活性黑5厌氧生物脱色的自催化作用研究

Autocatalysis in biological decolorization of Reactive Black 5 under anaerobic condition.

该文研究了活性黑5(RB5)经沼泽红假单胞菌W1脱色后的代谢物对RB5厌氧生物脱色的影响,实验结果表明:RB5的脱色代谢物能明显促进W1对RB5的脱色,同时对菌株W1生长有促进作用;不同浓度RB5的脱色代谢物均能促进菌株W1对RB5的脱色,并使培养液氧化还原电位(ORP)降低,其中200 mg/L RB5脱色产物对脱色的促进作用最大;RB5的脱色代谢物对RB5厌氧污泥脱色的促进作用与纯菌相似,不同的是它对厌氧污泥生长有一定抑制作用。循环伏安分析的实验结果表明:RB5脱色代谢物具有氧化还原介体的性质,其可逆的氧化还原峰分别位于83和-220 mV,说明RB5脱色代谢物对脱色的作用是通过氧化还原介体的机制实现的。通过对比RB5、W1胞外代谢物和RB5脱色代谢物的循环伏安特性可知,氧化还原介体来自RB5的脱色产物,即RB5厌氧生物脱色时具有自催化的特性。

The effects of decolorization metabolites （DM） of Reactive Black 5 （RB5） from Rhodopseudomonas palustris W1 on the biodecolorization of RB5 under anaerobic condition were investigated. The results indicated that DM significantly enhanced the decolorization rate of RB5 and the growth rate of W1. DM of different concentration RB5 played a crucial role for stimulating decolorization, in which DM of 200 mg/L RB5 brought the highest effect, and accelerated the decrease of ORP as well. Stimulation of decolorization of anaerobic sludge by DM was similar to decolorization of W1, but it differed in that DM would slightly inhibit the growth of bacteria in anaerobic sludge. Cyclic vohammogram of DM showed that pair current peaks of reversible oxidation and reduction appeared at potential of 83 and - 200 mV, respectively, indicating DM may present as redox mediators to enhance the RB5 decolorization. Comparison of cyclic voltammogram of RB5 solution, DM, and extracellular metabolites （EM） of the strain W1 further demonstrats that the redox mediators existing in the DM of RB5 decolorizaiton, namely RB5 play the role of autocatalysis in the process of an anaerobic biodecolorization.