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Protein factors increasing yield of a biofuel precursor in microscopic algae

Tokyo Institute of Technology

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IMAGE: Microalgae are a promising source of biofuel feedstock, as they produce triacylglycerol (TAG) as a major storage lipid, especially under nutrient-depleted conditions. LRL1 was involved in the regulatory mechanism during... view more 

Credit: Tokyo Tech

As an alternative to traditional fossil fuels, biofuels represent a more environmentally friendly and sustainable fuel source. Plant or animal fats can be converted to biofuels through a process called transesterification. In particular, the storage molecule triacylglycerol (TAG), found in microscopic algae, is one of the most promising sources of fat for biofuel production, as microalgae are small, easy to grow, and reproduce quickly. Therefore, increasing the yield of TAG from microalgae could improve biofuel production processes. With this ultimate goal in mind, Professor Hiroyuki Ohta from the Tokyo Institute of Technology and colleagues investigated the conditions under which the model microalga Chlamydomonas reinhardtii produces more TAG.

It is known that microalgae produce greater amounts of TAG when grown in environments with few nutrients. However, according to Dr. Ohta, "While low-nitrogen environments cause microalgae to produce more TAG, this strongly reduces microalgal growth and reproduction, decreasing potential gains in TAG yield." In an attempt to find conditions under which C. reinhardtii both produces more TAG and grows well, the team of researchers gave the microalga sufficient nitrogen but limited the amount of phosphorus in the environment. Under these conditions, TAG production was increased and cell growth was still promoted, increasing the overall yield of TAG.

In this experiment, the scientists used co-expression analysis to identify a C. reinhardtii protein, which they name Lipid Remodeling reguLator 1 (LRL1), that is involved in TAG production in phosphorus-limited environments. Functional analyses, in which the LRL1 gene was disrupted, revealed additional genes involved in TAG accumulation and C. reinhardtii growth under phosphorus depletion. Together, the results shed light on the underlying biochemical pathways involved in this process. A better understanding of these pathways has the potential to improve TAG--and therefore biofuel--production processes. Notes Dr. Ohta, "The discovery of proteins involved in TAG production under nutrient-depleted conditions could one day lead to methods to increase TAG yield, ultimately making biofuel production more efficient and cost-effective." This could in turn help reduce our reliance on fossil fuels and promote the widespread use of biofuels derived from microalgae.

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About Tokyo Institute of Technology

Tokyo Institute of Technology stands at the forefront of research and higher education as the leading university for science and technology in Japan. Tokyo Tech researchers excel in a variety of fields, such as material science, biology, computer science and physics. Founded in 1881, Tokyo Tech has grown to host 10,000 undergraduate and graduate students who become principled leaders of their fields and some of the most sought-after scientists and engineers at top companies. Embodying the Japanese philosophy of "monotsukuri," meaning technical ingenuity and innovation, the Tokyo Tech community strives to make significant contributions to society through high-impact research. Website: http://www.titech.ac.jp/english/

About Kyoto University

Kyoto University is one of Japan and Asia's premier research institutions, founded in 1897 and responsible for producing numerous Nobel laureates and winners of other prestigious international prizes. A broad curriculum across the arts and sciences at both undergraduate and graduate levels is complemented by numerous research centers, as well as facilities and offices around Japan and the world.

For more information please see: http://www.kyoto-u.ac.jp/en

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