Hydrothermal cell disruption of Nannochloropsis sp and its influence on lipid extraction

Cell wall disruption is a critical challenge for algal biofuel. Here, we reported Hydrothermal treatment (HTT) of high solid content (20% w/w) Nannochloropsis sp. and its influence on extraction of lipid. Various process variables were specifically studied including reaction temperature (120-200 degrees C) and retention time (0-60 min). SEM and TEM images revealed the cell morphology before and after HTT. A high extraction yield (84%) of lipid was obtained at 180 degrees C with a retention time of 60 min, without the use of any catalysts. GC-MS revealed that the main compounds in the extracts were fatty acids, hydrocarbons and esters. UPLC MS/MS uncovered the detailed varieties of glyceride, phospholipid and glycolipid, and demonstrated that (16:0/16:0/16:1) triglyceride (TAG) was the most abundant TAG. HTT might be a promising method to break microalgae cell wall for lipid extraction.