Industrial microbiology or microbial biotechnology is the application of scientific and engineering principles to the processing of materials by microorganisms (such as bacteria, fungi, algae, protozoa and viruses) or plant and animal cells to create useful products or processes. Vaccines. 2  Vaccines are essential to protect humans and animals from microbial diseases. 3  Recombinant DNA technology has allowed for the production of vaccines that offer protection without risk of infection (e.g. hepatitis B vaccine). 4  New vaccines are being developed by industrial microbiologists every day.