Whereas for oxidation reactions the local pH decreases, and a higher pH is appropriate. Then a buffer should be chosen to have good buffering at the local pH optimum, which in a perfect system will be the 'idea' enzyme activity pH. Further significant developments can be achieved with the utilisation of a less densely structured porous electrode to facilitate the mass transport of species. Moreover, as high current density bioelectrochemical systems reach the mass transport limits of current electrode architectures, a shift towards more dynamic flow technology, such as gas diffusion electrodes, may be required to make advances in the future.