Monday, November 25, 2013

Concerning Scripps work on lipids in algae

From Research Unlocks Algae Biofuel Potential

The research when patented and commercially available has the potential to move algae to the forefront of the most promising feedstocks for future biofuel production. Algae’s advantages include their widespread availability, higher oil yields and that they reduce the pressure on cultivated land for production of biodiesel. Thus, algae will be the future of fuel.

Of a change in world view:

When well-nourished, the algae do grow well, but produce carbohydrates instead of the desired lipids for conversion to fuel.


By metabolically engineering a lessening of the fat-reducing lipases enzymes, the researchers were able to increase lipids without compromising growth.


Hildebrand said that the accomplishment was significant, commenting, "Scientifically this is a huge achievement. Five years ago people said you would never be able to get more lipids without affecting growth negatively'. This paper shows that there isn't an intrinsic barrier and gives us hope of more new things that we can try - it opens the door to a lot more work to be done.' '

See also Scripps oceanography researchers engineer breakthrough for biofuel production including text

As reported in this week's online edition of the Proceedings of the National Academy of Sciences, Scripps graduate student Emily Trentacoste led the development of a method to genetically engineer a key growth component in biofuel production. (...)

By metabolically engineering a "knock-down" of fat-reducing enzymes called lipases, the researchers were able to increase lipids without compromising growth. The genetically altered strains they developed, the researchers say, could be produced broadly in other species.

"These results demonstrate that targeted metabolic manipulations can be used to increase accumulation of fuel-relevant molecules.… with no negative effects on growth," said Trentacoste. "We have shown that engineering this pathway is a unique and practical approach for increasing lipid yields."

Note however text from US Patent No 8,592,188 (Solazyme) :

The present invention also provides for the use of an inducible promoter to express a gene of interest. In particular, the use of an inducible promoter to express a lipase gene permits production of the lipase after growth of the microorganism when conditions have been adjusted, if necessary, to enhance transesterification, for example, after disruption of the cells, reduction of the water content of the reaction mixture, and/or addition sufficient alcohol to drive conversion of TAGs to fatty acid esters.

Inducible promoters useful in the invention include those that mediate transcription of an operably linked gene in response to a stimulus, such as an exogenously provided small molecule (e.g, glucose, as in SEQ ID NO:1), temperature (heat or cold), light, etc. Suitable promoters can activate transcription of an essentially silent gene or upregulate, preferably substantially, transcription of an operably linked gene that is transcribed at a low level. In the latter case, the level of transcription of the lipase preferably does not significantly interfere with the growth of the microorganism in which it is expressed.


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