title: Microalgae growth-promoting bacteria as "helpers" for microalgae: a novel approach for removing ammonium and phosphorus from municipal wastewater.
abstract: A combination of microalgae (Chlorella vulgaris or C. sorokiniana) and a microalgae growth-promoting bacterium (MGPB, Azospirillum brasilense strain Cd), co-immobilized in small alginate beads, was developed to remove nutrients (P and N) from municipal wastewater. This paper describes the most recent technical details necessary for successful co-immobilization of the two microorganisms, and the usefulness of the approach in cleaning the municipal wastewater of the city of La Paz, Mexico. A. brasilense Cd significantly enhanced the growth of both Chlorella species when the co-immobilized microorganisms were grown in wastewater. A. brasilense is incapable of significant removal of nutrients from the wastewater, whereas both microalgae can. Co-immobilization of the two microorganisms was superior to removal by the microalgae alone, reaching removal of up to 100% ammonium, 15% nitrate, and 36% phosphorus within 6 days (varied with the source of the wastewater), compared to 75% ammonium, 6% nitrate, and 19% phosphorus by the microalgae alone. This study shows the potential of co-immobilization of microorganisms in small beads to serve as a treatment for wastewater in tropical areas.
authors.affiliation: The Environmental Microbiology Group, The Center for Biological Research of the Northwest (CIB), P.O. Box 128, La Paz, B.C.S. 23000, Mexico.
authors.forename: Luz E
authors.initials: LE
authors.lastname: de-Bashan
authors.forename: Juan-Pablo
authors.initials: JP
authors.lastname: Hernandez
authors.forename: Taylor
authors.initials: T
authors.lastname: Morey
authors.forename: Yoav
authors.initials: Y
authors.lastname: Bashan
mesh_terms: D015806:Azospirillum brasilense / Q000502:physiology*; D019149:Bioreactors; D002708:Chlorella / Q000502:physiology*; D010758:Phosphorus / Q000302:isolation & purification*; D000644:Quaternary Ammonium Compounds / Q000302:isolation & purification*; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*
chemical_list: D000644:Quaternary Ammonium Compounds; D010758:Phosphorus