Growth of bacterial cultures:

Growth is defined as an increase in cellular constituents which leads to a rise in cell number. As we are aware, microorganisms reproduce by binary fission or by budding. In order to study growth, normally one follows the changes in the total population number. The cells copy their DNA almost continuously and divide again and again by the process called binary fission . Binary fission which has been described earlier a s the form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size. Fortunately, few prokaryotic populations can sustain exponential growth for long. Environments are usually limiting in resources such as food and space. Prokaryotes also produce metabolic waste products that may eventually pollute the colony's environment. Still, you can understand why certain bacteria can make you sick so soon after infection or why food can spoil so rapidly. Refrigeration retards food spoilage not because the cold kills the bacteria on food but because most microorganisms reproduce very slowly at such low temperatures.

Binary fission:

In the process of binary fission, the cell elongates and the DNA is replicated. Cell wall and plasma membrane begin to grow inward and cross-wall forms completely around the divided DNA. At the end the cell separates into two individual cells similar to the parent cell and contains all the contents a cell requires for its living including DNA (Figure 1).

Few bacterial species reproduce by budding. In this method, the cell forms a small initial growth, it enlarges and then it separates from the parent cell. Some filamentous bacteria like actinomycetes reproduce by producing chains of conidiospores and a few bacteria simply fragment.