Enzymatic hydrolysis of naringin by the action of naringinase is one of the standard practices adopted in the citrus fruit juice industry for debittering. In the present study, a submerged fermentation condition was optimized for producing naringinase from Aspergillus niger van Tieghem MTCC 2425. As per Placket–Burman design, pH (3–5), incubation temperature (26–30 °C), and inducer concentration (12–18 g·L⁻¹) were the most important factors influencing the naringinase production. Naringin from citrus waste was used as an inducer. A rotatable central composite design was employed on these three variables and the numerical optimization predicted that fermentation at 29.8 °C, pH 4.7, and inducer concentration of 14.9 g L⁻¹ would yield a maximum naringinase activity of 545.2 IU g⁻¹. During partial purification, ion exchange chromatography led to a 9.92-fold increase in enzyme activity resulting a specific activity of 5460 IU g⁻¹ with an activity recovery of 17%. As reflected by SDS–PAGE profile, the partially purified naringinase showed the molecular weight bands of 10–20, 65, and 80 kDa, respectively. The purified form of enzyme showed optimum stability at pH 5 and 50 °C. The naringinase activity was completely retained up to 150 days when stored at 4 °C.

通过柚皮苷酶的作用对柚皮苷进行酶促水解是柑橘类果汁工业中用于脱苦的标准做法之一。在本研究中，优化了深层发酵条件以从黑曲霉van Tieghem MTCC 2425生产柚皮苷酶。 根据Placket-Burman 设计、pH (3-5)、孵育温度 (26-30 °C) 和诱导剂浓度 ( 12-18 g·L ^-1 ) 是影响柚皮苷酶产量的最重要因素。柑橘废料中的柚皮苷用作诱导剂。对这三个变量采用可旋转的中心复合设计，数值优化预测发酵温度为 29.8 °C，pH 4.7，诱导剂浓度为 14.9 g L ^-1将产生545.2 IU g ^-1的最大柚皮苷酶活性。在部分纯化过程中，离子交换层析使酶活性增加了 9.92 倍，导致比活性为 5460 IU g ^-1，活性恢复率为 17%。正如 SDS-PAGE 谱所反映的那样，部分纯化的柚皮苷酶分别显示出 10-20、65 和 80 kDa 的分子量条带。纯化形式的酶在 pH 5 和 50 °C 下表现出最佳稳定性。在 4°C 下储存时，柚皮苷酶活性可完全保留长达 150 天。