Discovery of microbial predators of dead cells. Tenuifilaceae

In this study, we discovered anaerobic predator of dead cells and obtained the first isolates with this capacity from a subsurface aquifer and bioreactor. Bacteria comprise one of the largest pools of biomass on Earth (more than 70 Gt), only second to plants, most of them resides in oxygen-independent (anaerobic) environments. Although dead bacterial cell degradation in anaerobic environment was believed to be initiated by autolysis of the bacterial cell itself or by hydrolytic enzymes by some microorganisms, cell degrading bacteria has not been discovered and these mechanisms remained unclear. We show that first anaerobic isolates capable of degrading dead bacterial cell and two predation strategies involve cell-to-cell contact and excretion of cell-detached lytic enzymes. Degradation of dead cells is the last step of the global carbon cycle and, here, we provide the first insight into what organisms and strategies may be involved accomplishing this in the massive and diverse anaerobic microbial world.