(N/A) Single Cell Protein $(SCP)$
Single Cell Protein $(SCP)$ refers to protein extracted from pure or mixed cultures of algae,yeasts,fungi,or bacteria,which serves as an alternative protein source for human food or animal feed. Microbes like $Spirulina$ are grown on industrial scales using waste materials such as molasses,sewage,and animal manure. $SCP$ is a rich source of proteins,carbohydrates,fats,minerals,and vitamins. Additionally,microorganisms like $Methylophilus$ $methylotrophus$ have a high rate of biomass production,making them efficient for large-scale protein synthesis.
$(b)$ Soil
Microbes are essential for maintaining soil fertility. They contribute to the formation of nutrient-rich humus through the decomposition of organic matter. Many bacteria and cyanobacteria are capable of fixing atmospheric nitrogen into forms usable by plants. $Rhizobium$ is a symbiotic bacterium found in the root nodules of leguminous plants. $Azospirillum$ and $Azotobacter$ are free-living nitrogen-fixing bacteria,while $Anabaena$,$Nostoc$,and $Oscillatoria$ are examples of nitrogen-fixing cyanobacteria.