Algae are preferably provided in the form of a wet algal  biomass, which is a water suspension. In a preferred  embodiment, the water content in the water suspension is at  least 50 wt. %, more preferably 75-90 wt. %. This is an  advantage of the present method, which can be applied  directly to harvested biomass (optionally after some con- centration) and which does not require complete dewatering  and drying of the biomass, which may consume a lot of  energy. Any suitable type of algae can be used.  In a further step, algae are subjected to cell lysis with the  ionic liquid. This can take place, for example, in a lysis  reactor. In one embodiment, the algae together or separately  with the ionic liquid are introduced in a lysis reactor. In  another embodiment, the ionic liquid is formed in situ, e.g.  in the lysis reactor, from a respective base and an acid. This  is particularly convenient if the acid in the ionic liquid is  carbonic acid; the conjugate can then be generated in situ by  addition of a gaseous CO$_{2 }$ to the base.  In a preferred embodiment, an organic solvent, preferably,  an alcohol, and more preferably methanol or ethanol, can be  added to the mixture of the ionic liquid and the algae. 50  Organic solvents can in this way reduce the viscosity, on one  hand, and on the other hand act as (trans)esterification  agents, that is, they favor fatty acid esters formation. Fatty  acids methyl esters (or other alcohol esters) can be directly  formed during the lysis process. The preferred organic 55  solvent is methanol as it results in fatty acid methyl esters,  which is favourable for the use in biofuel. The use of  methanol can lead to a transesterification yield higher than  90%, in combination with the ionic liquids used in the  present invention. Conventional ionic liquids such as  [BMIM]Cl do not achieve such high transesterification  yields as seen in Example 9 below.  The ratio of the conjugated ionic liquid to algae suspen› sion, which can be used, depends on the base. In the absence  of alcohol, the mass ratio of the conjugated ionic liquid to  cell suspension is preferably in the range of 5: 1 to 3: 1  ( calculated based on the water content of the cell suspension  30  85 wt. %). In the presence of methanol, the mass ratio of  conjugate acid to cells suspension (water content 85 wt.%)  is preferably in the range of 7: 1 to 3: 1 and the mass ratio of  alcohol to cell suspension ( containing about 85 wt. % of  water) is in the range of 2:1 to 0.5:1.  Preferably, the cell lysis is performed at temperatures of  100°  C., or less (generally about 80°  C.). Preferably, a closed  apparatus is used, optionally, under CO$_{2 }$ pressure. The  duration of the cell lysis should be sufficient to effect lysis  but is generally less than 60 min.  As a result of the cell lysis, at least two phases are formed,  including a hydrophobic phase and a hydrophilic phase.  These phases are substantially immiscible. The hydrophilic  phase mainly contains water, the ionic liquid, alcohol (if  used) and hydrophilic algae components (glycerol, water  soluble proteins,  carbohydrates and metabolites). The  hydrophobic phase mainly contains fatty acids and their  glycerol esters, waxes and, optionally, the extractant (if  used). Optionally, a solid phase is additionally formed as a  third phase. This solids phase may for example contain a part  of ionic liquid in the form of a precipitate, which is undis› solved at the lysis or separation temperature.  Subsequently, the hydrophobic phase is separated by  physical separation methods such as decanting, centrifuga› tion, etc. The hydrophobic phase has generally a lower  density than the hydrophilic phase is therefore the present as  the upper layer. The upper hydrophobic layer can be recov- ered by mechanical separation or spilling. The two or three  phases may be allowed to separate using the forces of  gravity or separation might be accelerated, for example by  centrifugation. The precipitated ionic liquid can be filtered  off and reused in the step of algal cell lysis.  Once the lipid-containing hydrophobic layer is separated  from the mixture, the hydrophilic phase containing the ionic  liquid, water, hydrophilic algae components and optionally  alcohol can be recovered for reuse in the step of algal cell  lysis. The phases separation and oil recovery can be favored  by temperature reduction, preferably at room temperature or  35  40  45  60 65 US 10,035,971 B2  6  5  TABLE I-continued  pKa pKa  Base  Structural  formula  water other solvent  1,8-diazabicyclo-[5.4.0]undec- 7-ene (DBU)  1,5,7-Triazabicyclo[4.4.0]dec-5- ene(TBD)  imino-tris-(dimethylamino)› phosphorane  H  0~  I  H  G:~)  N  N  I  I  H  H  24.3  (Acetonitrile)  21.7 (THF)  27.9 (THF) 