He states that the purpose is not carbon capture but energy production, as all carbon consumed will be released upon combustion.

Carbon neutral combustion is still a win.

which could make it a carbon neutral energy production technology.

wouldn't take much to sequester it instead of merely burning it. then the net is carbon negative.

My tinfoil hat is buzzing. What happens when this bacteria is released in our lakes and oceans?

They die. The bacteria are dependent on a constant stream of hydrogen gas at higher concentration than typically found on earth. They simply cannot compete with any other organism outside of the reactor for which they are designed.

Scenario: Mixing in the chamber isn't complete, after a few generations, bacteria that can survive in a low H environment continue to breed. Worker forgets to purchase reactor before maintenance, bacteria escapes. Hilarity ensues.

Are there not hydrogen rich microzones (volcanic fissues? atmospheric layers?) where these might thrive?

I'm not actually worried about bugs taking over the world. But we ought to avoid hand-waving away possible unintended consequences, because that tends to be how we get ourselves into environmental problems in the first place.

While there are certainly conditions in which these bacteria might thrive, their inbuilt inefficiency -- secreting large quantities of energy-rich alcohol -- suggests that, in their current form, they'd be relatively easy to outcompete. They don't seem to have any particular advantage in an environment where their unique characteristics are not beneficial -- and very few environments would seem to fit that bill.

That's like worrying about cattle getting loose and taking over Africa. The same things that make them useful to us also make them horrible at competing in a natural setting.

It dies because there is no hydrogen to consume ?

How do we know it won't adapt before then, as have thousands of other types of bacteria?