Singapore-led research team develops greener techniques for biodiesel production

In Singapore, a team of National University of Singapore researchers from the Department of Chemical and Biomolecular Engineering has developed a set of environment-friendly techniques to produce biodiesel entirely from waste grease more cheaply and efficiently.

Traditionally, the high free fatty acid content in waste grease makes it unsuitable for biodiesel production due to technical issues. Current catalysts could not process the waste grease in a single step until the NUS team’s recent discovery, which had been published in leading journals such as Bioresource Technology and Green Chemistry.

The NUS team led by Associate Professor Li Zhi pioneered an innovative one-step approach with specially engineered high-performance catalysts. Besides achieving impressive biodiesel conversion yields under optimal conditions, they can be easily separated from the biodiesel mixture at the end of the transformation process for multiple reuse with little deterioration in performance.

One method employs whole-cell Escherichia coli (E. coli) bacteria, producing a 97 per cent biodiesel conversion yield in 72 hours.

Another involves specially formulated magnetic nano-sized solid acid particles. When combined with methanol, they efficiently catalyse waste grease, yielding up to 98 per cent biodiesel in 24 hours.

The third is a recyclable magnetic nano-biocatalyst created using an enzyme derived from a fungus. This catalyses waste grease laden with methanol into biodiesel, achieving a remarkable 99 per cent biodiesel yield in 12 hours.

Among the three techniques, the natural system of whole-cell E.coli shows the most potential as the biocatalyst can be produced in l http://news.nus.edu.sg/highlights/8855-biodiesel-from-waste-grease arge amounts at low costs.