This is the first of these articles that I've seen where the reporter actually bothered to interview an industry expert who pointed out an obvious issue -- there's probably not that much hydrogen in the air. The explanation for this from statistical mechanics is that at the temperatures commonly observed in the atmosphere molecular hydrogen has a speed distribution that encompasses the escape velocity of the Earth.
Think ways to create incredibly small amounts of energy just about anywhere. Useful for a smart tag on a box of milk (their example). But they did say they would love if it were possible to scale up and point out that being a big reach. But then plenty of big reaches have been made so I would suggest not considering that impossible.
Enzymes are much too unstable and expensive to ever make sense in electricity production, especially when compared to inorganic solutions like PV.
The other way around is more sensible though, using electricity to produce hydrogen (Enzymatic electrolysis cells, EFCs), for example from distillery wastewater.
Yes, that drives cost down but even on the biggest scale, like insulin, enzymes are still orders of magnitude more expensive than inorganic catalysts (e.g. platinum for hydrogen fuel cells)
Why one way but not the other - just that pouring power onto the grid requires cooperation but producing hydrogen doesn't, or is there something more fundamental at play?
The fundamental principle would be that enzymes have an comparative advantage when utilising and producing complex organic molecules as fuel for hydrogen production (such as glucose in wastewater) while inorganic catalysts are cheaper, more stable but limited to simple reactions
