Ngo Anna Christina R, Devanadera Mark Kevin P, Dedeles Gina R
The Graduate School, University of Santo Tomas.
Research Center for the Natural and Applied Sciences, University of Santo Tomas.
J Health Pollut. 2016 Jun 16;6(10):42-55. doi: 10.5696/2156-9614-6-10.42. eCollection 2016 Jun.
Discharge of textile dyes into the environment poses a significant threat. They are poorly biodegradable and toxic due to their complex composition and aromatic structures. In the search for alternatives to physical and chemical treatments, biodegradation of synthetic dyes by various microbes is emerging as an effective and promising approach.
The decolorization of synthetic dyes by yeast co-cultures and consortia from leaves and fruit peels was assessed at a 50 μg/mL dye concentration.
Yeasts isolates from leaves and fruit peels were screened for potential decolorization of synthetic dyes at 25-50 μg/mL. Decolorization parameters were optimized for synergistic properties and development of yeast co-cultures and consortium. Possible decolorization reactions were initially assessed by cell immobilization, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and Fourier transform infrared spectroscopy (FTIR) analysis.
A total of 16 organisms were isolated from rose, mango, and pineapple leaves and pineapple fruit peels. Only 4 organisms showed high decolorization of four synthetic dyes: Direct Pink B, Disperse Yellow 5G, Direct Fast Orange S, and Reactive Turquoise Blue G. The optimum condition for best decolorizers of selected dyes at 50 μg/mL were Candida guilliermondii (Y011) for Direct Pink B at pH 9, 37°C; C. dubliniensis (Y014) for Disperse Yellow 5G at pH 4, 25°C; C. guilliermondii (Y004) for Direct Fast Orange S at pH 7, 25°C, and C. famata (Y003) for Reactive Turquoise Blue G at pH 4, 35°C. None of the 4 yeast isolates showed any antagonistic activity when subjected to the lawn-spotting method for the formation of co-cultures and consortium. The best co-cultures obtained 61% decolorization of Direct Pink B, 65% decolorization of Disperse Yellow 5G, 41% decolorization of Direct Fast Orange S, and 50-51% decolorization of Reactive Turquoise Blue G. Immobilized yeast cells were active in decolorizing the dyes and SDS-PAGE analysis confirmed the presence of an extracellular protein. The results of FTIR also showed changes in the functional group of Direct Pink B, but minimal changes in the functional groups of Reactive Turquoise Blue G, indicating a different decolorization pathway.
Yeasts in co-cultures and consortia can decolorize toxic synthetic dyes through different decolorization pathways such as enzyme degradation and bioaccumulation. This technique may have a use in the treatment of wastewater systems.
纺织染料排放到环境中构成了重大威胁。由于其复杂的成分和芳香结构，它们很难被生物降解且具有毒性。在寻找物理和化学处理方法的替代方案时，各种微生物对合成染料的生物降解正成为一种有效且有前景的方法。
在染料浓度为50μg/mL的情况下，评估酵母共培养物以及来自树叶和果皮的菌群对合成染料的脱色效果。
筛选从树叶和果皮中分离出的酵母，检测其在25 - 50μg/mL浓度下对合成染料的潜在脱色能力。针对酵母共培养物和菌群的协同特性及发展对脱色参数进行优化。最初通过细胞固定化、十二烷基硫酸钠聚丙烯酰胺凝胶电泳（SDS - PAGE）和傅里叶变换红外光谱（FTIR）分析来评估可能的脱色反应。
从玫瑰、芒果、菠萝叶以及菠萝果皮中共分离出16种微生物。只有4种微生物对4种合成染料：直接桃红B、分散黄5G、直接耐晒橙S和活性翠蓝G表现出高脱色率。在50μg/mL浓度下，所选染料的最佳脱色菌的最佳条件为：对直接桃红B，季也蒙毕赤酵母（Y011），pH 9，37°C；对分散黄5G，都柏林毕赤酵母（Y014），pH 4，25°C；对直接耐晒橙S，季也蒙毕赤酵母（Y004），pH 7，25°C；对活性翠蓝G，法马塔假丝酵母（Y003），pH 4，35°C。当采用菌苔点种法形成共培养物和菌群时，这4种酵母分离株均未表现出任何拮抗活性。得到的最佳共培养物对直接桃红B的脱色率为61%，对分散黄5G的脱色率为65%，对直接耐晒橙S的脱色率为41%，对活性翠蓝G的脱色率为50 - 51%。固定化酵母细胞对染料具有脱色活性，SDS - PAGE分析证实存在一种细胞外蛋白。FTIR结果还显示直接桃红B的官能团发生了变化，而活性翠蓝G的官能团变化极小，表明脱色途径不同。
共培养物和菌群中的酵母可通过酶降解和生物积累等不同脱色途径对有毒合成染料进行脱色。该技术可能在废水处理系统中有用。
