Bacterial shape and arrangement vary from species to species. Bacteria exist in many forms, but the most common types are bacilli, cocci and spirilla. Some bacteria are pleomorphic, i.e. they live in variable shapes. Bacteria are prokaryotic cells as they have a primitive nucleus, i.e. bacteria devoid of a nucleus and a nuclear membrane that …
Simple staining is one of the conventional staining techniques. From the name, it is quite clear that it is a very simple or direct staining method that uses a single stain only. The microorganisms are invisible to the naked eye, and to make them visible, staining is performed that gives divergence to a microscopic image. …
Membrane filtration method is an alternative to the MPN method for the microbiological analysis of water. Sometimes, it also refers to as “Millipore filter technique” or “MF technique”. The Millipore filter technique was named by the two scientists Goetz and Tsuneishi in 1951. Membrane filtration method makes the use of membrane filter, or we can …
A most probable number method is practised for the qualitative and quantitative water to determine microorganisms’ presence (mainly coliforms). “MPN” is an acronym for most probable number. Multiple tube fermentation test or MPN method determines the quality of water by quantifying the number of coliforms in 100 ml of the water sample. MPN test involves …
Acetic acid production refers to the production of acetic acid or vinegar through two steps modification via two different microorganisms. The first step involves the conversion of sugar into ethanol by the yeast (mainly Saccharomyces cerevisiae). In the second step, oxidation of ethanol into acetic acid takes place by the bacteria like Acetobacter, Gluconabacter sp. …
Production of citric acid is an industrial process that uses raw materials like substrates, citric acid growth-promoting microorganisms and enzymes etc. for the commercial production of citric acid. Generally, the commercial production of citric acid works out best by employing the fermentation method. Globally, there is around 7, 36,000 tonnes/year production of citric acid. The …
A nucleotide is a compound, which can form a polynucleotide chain by the union of nitrogenous bases and sugar-phosphate group. Monomers of nucleotide units are connected via a covalent phosphodiester bond. Nitrogenous bases, i.e. purines and pyrimidine, are attached via weak hydrogen bonds. The bases link with a deoxyribose pentose sugar via an N-glycosidic bond. …
The bright-field microscopy produces an image with a coloured specimen having lightened background. Generally, the microorganisms do not absorb light, but the organisms can absorb the light after staining. The optical lens, i.e. condenser lens and the path of light coming from the light source illuminator produce a bright-field image with higher contrast and magnification. …
The continuous culture is an open cultivation process, in which the cell growth is maintained in the continuous mode of operations. It works as an open cultivation system, in which the fresh nutrient medium is continuously added into the culture vessel rather than recycling and reuse of the nutrients or substrate. There is an inlet pump …
The active site of an enzyme is the region, which shows the highest metabolic activity by catalysing the enzyme-substrate complex into the products. The active site is found deep inside the enzyme, which resembles a hole or small depression. An active site is a region combining the specific substrate molecule with the enzyme and thus …