Enzymatic hydrolysis of agar: purification and characterization of β-neoagarotetraose hydrolase from Pseudomonas atlantica

Abstract

Agarose is degraded by a β-agarase from Pseudomonas atlantica to neoagarooligosaccharides of degree of polymerization (DP) 4, 6, 8, and 10. A β-neoagarotetraose hydrolase cleaves the central β-linkage in neoagarotetraose and the β-linkage near the nonreducing end in neoagarohexaose and -octaose to yield neoagarobiose. The β-neoagarotetraose hydrolase was localized on or outside the cytoplasmic membrane, in the cell wall region. The enzyme was activated by NaCl, KCl, CaCl₂, MnCl₂, and MgSO₄, has a K_m of 3.4 × 10⁻³ M for neoagarotetraose, was free from β-agarase and α-neoagarobiose hydrolase activity, and showed no transglycosidic activity.