Algae are known to grow at high rates compared to terrestrial plants that contain comparable amounts ofcarbohydrates by weight. Therefore, this renders them attractive in terms of any biorefinery concept. In thisworkthe greenalgaUlvarigida,containing40wt.%of carbohydrateswaspretreated with a switchableionic liquid(SIL),distillableionic liquid(DIL)and low-viscosity ionic liquid(LVIL). The SIL DBU–MEA–SO2waspreparedfroma mixture of mono-ethanolamine (MEA) and 1,8-diazabicyclo-[5,4,0]-undec-7-ene (DBU) that was coupledwith sulfur dioxide (SO2), whereas the DIL [TMGH+][EtCO2−] (1,1,3,3-tetramethylguanidine propionate) wassynthesized by a simple acid–base neutralization reaction. Consequently, the LVIL [HDBU+][5OF−] protonated1,8-diazabicyclo-[5,4,0]-undec-7-ene- 2,2,3,3,4,4,5,5-octafluoro-1-pentoxide was used as received. Thetreatments were carried out in the temperature range of 100–160 °C for 6 h. The products obtained after thetreatments were analyzed using different techniques like ICP, OES, SEM, TEM, TGA, FTIR and carbohydrate deter-mination by GC. Upon treatment with DIL up to 67 wt.% of carbohydrates could be dissolved. For thefirst time,processing ofU. rigidawas carried out in ionic liquids so that the mass balance of the process was obtained. Itcan be concluded that 1,1,3,3-tetramethylguanidine propionate shows significant potential when aiming atreleasing carbohydrates from algal biomass that, consequently, can be applied in the production of platformchemicals and/or biofuels such as bioethanol.
Elsevier, 2015. Vol. 12, 262-273 p.