大肠杆菌异源表达的Indigoidine与靛蓝的稳定性比较

Comparison of stability between heterologous expressed indigoidine in Escherichia coli and indigo

【背景】Indigoidine是一种来源于微生物的无毒天然蓝色素。【目的】比较Indigoidine和靛蓝的色素稳定性,进而评价Indigoidine的色素稳定性。【方法】构建重组菌株Escherichia coli DH5α/p28s异源表达Indigoidine,考察可见光、紫外线、pH、温度、氧化还原剂、食品添加剂和金属离子对其与商品级靛蓝色素稳定性的影响。【结果】以N,N-二甲基甲酰胺为溶剂,Indigoidine和靛蓝都对可见光、紫外线敏感;2种色素在pH1.0-11.0时稳定,强碱性pH对色素破坏作用很大;Indigoidine抗Vc还原能力强于靛蓝,氧化剂可不同程度地降低2种色素的保存率;2种色素热稳定性不佳,在75℃以下时Indigoidine的色素稳定性优于靛蓝;食品添加剂中的柠檬酸和苯甲酸分别对Indigoidine和靛蓝均具有显著的护色效果;对这2种色素,Ca^(2+)、Mg^(2+)均具有护色效果,Na^(+)、K^(+)、Li^(+)总体上没有明显的破坏作用,而Zn^(2+)、Al^(3+)、Cu^(2+)、Fe^(2+)、Fe^(3+)则具有显著的破坏作用。【结论】Indigoidine色素稳定性明显优于靛蓝,具有广阔的开发应用前景。

[Background] Indigoidine is a nontoxic blue pigment produced by microorganisms.[Objective] Comparison of the stability of heterologous expressed indigoidine in Escherichia coli and commercial indigo. [Methods] Recombinant E. coli DH5α/p28s strain was constructed to produce indigoidine. The effects of light, UV, pH, temperature, oxidant, reductant, food additive, metal ion on the stability of the two pigments were investigated. [Results] When N,N-dimethylformamide(DMF) was used as solvent, both indigoidine and indigo were sensitive to visible light and UV. The colors of the two pigments were stable at pH 1.0-11.0, but higher pH had a great destructive effect. The tolerance of indigoidine to Vc reduction was stronger than that of indigo. Both maximal absorption values were reduced at a certain degree by oxidant. Indigoidine showed distinguished better thermal stability than indigo below 75 ℃, but both were bleached at higher temperature. The food additive citric acid and benzoic acid had significant protective effect on the stability of indigoidine and indigo respectively. Ca^(2+) and Mg^(2+) showed certain color-keeping effect on both pigments, while Na^(+)、K^(+) and Li^(+) had no overall destruction impact, but Zn^(2+)、Al^(3+)、Cu^(2+)、Fe^(2+) and Fe^(3+) exhibited notable destruction on both. [Conclusion] Indigoidine exhibits much better overall stability than indigo, suggesting a broader prospect of development and application.