Explain Fungi - Nutritional Types of Microorganisms?
Fungi are filamentous, eukaryotic microorganisms, ubiquitous in nature. These grow best in dark and moist habitats. Their habitats are diverse. While few are aquatic, most are terrestrial. These are present almost everywhere where the organic material is present and play a very important role in mineralization. Most fungi are saprophytes, i.e., grow on dead organic materials while few are parasitic i.e., grow on plants, animals and humans. Fungi are chemoorganotrophs, i.e., use organic compounds as a source of carbon, electrons and energy. These have simple nutritional requirements and can be easily grown in laboratory on simple media. Fungi are found as common contaminants of food, on microbial culture media, paper, cloth and moist surfaces.
Most of the fungi are aerobic (i.e., grow in the presence of oxygen). Some may be obligate anaerobes (i.e. thrive in the absence of oxygen or free air e.g. those found in rumen of cattle). Yeasts are, however, facultative anaerobes (i.e. survive either in the presence or absence of oxygen) and found in habitats rich in sugar. These are unicellular fungi which can obtain energy by fermentation. Understanding of the nutritional requirement of the organism is therefore needed for its cultivation and maintenance in the laboratory. These nutritional needs can be supplied in the laboratory through culture media. Now that we know about the nutritional requirements of microorganism, let us next see how these requirements are met by preparing culture media in the laboratory. First we will learn about the types of media and then discuss the composition of some commonly used culture media in microbiology laboratory.