Preliminary Optimization of Fermentation Conditions for Production of Naringinase by Aspergillus niger DB056

Abstract:

In this study, α-rhamnosidase activity and naringinase activity were adopted to evaluate effects of conditions on naringinase production by Aspergillus niger DB056. The results showed that fermentation temperature, mycelia morphology, initial pH, inoculation amount and medium volume had important impacts on naringinase production. Optimum conditions, including initial pH 8.0, adding 5 class beads, 45 mL medium in 250 mL flask, inoculation amount 7%, culture temperature 34°C and rotatory speed 190 r/min, were proved superior to get high α-rhamnosidase and naringinase yield. Under these conditions, the enzyme activity detected by high performance liquid chromatography method were 1076.32 U/mL for α-rhamnosidase and 420.68 U/mL for naringinase, which increased by 72.35% and 78.03% comparing with the initial condition. Furthermore, the results also showed Aspergillus niger DB056 could synthesize naringinase not only rapidly in the logarithm grown phase, but also continuously in the stationary and death phase. The present study elucidated effects of fermentation conditions on naringinase production by Aspergillus niger DB056 and provided a preliminarily optimized conditions for naringinase fermentation. It set a basic foundation for further study to enhance the productivity of naringinase by Aspergillus niger DB056.

Key words:Aspergillus niger, Fermentation condition, α-rhamnosidase, Naringinase