Biomass and microbial lipids production by Yarrowia lipolytica W29 from eucalyptus bark hydrolysate

Abstract

Using lignocellulosic biomass hydrolysate as a renewable and abundant feedstock for microbial lipids production is a sustainable and economic high-potential approach. This study investigated the potential of the oleaginous yeast Yarrowia lipolytica to produce lipids-rich biomass from eucalyptus bark hydrolysate (EBH) obtained by enzymatic hydrolysis of the biomass pretreated by steam explosion. The effect of EBH concentration (undiluted and 1:3 v/v diluted) and medium supplementation (CSL and KH2PO4) was evaluated in Erlenmeyer flasks and lab-scale stirred tank bioreactor, respectively. Additionally, the effect of volumetric oxygen transfer coefficient (kLa) and mode of operation (batch and two-stage repeated batch) was also assessed in the bioreactor. Under the best experimental conditions (undiluted EBH, 2 g⋅L−1 CSL, 1.8 g⋅L−1 (NH4)2SO4, and kLa of 66 h−1), Y. lipolytica W29 grown in batch cultures accumulated 26 % (w/w) of intracellular lipids, corresponding to 5.6 g⋅L−1 of concentration. Lipids of Y. lipolytica were highly unsaturated and mainly composed of oleic acid (48 %), followed by palmitoleic (20 %), linoleic (17 %) and palmitic acids (14 %). This composition of Y. lipolytica lipids suggests their potential use as feedstock for biodiesel (a renewable biofuel). This work demonstrated the robust features of Y. lipolytica W29 as a potential lipids production platform to implement lignocellulose-based biorefineries.