Scale-up from shake flasks to pilot-scale production of the plant growth-promoting bacterium Azospirillum brasilense for preparing a liquid inoculant formulation

• Published in: Applied microbiology and biotechnology 2013-11, Vol.97 (22), p.9665-9674
• Main Authors: Trujillo-Roldán, Mauricio A, Valdez-Cruz, Norma A, Gonzalez-Monterrubio, César F, Acevedo-Sánchez, Eduardo V, Martínez-Salinas, Carlos, García-Cabrera, Ramsés I, Gamboa-Suasnavart, Ramsés A, Marín-Palacio, Luz D, Villegas, Jesús, Blancas-Cabrera, Abel
• Format: Article
• Language: English
• Subjects: aboveground biomass; Analysis; Azospirillum brasilense; Azospirillum brasilense - growth & development; Bacteria; Bacterial Load; Biomass; Biomedical and Life Sciences; Bioreactors; Biotechnological Products and Process Engineering; Biotechnology; Cereal crops; Colony Count, Microbial; Corn; corn cobs; Crop yield; Fermentation; greenhouses; growth promotion; Industrial Microbiology - methods; Life Sciences; Mass transfer; Microbial Genetics and Genomics; Microbiology; Nitrogen; Oxygen; Plant growth; Preservation, Biological - methods; Production processes; Proteobacteria; shelf life; Studies; temperature; Time Factors; Zea mays; Zea mays - growth & development; Zea mays - microbiology
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-013-5199-9

Azospirillum brasilense has industrial significance as a growth promoter in plants of commercial interest. However, there is no report in the literature disclosing a liquid product produced in pilot-scale bioreactors and is able to be stored at room temperature for more than 2 years. The aim of this work was to scale up a process from a shake flask to a 10-L lab-scale and 1,000-L pilot-scale bioreactor for the production of plant growth-promoting bacterium A. brasilense for a liquid inoculant formulation. Furthermore, this work aimed to determine the shelf life of the liquid formulation stored at room temperature and to increase maize crops yield in greenhouses. Under a constant oxygen mass transfer coefficient (K L a), a fermentation process was successfully scaled up from shake flasks to 10- and 1,000-L bioreactors. A concentration ranging from 3.5 to 7.5 × 10⁸ CFU/mL was obtained in shake flasks and bioreactors, and after 2 years stored at room temperature, the liquid formulation showed one order of magnitude decrease. Applications of the cultured bacteria in maize yields resulted in increases of up to 95 % in corncobs and 70 % in aboveground biomass.