| 糖蜜酒精废水脱色微生物的筛选及鉴定 |
| 摘要点击 2128 全文点击 982 投稿时间：2011-11-13 修订日期：2012-03-12 |
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| 中文关键词 糖蜜酒精废水 生物脱色 黄曲霉 筛选 鉴定 |
| 英文关键词 molasses spentwash decolorization Aspergillus flavus screening identification |
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| 中文摘要 |
| 从自然界中筛选能够脱色糖蜜酒精废水的微生物, 为实际废水的生物处理提供优良的脱色菌种. 以废水中较难降解的色素之一类黑精的模拟合成物为目标底物建立选育模型进行初筛, 以对未经厌氧处理的废水原液的脱色能力为复筛依据, 并通过摇瓶实验测试菌株的脱色性能, 凝胶过滤色谱测试脱色前后糖蜜酒精废水色素相对分子质量分布. 从采集的土壤样品中分离获得1株糖蜜酒精废水脱色菌株A5P1, 经形态学分析和ITS序列分析鉴定为黄曲霉(Aspergillus flavus). 结果表明, 最佳脱色条件为: 接种量4.3×104个· mL-1, 培养基初始pH 4.5, 培养温度39℃, 菌株A5P1对未处理的糖蜜酒精废水4 d培养脱色率可达到53.0%, COD减少80%. 凝胶过滤色谱结果表明菌株A5P1既可脱除糖蜜酒精废水色素中大分子质量组分, 又可减少小分子质量组分含量. 酶活测定实验发现菌体细胞中至少存在产过氧化氢酶、漆酶和不依赖锰的锰过氧化物酶等脱色相关酶. 初步认为菌株A5P1对色素有一定的吸附作用, 但脱色机制主要为生物降解. |
| 英文摘要 |
| Microorganisms were screened from the natural environment for decolorization of molasses spent wash, and the isolated strains were then employed in the treatment of actual wastewater. The primary screening was carried out on agar plates supplemented with synthesized melanoidin as the target substrate, since melanoidin is one of the most refractory pigments in wastewater. Promising microorganisms were further selected through secondary screening by decolorization of untreated actual wastewater in shaking flask cultures. Gel filtration chromatography was used to determine the molecular weight distribution of pigments in molasses spent wash before and after decolorization. A strain named A5P1 was isolated from the soil samples collected, showing a good ability of decolorizing molasses spent wash, and was later identified as Aspergillus flavus by morphology and ITS sequence analysis. Experimental study of factors affecting the decolorization performance of strain A5P1 gave the optimal conditions as follows: 4.3×104 mL-1 of inoculum size, medium with initial pH of 4.5 and cultivation at 39℃. It could decolorize 53.0% of the pigments in the untreated molasses spent wash and decreased 80% of chemical oxygen demand after four-day incubation. The result of gel filtration chromatography demonstrated that both the large and small molecular weight fractions of pigments in the molasses spent wash could be removed by strain A5P1. Based on the measurement of enzyme activities, at least three different kinds of enzymes, i. e. the enzyme with H2O2-producing activity, laccase and manganese peroxidase were involved in the decolorization process. Therefore, the decolorization mechanism of strain A5P1 was preliminarily considered to be mainly biodegradation, with bioadsorption as a minor reaction. |
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