Gedalanga Phillip B, Pornwongthong Peerapong, Mora Rebecca, Chiang Sheau-Yun Dora, Baldwin Brett, Ogles Dora, Mahendra Shaily
Department of Civil and Environmental Engineering, University of California, Los Angeles, California, USA.
Appl Environ Microbiol. 2014 May;80(10):3209-18. doi: 10.1128/AEM.04162-13. Epub 2014 Mar 14.
Bacterial multicomponent monooxygenase gene targets in Pseudonocardia dioxanivorans CB1190 were evaluated for their use as biomarkers to identify the potential for 1,4-dioxane biodegradation in pure cultures and environmental samples. Our studies using laboratory pure cultures and industrial activated sludge samples suggest that the presence of genes associated with dioxane monooxygenase, propane monooxygenase, alcohol dehydrogenase, and aldehyde dehydrogenase are promising indicators of 1,4-dioxane biotransformation; however, gene abundance was insufficient to predict actual biodegradation. A time course gene expression analysis of dioxane and propane monooxygenases in Pseudonocardia dioxanivorans CB1190 and mixed communities in wastewater samples revealed important associations with the rates of 1,4-dioxane removal. In addition, transcripts of alcohol dehydrogenase and aldehyde dehydrogenase genes were upregulated during biodegradation, although only the aldehyde dehydrogenase was significantly correlated with 1,4-dioxane concentrations. Expression of the propane monooxygenase demonstrated a time-dependent relationship with 1,4-dioxane biodegradation in P. dioxanivorans CB1190, with increased expression occurring after over 50% of the 1,4-dioxane had been removed. While the fraction of P. dioxanivorans CB1190-like bacteria among the total bacterial population significantly increased with decrease in 1,4-dioxane concentrations in wastewater treatment samples undergoing active biodegradation, the abundance and expression of monooxygenase-based biomarkers were better predictors of 1,4-dioxane degradation than taxonomic 16S rRNA genes. This study illustrates that specific bacterial monooxygenase and dehydrogenase gene targets together can serve as effective biomarkers for 1,4-dioxane biodegradation in the environment.
对食二恶烷假诺卡氏菌CB1190中的细菌多组分单加氧酶基因靶点进行了评估，以确定其作为生物标志物的用途，用于识别纯培养物和环境样品中1,4 - 二恶烷的生物降解潜力。我们使用实验室纯培养物和工业活性污泥样品进行的研究表明，与二恶烷单加氧酶、丙烷单加氧酶、乙醇脱氢酶和醛脱氢酶相关的基因的存在是1,4 - 二恶烷生物转化的有前景的指标；然而，基因丰度不足以预测实际的生物降解。对食二恶烷假诺卡氏菌CB1190和废水样品中的混合群落中二恶烷和丙烷单加氧酶的时间进程基因表达分析揭示了与1,4 - 二恶烷去除率的重要关联。此外，乙醇脱氢酶和醛脱氢酶基因的转录本在生物降解过程中上调，尽管只有醛脱氢酶与1,4 - 二恶烷浓度显著相关。丙烷单加氧酶的表达在食二恶烷假诺卡氏菌CB1190中与1,4 - 二恶烷生物降解呈现时间依赖性关系，在1,4 - 二恶烷被去除超过50%后表达增加。虽然在进行活性生物降解的废水处理样品中，食二恶烷假诺卡氏菌CB1190样细菌在总细菌群体中的比例随着1,4 - 二恶烷浓度的降低而显著增加，但基于单加氧酶的生物标志物的丰度和表达比分类学16S rRNA基因更能预测1,4 - 二恶烷的降解。这项研究表明，特定的细菌单加氧酶和脱氢酶基因靶点共同可作为环境中1,4 - 二恶烷生物降解的有效生物标志物。
