Effect of Dietary Oxalate on the Gut Microbiota of the Mammalian Herbivore Neotoma albigul
Oxalate is not metabolized by mammalian enzymes but rather is biotransformed into formate and CO2 by gut microbes (7, 18–21). While some oxalate-degrading bacteria, such as Oxalobacter formigenes, biotransform oxalate for use as a carbon and energy source, the growth of other oxalate-degrading bacteria, such as Lactobacillus acidophilus, is inhibited by the presence of oxalate, even though these bacteria biotransform the compound when present (7, 22). Additionally, the by-products of microbial oxalate degradation, formate and CO2, may be used by a number of bacteria in the process of acetogenesis or methanogenesis, potentially benefitting other gut bacteria not directly involved in the oxalate degradation function (23). While there is no direct evidence for either acetogenesis or methanogenesis, several known acetogenic taxa, such as Clostridium, Streptococcus, and Ruminococcus, are prevalent in the N. albigula gut (24–26). These attributes constitute a unique system to isolate the interactions between dietary toxins and gut microbes, along with their contribution to the overall metabolism of the host.