Anthraquinone dyes are a class of typical carcinogenic and hard-biodegradable organic pollutants.This study aimed to enhance the decolorization of anthraquinone dye by rationally designing an expected immobilized system.Reactive blue 4(RB4) was used as a substrate model and a previous isolated dyedegrading strain Aspergillus flavus A5pl was purposefully immobilized.Considering the effects of cell attachment and mass transfer,the polyurethane foam(PUF) with open pore structure was selected as the immobilization carrier.Results showed that the RB4 decolorization efficiency was significant enhanced after immobilization.Compared to the free mycelium system,the decolorization time of200 mg·L^(-1)RB4 was shortened from 48 h to 28 h by the PUF-immobilized cell system.Moreover,the PUF-immobilized system could tolerate RB4 up to 2000 mg-L^(-1).In the packed bed bioreactor(PBBR),an average decolorization efficiency of 93.3% could be maintained by the PUF-immobilized system for26 days.The decolorization process of RB4 was well described by the logistic equation and the degradation pathway was discussed.It was found that the higher specific growth rate of the PUF-immobilized cells was one of reasons for the enhanced decolorization.The good performance of the PUFimmobilized cell system would make it have potential application value for RB4 bioremediation.
Wenbo YangQingyun LiShiqi GuoShijie SunAixing TangHaibo LiuYouyan Liu
为了寻找高效的产纤维素酶增效蛋白菌株,建立一种筛选方法从土壤中筛选得到一株产纤维素酶增效蛋白的细菌POEP1,其所产增效蛋白对纤维素酶(来源于黑曲霉Aspergillus niger)的滤纸酶活有明显的增效作用,通过对其进行16SrDNA分类鉴定,确定该菌株为栖稻假单胞菌(Pseudomonas oryzihabitans)。为进一步提高POEP1产纤维素酶增效蛋白的水平,对其培养条件进行优化。采用单因子试验筛选出最佳碳源为麦麸,最佳氮源为黄豆粉。再通过Plackett-Burman设计对与发酵相关的11个因子进行试验,筛选出麦麸、黄豆粉和KH2PO4为3个主要显著因子;由Box-Behnken实验结合响应面分析确定主要因子的最优水平为:麦麸质量浓度32.3 g L 1,黄豆粉质量浓度24.7 g L 1,KH2PO4质量浓度4.36 g L 1。优化后纤维素酶增效蛋白的产量提高1.7倍,增效活力由15.79 U mL 1增至43.31 U mL 1。
