Imagine running your car on shrimp.

I don't mean pouring buckets of the tasty creatures into your fuel tank. But they might help biofuels, particularly biodiesel, replace at least some petroleum-based diesel - increasingly the fuel of choice for efficient vehicles.

It's not guaranteed and even if it works, it would be years away. Still, this is a glimpse at yet another bit of the research that -for environmental, economic or energy-security reasons - aims to reduce our dependence on fossil fuels.

Shrimp and biofuel have been linked for a while, but I got an update at a recent biogas conference in London, Ont. ("You are living the life," a colleague remarked when I mentioned the event.)

The main source of the two types of biofuels - ethanol, which replaces gasoline, and biodiesel - is vegetable matter. For now, that's mainly corn and soy.

Ethanol is made from plants' cellulose, or fibrous material; biodiesel, from fats.

Biofuels are controversial in part because their current source crops could be used as food, or occupy land where food could be grown.

The amount that could conceivably be grown would make barely a dent in the global fossil-fuel demand. (Biodiesel can also be made from animal fats, including slaughterhouse leftovers - a great use of troublesome wastes, but in even shorter supply.)

And converting vegetable oils to biodiesel requires a catalyst. Most now are toxic, must be mixed with large quantities of water and can't be reused, creating potential issues for pollution and water shortages.

Enter shrimp: A Chinese experiment is heating them until they form a lattice-like structure with a huge surface area. Coating that surface with potassium fluoride creates a catalyst that's much more effective and can be reused.

A promising source of biofuels is algae - the microscopic critters better known as pond scum. They grow quickly and in vast numbers. Inside shells made of cellulose, they're full of fat cells, or lipids.

Several speakers at the conference described the promise and pitfalls of algae. In theory, and conservatively, enough could be grown to satisfy the United States' entire oil demand on just 0.25 per cent of its land area.

But the stuff doesn't grow by itself: It requires a salt-watery home, nutrients and the proper temperature, which consume money and energy. The costs mount if the algae are produced indoors, where it's easier to control temperatures and keep unwanted wild varieties from contaminating the crop.

Enter shrimp again: A Texas project is using shrimp excrement to feed algae, then feeding the algae shells to the shrimp in a reduced-cost, waste-free loop.

But shrimp's true starring role might come from algae's most difficult problems: First, it's difficult to extract lipids from inside the tough cells. Second, the lipids are extremely diluted and must be concentrated, with additional energy and expense.

Research, including an Ontario project, aims to increase the growth rate and lipid content while thinning the cell wall. But nature is often a nuisance: Various nutrients can be added to help the algae along, but they work at odds with each other. For example, nitrogen increases lipid content but slows growth; carbon dioxide does the opposite.

Not surprisingly, the giant Monsanto Co. sees this dilemma as another opportunity for genetic engineering.

But there's a more benign potential solution: Feed algae to shrimp, which have no trouble with the cell walls. The 0.1 per cent concentration of lipids in the algae soars to 24 per cent in the shrimp. And extracting it would be simple.

Of course, the speakers noted, raising shrimp isn't a slam-dunk. The rule seems to be: Solve one problem, create another.

Even so, I'm intrigued. And I trust that by the time I can afford my BMW 7 Series, it will be available with shrimp power. Coconut curry, if you please.

peter.gorrie@sympatico.ca

Copyright 2012 Toronto Star Newspapers Limited