Journal of Agricultural Studies ISSN 2166-0379 2020, Vol. 8, No. 4 http://jas.macrothink.org 726 Cultivation of Azospirillum brasilense in Vinasse and Potential Use in Fertigation Marcelo Teixeira Silva Postgraduate Program in Clean Technologies, Cesumar University (Unicesumar), Brazil Francielli Gasparotto Cesumar University (Unicesumar) and Cesumar Institute of Science, Technology and Innovation – ICETI, Brazil Bárbara Maria Lustri, Natalia Caetano Vasques Postgraduate Program in Clean Technologies, Cesumar University (Unicesumar), Brazil Natália Ueda Yamaguchi Cesumar University (Unicesumar) and Cesumar Institute of Science, Technology and Innovation – ICETI, Brazil Received: Oct. 22, 2020 Accepted: Dec. 9, 2020 Published: Dec. 10, 2020 doi:10.5296/jas.v8i4.17862 URL: https://doi.org/10.5296/jas.v8i4.17862 Abstract Vinasse, residue from the sugar-energy sector, has been applied as a fertilizer in sugarcane fields due to its nutritional characteristics, which may reduce nitrogen fertilization, especially if associated with diazotrophic bacteria. The objective was to evaluate the use of vinasse as culture medium for Azospirillum brasilense and the chemical changes caused in the residue after bacterial colonization. The experimental design was completely randomized with 9 treatments: T0-control (nutrient broth DYGs inoculated with A. brasilense); T1- 100% vinasse inoculated with A. brasilense; T2- 75% vinasse inoculated with A. brasilense; T3- 25% vinasse inoculated with A. brasilense; T4- 50% vinasse inoculated with A. brasilense; T5- 100% vinasse; T6- 75% vinasse; T7- 25% vinasse and T8- 50% vinasse. Microbial growth was evaluated in a spectrophotometer, by turbidimetry (700nm). Chemical characterization of vinasse was carried out before bacterial inoculation and on days 1, 3, 5