Microwave-assisted transesterification of lignocellulose-derived yeast oils for biofuel application

Purpose and goal

The project addressed the main limitations of microbial oils-based biodiesel, particularly in carbon source cost, yeast productivity, and lipid extraction efficiency. Utilization of low value non-food substrates for lipid production was achieved by improving yeast strains robustness and lipid accumulation in wheat straw hydrolysates. Process conditions optimization allowed for improved yeast lipid content and lipid titre. Microwave-based extraction and transesterification methods were assessed for application in lignocellulosic fermentation conditions.

Expected results and effects

The project main results include a collection of yeast strains with improved biomass production and lipid accumulation (over 20% dry weight) in the presence of lignocellulosic hydrolysates inhibitors. Additionally, optimization of the process conditions led to a significant increase in the lipid content. Applying genetic tools can further improve these strains, namely utilization of additional carbon sources and enhanced lipid accumulation. These results contribute to a cost competitive microbial biodiesel produced from low value raw materials relevant in Sweden.

Planned approach and implementation

This project was divided into three work packages to address the research goals (WP1-3), and one WP dedicated to the results dissemination and exploitation. Yeast strains developed in WP1 showed improved performance in lignocellulosic hydrolysates, and optimization of the process conditions for such yeast led to high lipid accumulation (WP2). Microwave-based methods showed potential for biodiesel applications, but funding-associated reasons did not allow the in-depth analysis of this technology (WP3). The work developed was presented in several international conferences.