Researchers found a way to greatly enhance biofuel production in algae in hopes of helping the world move away from fossil fuels.
Scientists are scrambling to loosen fossil fuel dependence because the carbon dioxide emissions it creates are drastically harming the environment, a Scripps Institution of Oceanography news release reported.
The issue of lipid oil ("fat molecules that store energy that can be produced for fuel") production has been a huge roadblock in terms of achieving efficient algal biofuel. Algae tend to only create these lipids when they are deprived of nutrients; but depriving the marine plants of sustenance keeps them from growing.
"When we first began investigating ways to increase microalgal lipids through engineering, we noticed two things about the majority of techniques that had been attempted. The first was that most of the previous methods focused on either lipid biosynthesis or carbohydrate biosynthesis," first author of the study and Scripps graduate student Emily Trentacoste told Headlines and Global News. " The second was that the majority of these methods, even if they did increase lipids, simultaneously decreased growth, which is unfavorable for biofuel production systems. The downstream pathway of lipid breakdown, conversely, was being ignored as a potential engineering target. We decided to focus on this pathway and hypothesized that disrupting lipid breakdown could increase lipid accumulation without affecting growth."
Trentacoste and her researcher team looked at genetic expression ( "transcriptomics") and pinpointed enzymes in the tiny algae known as "diatoms." The researchers metabolically engineered a mechanisms to "knock down" fat-depleting enzymes called lipases. This system allowed the researchers to increase lipid production in the algae without depriving them of nutrients.
"These results demonstrate that targeted metabolic manipulations can be used to increase accumulation of fuel-relevant molecules.... with no negative effects on growth," Trentacoste said in the news release. "We have shown that engineering this pathway is a unique and practical approach for increasing lipid yields."
The researchers are now working to produce strains of the algae that can be grown in natural envirnonemnts.
"Lipid metabolism is still poorly understood in microalgae. We are currently using the strains developed in this study to do in-depth metabolomic analyses, which will give us a better understanding of how our manipulations are affecting the cell and its metabolic pathways, thus helping to elucidate more of the pathway of lipid metabolism. We are also using the results seen in this study to generate strains that can be grown in outdoor pond production systems," Trentacoste told HNGN.
The team has high hopes for the future of algal biofuel, and their research.
"Scientifically this is a huge achievement," Mark Hildebrand, a marine biology professor at Scripps and a coauthor of the study, said in the news release. "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."
