On the Decomposition of Agar-agar by an Aerobic Bacterium

Abstract
A bacterium capable of liquefying agar was isolated from marine sediments around Williams Island, where it occurred in large numbers. It was found to attack rapidly the hemicellulose complex of agar, and to use it as a source of energy. A large part of the C was liberated as CO2, and a part was utilized for synthesis of bacterial cell substance. For decomposition of agar, the bacterium needs a source of N for synthesis of cell substance. The N of the agar is not utilized readily. Nitrate N is a much better source of N than NH4 salts. The bacterium is capable of producing an enzyme which hydrolyzes mannan and starch to reducing sugars. Under unfavorable conditions of growth, it allows the sugar to accumulate. A theory is suggested to explain the role of the agar-liquefying bacterium in the cycle of life in the sea.