Tailored production of citric acid and mannitol by Yarrowia lipolytica from corn stover pretreated by glycerol-assisted instant catapult steam explosion

Abstract

Yarrowia lipolytica CGMCC 2.1506 was studied for tailored production of citric acid and mannitol by co-utilization of glucose and glycerol as carbon sources. Firstly, optimal cultivation conditions for producing the two products were determined using synthetic (SYN) media. The determined conditions were further applied and verified by Y. lipolytica cultivated with corn stover enzymatic hydrolysate (CSH) media derived from glycerol-assisted instant catapult steam explosion (ICSE) without detoxification, glycerol removal or nutrient addition. A high citric acid concentration of 63.8 ± 2.6 g/L was achieved from CSH media containing 50.0 ± 0.8 g/L glucose and 46.3 ± 2.3 g/L glycerol, in a 5 L bioreactor at pH 5.5. In contrast, a high mannitol concentration of 37.1 ± 1.5 g/L was obtained from a similar hydrolysate at pH 3.5. This study demonstrated that the integrated process based on glycerol-assisted ICSE pretreatment and tailored production of two important building block chemicals by Y. lipolytica is promising for biorefining of lignocellulosic biomass.