Microbiologic Degradation of Rubber

This article begins by providing a brief overview of the degradation of vulcanized natural rubber by microorganisms of the Streptomyces genus. A study of the degradation of rubber rings in the joints of water distribution pipe is discussed. Samples were obtained of deteriorated rings from water utilities in the Netherlands. The bacteriologic examination of the rings is described, and experimental results demonstrated that, without exception, the same species of Streptomyces was isolated. Two types of this species of Streptomyces were often found together: Type 1 first forms white and then pink colonies on glucose-peptone agar; and, Type 2 forms smaller, round, and orange-colored colonies. Whether these two types are two different species or just variations of the same species remains to be investigated. The article goes on to discuss pure-culture tests, the effect of compression, the role of Streptomyces, tests of resistance to attack, and the significance of protein content.