a) Single cell protein (SCP): They are the dried cells of micro organisms that are used as animal feed and dietary protein supplement. The micro-organisms used belong to bactaria, fungi and algae. Aspergillus niger, Saccharomyces cerevisiae and others are used in its production.

b) Soil: Microbes play an important role in maintaining the fertility of soil. Bactaria, fungi and cyanobactaria are mainly involved in it. Certain microbes such as Rhizopus help in nitrogen fixation.