Engineered Yeasts Gain Ability to Pump Out Alkanes

In Singapore, researchers from Nanyang Technological University have introduced molecular pumps into genetically engineered yeast Saccharomyces cerevisiae that allowed it to extrude the alkane that it produced. This mechanism called efflux pump system could alleviate the problem of alkane toxicity in yeast which limits the productivity of yeast-based alkane production system.

Akane is a hydrocarbon component of gasoline fuels that can be biologically produced in microbial hosts like S. cerevisiae but it is known to be toxic to S. cerevisiae. The efflux pump mechanism consisting of two alkane-transporting molecules designated as ABC2 and ABC3 was introduced into S. cerevisiae from a non-conventional species of yeast that can utilize alkanes as carbon source. The engineered yeast cells that expressed and localized ABC2 and ABC3 on their plasma membrane were shown to maintain lower intracellular concentration of alkane chains having 10 carbons (decane) and 11 carbons (undecane). The improved yeast version exhibited over 80-fold increase in the tolerance limit against decane.

The ability to pump out the target alkane products from the cell will not only protect the cell but also increase the final biofuel productivity. Published in the journal Biotechnology for Biofuels, this work was acknowledged by the authors as the first proof of concept for using transport engineering to enhance alkane-producing microbes which will be useful in the production and recovery of next-generation biofuels.