Microbiologists study microscopic organisms like bacteria, algae, or fungi in order to solve practical problems. Microbiologists have developed genetically engineered crops, biofuels, and drugs to treat infectious diseases. What they study may be small, but their contributions are BIG! Types of microbiologists include bacteriologists, clinical microbiologists, immunologists, and virologists. To become a microbiologist, you should major in biology or a related field, but to be able to do independent research, you must obtain a doctorate.