摘要
      基于微藻的废水处理系统（AWWTS）最近在缓解城市废水中的抗生素抗性基因（ARGs）方面显示出了前景。然而，由于MWW中存在大量的ARGs，使用间接的传统水质参数来监测废水中ARGs的减少将使该过程不那么繁重，经济上也负担得起。为了在ARGs和水质参数之间建立一种稳健的关系，本研究在室外环境条件下采用了单一培养的不同微藻菌株（CM2、KL10）和多物种组合（CK和WW）进行MWW处理。使用实时PCR对MWW影响物和流出物中的研究基因进行定量。所有的培养物都显著提高了MWW的物理化学性质。在本研究分析的14个基因中，在所有培养物中，tetO、tetW、tetX和ermB在治疗的前4天内都下降到无法检测的程度。其他基因，包括blaCTX、sul1、cmlA、aadA、int1和uidA，也下降到超过2对数下降值（LRV）。可移动遗传元件int1与大多数ARGs呈正相关，尤其是sul1（r≤0.99，p<0.01）和aadA（r≤0.97，p<0.01）。同样，大肠杆菌指示基因uidA与所研究的基因呈正相关，特别是与aadA、blaCTX、，blaTEM和cmlA（r≤0.99，p<0.01）。一些研究的基因也与总溶解固体（TDS）呈正相关（r≤0.98，p<0.01），和/或与总悬浮固体（TSS）呈负相关（r≥-0.98，p<0.01）和pH（r≤-0.98，p<0.01）。，发现KL10和CM2在基因抑制方面比它们的多物种对应物更一致。研究结果表明，TDS、TSS和大肠杆菌等水质参数是AWWTS中ARGs缓解的可靠指标，并进一步突出了单一栽培相对于多物种培养在MWW流基因抑制方面的优势。
Abstract
Microalgae-based wastewater treatment systems (AWWTS) have recently shown promise in the mitigation of antibiotic resistance genes (ARGs) from municipal wastewater (MWW). However, due to the large number of ARGs that exist in MWW, the use of indirect conventional water quality parameters to monitor ARGs reduction in wastewater would make the process less burdensome and economically affordable. In order to establish a robust relationship between the ARGs and water quality parameters, the current study employed different microalgae strains in monoculture (CM2, KL10) and multi-species combinations (CK and WW) for the MWW treatment under outdoor environmental conditions. The studied genes were quantified in the MWW influents and effluents using real-time PCR. All the cultures substantially improved the physicochemical qualities of the MWW. Out of the 14 genes analyzed in this study, tetO, tetW, tetX and ermB were decreased beyond detection within the first 4 days of treatment in all the cultures. Other genes, including blaCTX, sul1, cmlA, aadA, int1 and uidA were also decreased beyond a 2 log reduction value (LRV). The mobile genetic element, int1, correlated positively with most of the ARGs, especially sul1 (r ≤ 0.99, p < 0.01) and aadA (r ≤ 0.97, p < 0.01). Similarly, the Escherichia coli indicator gene, uidA, correlated positively with the studied genes, especially with aadA, blaCTX, blaTEM and cmlA (r ≤ 0.99 for each, p < 0.01). Some of the studied genes also correlated positively with total dissolved solids (TDS) (r ≤ 0.98, p < 0.01), and/or negatively with total suspended solids (TSS) (r ≤ −0.98, p < 0.01) and pH (r ≤ −0.98, p < 0.01). Among the tested cultures, both monocultures, i.e., KL10 and CM2 were found to be more consistent in gene suppression than their multi-species counterparts. The findings revealed water quality parameters such as TDS, TSS and E. coli as reliable proxies for ARGs mitigation in AWWTS and further highlight the superiority of monocultures over multi-species cultures in terms of gene suppression from the MWW stream.

https://www.mdpi.com/2079-6382/11/11/1531