枯草芽孢杆菌发酵豆渣制备多肽及其活性研究

以纤维素酶酶解后的豆渣为原料，利用枯草芽孢杆菌（Bacillus subtilis）液态发酵豆渣制备大豆多肽，并以大豆多肽得率为响应值，通过单因素试验及响应面法对其制备工艺进行优化，并测定其抗氧化活性与抑菌活性。结果表明，枯草芽孢杆菌液态发酵豆渣制备大豆多肽的最优工艺条件为：接种量3%、发酵温度37 ℃、发酵时间60 h。在此优化条件下，大豆多肽得率为88.12%；其对1,1二苯基-2-三硝基苯肼（DPPH）自由基和2,2-联氮-双-3-乙基苯并噻唑啉-6-磺酸（ABTS）自由基清除能力的半效应浓度（EC50）值分别为（2.36±0.05） mg/mL、（2.97±0.03） mg/mL；多肽质量浓度为25 mg/mL时，大肠杆菌（Escherichia coli）和金黄色葡萄球菌（Staphylococcus aureus）抑菌圈直径分别为（27.65±0.32） mm、（23.18±0.14） mm。结果表明，大豆多肽具有一定的抗氧化及抑菌活性。

Preparation and activity of peptides from soybean dregs by fermentation with Bacillus subtilis

Using soybean dregs after enzymatic hydrolysis by cellulase as raw materials, soybean polypeptides were prepared soybean dregs by liquid fermentation wit Bacillus subtilis. Taking the yield of soybean polypeptides as response value, the preparation process was optimized by single factor tests and response surface methodology, and the antioxidant activity and antibacterial performance were determined. The results showed that the optimum fermentation conditions for soybean polypeptides preparation were as follows: inoculum 3%, fermentation temperature 37 ℃ and time 60 h. Under the optimized conditions, the soybean polypeptides yield was 88.12%. The half-effect concentrations (EC50) value of 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) radical and 2,2-biazo-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity were (2.36±0.05) mg/ml and (2.97± 0.03) mg/ml, respectively. When the mass concentration of peptide was 25 mg/ml, the inhibition zone diameter of Escherichia coli and Staphylococcus aureus were (27.65±0.32) mm and (23.18±0.14) mm, respectively. The results showed that soybean polypeptide had antioxidant and bacteriostatic activities.