What time scale are we referring to? Furthermore, are you prepared to relocate?
I would say that the energy sector is rapidly growing due to the recognition of our environmental responsibility and the uptake of EV vehicles. I believe there is a trend towards a diverse set of sustainable energy sources.
However, my opinion is that biofuel cells (microbial/enzymatic) are, at present, rather niche.
Currently, microbial fuel cell work is is mostly restricted to academia, though I believe these systems have a place in the energy landscape of the future. In what time scale is hard to predict.
A microbial fuel cell is very good theoretical base for future energy source. The time frame needed for transformation from laboratory to full scale can be hardly predicted.