Department of Agricultural Microbiology, Faculty of Agriculture, Beni-Suef University, Beni-Suef, Egypt.
Agricultural Microbiology Department, Faculty of Agriculture, Ain Shams University, Hadayek Shubra, Cairo, 11241, Egypt.
Sci Rep. 2023 Oct 5;13(1):16755. doi: 10.1038/s41598-023-43955-5.
Bioconversion using fungi, as natural factory of many applicable bioactive compounds, as enzymes utilizing agro-residue substrates as a solid, abundant, low-cost growth and enzyme production media. This study characterized and applied a tannase enzyme (308 U/mg) from Aspergillus niger A8 + Trichoderma viride co-cultures utilizing pomegranate peels. The partially purified enzyme showed maximal relative activity at 37-65 °C for 10 min and kinetics of thermal inactivation energy at a high point at 60 °C for 0.040/min. The half-life was 37 °C for 58.6 min, temperature coefficient Q of tannase was maximal for 1.38 between 40 and 50 °C, and the activation energy was 17.42 kJ/mol. The enzyme activity peaked in the pH range of 4-8, and the maximum relative activity (100.6%) for tannase was achieved at pH 6. The K and V values for purified enzymes using tannic acid were 7.3 mg/mL and 3333.33 U/mL, respectively. The enzyme reduced the total tannin content in all tannin-rich substrates after 12h. The gallic acid (GA) had total phenols of 77.75 ppm and antioxidant activity of 82.91%. It was observed that the GA as antimicrobial influencer exhibited the largest inhibitory zone diameter (IZD) of 31 ± 1.0 mm against Pseudomonas aeruginosa ATCC27853. The GA minimum inhibitory concentration value was ranged from 7770.0-121.41 µg/mL. The obtained GA showed a bactericidal effect against all bacterial strains except Shigella sonnei DSM5570 and Salmonella typhi DSM17058, which showed bacteriostatic behavior.
利用真菌进行生物转化，真菌是许多适用生物活性化合物的天然工厂，可利用农业残留物作为固体、丰富、低成本的生长和酶生产介质来利用酶。本研究对黑曲霉 A8+绿色木霉共培养物利用石榴皮产生的单宁酶（308 U/mg）进行了特性分析和应用。部分纯化的酶在 37-65°C 下具有最大相对活性，10 分钟内热失活动力学能量最高点为 60°C，为 0.040/min。半衰期为 37°C 时为 58.6 分钟，单宁酶的温度系数 Q 在 40-50°C 之间最大为 1.38，活化能为 17.42 kJ/mol。酶活性在 pH 4-8 范围内达到峰值，单宁酶的最大相对活性（100.6%）在 pH 6 时达到。用单宁酸测定纯化酶的 K 和 V 值分别为 7.3 mg/mL 和 3333.33 U/mL。该酶在 12 小时后降低了所有富含单宁的底物中的总单宁含量。没食子酸（GA）的总酚含量为 77.75 ppm，抗氧化活性为 82.91%。观察到 GA 作为抗菌影响因子，对铜绿假单胞菌 ATCC27853 的抑菌圈直径（IZD）最大为 31±1.0 mm。GA 的最小抑菌浓度值范围为 7770.0-121.41 µg/mL。所得到的 GA 对除宋内志贺菌 DSM5570 和伤寒沙门氏菌 DSM17058 以外的所有细菌菌株均表现出杀菌作用，这两种细菌表现出抑菌作用。
