抄録
We have found many novel and useful enzyme-producing microorganisms from the deep-sea and deep-subsurface. Alkaline mannnanase is useful for detergents and bleaching of kraft pulp. A novel species of alkaliphilic Bacillus isolates JAMB-750 produced alkaline mannanase extracellularly. The optimal pH of the enzyme is the highest among mannanases reported to date. Agaro- or neoagaro-oligosaccharides are known to show various physiological activities. We isolated many β-agarases, which were produced by deep-sea microorganisms. A β-agarase from an Agarivorans sp. produced neoagarobiose as the final product from agar. Neoagarobiose is useful for cosmetic additive. An alkaline and thermostable α-glucosidase was found in a Geobacillus sp. that was isolated from the sediment of the Mariana Trench. The enzyme possessed a strong transglycosylation activity toward non-sugar molecules with maltose as a sugar donor. A highly alkaline protease was found in culture broth of an extremely anaerobic alkaliphile isolated from a mine water containment dam at 3,200 m below land surface. The enzyme showed the maximal activity greater than pH 12.6 at 40°C. According to the deduced amino acid sequence of the mature enzyme, it forms a new cluster in a phyrogenetic tree of subtilase family A.
