A biotech boost to biofuels

Stabilising bacterial membranes with tailored chemicals. Credit: Second Bay Studios, USA.

Compared to bioethanol, biobutanol is a more promising alternative to fossil fuels due to its better energy density, low vapour pressure and lower tendency to absorb water from the air.

However, fermentative production of butanol by microorganisms such as Escherichia coli remains limited due to the microbes’ poor tolerance to butanol. Increasing the concentration of butanol produced by the cells compromises the integrity of the microbes’ membranes, resulting in filamentous growth (cell lengthening) and the release of lipopolysaccharides.

To mitigate butanol’s adverse effects on E. coli, researchers at the Singapore Centre for Environmental Life Sciences Engineering on NTU’s campus, led by Visiting Prof Guillermo Bazan and Dr Jamie Hinks, developed a compound that can help stabilise the bacteria’s membranes.

Called S6, the compound is made up of six hydrophobic benzene rings surrounded by six hydrophobic side chains. S6 is able to spontaneously intercalate into and stabilise the bacteria’s membranes, doubling the concentration of butanol tolerated by the cells.

The researchers hope that by improving the properties of microorganisms with materials like S6, microbial production of biofuels may provide a sustainable and economical alternative to fossil fuels.

The research “A chain-elongated oligophenylenevinylene electrolyte increases microbial membrane stability” was published in Advanced Materials (2019), DOI: 10.1002/ adma.201808021.

The article appeared first in NTU’s research & innovation magazine Pushing Frontiers (issue #16, February 2020).