关键词: 菊粉酶, 黑曲霉, 发酵培养基, 优化, 响应面法

Abstract:

The production of endoinulinase by Aspergillus niger in submerged cultivation was studied. Burdock was used
as the only carbon source. Among 20 Aspergillus niger strains tested, strain 08013 exhibited the highest endoinulinase
activity of 3.27 U/mL in the fermentation supernatant. Preliminary results from this study showed that the optimal
fermentation time, metal ion, carbon source, organic nitrogen source and inorganic nitrogen source were 108 h, 0.5 g/100 mL of
sodium ion, burdock, 2 g/100 mL of yeast extract, 2 g/100 mL of (NH4)2HPO4, respectively. Response surface Box-
Behnken design was used to optimize burdock, yeast extract and (NH4)2HPO4 concentration. A mathematical model
was developed and analyzed indicating the effect of the studied variables on endoinulinase activity. The optimal culture
medium for producing endoinulinase contained 9.98% of burdock juice, 1.74 g/100 mL of yeast extract and 1.82 g/100 mL
of (NH4)2HPO4. The maximum predicted endoinulinase activity under the optimized conditions was 7.23 U/mL, which
was close to the experimental value of 7.26 U/mL. Thus the regression model developed in this study had good prediction
ability. This experimental value exhibited an increase of 122% compared with that obtained before optimization.

Key words: inulinase, Aspergillus niger, fermentation medium, optimization, response surface analysis