Nitrogenous disinfection by-products (N-DBPs) in chlorinated drinking water are receiving increasing attention due to their elevated toxicities. An effective strategy to control the formation of N-DBPs is to reduce their nitrogenous precursors (e.g., amino acids [AAs], believed to be the important N-DBP precursors) before disinfection. So far, little information is available about the effectiveness of conventional microbial degradation at controlling the formation of N-DBPs. In this study, the biodegradability of 20 AAs was investigated, and the impacts of microbial degradation for the selected 6 typical AAs on the formation of N-DBPs (haloacetonitriles and haloacetamides) and traditional carbonaceous DBP (chloroform) were investigated. The results indicated that glycine, arginine, aspartic acid, asparagine, alanine and serine were susceptible to biodegradation, and the formation potentials (FPs) of DBPs were remarkably reduced after biodegradation. The highest chloroform FP reduction rates from tryptophan and tyrosine were 85.4% and 56.2%, respectively. The FPs of dichloroacetonitrile and trichloroacetamide were also reduced after biodegradation of the all selected AA samples during chlor(am)ination. Dichloroacetamide FPs decreased continuously with incubation time during chlorination for phenylalanine, asparagine, aspartic acid, and the mixed AAs, and the highest reduction rates were 78.7%, 74.6%, 46.7% and 35.3% respectively. The results of integrated toxicity analysis indicated that the pre-treatment of microbial degradation significantly decreased the integrated toxicity of DBPs formed from AAs. Moreover, the microbial community analysis revealed that Proteobacteria was predominant at phylum level in the mixed AA sample, and the dominant genera were Acinetobacter and Pseudomonas. Proteobacteria may play an important role in controlling DBP precursor.

氯化饮用水中的氮消毒副产物（N-DBPs）由于毒性较高而受到越来越多的关注。控制N-DBP形成的有效策略是在消毒前减少其含氮前体（例如，氨基酸[AAs]，被认为是重要的N-DBP前体）。到目前为止，关于常规微生物降解在控制N-DBP形成方面的有效性的信息很少。在这项研究中，研究了20种AA的生物降解性，并研究了所选6种典型AA的微生物降解对N-DBP（卤代乙腈和卤代乙酰胺）和传统碳质DBP（氯仿）形成的影响。结果表明，甘氨酸，精氨酸，天冬氨酸，天冬酰胺，丙氨酸和丝氨酸易被生物降解，生物降解后DBPs的形成潜能（FPs）显着降低。色氨酸和酪氨酸对氯仿FP的最高还原率分别为85.4％和56.2％。在氯（氨）化过程中所有选择的AA样品生物降解后，二氯乙腈和三氯乙酰胺的FP也降低。苯丙氨酸，天冬酰胺，天冬氨酸和混合AA的氯化过程中，二氯乙酰胺FPs随着氯化时间的延长而连续下降，最高还原率分别为78.7％，74.6％，46.7％和35.3％。综合毒性分析的结果表明，微生物降解的预处理显着降低了AA形成的DBP的综合毒性。而且，变形杆菌是在混合AA样品中门级主要的，主要的属有不动杆菌及假单胞菌。变形杆菌可能在控制DBP前体中起重要作用。