Degradation of Algal Cell Walls by Enzymes and Dyes
With the annual potential of over 1.3 billion dry tons of biomass, the prospective growth of biofuels is great. The National Renewable Energy Laboratory (NREL) leads the DOE’s National Bioenergy Center, with research spanning the full spectrum from fundamental science to demonstration in fully integrated pilot plants.
The distinguishing aspects are that currently, lipid extraction from algae is a difficult process and is performed with solvents or high pressure. These processes use toxic solvents and/or are very high in energy use. This technology provides for a simple, low energy input process option for extracting the oils from the cells by first weakening the cell walls using enzymes. This weakening or degrading of the cell walls also serves as a form of "pretreatment" to the recalcitrant cell walls and provides for easier use of the residual biomass post oil removal. The weakened algal cell walls may also be more permeable to DNA and be the basis of facilitate transformation of green algae.Description
NREL scientists have invented a way to solve the problem of oil extraction from algal cells. By making the cell walls weak and or completely digesting them, the cells are easy to break whereas the oils then become easy to collect. Also in doing so, may make the algae more amenable to transformation which is all but impossible currently in green algae outside of Chlamydomonas. Treating with enzymes may also make the residual algal biomass easily fermentable in downstream processes.
Using purified enzymes, NREL scientists have developed a method to determine whether enzymatic treatment eases release of internal lipid bodies. NREL scientists used release of chlorophyll into the supernatant after treatment as a proxy for lipids since chlorophyll displays robust auto-fluorescence and can easily be read on a plate reader. We had previously discovered that using lysozyme, one of our most active commercially available enzymes, created a situation where the lipid- and chlorophyll- containing organelles were easily released from the cells but these organelles did not leave the immediate proximity of the lysed cells even under vigorous vortexing yet became stuck in the cell debris matrix. Using purified viral enzymes, chlorophyll release was greatly increased over non-treated cells by >25 fold indicating that the organelles were not being stuck in the cell debris matrix as observed with other enzymes.Benefits
Increase rate of algal extraction
Decrease cost of algal extraction
|Title and Abstract||
Disruption of cell walls for enhanced lipid recovery
Presented herein are methods of using cell wall degrading enzymes for recovery of internal lipid bodies from biomass sources such as algae. Also provided are algal cells that express at least one exogenous gene encoding a cell wall degrading enzyme and methods for recovering lipids from the cells.
|National Renewable Energy Laboratory||03/24/2015
|Technology ID||Development Stage||Availability||Published||Last Updated|
|NREL ROI 10-56||Prototype||Available||12/20/2012||11/30/2012|