Future microorganisms for sustainable production

More robust microorganisms can play an important role in future production of fuels and chemicals. But changing nature’s design can be problematic. Lina Lindahl will soon defend her thesis in this research field.
​Our society is in great need of greener, alternative ways to produce fuels, materials and chemicals. One way of doing this is to replace fossil raw materials with biomass from forest and agriculture. Microorganisms can then be used to produce the desired compounds from the biomass.

But this environmentally friendly production needs to be made more efficient. Therefore, researchers are now trying to developing more robust microorganisms that can retain a high productivity also under unfavorable conditions.

Lina Lindahl has attempted to change the protective coat of the microorganisms, its cell membrane, to make it more resilient.
– I have investigated how the lipid composition in membranes can be changed to reduce the diffusion of acetic acid, which is one of several substances that prevent efficient production, she says.

In her research, Lina Lindahl, has compared the lipid composition of the yeast Saccharomyces cerevisiae, which has already proved useful for industrial production, with another yeast with the capability to handle acetic acid significantly better.
– By comparing the two yeasts, I could identify a group of lipids called sphingolipids, and then show that their presence decreases the acetic acid diffusion rate across the cell membrane.

Next, she tried to increase Saccharomyces cerevisiae’s production of sphingolipids using genetic engineering, thus increasing the yeast’s resistance to acetic acid. But this turned out to be difficult.
– Lipid production in yeast is very strictly regulated. Attempts at the genome level were not enough – but it should be possible, Lina Lindahl says.
– Changing the lipid composition of the cell membrane to create more robust microorganisms is a new research field, with few successful experiments. We did not really know how difficult it would be to get results, but we realized that solutions evolved in nature creations is not always easy to imitate. My dissertation presents methodology and new thinking in this research field.

On June 2, Lina Lindahl defends her thesis entitled “Towards membrane engineering as a tool in cell factory design: A case study on acetic acid tolerance in Saccharomyces cerevisiae”.
– It's great to do research, and it would be nice to stay at Chalmers. But it’s also tough with long experiments in the lab, especially if you have a family. I do not know where I will continue my career – I keep my options open!

Text: Mia Malmstedt
Photo: Martina Butorac

Published: Tue 30 May 2017.