In microbiology, an endospore is a dormant, tough, and non-reproductive structure produced by certain bacteria of the Firmicute phylum that is not capable of reproducing. Lack of nutrients is usually the catalyst for endospore formation, which occurs most frequently in Gram-positive bacteria. The bacterium divides within its own cell wall during the process of endospore formation. Then one side completely engulfs the other. Endospores allow bacteria to remain dormant for long periods of time, sometimes even centuries. When the environment becomes more favourable, the endospore has the ability to reactivate and return to the vegetative state. Bacillus and Clostridium are examples of bacteria that can produce endospores in their cells.
The endospore is made up of the bacterium’s DNA as well as a portion of its cytoplasm, and it is protected from the environment by a very tough outer coating. Endospores are capable of surviving in the absence of nutrients. Extreme temperatures, desiccation, ultraviolet radiation as well as chemical disinfectants are not a problem for these plants. The majority of the time, they can be found in soil or water, where they can survive for extended periods of time. Bacteria produce a single endospore on the inside of their cells.