AN INTEGRATED AND VERSATILE BIOREFINERY MODEL TO PRODUCE LIPIDS FROM SECOND GENERATION BIOMASS

In order to replace fossil fuels and products with biofuels and bioproducts, and, at the same time, to avoid the competition food versus fuel related to renewable resources, innovative processes aimed to valorize lignocellulosic biomass and agro-food waste as raw material are highly attractive. Arundo donax L. or giant reed was defined as a promising lignocellulosic crop in the biorefinery field. The present study focused on investigating innovative, tailored and integrated strategies to firstly produce glucose and xylose from A. donax, by using green catalysts and microwaves as heating system, and then on fermenting them into fatty acid methyl esters (FAMEs) by oleaginous yeasts Lypomyces starkeyi and Cryptococcus curvatus. Moreover, glycerol deriving from FAMEs production was recycle as a fermentative substrate according to a zero waste biorefinery scheme. The quantitative conversion of hemicellulose into xylose was performed by optimizing both homogeneous and heterogeneous catalysis. The cellulose remained in the solid residue recovered at the end of the first step was then hydrolyzed by testing dilute H2SO4 or the enzymatic mixture Ctec2, obtaining an overall yield of about 40-50% g glucose/ g glucan for both approaches.