title: Enhanced activity of ADP glucose pyrophosphorylase and formation of starch induced by Azospirillum brasilense in Chlorella vulgaris.
abstract: ADP-glucose pyrophosphorylase (AGPase) regulates starch biosynthesis in higher plants and microalgae. This study measured the effect of the bacterium Azospirillum brasilense on AGPase activity in the freshwater microalga Chlorella vulgaris and formation of starch. This was done by immobilizing both microorganisms in alginate beads, either replete with or deprived of nitrogen or phosphorus and all under heterotrophic conditions, using d-glucose or Na-acetate as the carbon source. AGPase activity during the first 72h of incubation was higher in C. vulgaris when immobilized with A. brasilense. This happened simultaneously with higher starch accumulation and higher carbon uptake by the microalgae. Either carbon source had similar effects on enzyme activity and starch accumulation. Starvation either by N or P had the same pattern on AGPase activity and starch accumulation. Under replete conditions, the population of C. vulgaris immobilized alone was higher than when immobilized together, but under starvation conditions A. brasilense induced a larger population of C. vulgaris. In summary, adding A. brasilense enhanced AGPase activity, starch formation, and mitigation of stress in C. vulgaris.
authors.affiliation: Environmental Microbiology Group, Northwestern Center for Biological Research (CIBNOR), Av. Instituto Politécnico Nacional 195, Col. Playa Palo de Santa Rita Sur, La Paz, B.C.S. 23096, Mexico.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Choix
authors.affiliation: Environmental Microbiology Group, Northwestern Center for Biological Research (CIBNOR), Av. Instituto Politécnico Nacional 195, Col. Playa Palo de Santa Rita Sur, La Paz, B.C.S. 23096, Mexico; The Bashan Foundation, 3740 NW Harrison Boulevard, Corvallis, OR 97330, USA.
authors.forename: Yoav
authors.initials: Y
authors.lastname: Bashan
authors.affiliation: Centro de Biotecnología Genómica, Instituto Politécnico Nacional, Blvd. Del Maestro S/N, Col N. Mendoza, Reynosa, Tam. 88710, Mexico.
authors.forename: Alberto
authors.initials: A
authors.lastname: Mendoza
authors.affiliation: Environmental Microbiology Group, Northwestern Center for Biological Research (CIBNOR), Av. Instituto Politécnico Nacional 195, Col. Playa Palo de Santa Rita Sur, La Paz, B.C.S. 23096, Mexico; The Bashan Foundation, 3740 NW Harrison Boulevard, Corvallis, OR 97330, USA. Electronic address: luzb@cals.arizona.edu.
authors.forename: Luz E
authors.initials: LE
authors.lastname: de-Bashan
mesh_terms: D020418:Algal Proteins / Q000378:metabolism*; D000464:Alginates / Q000378:metabolism; D015806:Azospirillum brasilense / Q000254:growth & development / Q000378:metabolism*; D001709:Biotechnology / Q000379:methods; D018914:Cells, Immobilized / Q000378:metabolism; D048408:Chlorella vulgaris / Q000254:growth & development / Q000378:metabolism*; D018920:Coculture Techniques; D003470:Culture Media / Q000737:chemistry; D005947:Glucose / Q000378:metabolism; D051599:Glucose-1-Phosphate Adenylyltransferase / Q000378:metabolism*; D019346:Sodium Acetate / Q000378:metabolism; D013213:Starch / Q000378:metabolism*
chemical_list: D020418:Algal Proteins; D000464:Alginates; D003470:Culture Media; D019346:Sodium Acetate; D013213:Starch; D051599:Glucose-1-Phosphate Adenylyltransferase; D005947:Glucose
keywords: AGPase; Azospirillum; Chlorella; Heterotrophy; Microalgae growth-promoting bacteria