"Unlike many other biofuels, algae doesn't displace food crops. That's significant because one fundamental dilemma with biofuels is that they'll crush our economy with rising food costs, by competing with edible crops for arable land.
But algae aren't great multitaskers. 'Algae usually just reproduce or make oil,' says Tom Todaro, CEO of Sustainable Oils. 'They don't usually do both. Under favorable conditions they'd rather multiply than store their energy.'
So there's a dilemma: You want your algae to multiply so you have a lot of it, but if they're spending energy multiplying they won't make any oil. That's why companies such as Sustainable Oils are trying to engineer algae that balance the two imperatives, multiplying rapidly in the first few days of life, and making oil thereafter."