Can IPTG in alkaline conditions become toxic to the bacteria?

Hi everyone! Currently I am attempting to measure the beta -galactosidase activity by inducing the lac operon in E.coli cells. I am trying to grow my cells in alkaline conditions with a pH > 8.5 but when I induce the cells with IPTG they are not growing. The IPTG concentration I have tried using is 0.1 and 1mM. Is there a chance that IPTG in these concentrations in alkaline conditions becomes toxic to my bacteria? Should I lower the concentration or do you think that the problem lies elsewhere?

Experiment: Protein expression and purification Bacteria - Bacillus subtilis GCSF