarotetraose and neoagarobiose, which have a whitening effect on skin, delaying starch degradation, and inhibiting bacterial growth.