Microbial lipids have the potential to substantially reduce the use of liquid fossil fuels, though one obstacle is the energy costs associated with the extraction and subsequent conversion into a biofuel. Here we report a one-step method to produce fatty acid methyl esters (FAME) from Rhodotorula glutinis by combining lipid extraction in a microwave reactor with acid-catalysed transesterification. The microwave did not alter the FAME profile and over 99% of the lipid was esterified when using 25 wt% H2SO4 over 20 minutes at 120 °C. On using higher loadings of catalyst, similar yields were achieved over 30 seconds. Equivalent amounts of FAME were recovered in 30 seconds using this method as with a 4 hour Soxhlet extraction, run with the same solvent system. When water was present at less than a 1:1 ratio with methanol, the main product was FAME, above this the major products were FFA. Under the best conditions, the energy required for the microwave was less than 20% of the energy content of the biodiesel produced. Increasing the temperature did not change the energy return on investment (EROI) substantially; however, longer reaction times used an equivalent amount of energy to the total energy content of the biodiesel.
- Department of Chemical Engineering - Professor
- Reaction and Catalysis Engineering research unit (RaCE)
- Centre for Sustainable and Circular Technologies (CSCT)
- Water Innovation and Research Centre (WIRC)
- Centre for Integrated Bioprocessing Research (CIBR)
Person: Research & Teaching