Jadhav J P, Parshetti G K, Kalme S D, Govindwar S P
Department of Biochemistry, Shivaji University, Kolhapur 416 004, Maharashtra, India.
Chemosphere. 2007 Jun;68(2):394-400. doi: 10.1016/j.chemosphere.2006.12.087. Epub 2007 Feb 9.
Saccharomyces cerevisiae MTCC 463 decolourizes toxic azo dye, methyl red by degradation process. Methyl red (100mgl(-1)) is degraded completely within 16min in plain distilled water under static anoxic condition, at the room temperature. Effect of physicochemical parameters (pH of medium, composition of medium, concentration of cells, concentration of dye, temperature and agitation) on methyl red decolourization focused the optimal condition required for decolourization. Biodegradation (fate of metabolism) of methyl red in plain distilled water was found to be pH dependent. Cells of Saccharomyces cerevisiae could degrade methyl red efficiently up to 10 cycles in plain distilled water. Analysis of samples extracted with ethyl acetate from decolourized culture flasks in plain distilled water (pH 6.5) and at pH 9 using UV-VIS, TLC, HPLC and FTIR confirm biodegradation of methyl red into several different metabolites. A study of the enzymes responsible for the biodegradation of methyl red in the control and cells obtained after decolourization in plain distilled water (pH 6.5) and at pH 9 showed different levels of the activities of laccase, lignin peroxidase, NADH-DCIP reductase, azoreductase, tyrosinase and aminopyrine N-demethylase. A significant increase in the activities of lignin peroxidase and NADH-DCIP reductase was observed in the cells obtained after decolourization in plain distilled water (pH 6.5), however cells obtained at pH 9 shows increased activities of azoreductase, tyrosinase, lignin peroxidase and NADH-DCIP reductase. High efficiency to decolourize methyl red in plain distilled water and low requirement of environmental conditions enables this yeast to be used in biological treatment of industrial effluent containing azo dye, methyl red.
酿酒酵母MTCC 463通过降解过程使有毒偶氮染料甲基红脱色。在室温下，静态缺氧条件下，甲基红（100mg l⁻¹）在纯蒸馏水中16分钟内完全降解。物理化学参数（培养基pH值、培养基组成、细胞浓度、染料浓度、温度和搅拌）对甲基红脱色的影响确定了脱色所需的最佳条件。发现甲基红在纯蒸馏水中的生物降解（代谢命运）取决于pH值。酿酒酵母细胞在纯蒸馏水中最多可高效降解甲基红10个循环。使用紫外可见光谱、薄层色谱、高效液相色谱和傅里叶变换红外光谱对在纯蒸馏水（pH 6.5）和pH 9条件下脱色培养瓶中用乙酸乙酯萃取的样品进行分析，证实甲基红生物降解为几种不同的代谢物。对在纯蒸馏水（pH 6.5）和pH 9条件下脱色后得到的对照细胞和细胞中负责甲基红生物降解的酶的研究表明，漆酶、木质素过氧化物酶、NADH-DCIP还原酶、偶氮还原酶、酪氨酸酶和氨基比林N-脱甲基酶的活性水平不同。在纯蒸馏水（pH 6.5）中脱色后得到的细胞中观察到木质素过氧化物酶和NADH-DCIP还原酶的活性显著增加，然而在pH 9条件下得到的细胞中偶氮还原酶、酪氨酸酶、木质素过氧化物酶和NADH-DCIP还原酶的活性增加。该酵母在纯蒸馏水中对甲基红的高效脱色能力以及对环境条件的低要求使其可用于含偶氮染料甲基红的工业废水的生物处理。
