Understanding the Dependence of Micropollutant Biotransformation Rates on Short-Term Temperature Shifts.,Environmental Science & Technology

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Understanding the Dependence of Micropollutant Biotransformation Rates on Short-Term Temperature Shifts.
Environmental Science & Technology ( IF 10.8 ) Pub Date : 2020-09-08 , DOI: 10.1021/acs.est.0c04017
Paola Meynet _{1,

2} , Russell J Davenport ₁ , Kathrin Fenner _{2,

3}

Affiliation

Temperature is a key factor that influences chemical biotransformation potential and rates, on which exposure and fate models rely to predict the environmental (micro)pollutant fate. Arrhenius-based models are currently implemented in environmental exposure assessment to adapt biotransformation rates to actual temperatures, assuming validity in the 0–30 °C range. However, evidence on how temperature shifts affect the physicochemical and microbial features in biological systems is scarce, questioning the validity of the existing modeling approaches. In this work, laboratory-scale batch assays were designed to investigate how a mixed microbial community responds to short-term temperature shifts, and how this impacts its ability to biotransform a range of structurally diverse micropollutants. Our results revealed three distinct kinetic responses at temperatures above 20 °C, mostly deviating from the classic Arrhenius-type behavior. Micropollutants with similar temperature responses appeared to undergo mostly similar initial biotransformation reactions, with substitution-type reactions maintaining Arrhenius-type behavior up to higher temperatures than oxidation-type reactions. Above 20 °C, the microbial community also showed marked shifts in both composition and activity, which mostly correlated with the observed deviations from Arrhenius-type behavior, with compositional changes becoming a more relevant factor in biotransformations catalyzed by more specific enzymes (e.g., oxidation reactions). Our findings underline the need to re-examine and further develop current environmental fate models by integrating biological aspects, to improve accuracy in predicting the environmental fate of micropollutants.

中文翻译：

了解微污染物生物转化率对短期温度变化的依赖性。

温度是影响化学生物转化潜力和速率的关键因素，暴露和结局模型依靠该模型来预测环境（微）污染物的结局。假设在0–30°C范围内有效，目前在环境暴露评估中采用基于Arrhenius的模型来使生物转化率适应实际温度。但是，关于温度变化如何影响生物系统中的物理化学和微生物特征的证据很少，这质疑了现有建模方法的有效性。在这项工作中，设计了实验室规模的分批测定法，以研究混合微生物群落如何应对短期温度变化，以及这如何影响其生物转化一系列结构多样的微污染物的能力。我们的研究结果表明，在高于20°C的温度下，三种动力学响应明显不同，大多数情况下与经典的Arrhenius型行为不同。具有相似温度响应的微污染物似乎经历了大部分相似的初始生物转化反应，其中取代型反应可保持Arrhenius型行为，直至其温度高于氧化型反应。在20°C以上时，微生物群落的组成和活性也发生了明显变化，这主要与观察到的与Arrhenius型行为的偏离有关，其中组成变化已成为由更特定的酶（例如氧化）催化的生物转化中更相关的因素。反应）。我们的发现强调，有必要通过整合生物学方面来重新审查并进一步开发当前的环境命运模型，

更新日期：2020-10-06

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