skip to main content


Title: Combined algal processing: A novel integrated biorefinery process to produce algal biofuels and bioproducts

Here, the development of an integrated biorefinery process capable of producing multiple products is crucial for commercialization of microalgal biofuel production. Dilute acid pretreatment has been demonstrated as an efficient approach to utilize algal biomass more fully, by hydrolyzing microalgal carbohydrates into fermentable sugars, while making the lipids more extractable, and a protein fraction available for other products. Previously, we have shown that sugar-rich liquor could be separated from solid residue by solid-liquid separation (SLS) to produce ethanol via fermentation. However, process modeling has revealed that approximately 37% of the soluble sugars were lost in the solid cake after the SLS. Herein, a Combined Algal Processing (CAP) approach with a simplified configuration has been developed to improve the total energy yield. In CAP, whole algal slurry after acid pretreatment is directly used for ethanol fermentation. The ethanol and microalgal lipids can be sequentially recovered from the fermentation broth by thermal treatment and solvent extraction. Almost all the monomeric fermentable sugars can be utilized for ethanol production without compromising the lipid recovery. The techno-economic analysis (TEA) indicates that the CAP can reduce microalgal biofuel cost by $0.95 per gallon gasoline equivalent (GGE), which is a 9% reduction compared to the previousmore » biorefinery scenario.« less
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 2211-9264
Grant/Contract Number:
AC36-08GO28308; AC36-08-GO28308;
Published Article
Journal Name:
Algal Research
Additional Journal Information:
Journal Volume: 19; Journal Issue: C; Journal ID: ISSN 2211-9264
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Bioenergy Technologies Office (EE-3B)
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANAYLYTICAL CHEMISTRY; algal biofuels; CAP process; ethanol; fermentation; technoeconomic analysis; biorefinery; microalgal biofuel; pretreatment; extraction
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1330940