title: Increased growth of the microalga Chlorella vulgaris when coimmobilized and cocultured in alginate beads with the plant-growth-promoting bacterium Azospirillum brasilense.
abstract: Coimmobilization of the freshwater microalga Chlorella vulgaris and the plant-growth-promoting bacterium Azospirillum brasilense in small alginate beads resulted in a significantly increased growth of the microalga. Dry and fresh weight, total number of cells, size of the microalgal clusters (colonies) within the bead, number of microalgal cells per cluster, and the levels of microalgal pigments significantly increased. Light microscopy revealed that both microorganisms colonized the same cavities inside the beads, though the microalgae tended to concentrate in the more aerated periphery while the bacteria colonized the entire bead. The effect of indole-3-acetic acid addition to microalgal culture prior to immobilization of microorganisms in alginate beads partially imitated the effect of A. brasilense. We propose that coimmobilization of microalgae and plant-growth-promoting bacteria is an effective means of increasing microalgal populations within confined environments.
authors.affiliation: Department of Biology, Pontificia Universidad Javeriana, Santafe de Bogota, Colombia.
authors.forename: L E
authors.initials: LE
authors.lastname: Gonzalez
authors.forename: Y
authors.initials: Y
authors.lastname: Bashan
mesh_terms: D000464:Alginates; D015806:Azospirillum brasilense / Q000254:growth & development*; D018914:Cells, Immobilized; D002708:Chlorella / Q000254:growth & development*; D003470:Culture Media; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D008863:Microspheres; D010860:Pigments, Biological / Q000096:biosynthesis; D018505:Waste Management; D014871:Water Microbiology
chemical_list: D000464:Alginates; D003470:Culture Media; D006603:Hexuronic Acids; D010860:Pigments, Biological; D020723:Glucuronic Acid