Screening was undertaken to isolate bacteria producing a stable and strong porphyran-decomposing enzyme. By an aerobic screening method, 78 strains producing the enzyme were isolated from the soil of agar plants in Nagano Prefecture. Of these strains, strain S-22 produced a large quantity of extracellular porphyran-decomposing enzyme when grown in porphyran supplemented medium. The enzyme exhibited a high activity at a range of pH 5.5 to 6 and at 50°C, and showed a substrate specificity on porphyran, but no activity on k-carrageenan, dextran, or pectin. The enzyme produced neutral oligosaccharides of various sizes, which were indicated as spots of neoagarotetraose and neoagarobiose on TLC.
According to Bergey's Manual Systematic Bacteriology (1986), the strain S-22 was identified as the genus Arthrobacter.