Corrinoids are ring-shaped compounds that are essential for living things (such as vitamin B12). However, only Bacteria and Archaea can make corrinoids, and not all members of these groups are capable of corrinoid biosynthesis. These organisms depend on corrinoids for functions such as the detoxification of halogenated compounds. Frank Loffler from the University of Tennessee shows us that, depending on the structure of a region of a corrinoid called the lower base, some corrinoids function better than others for dechlorination. Interestingly, purine (typically used in the biosynthesis of nucleotides) was observed as a lower base, something that has not been seen before.
Since not all microbes make corrinoids, its biosynthesis is a community function. Changes in the lower base of a corrinoid in one organism can ripple through the community to impact many taxa. In the dechlorination corrinoid experiment, growth of a second microbe depended on the function (and type of lower base) of corrinoids in the first microbe. Frank’s work in the environment demonstrates that the redox state of the environment is linked to both the type of lower base on a corrinoid and the quanitity of corrinoid produced. Both quantity and quality of corrinoids impact microbial communities, making this a great system to study community interactions.