Ricardo M. Couto

Supercritical fluid extraction of lipids from the heterotrophic microalga Crypthecodinium cohnii

Microalgae biomass can be a feasible source of ω‐3 fatty acids due to its stable and reliable composition. In the present study, the Crypthecodinium cohnii growth and docosahexaenoic acid (DHA, 22:6ω3) production in a 100 L glucose‐fed batch fermentation was evaluated. The lipid compounds were extracted by supercritical carbon dioxide (SC‐CO2) from C. cohnii CCMP 316 biomas, was and their fatty acid composition was analysed. Supercritical fluid extraction runs were performed at temperatures of 313 and 323 K and pressures of 20.0, 25.0 and 30.0 MPa. The optimum extraction conditions were found to be 30.0 MPa and 323 K. Under those conditions, almost 50% of the total oil contained in the raw material was extracted after 3 h and the DHA composition attained 72% w/w of total fatty acids. The high DHA percentage of total fatty acids obtained by SC‐CO2 suggested that this extraction method may be suitable for the production of C. cohnii value added products directed towards pharmaceutical purposes. Furthermore, the fatty acid composition of the remaining lipid fraction from the residual biomass with lower content in polyunsaturated fatty acids could be adequate for further uses as feedstock for biodiesel, contributing to the economy of the overall process suggesting an integrated biorefinery approach.

Synthesis of fatty acid methyl esters via direct transesterification with methanol/carbon dioxide mixtures from spent coffee grounds feedstock

The feasibility of in situextraction and transesterification of spent coffee ground oil into fatty acid methyl esters with supercritical methanol has been investigated in the temperature range 473–603 K, and in the pressure range 10.0–30.0 MPa. At 30.0 MPa and 603 K, a fatty acid methyl esters (FAME) yield of 84.9% was obtained. Carbon dioxide was added to methanol with the aim of reducing the operating temperature and pressure. It was demonstrated that at a reaction temperature of 573 K, pressure of 10.0 MPa and a CO2/MeOH molar ratio of 0.11, a FAME yield of 93.4% was obtained.

Supported Ionic Liquid Membranes and Ion-Jelly® Membranes with [BMIM][DCA]: Comparison of Its Performance for CO2 Separation.

In this work, a supported ionic liquid membrane (SILM) was prepared by impregnating a PVDF membrane with 1-butyl-3-methylimidazolium dicyanamide ([BMIM][DCA]) ionic liquid. This membrane was tested for its permeability to pure gases (CO2, N2 and O2) and ideal selectivities were calculated. The SILM performance was also compared to that of Ion-Jelly® membranes, a new type of gelled membranes developed recently. It was found that the PVDF membrane presents permeabilities for pure gases similar or lower to those presented by the Ion-Jelly® membranes, but with increased ideal selectivities. This membrane presents also the highest ideal selectivity (73) for the separation of CO2 from N2 when compared with SILMs using the same PVDF support but with different ionic liquids.

Task specific ionic liquids as polarity shifting additives of common organic solvents

The effect of addition of small quantities of room temperature ionic liquids (RTILs) to common organic solvents (acetonitrile, ethanol, tetrahydrofuran, isopropanol and chloroform) on polarity is explored. It is found that solvent polarity always increases with addition of RTILs following a linear increase until reaching a plateau. [C2OHMIM][PF6], [C10MIM][BF4] and [EMIM][NTf2] have a dramatic influence on the polarity of acetonitrile, displacing it by more than 0.15 on the normalized polarity scale (ENT). When the same RTIL ([BMIM][BF4]) is added in the same quantity to different solvents, it is observed that the polarity obtained follows generically the same trend as the polarities of the pure solvents, with the exception of chloroform, which has a higher polarity than tetrahydrofuran when pure, but lower when [BMIM][BF4] is added.