ABSTRACT
The fungi and yeasts are important groups of non-photosynthetic microorganisms that exist widely in nature and are active in the stabilization of organic residues in both the soil environment and the aqueous environment. Aerobic metabolism permits the fungi to obtain the maximum energy from the substrate for synthesis of new cell protoplasm. In the natural environment fungi compete with bacteria for nutrients to survive. The lower nitrogen and phosphorus content of fungi protoplasm than bacteria protoplasm gives the fungi an advantage over bacteria when metabolizing organic compounds in low nitrogen and low phosphorus environments. Yeasts have a chemical composition between fungi and bacteria. A few fungi have developed the ability to produce antibiotic substances that prevent the bacteria from growing near these fungi. Yeasts belong to the Ascomycotina. They are similar to bacteria in that they are single cells, but their other characteristics favor fungi.
