Microbiology is a broad field, and there are many different sub-disciplines. It's difficult to give a single "subdivision" without more context.

To give you a better answer, could you please tell me:

* What are you interested in learning about? Are you interested in specific types of microbes, like bacteria or viruses? Or specific applications, like food safety or environmental microbiology?

* What level of detail are you looking for? Are you interested in a broad overview, or more specific areas of research?

Once I have more information, I can provide you with a more tailored response.

Here are some examples of common subdivisions within microbiology:

* Bacteriology: The study of bacteria

* Virology: The study of viruses

* Mycology: The study of fungi

* Parasitology: The study of parasites

* Immunology: The study of the immune system

* Medical Microbiology: The study of microbes that cause disease in humans

* Environmental Microbiology: The study of microbes in the environment

* Food Microbiology: The study of microbes in food

* Industrial Microbiology: The study of microbes used in industrial processes

* Microbial Genetics: The study of the genetics of microbes

* Microbial Physiology: The study of the functions of microbes

* Microbial Ecology: The study of the interactions between microbes and their environment

Let me know if you have any specific questions about any of these sub-disciplines.