黑曲霉分泌微生物絮凝剂的效果及其絮凝特性

摘要

为了降低黑曲霉分泌絮凝剂的培养成本，提高微生物絮凝剂活性和产量，优化了培养条件，获得该菌产絮凝剂的最佳培养条件为：初始pH 7条件下，25℃恒温培养48 h，此时制备的絮凝剂对高岭土絮凝率达到96％以上．利用红外光谱法分析絮凝剂成分，推断其主要由多糖、核酸和蛋白质构成．在此基础上研究微生物絮凝剂对污泥脱水和Cr（Ⅵ）还原能力，结果显示黑曲霉分泌的微生物絮凝剂对污泥脱水有良好效果，当其投加质量浓度为27 mg/L时，污泥含水率从97.1％降至78.2％．微生物絮凝剂处理Cr（Ⅵ）溶液时，对低质量浓度Cr（Ⅵ）还原效果较好，在pH值1～5，还原能力均较高，对质量浓度为20 mg/L 的Cr（Ⅵ）的还原率均大于99％．%To reduce the cultivation cost of microbial flocculant secreted by Aspergillus niger,and im-prove the activity and production of bioflocculant,the culture conditions were investigated.The result showed that under the optimal cultural conditions of initial pH value 7,cultural time 48 h,cultural tem-perature 25 ℃,the flocculation effect of kaolin suspensions using this bioflocculant was over 96.0%.In-frared spectroscopy observation revealed that the produced bioflocculant was mainly composed of polysac-charides,nucleic acid and protein.The bioflocculant was found as a highly effective dewatering agent of sludge.At the dose of 27.0 mg/L,the moisture content of sludge decreased from 97.1% to 78.2%. When dealing with different concentrations of Cr(Ⅵ)solution,the bioflocculant showed better reduction efficiency towards Cr(Ⅵ)solution of lower concentration as pH value ranged from 1 ~5 ,and the reduc-tion rate of 20 mg/L Cr(Ⅵ)exceeded 99%.