Biomass and microbial lipids production by Yarrowia lipolytica W29 from eucalyptus bark hydrolysate
Bruna Dias, Marlene Lopes, Helena Fernandes, Susana Marques, Francisco Gı́rio, Isabel Belo
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.