A study on neoagarobiose production by using alcanivorax sp. A28-3 lysate

Abstract

A neoagarobiose hydrolase (NABH) activity was found in the cell lysate of Alcanivorax sp. A28-3, an agar-degrading microorganism newly isolated from the surface of Gelidium amansii, a red alga. Alcanivorax sp. A28-3was cultured in an artificial sea water medium at 28 ℃, 200rpm for 48 hours and then homogenized. The resulting cell lysate was used for the degradation of neoagarobiose to produce D-galactose and 3,6-anhydro-L-galactose. Being different from other Alcanivorax strains, Alcanivorax sp. A28-3 could utilize various monosugars including D-glucose and D-galactose. However, NABH was produced only when agar or neoagarobiose was in the medium as the sole carbon source. The optimum conditions for neoagarobiose hydrolysis by this enzyme was 35 ℃ and pH 7.0. Thin-layer chromatography, high performance liquid chromatography (HPLC), and gas chromatography-mass spectrometry analyses of the hydrolysate showed the formation of D-galactose and 3,6-anhydro-L-galactose. By treating 5 g/L of neoagarobiose with the cell lysate at a NABH activity of 0.025 U/ml, 35℃, and pH 7.0 for 4 hours, 2.75 g/L of galactose was produced.