Novel bio-based solid acid catalyst derived from waste yeast residue for biodiesel production

Abstract

Single cell oils or microbial lipids produced by oleaginous microorganisms are being utilized for various applications such as nutrition, fuels and valuable chemicals. However, after the extraction of value added products from microbial cells, the residue is generally burned or discarded. In the present study, synthesis of a novel bio-based solid acid catalyst from waste yeast residue has been carried out through sulfonation for biodiesel production. The obtained yeast residue based solid acid (YSA) catalyst showed higher fatty acid methyl ester (FAME) yield of 96.2 wt % for waste cooking oil at 60 °C and 94.8 wt % for yeast oil at 70 °C with 4 wt % catalyst concentration and 10:1 methanol to oil molar ratio. The FAME profile indicated the presence of elevated monounsaturated fatty acid content with improved oxidative stability and cold flow properties. The catalyst revealed high catalytic activity, high thermal stability and can be regenerated with its activity maintained up to four cycles. Furthermore, the biodiesel properties were abided with the international fuel standards.