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Direct Wet Algae to Biodiesel 1

Researchers at the University of Michigan have published the feasibility of a two-step hydrolysis-solvolysis process to produce biodiesel directly from wet algal biomass, eliminating the need for costly biomass drying, organic solvent extraction and catalysts. The paper on the process was published in the ACS journal Energy & Fuels. 

In the first step, wet algal biomass contained 80 percent moisture and was reacted with subcritical water to hydrolyze intracellular lipids, conglomerate cells into an easily filterable solid that retained the lipids and produced a sterile, nutrient-rich aqueous phase. In the second step, the wet, fatty acid-rich solids underwent supercritical transesterification with ethanol to produce fatty acid ethyl esters (FAEEs). The team used Chlorella vulgaris algae, which contained 53.3 percent lipid content. 
Thu September 02 2010 04:40:19 AM by Jacintha Algae biofuel 1510 views

Comments - 1

  • Richard wrote:
    Tue September 21 2010 09:56:00 AM

    In the first step, the wet algal biomass underwent a reaction under subcritical water conditions in temperatures of 250 degrees Celsius, which transformed the wet algae into a paste-like state, according to Phillip Savage, lead researcher on the project.

    The goal here, according to researcher Robert Levine who authored the paper, was to hydrolyze?separate from water?intracellular lipids and conglomerate them into an easily filterable solid that retained high lipid content.

    ?We wanted to convert the lipids into mostly fatty acids in the form of triglycerides or other phospholipids that contained fatty acid groups, so we could hydrolyze those into fatty acids,? he said.

    "We also wanted to release a lot of the nonlipid components into a sterile nutrient-rich aqueous phase that we could recycle into our process from which we could grow additional microorganisms."

    In the second step, the remaining solids (containing approximately 80 to 90 percent fatty acids) underwent a supercritical transesterification process with ethanol that produced fatty acid ethyl esters (FAEE).

    "We chose ethanol instead of methanol because we wanted to use entirely biologically-derived ingredients, and also because the solid that remained after the process will probably have some minor alcohol residue, which we want to be used as fertilizer, animal feed and so forth, "Levine said.

    Richard Spyros

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