title: Growth of Chlamydomonas reinhardtii in acetate-free medium when co-cultured with alginate-encapsulated, acetate-producing strains of Synechococcus sp. PCC 7002.
abstract: BACKGROUND
  The model alga Chlamydomonas reinhardtii requires acetate as a co-substrate for optimal production of lipids, and the addition of acetate to culture media has practical and economic implications for algal biofuel production. Here we demonstrate the growth of C. reinhardtii on acetate provided by mutant strains of the cyanobacterium Synechococcus sp. PCC 7002.
  
  
  RESULTS
  Optimal growth conditions for co-cultivation of C. reinhardtii with wild-type and mutant strains of Synechococcus sp. 7002 were established. In co-culture, acetate produced by a glycogen synthase knockout mutant of Synechococcus sp. PCC 7002 was able to support the growth of a lipid-accumulating mutant strain of C. reinhardtii defective in starch production. Encapsulation of Synechococcus sp. PCC 7002 using an alginate matrix was successfully employed in co-cultures to limit growth and maintain the stability.
  
  
  CONCLUSIONS
  The ability of immobilized strains of the cyanobacterium Synechococcus sp. PCC 7002 to produce acetate at a level adequate to support the growth of lipid-accumulating strains of C. reinhartdii offers a potentially practical, photosynthetic alternative to providing exogenous acetate into growth media.
authors.affiliation: Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717 USA.
authors.forename: Jesse B
authors.initials: JB
authors.lastname: Therien
authors.affiliation: Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717 USA.
authors.forename: Oleg A
authors.initials: OA
authors.lastname: Zadvornyy
authors.affiliation: Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, Colorado 80401 USA.
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Posewitz
authors.affiliation: Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717 USA ; Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802 USA.
authors.forename: Donald A
authors.initials: DA
authors.lastname: Bryant
authors.affiliation: Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717 USA.
authors.forename: John W
authors.initials: JW
authors.lastname: Peters
keywords: Acetate production; Algae; Alginate immobilization; Biofuels; Co-culture; Cyanobacteria; Lipid production