选择性抑制技术测定活性污泥细菌、真菌活性分布的适用性分析

以葡萄糖为唯一碳源,采用放线菌酮和硫酸链霉素作为真菌、细菌抗生素以抑制其活性,以基质诱导耗氧速率为考察指标,以好氧污泥、土壤污泥以及厌氧污泥为研究对象,对选择性抑制技术测定活性污泥中细菌、真菌分布的适用性进行了系统评估.随抗生素的投加,好氧污泥和土壤污泥的耗氧速率减小,厌氧污泥的耗氧速率反而增大,此方法对厌氧污泥不适用.当放线菌酮为1mg/g、硫酸链霉素为2mg/g时,抗生素对好氧污泥的抑制功效即D值为1,但并不能通过改变投药量使土壤污泥D值接近于1,说明所用抗生素对好氧污泥活性具有选择性抑制作用,而对土壤污泥活性抑制不具选择性.结果表明,选择性抑制技术能够用于测定好氧活性污泥中细菌和真菌的数量分布,但也存在着抗生素抑制作用失效、不完全抑制和实验结果精确度不高等问题,因此需要在抗生素选择、微生物活性指标选择等方面进行更深入的研究.

Feasibility of Antibiotic Selective Inhibition Method Applied for Measuring Bacterial and Fungal Activities Distribution in Activated Sludge

The study evaluated the selective inhibition method for measuring the fungal and bacterial distribution in the activated sludge, using glucose as sole carbon source, and cycloheximide and streptomycin as bactericide and fungicide, respectively, substrate-induced oxygen uptake rate (OUR) as bioactivity index. Three samples were examined, i.e., aerobic sludge in a wastewater treatment plant, soils and anaerobic sludge. As selective microbial biocides were applied, the OUR of aerobic and soils sludge reduced, whereas the OUR of anaerobic sludge was stimulated. When 1 mg/g cycloheximide and 2 mg/g streptomycin were applied, the inhibition index D of aerobic sludge was approximatelly 1; however, the values of D for soils were greater than 1 at all the dosages of bactericide or fungicide applied in this study. These results suggested that the antibiotics used in this study could selectively inhibit aerobic sludge and partially inhibit the soils. It was found that the selective inhibition method was suitable for aerobic sludge analysis, but encountered problems for the other samples, e.g., failure inhibition effect of antibiotic, partial inhibition and low accuracy. Further studies are therefore needed in the selection of antibiotic and microbial activity parameter.