title: Enhanced accumulation of starch and total carbohydrates in alginate-immobilized Chlorella spp. induced by Azospirillum brasilense: I. Autotrophic conditions.
abstract: The effect of the microalgae-growth promoting bacterium Azospirillum brasilense on accumulation of total carbohydrates and starch in two species of Chlorella (Chlorella vulgaris and Chlorella sorokiniana), when the bacterium and each microalga were jointly immobilized in alginate beads was studied under autotrophic conditions for 144 h in synthetic medium. The interaction of the bacterium with the microalgae enhanced accumulation of total carbohydrate and starch. Cells of Chlorella accumulated the highest amounts of carbohydrate after incubation for 24h. Yet, this did not coincide with the highest affinity and volumetric productivity measured in these cultures. However, after incubation for 72 h, mainly in jointly immobilized treatments of both microalgae species, the cultures reached their highest total carbohydrate content (mainly as starch) and also the highest affinity and volumetric productivity. These results demonstrate the potential of A. brasilense to affect carbohydrates and starch accumulation in Chlorella spp. when both microorganisms are co-cultured, which can be an important tool for applications of microalgae.
authors.affiliation: Environmental Microbiology Group, Northwestern Center for Biological Research (CIBNOR), Av. Instituto Politecnico Nacional 195, Col. Playa Palo de Santa Rita, La Paz, B.C.S. 23096, Mexico.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Choix
authors.forename: Luz E
authors.initials: LE
authors.lastname: de-Bashan
authors.forename: Yoav
authors.initials: Y
authors.lastname: Bashan
mesh_terms: D000464:Alginates; D052818:Autotrophic Processes; D015806:Azospirillum brasilense / Q000254:growth & development / Q000378:metabolism*; D001709:Biotechnology / Q000379:methods*; D050260:Carbohydrate Metabolism; D018914:Cells, Immobilized / Q000378:metabolism*; D002708:Chlorella / Q000254:growth & development / Q000378:metabolism*; D048408:Chlorella vulgaris / Q000254:growth & development / Q000378:metabolism*; D018920:Coculture Techniques; D003470:Culture Media; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D013213:Starch / Q000378:metabolism*
chemical_list: D000464:Alginates; D003470:Culture Media; D006603:Hexuronic Acids; D020723:Glucuronic Acid; D013213:Starch