The integrated production of microbial lipids and bio-SiO2 from rice husks by an organic electrolytes pretreatment technology

In this study, a full dissolution behavior of rice husks (RHs) in ionic liquids-based organic electrolytes was achieved, and physicochemical effect of the dissolution pretreatment on the structures of RHs was elucidated. The physicochemical changes led to an enhanced subsequent enzymatic saccharification of RHs, and a total reducing sugars (TRSs) yield of 0.70 g g−1, and a glucose yield of 0.43 g g−1 were obtained. The hydrolysates could be used as carbon sources for the cultivation of Rhodosporidium toruloides Y4 for the production of microbial lipids with a satisfactory productivity of cell biomass (13.3 g L−1) and lipid content (32.5%) after 100 h cultivation. Further pyrolysis of the residuals after the enzymatic hydrolysis at 600 °C for 3 h resulted in new uniform, spherical silica powder materials with particle size around 150 nm, and surface area of 179.3 m2 g−1.