黑曲霉DB056产柚苷酶发酵条件初步优化

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

摘要:

以α-鼠李糖苷酶活力和柚苷酶活力为考察指标, 研究了发酵条件对黑曲霉DB056产柚苷酶的影响。结果表明: 发酵温度、菌丝形态、培养基初始pH、接种量和装液量对黑曲霉DB056产柚苷酶都具有重要影响。初步优化得到黑曲霉DB056产柚苷酶的条件为: 培养基初始pH 8.0, 玻璃珠添加个数5个, 装液量45 mL, 接种量7%, 发酵温度34°C, 摇床转速190 r/min。采用此条件进行发酵, 高效液相色谱法检测α-鼠李糖苷酶活力最大可达1076.32 U/mL, 柚苷酶活力最大可达420.68 U/mL, 分别比初始条件提高了72.35%和78.03%。黑曲霉DB056不仅在对数生长期能快速合成柚苷酶, 在稳定期及衰亡期也会不断地分泌柚苷酶。阐明了发酵条件对黑曲霉DB056产柚苷酶的影响并获得了经过初步优化的发酵条件, 为进一步优化发酵条件, 提高黑曲霉DB056产柚苷酶的产量奠定了良好的基础。

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.