好食脉胞菌发酵过程中酶活性变化对麸皮阿魏酸释放的影响

Effect of enzyme activity during Neurospora sitophila fermentation on the release of ferulic acid from bran

添加不同的辅助性碳源(0.1 g/L)、氮源(0.2 g/L)诱导好食脉孢菌固态发酵小麦麸皮中总阿魏酸释放量的影响以及在发酵过程中阿魏酸酯酶、木聚糖酶、纤维素酶的活性和总阿魏酸释放量之间的相关性。结果表明,随着发酵时间的增长,总阿魏酸释放量与3种酶活性均先提高后下降。当发酵到第3 d时,单独添加葡萄糖作为辅助性碳源、尿素作为辅助性氮源的培养基中,总阿魏酸释放量最高,分别为1.94 mg/g和1.67 mg/g,比空白对照分别提高了1.42倍和1.23倍。以葡萄糖和尿素为辅助性碳、氮源时,阿魏酸酯酶酶活有最高分别为8.33、10.77 U;以木聚糖和尿素为辅助性碳氮源时木聚糖酶酶活有最高,分别为7.06、6.84 U;以木聚糖和硫酸铵作为辅助性碳氮源的培养中,纤维素酶酶活有最高,分别为3.87、3.96 U。此外,总阿魏酸释放量的变化与3种酶活性的研究结果表明,麸皮发酵过程中总阿魏酸的释放量与阿魏酸酯酶和木聚糖酶的活性呈正相关,与纤维素酶的活性呈负相关。由此可见,阿魏酸酯酶和木聚糖酶的酶活越强,越有利于麸皮中总阿魏酸的释放。

The effect of different auxiliary carbon sources(0.1 g/L) and nitrogen sources(0.2 g/L) on the release of ferulic acid in the solid state fermentation of wheat bran by Neurospora sitophila was studied. The correlation between the activity of ferulic acid esterase, xylanase, cellulase and total ferulic acid release in the fermentation process were studied too. The results showed that with the increase of fermentation time, the release amounts of total ferulic acid and the activity of the three enzymes increased at first and then decreased. With glucose and urea as sole auxiliary carbon source and nitrogen source, the release amounts of total ferulic acid achieved the highest value, at 1.94 mg/g and 1.67 mg/g respectively, which was 1.42 times and 1.23 times higher than that of the blank control. With the glucose as auxiliary carbon and urea as sole auxiliary nitrogen source, the highest ferulic acid esterase activity of 8.33 U and 10.77 U were obtained, respectively. With xylan as sole auxiliary carbon source and urea as sole auxiliary nitrogen source, the highest xylanase activity of 7.06 U and 6.84 U were obtained, respectively. With xylan and ammonium sulfate as sole auxiliary carbon and nitrogen source, the highest cellulase activity of 3.87 U and 3.96 U were obtained, respectively. Moreover,the results showed the positive correlation between the total release amounts of ferulic acid with the activity of the ferulic acid esterase and xylanase, and the negative correlation between the total release amounts of ferulic acid with the activity of cellulase. Thus, the higher ferulic esterase and xylanase activity were beneficial to the release of ferulic acid in bran.