Optimization of spray drying conditions for the green manufacture of γ-aminobutyric acid-rich powder from Lactobacillus brevis fermentation broth

Lactobacillus brevis TCCC 13007 was used to produce γ-aminobutyric acid. The fermentation broth was degermed, decolorized and deionized before the green-style spray drying, and the process parameters were optimized. Single-factor experiments were carried out to optimize 7 factors to investigate their effects on spray drying. Maltodextrin was found to be a good drying aid that significantly improves the drying process. Response surface methodology was used to assess the combined effects of air inlet temperature, spray pressure and amount of maltodextrin, to optimize the spray drying process parameters of the γ-aminobutyric acid-containing eluent. The optimized variables were applied for the following evaluation of the powder collection rate and comprehensive product score evaluation. Using the optimum parameters of spray drying, the powder collection rate reached 62.74 %, the comprehensive score was 85, and the γ-aminobutyric acid content was 67.5 %, and the recovery rate of GABA was 60.71 %. These results lay the foundation of further industrial scale-up of γ-aminobutyric acid production from fermentation broth.