Microorganisms are useful to us in many ways. For example

• Bacteria like Lactobacillus convert milk into curd.
• Bacteria are also involved in the making of cheese.
• Acetobacter aceti is used for producing acetic acid from alcohol.
• Yeast is used in the commercial production of alcohol, wine and bakery products.
• Some specific microorganisms are helpful in manufacturing of antibiotics.
• Microorganisms act as cleansing agents and decompose the waste products into manure.
• Dead or weakened microbes are used in the preparation of vaccines.
• Some bacteria fix atmospheric nitrogen and increase soil fertility.
• Algae, yeast, fungi or bacteria may be used as an ingredient or a substitute for protein-rich foods that are suitable for human or animal consumption.
• Some microorganisms are taken as probiotics, that are believed to provide health benefits when consumed.