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Title: Inhibition of Alkaline Flocculation by Algal Organic Matter for Chlorella vulgaris

Alkaline flocculation is a promising strategy for the concentration of microalgae for bulk biomass production. However, previous studies have shown that biological changes during the cultivation negatively affect flocculation efficiency. The influence of changes in cell properties and in the quality and composition of algal organic matter (AOM) were studied using Chlorella vulgaris as a model species. In batch cultivation, flocculation was increasingly inhibited over time and mainly influenced by changes in medium composition, rather than biological changes at the cell surface. Total carbohydrate content of the organic matter fraction sized bigger than 3 kDa increased over time and this fraction was shown to be mainly responsible for the inhibition of alkaline flocculation. The monosaccharide identification of this fraction mainly showed the presence of neutral and anionic monosaccharides. An addition of 30–50 mg L-1 alginic acid, as a model for anionic carbohydrate polymers containing uronic acids, resulted in a complete inhibition of flocculation. Furthermore, these results suggest that inhibition of alkaline flocculation was caused by interaction of anionic polysaccharides leading to an increased flocculant demand over time.
 [1] ;  [1] ;  [2] ;  [1] ;  [3] ;  [4] ;  [5] ;  [2] ;  [1]
  1. KU Leuven Kulak, Kortrijk (Belgium)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  3. IRF Life Siences, Kortrijk (Belgium)
  4. KU Leuven, Leuven (Belgium)
  5. KU Leuven Kulak, Kortrijk (Belgium); Leuven Food Science and Nutrition Research Centre (LFoRCe), Heverlee (Belgium)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 0043-1354
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Water Research; Journal Volume: 88; Related Information: Water Research
Research Org:
NREL (National Renewable Energy Laboratory (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
09 BIOMASS FUELS; 59 BASIC BIOLOGICAL SCIENCES Extracellular polymeric substances; Dissolved organic matter; Coagulation; Harvesting; Microalgae; Biofuels