Dec 19, 2008

X-Algae: Mutant algae for biofuel production?

Chlorophyll A structure showing the central magnesium atom in green, nitrogen in blue, oxygen in red, carbon in black and hydrogen in white. Image credits: Wikipedia

Researchers have found that genetic truncation of the size of chlorophyll arrays in algae leads to higher photosynthetic algal yields, by increasing light absorption/mass of algae. This article is available online. M. Mitra and A. Melis, "Optical properties of microalgae for enhanced biofuels production," Opt. Express 16, 21807-21820 (2008).

"Abstract: Research seeks to alter the optical characteristics of microalgae in order to improve solar-to-biofuels energy conversion efficiency in mass culture under bright sunlight conditions. This objective is achieved by genetically truncating the size of the light-harvesting chlorophyll arrays that serve to absorb sunlight in the photosynthetic apparatus."
Nature optimizes each algae to maximize its light absorption to survive in the wild. However, the large size of these light-absorbing chlorophyll arrays leads to sub-optimal light utilization when growing algae for biofuel production, because light has to be distributed as far as possible in the growth medium to ensure optimal light utilization and increased yields per unit time per unit area. When grown in the mass culture, the mutant algae evolved oxygen at a 2 to 3-fold higher rate compared to the wild-unmodified algae, indicating potential algal biofuel yield increases of 100% to 200%.

Implications for algal biofuel production:
Previous posts (yields, CO2 capture, economics) on this blog have focused on various aspects of algal biofuel production. Because algal yields significantly influence the economics, increasing the light absorption per unit volume in the algal growth medium would lead to accelerated commercialization.


Anonymous said...

This genetic modification is going to be the end of us all. One day some mutant plants will all turn into Venus fly traps, only they will turn into Venus-human-traps and will eat humans/cars and anything. Stop GMO already!

Pradeep said...

Every technology comes with inherent risks and potential opportunities. The key is to manage these risks vs. potential gains.

My 2¢:

1. The fuel itself, is not likely to be consumed by humans/animals (diesel/ethanol). Therefore, what we have to focus on is the algae cake. There has been some talk about using this algae cake as fish feed.

2. As I mentioned in my writeup, Nature optimizes the algae such that each alga has high number of chlorophyll units. On the other hand, in the case of cross-contamination of algal cultures, the genetically modified algae with truncated ChlA units will likely not survive in the wild.

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