地衣芽孢杆菌TG116胞外蛋白酶产酶条件与酶学性质

【背景】从独角莲中分离得到的地衣芽孢杆菌TG116是一株对植物病原菌具有广谱抗性作用的生防菌株。【目的】优化TG116的产酶条件并探索其酶学性质,进一步了解其抗菌机制。【方法】采用Folin-Phenol显色法与响应曲面法,优化菌株TG116的产酶条件并研究其蛋白酶的酶学性质。【结果】菌株TG116产酶最适条件为:温度40.83°C,p H 8.01,发酵时间53.74 h,增加通气量可以显著提高酶活力。按照优化后的条件培养48 h后,上清液蛋白酶活力从57.46 U/mL达到了254.07 U/mL。酶学性质研究表明:该酶为碱性蛋白酶,最适反应pH为8.5,最适反应温度为50°C,具有良好的温度和pH稳定性,EDTA对酶活具有强烈的抑制作用,金属离子Mg~(2+)、Ca~(2+)、Na~+、Co~(2+)、K~+等对酶活也具有一定的抑制作用。【结论】菌株TG116具有良好的p H与温度稳定性,在实际应用中蛋白酶不易失活,可以分解真菌的细胞壁蛋白成分,破坏细胞壁结构,从而抑制甚至杀死病原菌,达到抗菌作用。

Production and characterization of extracellular protease from biocontrol strain Bacillus licheniformis TG116

Background] Bacillus licheniformis TG116 isolated from Typhonium giganteum Engl is a biocontrol strain with broad-spectrum against plant pathogens. Objective] In order to optimize the enzyme production conditions of TG116 and explore its enzymatic properties. Methods] The optimization of enzyme production conditions and the enzymatic properties of proteases were investigated by Folin-Phenol chromogenic method and response surface methodology. Results] The optimal enzyme conditions to produce strain TG116 were temperature 40.83 °C, pH 8.01, and fermentation time 53.74 h and increasing aeration could significantly enhance enzyme activity. After 48 hours of incubation under optimized conditions, the protease activity of the supernatant reached 254.07 U/mL from 57.46 U/mL. The protein was alkaline protease, with optimum pH 8.5, the optimum temperature 50 °C and it has good temperature and pH stability. EDTA had strong inhibitory effect on enzyme activity and metal ions Mg2+, Ca2+, Na+, Co2+, K+ also have showed a certain inhibitory effect. Conclusion] Strain TG116 has great pH and temperature stability. The proteases are not easily inactivated in practical applications, which can decompose the cell wall protein components of fungi and destroy the cell wall structure, thus inhibiting and even killing pathogenic bacteria to achieve antibacterial effects.