Solid-state culture of Azospirillum brasilense: a reliable technology for biofertilizer production from laboratory to pilot scale

• Published in: Bioprocess and biosystems engineering Vol. 44; no. 7; pp. 1525 - 1538
• Main Authors: Martínez-Ramírez, C., Esquivel-Cote, R., Ferrera-Cerrato, R., Martínez-Ruiz, J. A., Rodríguez-Serrano, G., Saucedo-Castañeda, G.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.07.2021; Springer Nature B.V
• Subjects: Aeration; Azospirillum brasilense; Azospirillum brasilense - metabolism; Biofertilizers; Bioreactors; Biotechnology; Biotechnology - methods; Cell culture; Cell viability; Chemistry; Chemistry and Materials Science; Controlled conditions; Dimensionless numbers; Environmental Engineering/Biotechnology; Fermentation; Fertilizers; Food Science; Glycerol - chemistry; Hydrogen-Ion Concentration; Industrial and Production Engineering; Industrial Chemistry/Chemical Engineering; Industrial Microbiology - methods; Kinetics; Laboratories; Mathematical models; Microorganisms; Microscopy, Electron, Scanning; Models, Theoretical; Oxygen Consumption; Research Paper; Respirometry; Solid state; Stem Cells; Biofertilizer; Solid-state culture; Bioreactor with rotating helical ribbons; Scale-up; Azospirillum brasilense
• ISSN: 1615-7591; 1615-7605
• DOI: 10.1007/s00449-021-02537-3

A biofertilizer of Azospirillum brasilense was produced in solid-state culture (SSC) from laboratory to pilot scale. Similar operation conditions (continuous aeration and mild intermittent mixing) and two dimensionless numbers with similar L/D ratio and a similar working volume were applied to reach a scale-up factor of 75. An innovative bioreactor with rotating helical ribbons (15 kg wet matter) was used at pilot scale. A mathematical model was proposed and validated to evaluate the respirometry trends at laboratory and pilot scale exhibiting similar behavior. The cell viability was (1.3 ± 0.4) × 10 9 and (1.3 ± 0.3) × 10 9 colony-forming units per gram of initial dry mass at laboratory and pilot scale, at 36 and 43 h, respectively. A . brasilense maintains its viability twelve months of storage at 4 and 30 °C. This is the first report of A . brasilense being cultivated in SSC under controlled conditions. SSC processes involving unicellular microorganisms with tolerance to agitation are a promising technology to produce biofertilizers. Graphic abstract