Study of a Discontinuous Fed-Batch Fermentor for the Exploitation of Agricultural Biomasses to Produce II- Generation Biodiesel

Abstract

A discontinuous fed-batch fermenter was used to grow the oleaginous yeast Lipomyces starkey in the presence of hydrolysates of lignocellulosic wastes from Arundo donax (AD). The lignocellulosic materials were first steam-exploded and subsequently treated with commercial preparations of cellulases and ß- glucosidases, to obtain a mixture of fermentable sugar. The discontinuous fed-batch fermenter was adopted to maintain a lower concentration of the nitrogen sources, and consequently an higher C/N ratio, thus promoting the accumulation of triglycerides within the yeasts’ cells. Its use increased significantly the final concentration of biomass in comparison to that observed when using a batch fermenter. The composition of the biodiesel produced was compatible with a satisfactory performance as automotive fuel, in terms of both the resistance to oxidation and the cold performance.