Abstract:  In the presence of phages, 2-keto-D-gluconic acid fermentation by Pseudomonas fluorescens AR4, which was a phage- resistant mutant obtained from the mutation of the strain A46, was conducted in 200m3 fermentor. The results showed that the mutant resistance against the phages was stable, with shorter fermentation period and higher fermentation conversion rate than its parent. After 10 generations, its resistance against the phages and 2-keto-D-gluconic acid producing ability had not changed. The fermentation product of P. fluorescens AR4 could be used in the synthesis of sodium D-isoascorbate.

Key words:  , 2-keto-D-gluconic acid； Pseudomonas fluorescens； phage； phage-resistant mutant； sodium D-isoascorbate；