文摘
The main product obtained in the industrial cultivation of green microalgae Dunaliella salina is natural β-carotene. After the extraction of the valuable pigment an algae residue remains. This remnant was hydrolyzed under mild liquefaction conditions at 453 K for 1 h in various ethanol/water ratios. A heterogeneous acidic catalyst, Nafion NR50, was used in one experiment for comparison. The main compounds comprising the soluble fraction were identified. Methyl isobutyl ketone (MIBK) was used as extraction solvent to obtain 5-hydroxymethylfurfural (5-HMF) as a product. The 5-HMF solubility in the ternary ethanol/water/MIBK mixtures along the binodal curve was predicted by the quantum chemical method COSMO-RS. The partition of the 5-HMF in the MIBK rich extract and the aqueous phase was estimated based on the prediction. Theoretically, 96.2% of 5-HMF can be recovered in the MIBK rich extract in liquefaction conditions with an ethanol/water ratio of 50/50 (v/v). Experimentally, 10.3 mg of 5-HMF per gram of the remnant (dw) was recovered in the organic MIBK phase.