Technique	ONPG ,(/,)/,(
Principle	Orthonitrophenyl Galactoside Test ONPG is structurally similar to lactose with orthronitrophenyl subsitituted for glucose. Hydrolysis of ONPG, mediated by the enzyme Beta glactosidase releases galactose and orthonitrophenyl which is yellow . Bacteria that form beta galactosidase but not lactose permease will give a positive ONPG reaction but a negative lactose fermentation test since lactose permease is required for the lactose molecule to penetrate the bacterial cell. SEE ALSO PRIMARY TEST->O-F TEST
Cautions
Method
Results
Positive control
Negative control
Reagents
Reference