ABSTRACT
This short review will cover the metabolism of heterocyclic, mainly N-containing, compounds by bacteria that would belong to the genus Clostridium according to the old terms [1], although it has become clear that only species of cluster I can be correctly assigned to the genus Clostridium [2]. However, at the time the Biotechnology Handbook on clostridia [3] and the second edition of The Prokaryotes [4] were published, this discrimination could not be made due to the lack of 16S rDNA sequence data. Today, many organisms are still associated with their old names, although it has become clear that they should be renamed. Such a reclassification has been done quite cautiously, e.g., for the nicotinic acid-fermenting organism Clostridium barkeri of cluster XV, now known as Eubacterium barkeri [2]. Also, many members of the former genus Peptostreptococcus (Clostridium cluster XIII) have already been renamed, such as the purinolytic specialist Psc. barnesae [5] to Gallicola barnesae [6] or as the related glycine-utilizing Psc. magnus and Psc. micros to Finegoldia magna and Micromonas micros [7,8], both showing relationships to purine-utilizing clostridia. However, some species such as the purinolytic specialists C. acidiurici, C. cylindrosporum, and C. purinolyticum (cluster XII) remain to be renamed, as they still carry the name “Clostridium” although they belong to the same group as, e.g., Tissierella creatinophila, a specialist for degradation of creatine and similar compounds [9].
