Harvesting biofuel from solar panels

Illuminated diatoms under the microscope Copyright: Flickr/nebarnix

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Genetically-altered algae housed within ‘biological solar panels’ could be the future of biofuel production — but critics say it is early days yet.

Diatoms are a type of algae, typically found coating stones in rivers and lakes. They contain oil droplets within their cells that could be used as biofuel, say scientists at the Indian Institute of Science (IISc). One hectare of diatom cultivation could produce 10–200 times the oil produced by equivalent soybean cultivation, says T. V. Ramachandra, a professor of ecological sciences at IISc.

Normally diatom oil is used as a reserve nutrient, like fat in humans, and there is no mechanism to secrete it. However, diatom cells secrete silica outside the cell walls. If they could be made to secrete oil in a similar way, say the researchers, it could be harvested easily.

The researchers propose manipulating the diatoms’ genes to enhance oil production. The algae could then be suspended in a nutrient-rich solution within a solar panel, which would secrete oil when exposed to sunlight.

It may be possible "to milk diatoms for oil just as we milk cows", says Ramachandra.

The study, published in Industrial & Engineering Chemistry Research, has gained positive attention but experts warn it is too early to tell whether the idea is feasible — and production costs will have to be considered.

Ramachandra insists the diatom solar panel will be easy and inexpensive to produce, and will be especially useful in tropical countries like India with an abundance of sunlight.

He also points out that diatoms are plentiful, with 2,500 species in India alone, and says their oil does not need processing to be used as biofuel, which will keep down production costs.

Link to full article in Scientific American