Even if you can mass-produce an enzyme and its necessary cofactors, it might not be easy to use it in an industrial setting. Some enzymes need a very particular environment to be stable (pH, temperature, salinity etc) or can be destroyed by side-reactions with other things in your tank. Some work only when bound to particular cellular components (e.g. the cell membrane). If they need energy to work then it's probably as ATP or NADPH, so you'd have to somehow supply that in your bioreactor. And of course you have to keep the whole tank sterile without damaging the enzyme.
These problems notably plague attempts to use the even-holier grail of nitrogenases, basically enzymes for synthesizing ammonia using N2 and water. The current standard process for industrially fixing nitrogen (the Haber-Bosch process) is energy-inefficient and uses about 1-2% of the world's total energy supply, mostly in the form of natural gas. So significantly reducing its energy usage would be a huge deal, but we haven't been able to do it, nor do we fully understand how nitrogenases even work.
You could also try to culture bacteria that do the whole process and maintain the enzymes for you. In the case of methanol synthesis though, even if you could do this you'd have to keep tes culture alive and working 24/7 at a remote industrial site. A flare stack is a lot simpler.
These problems notably plague attempts to use the even-holier grail of nitrogenases, basically enzymes for synthesizing ammonia using N2 and water. The current standard process for industrially fixing nitrogen (the Haber-Bosch process) is energy-inefficient and uses about 1-2% of the world's total energy supply, mostly in the form of natural gas. So significantly reducing its energy usage would be a huge deal, but we haven't been able to do it, nor do we fully understand how nitrogenases even work.
You could also try to culture bacteria that do the whole process and maintain the enzymes for you. In the case of methanol synthesis though, even if you could do this you'd have to keep tes culture alive and working 24/7 at a remote industrial site. A flare stack is a lot simpler.