How to calculate the rate of glutamate release from glutamine using glutaminase assay with ammonia standard curve. The OD value of Zobell marine broth containing L-glutamine as a substrate (without culture inoculation) is higher than the OD value of 24 hours culture and lower than the 48 hours culture. (For example: 24 hours culture with L-glutamine as a substrate has the OD value of 0.563 at 450nm and the 48 hours culture has the OD value of 1.063 at 450nm. Whereas, the broth which is not inoculated with any culture has an OD value of 0.951 at 450nm).

In this case how can i prove that bacterial culture is capable of producing glutaminase enzyme?

Can anyone explain this please?