ASABE Technical Library - Abstract

Abstract. To combat the limitations of commercializing microalgal-derived biofuels, alternative lipid extraction procedures must be employed. The use of enzymes for cell wall and organelle disruption and lysis are advantageous over traditional extraction techniques such as the energy-intensive process of drying and pressing. The use of autolytic enzymes provides an opportunity for establishing a pretreatment method as part of an integrated aqueous enzymatic lipid extraction process from microalgae. A study was conducted to evaluate the effect of autolysin, an autolytic metalloproteinase, on Chlamydomonas reinhardtii cell lysis and enhanced lipid extraction in comparison to traditional disruption techniques. Increased temperature and controlled mixing were utilized as augmenting factors to improve the pretreatment of microalgae cells. The extent of cell lysis was measured by direct cell count and visualized using electron microscopy. Furthermore, recoverable lipids before and after autolysin treatment were determined by subsequent solvent extraction. Autolysin treatment at room temperature and constant mixing was capable of lysing over 50% of cells which could be increased to over 80% by increasing the incubation temperature. Pretreatment with autolysin significantly increased lipid yield as quantified by solvent extraction. Results indicate that autolysin combined with controlled mixing and incubation temperatures can enhance cell lysis and facilitate improved lipid extraction with subsequent secondary treatments. The pretreatment established represents a novel application of autolysin in catalyzing whole cell lysis beyond previous cell transformation applications of this enzyme.