How to Become a Microbiologist. A bachelor’s degree in microbiology or a closely related field is needed for entry-level microbiologist jobs. A Ph.D. is typically needed to carry out independent research and to work in colleges and universities.icrobiologists typically need a Ph.D. to carry out independent research and work in colleges and universities. Graduate students studying microbiology commonly specialize in a subfield such as bacteriology or immunology.