Clean as you go and there's more potential biofuel, three inventors from North Wales have developed a box that can capture the exhaust gases of cars so they can be used to grow algae.
There are a number of technical difficulties that need to be overcome. Firstly, how do they stop the exhaust gases choking the engine/blowing the exhaust system apart? Secondly, and one for the plant scientists, Does chlorophyll get as closely attached to carbon monoxide as haemoglobin? if it does then the algae are going to be gonners. But a nice idea, a car that cleans as it goes.