Bio-batteries?

Peter over at Bayou Renaissance Man alerts us to experiments harvesting electricity from cockroaches.

His initial reactions are slightly different than mine:

I've already seen that movie, thank you very much
(picture source)

Seriously though, the tech looks pretty interesting. I don't have the background to determine the efficiencies of the process, but I wonder if that reaction chain could be replicated, instead of having to rely on the cockroaches themselves.