Aim: Isolation of bacteria from soil by serial dilution method 
       Principle: Isolation is often essential for taxonomic and experimental work on micro-organisms. 
       In the microbiological sense, it is the process of separating a single species of microorganism 
       from its natural habitat and growing it by itself, without interference from other organisms, on a 
       sterile  substratum, i.e. in medium. The micro-organism can then be distinguished from other 
       species by its individual characters (even if artefacts of laboratory conditions) and propagated to 
       provide  experimental  material.  Methods  of  isolating  micro-organisms  from  a  natural 
       environment, such as soil, litter, air, or water, are numerous. 
       Serial dilution, as the name suggests, is a series of sequential dilutions that are performed to 
       convert a dense solution into a more usable concentration. In simple words, serial dilution is the 
       process of stepwise dilution of a solution with an associated dilution factor. In biology, serial 
       dilution is often associated with reducing the concentration of cells in a culture to simplify the 
       operation. 
        
       Material Required: 
       Nutrient agar media, petri dish, test tubes, pipette, incubator, autoclave, soil sample. 
        
       Method: 
         1.  Prepare 100 ml of nutrient agar media and autoclave it along with clean petri dishes.  
         2.  Meanwhile, arrange 7 test tubes in a row and add 9 ml distilled water to each tube. 
         3.  Mark the tubes as 10-1 upto 10-7 
         4.  Add 1 ml of sample in first test tube and mix well by vortexing. 
         5.  Now take 1 ml from first test tube and add it to the second test tube. Repeat the steps till 
          7th tube is reached. 
         6.  After autoclaving pour 15 - 18 ml of media in each petri dish inside the laminar air flow 
          and allow them to solidify. 
         7.  After the media is solidified, take 1 ml from any of the dilution and add it to the agar 
          plate.  
         8.  Incubate the plates at 37o C from 48 hours 
         9.  Observe the growth. 
       Result: 
        
       Precautions: 
        
                  
                        Always autoclave media. 
                        Never open autoclave media outside laminar air flow. 
                        Do not talk while working on laminar cabinet