NASA looks at plant biomass as new source of biofuel in space

NASA research scientist Chad Paavola has a problem to solve: When astronauts leave the earth for long periods of time, they’re going to need to produce plants for food and the air they breathe.

Some of the crops will be edible and some won’t, such as the leaves and stems of the plants. But what happens to the inedible biomass while they are in orbit?

Paavola told the Cleantech Group today that he and a team of scientists at Moffett Field, Calif.-based NASA Ames Research Center are researching a way to transform those inedible parts into useful resources such as biofuels, chemicals and even recovering some of it for food.

Using bionanotechnology, the research team is assembling enzyme structures with multiple functions, modeled after a natural enzyme complex that breaks down inedible plant material into usable sugars.

“The goal is to understand how multiple enzymes work together to break down cellulose,” he said, explaining that cellulose is an attractive raw material for producing sugar because it’s abundant (see From corn to cellulose and beyond).

He said the idea is that they could then create tailored mixtures of enzymes to break down different feedstocks for biofuels and food, in a potentially cost efficient way.

It’s not easy to access the sugar in cellulose because it is arranged in structures called polymers that are difficult to break down. In nature, enzyme complexes, called cellulosomes, are some of the most effective ways to convert cellulose into usable sugars.

Paavola that to better understand how cellulosomes work and to mimic their function, the scientists built enzyme complexes modeled after natural cellulosomes.

The most enzymes on a single complex had been four. But Paavola said the scaffold they created is double sided and more efficient, allowing for nine enzymes on each side, for a total of 18.

Paavola said the team’s cellulosome research, being funded through an undisclosed amount of discretionary funds from NASA Ames Research Center, is far from over.

“We need to understand the basic interaction of the enzymes before we can understand the potential of the process,” he said.

Next, he said the team plans to expand the process to breakdown real biomass.

Although, Paavola didn’t have a timeframe for how long that could take, he said the patented process has applications beyond space in the commercial sector. The technology could eventually reach NASA’s technology transfer division where it would be licensed to industrial entities that would take the concept to market.

He cited biofuel companies such as Novozymes and Genencor that might be interested in the technology, as well as chemical companies or ag-commodities companies such as Archer Daniels Midland (see Another cellulosic powerhouse formed and Novozymes says government cellulosic support critical).

“Once we have developed something that is an improvement over existing technology, we’re agnostic as to who takes the ball and runs with it,” he said.

The NASA research team, which includes Suzanne Chan, Hiromi Kagawa, Yifen Li, Shigenobu Mitsuzawu, Paavola and Jonathan Trent, published a report last month on their findings called "The Rosettazyme: A Synthetic Cellulosome."

Trent is also known for a unique way of making biofuel from algae offshore, in a Google-backed experiment that cleans waste water while removing carbon dioxide from the air (see NASA’s got a new way to get biofuel from algae).

Other companies are already exploring the potential of biofuels from cellulose. In 2007, Chevron and the Texas A&M Agriculture and Engineering BioEnergy Alliance said they entered into a strategic research agreement to accelerate the production and conversion of crops for manufacturing ethanol and other biofuels from cellulose (see Chevron pumps more money into university biofuel research).