Chloroplast could provide new ways to produce biofuels

Researchers from Michigan State University are experimenting with harvesting seed oil in the hope of developing a biofuel that could one day power jets and cars.

In a recently published study detailing their work, the scientists demonstrate how chloroplast, where photosynthesis occurs, participates in new ways to provide seed oil precursors.

More commonly known as vegetable oil, seed oil is comprised of lipids, small molecules found in fats, oils, waxes and membranes that make up the boundaries of all living cell components. These lipids store significant amounts of energy.

The team from the University of Michigan has identified a new enzyme, named PLIP1, or Plastid Lipade 1, which interacts with lipids inside the chloroplast.

"The enzyme breaks down lipids that make up the chloroplast's internal membranes, the thylakoids, to be precise. The use and recycling of lipids keeps chloroplast membranes adjusted to developmental or environmental changes," said Kun Wang, a graduate student in the department of biochemistry and molecular biology and researcher at the MSU-DOE Plant Research Laboratory.

Leftover lipid products are then transported to the endoplasmic reticulum, a cellular factory, where they become building blocks for seed oil. Prior to the new research, it was thought that seed oil production was largely based on endoplasmic reticulum.

“Now, we are finding that the chloroplast is responsible for 10% of seed oil precursors. That might seem like a low number. However, seed oil comes from many sources, and the main one is responsible for 20 to 40 percent of final product. So, 10 percent is significant,” Wang said.

 

Industry application

According to the statement from MSU, Wang now wants to increase the level of PLIP1 in biofuel targeted plants, so they produce more seed oil.

“One advantage with PLIP1 is that it is found in most land plants, which makes it easy to experiment on different species,” Wang said.

Early test have led to unexpected results, smaller plants with more oil per seed, but fewer seeds and a higher defence activity.

“It seems oil production and plant defense functions don’t coexist well. We have a few ideas to bypass this limitation, and we’ve already filled out a patent application to try a new strategy to increase seed oil yield, using PLIP1,” Wang said.