Carbohydrate fermentation test
Phenol red broth base medium was used as a medium for this test.
Different sugar substrates namely, arabinose, sucrose, maltose,
lactose (BDH, UK), sorbitol (GPR, UK) and glucose (R & M Chemicals,
UK) were used. 0.1 g (0.1 % w/v) of each sugar substrate was added
to 100 ml of the medium. 5 ml of each mixture was transferred into
each tube. For gas detection, Durham tube was inserted into the test
tube containing glucose. All the tubes were sterilized for 15 min at
121 °C. The tubes were inoculated with a single colony of the
bacteria under study. The positive reaction of the bacteria was
indicated by the changes in the colour of the medium [19].