Stoeva Magdalena K, Nalula Gilbert, Garcia Nicholas, Cheng Yiwei, Engelbrektson Anna L, Carlson Hans K, Coates John D
Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, United States.
Energy Biosciences Institute, Berkeley, CA, United States.
Front Microbiol. 2019 Apr 2;10:654. doi: 10.3389/fmicb.2019.00654. eCollection 2019.
Hydrogen sulfide is a toxic and corrosive gas, produced by the activity of sulfate-reducing microorganisms (SRM). Owing to the environmental, economic and human-health consequences of sulfide, there is interest in developing specific inhibitors of SRM. Recent studies have identified perchlorate as a promising emerging inhibitor. The aim of this work is to quantitatively dissect the inhibitory dynamics of perchlorate. Sulfidogenic mixed continuous-flow systems were treated with perchlorate. SRM number, sulfide production and community structure were monitored pre-, during and post-treatment. The data generated was compared to a simple mathematical model, where SRM growth slows as a result of inhibition. The experimental data supports the interpretation that perchlorate largely acts to suppress SRM growth rates, rendering planktonic SRM increasingly susceptible to wash-out. Surface-attachment was identified as an important parameter preventing SRM wash-out and thus governing inhibitory dynamics. Our study confirmed the lesser depletion of surface-attached SRM as compared to planktonic SRM during perchlorate treatment. Indirect effects of perchlorate (bio-competitive exclusion of SRM by dissimilatory perchlorate-reducing bacteria, DPRB) were also assayed by amending reactors with DPRB. Indeed, low concentrations of perchlorate coupled with DRPB amendment can drive sulfide concentrations to zero. Further, inhibition in a complex community was compared to that in a pure culture, highlighting similarities and differences between the two scenarios. Finally, we quantified susceptibility to perchlorate across SRM in various culture conditions, showing that prediction of complex behavior in continuous systems from batch results is possible. This study thus provides an overview of the sensitivity of sulfidogenic communities to perchlorate, as well as mechanisms underlying these patterns.
硫化氢是一种有毒且具腐蚀性的气体，由硫酸盐还原微生物（SRM）的活动产生。鉴于硫化物对环境、经济和人类健康造成的影响，人们对开发SRM的特异性抑制剂颇感兴趣。最近的研究已确定高氯酸盐是一种有前景的新型抑制剂。这项工作的目的是定量剖析高氯酸盐的抑制动力学。用高氯酸盐处理产硫化物的混合连续流系统。在处理前、处理期间和处理后监测SRM数量、硫化物产生情况和群落结构。将生成的数据与一个简单的数学模型进行比较，在该模型中，SRM的生长因抑制作用而减缓。实验数据支持这样的解释：高氯酸盐主要作用是抑制SRM的生长速率，使浮游SRM越来越容易被冲走。表面附着被确定为防止SRM被冲走并因此控制抑制动力学的一个重要参数。我们的研究证实，在高氯酸盐处理期间，与浮游SRM相比，表面附着的SRM消耗较少。还通过向反应器中添加异化高氯酸盐还原细菌（DPRB）来测定高氯酸盐的间接影响（DPRB对SRM的生物竞争排斥）。的确，低浓度的高氯酸盐与DPRB添加相结合可使硫化物浓度降至零。此外，将复杂群落中的抑制情况与纯培养中的抑制情况进行了比较，突出了两种情况之间的异同。最后，我们量化了各种培养条件下SRM对高氯酸盐的敏感性，表明从批次结果预测连续系统中的复杂行为是可能的。因此，本研究概述了产硫化物群落对高氯酸盐的敏感性以及这些模式背后的机制。
