Algae could soon become a valuable biofuel resource, according to research at the UA.

It's green, it's slimy and it smells. It also abundantly produces lipids, sugars and sometimes hydrogen gas, all of which are sought-after sources for renewable energy. You may think of it as mere pond scum, but algae could be a highly productive biofuel crop in the near future.

More than 300 times as productive a source for renewable energy as corn, algae could be used to make biodiesel to power vehicles and industries – if it can be produced at a low enough cost to be feasible economically.

In a collaborative research effort between several departments, scientists and engineers at the University of Arizona are studying ways to optimize the production of biofuels from algae.

The challenge: How to use environmental factors to control the rate at which the algae grow and produce lipids to maximize production while also reducing the cost of resources needed to grow algae.

"Right now the cost of production still exceeds the value of the final product," said Joel Cuello, professor in the department of agricultural and biosystems engineering. "So the challenge research-wise is trying to lower the production cost while increasing algae productivity."

One way to lower production cost is to use treated secondary wastewater to grow the algae. The algae purify the water by absorbing nutrients such as nitrogen and phosphorus, and at the same time eliminate the need to use costly fertilizers to supply the algae with nutrients.

"Wastewater has nitrates and phosphates that need to be removed anyway, so why not just feed it to the algae?" said Cuello.

Algae cells store fat as lipids, oil molecules that can be processed to make biodiesel. The researchers grow colonies of algae in flasks to test the effects of different environmental conditions on growth and lipid production.

Kimberly Ogden of the department of chemical and environmental engineering has a lab full of algae-filled flasks: "We grow the algae and then separate the lipid material that can be turned into fuel from the rest of the algae, which is mostly protein."

The goal, said Ogden, is to learn enough about the chemical structure of the oils to be able to process them into biodiesel with the same facilities currently used to process petroleum. Eventually algae oil could be blended with petroleum oil to make biodiesel.

"We use alternative water supplies and look at water recycling and reuse," said Ogden. "We don't want to use tap water – for one thing all the chlorine is probably not a good idea, and we don't want to be using the freshwater supplies."