Production of Single-Cell Oils from Lignocellulosic Biomass from Arundo Donax L.

Abstract

Single-cell oils (SCOs) raise a growing interest due to their potential for the production of biofuels, bioplastics and more recently of food additives. The production of SCOs by exploitation of residual lignocellulosic biomass has become a realistic target, due to the recent advances in enzyme hydrolysis technology. The fermentation of yeasts offers a useful alternative to microalgae, due to their ability to use several agroforestry wastes as feedstock and their simple cultural requirements. In addition, the microbial oils obtained from yeasts have a composition quite similar to that of vegetable oils. This study is focused on the exploitation of Giant reed (Arundo donax), a widely diffused perennial crop, well known for its capability to grow in marginal lands ensuring high biomass productivity. Different types of biomass, from crops cultivated under different agronomic management were tested. The effect of two types of treated sewage sludges as organic matter sources and inorganic nitrogen fertigation was evaluated to increase soil fertility. These practices were tested in order to improve crop composition and productivity. The hydrolysates from A. donax biomass have been evaluated as a growth medium for oleaginous yeasts, for the production of microbial oils. The production kinetics and the yields in microbial oils have been analyzed taking into account the composition of the different biomasses used, in order to contribute to a complete optimization of the productive cycle. In general, the treatment acid hydrolysis with HCl followed by enzymatic hydrolysis led to the best results in order to obtain glucose production for the development of biofuels.