Sunday, August 22, 2010

Looking for Algal Oil... with Near Infrared Light.

A new method has been introduced for telling which strains of algae are likely to be any good for turning into biofuels based on Near Infrared (NIR) spectroscopy. The near infrared spectrum runs the range of wavelengths 800 - 2500 nm, and is therefore just below the region of visible light but above the usual mid-infrared, at 2,500 - 30,000 nm. The discovery of infrared radiation is attributed to the British/German Astronomer Herschel, who also wrote 24 symphonies. However, NIR only came to practical use in the 1950s as an analytical device. NIR is less sensitive than normal (mid) IR but can penetrate samples more easily meaning they need less analytical preparation and in the case of algae can be examined in their raw state.

Algae very considerably in their composition, and while some varieties contain around 50% of their weight of oil, others hold as little as 5%. Not only this, but the "oil" should contain a high level of fatty acids to be converted into biodiesel: triglycerides rather than phospholipids.

The NIR method is highly specific for the detection of different kinds of fatty acids and it is intended to develop a database of fingerprints for different fatty acid components in algal biomass, with which to analyse actual algae. The method offers the promise of a rapid and precise screening of algae directly rather than the existing time-consuming, cumbersome and error-prone means for analysing algae, and may prove pivotal in the development of a putative fuel industry based on algae.

Related reading.
"Striking algal oil," Chemistry World, By Anna Lewcock.
"Oil from algae; salvation from peak oil," C.J.Rhodes, Science progress, 2010, Vol. 92, 39-90.

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