Abstract
Background: Lipids produced from filamentous fungi show great promise for biofuel production, but a major
limiting factor is the high production cost attributed to feedstock. Lignocellulosic biomass is a suitable feedstock for
biofuel production due to its abundance and low value. However, very limited study has been performed on lipid
production by culturing oleaginous fungi with lignocellulosic materials. Thus, identification of filamentous fungal
strains capable of utilizing lignocellulosic hydrolysates for lipid accumulation is critical to improve the process and
reduce the production cost.
Results: The growth performances of eleven filamentous fungi were investigated when cultured on glucose and
xylose. Their dry cell weights, lipid contents and fatty acid profiles were determined. Six fungal strains with high
lipid contents were selected to culture with the hydrolysate from dilute sulfuric acid pretreatment of wheat straw.
The results showed that all the selected fungal strains were able to grow on both detoxified liquid hydrolysate
(DLH) and non-detoxified liquid hydrolysate (NDLH). The highest lipid content of 39.4% was obtained by Mortierella
isabellina on NDLH. In addition, NDLH with some precipitate could help M. isabellina form pellets with an average
diameter of 0.11 mm.
Conclusion: This study demonstrated the possibility of fungal lipid production from lignocellulosic biomass. M.
isabellina was the best lipid producer grown on lignocellulosic hydrolysates among the tested filamentous fungi,
because it could not only accumulate oils with a high content by directly utilizing NDLH to simplify the
fermentation process, but also form proper pellets to benefit the downstream harvesting. Considering the yield and
cost, fungal lipids from lignocellulosic biomass are promising alternative sources for biodiesel production.
Keywords: Filamentous fungi, Mortierella isabellina, Microbial lipid, Biodiesel, Lignocellulosic biomass, Wheat straw