| Technique | STARCH HYDROLYSIS ,(/,)/,( |
| Principle | |
| Cautions | The reaction is not instantaneous and is best observed 30 min after addition of the ethanol. |
| Method | Inoculate starch agar and incubate the plates at 30 C for 5 days.The medium is flooded with Lugol's idoine solution, Alternatively the plate may be flooded with 95% ethanol. |
| Results | Lugol's Iodine :The
medium turns blue where starch has not been hydrolysed,
while hydrolysis is indicated by clear colourless zones Ethanol: Milky white areas indicate unhydrolysed starch wheras hydrolysis in indicated by clear zones. : |
| Positive control | Bacillus subtilis Some strains of Bacillus produce only restricted zones of hydrolysis that may not be obvious until the bacterial growth has been scraped away. |
| Negative control | Escherichia coli. |
| Reagents | |
| Reference |