Abstract: The fermentation conditions of this strain were optimized and scaled up in a 5 L bioreactor. First, through single factor experiment, orthogonal experiment, steepest climbing experiment and central composite design experiment at the shake flask level, the optimal medium composition was obtained as 49.55 g/L glycerol, 37.34 g/L soy peptone, 1.5 g/L KCl, 0.75 g/L MgSO4and 0.225 g/L K2HPO4, and the maximum production of phenazine-1-carboxylic acid (PCA) after 60 h fermentation was （6.01±0.17） g/L, which was 2.6 times as that before optimization. Then, the fermentation pH was optimized in 1 L bioreactors. When the pH was maintained at 6.8 during the culture process, the PCA production was the highest at （7.16±0.04） g/L, which was 1.2 times as that before optimization. Finally, under the optimal medium and pH conditions, the strain was scaled up cultured in 5 L bioreactors, and the maximum PCA production after 60 h of fermentation was (6.84±0.53) g/L. This study provided support for improving the production and industrial application of PCA.

Key words: Pseudomonas chlororaphis GP72-ND3ΔphzO, phenazine-1-carboxylic acid, fermentation optimization, central composite design, bioreactor