The different branches of microbiology are -
Bacteriology - The study of bacteria.
Mycology - The study of prokaryotic organisms (bacteria) and fungi which are eukaryotic in nature.
Protozoology - It is the sub-discipline that deals with the study of protozoa.
Phycology - The study of multicellular organisms.
Parasitology - Study of parasites.
Immunology - Study of Immune systems.
Virology - Virology is a branch of microbiology that deals with the study of viruses.
Nematology - Study of multicellular nematodes. Those who study nematology are known as nematologists.