Isolation and characterization of alkalotolerant bacteria and optimization of process parameters for decolorization and detoxification of pulp and paper mill effluent by Taguchi approach
Isolation and characterization of alkalotolerant bacteria and optimization of process parameters for decolorization and detoxification of pulp and paper mill effluent by Taguchi approach
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DOI：
10.1007/s10532-010-9356-x
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发表时间：
2010-11-01
期刊：
影响因子：
3.6
通讯作者：
Thakur, Indu Shekhar
中科院分区：
文献类型：
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作者：
Mishra, Monika;Thakur, Indu Shekhar
从制浆造纸污泥中分离到4株不同的细菌，其中1株具有较高脱色和木质素能力的耐碱菌株(LP1)经鉴定为芽孢杆菌属。通过16S RNA测序。首先对脱色的工艺参数进行了优化，筛选出生长因子，并用田口法进行了进一步的验证，采用L-8正交表，在两个水平上选择了时间、pH、温度、搅拌和接种量七个因素。在pH值为8、温度为35℃、搅拌速度为200转/分、蔗糖浓度为2.5%、时间为48 h、接种量为5%(w/v)、黑液浓度为10%的条件下，脱色效果最好。优化后，木质素脱色率和脱色率分别提高了2倍，分别为25-69%和28-53%，表明田口法对制浆造纸废水中木质素的脱色和脱木素具有重要意义。参与脱色的酶有木聚糖酶(54U/m l)和锰过氧化物酶(28U/m l)。以酿酒酵母MTCC-36为模型生物，用彗星试验对处理后的出水进行了毒性评价，结果表明，经细菌处理后的出水降低了58%。
Four different bacterial strains were isolated from pulp and paper mill sludge in which one alkalotolerant isolate (LP1) having higher capability to remove color and lignin, was identified as Bacillus sp. by 16S RNA sequencing. Optimization of process parameters for decolorization was initially performed to select growth factors which were further substantiated by Taguchi approach in which seven factors, % carbon, % black liquor, duration, pH, temperature, stirring and inoculum size, at two levels, applying L-8 orthogonal array were taken. Maximum color was removed at pH 8, temperature 35A degrees C, stirring 200 rpm, sucrose (2.5%), 48 h, 5% (w/v) inoculum size and 10% black liquor. After optimization 2-fold increase in color and lignin removal from 25-69% and 28-53%, respectively, indicated significance of Taguchi approach in decolorization and delignification of lignin in pulp and paper mill effluent. Enzymes involved in the process of decolorization of effluent were found to be xylanase (54 U/ml) and manganese peroxidase (28 U/ml). Treated effluent was also evaluated for toxicity by Comet assay using Saccharomyces cerevisiae MTCC 36 as model organism, which indicated 58% reduction after treatment by bacterium.