Innovative approach for co-production of single cell oil (SCO), novel carbon-based solid acid catalyst and SCO-based biodiesel from fallen Dipterocarpus alatus leaves

Abstract

A new approach for the co-production of SCO, carbon-based solid catalyst and SCO-FAME using Dipterocarpus alatus leaves (DL) was successfully demonstrated. Undetoxified DL hydrolysate (DLH) was converted into SCO by Rhodotorula mucilaginosa KKUSY14, resulting in SCO of 3.11 g/L with SCO yield reaching 0.19 g/g sugar and 24.9 g SCO/kilogram DL. DLS-SO3H and DLHW-SO3H catalysts were effectively prepared from DL solid residue and cell-free fermented DLH waste (DLHW) through direct sulfonation. The catalysts successfully catalyzed the direct transesterification of SCO-rich wet yeast with SCO-FAME yield >87% under optimal condition. The catalysts can be reused up to three cycles with SCO-FAME yield >80%. SCO-FAME yield of >83% was achieved with regenerated catalyst. The SCO-FAME profile consisted of high MUFA and low PUFA contents that improved cetane number, cold flow properties and oxidative stability. The estimated fuel properties of SCO-FAME based on FAME profiles were found to be in accordance with international biodiesel standards. This approach is a promising innovative strategy that could lead towards a green and economical process for biodiesel production. Furthermore, DLHW represents a new carbon material for novel solid acid catalyst preparation.