Zinc toxicity stimulates microbial production of extracellular polymers in a copiotrophic acid soil.
Zinc toxicity stimulates microbial production of extracellular polymers in a copiotrophic acid soil.
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DOI：
10.1016/j.ibiod.2016.10.004
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发表时间：
2017-04
影响因子：
4.8
通讯作者：
Chen L
中科院分区：
文献类型：
--
作者：
Redmile-Gordon M;Chen L
胞外聚合物（EPS）的产生对生物膜结构、微生物营养和栖息地的稳定性至关重要。然而，受重金属污染的土壤中微生物EPS的生产模式仍然不确定。在这里，我们调查的天然微生物生物量在草原土壤中处理精制甘油或粗未精制生物柴油副产品（BCP）与和无ZnCl 2的细胞外反应。我们提取了微生物EPS和更容易溶解的微生物产物（SMP），并定量总多糖，糖醛酸和蛋白质含量在这些各自的提取物。有机物的添加，特别是BCP，显著促进了EPS-多糖和蛋白质的产生，但对EPS-糖醛酸没有影响，而在SMP-组分中，多糖和糖醛酸均显著增加。在响应列入Zn 2+，EPS-和SMP-多糖增加。这意味着，首先，土壤微生物对Zn 2+毒性的耐受机制存在通过刺激SMP和EPS的生产，其次，生物燃料工业的副产品可能具有增值的生物修复的努力，以支持原位生产的微生物生物聚合物的用途。微生物膜和移动的聚合物可能会影响一系列土壤特性。最近对土壤中EPS研究的关注预计将有助于提高对其他复杂系统（如连续运行的生物反应器）中生物膜动力学的理解。生物多样性副产物（BCP）被证明是支持微生物在酸性土壤中产生EPS的。BCP处理的土壤中锌（ZnCl 2）的污染增加了EPS多糖的生产。这种EPS的增加伴随着可溶性糖醛酸产量的增加。了解EPS和SMP在土壤中的动力学将有助于土壤工程生物过程的设计。BCP驱动的过程中，土壤和反应器应包括锌作为生物膜形成的影响因素。
The production of extracellular polymeric substances (EPS) is crucial for biofilm structure, microbial nutrition and proximal stability of habitat in a variety of environments. However, the production patterns of microbial EPS in soils as affected by heavy metal contamination remain uncertain. Here we investigate the extracellular response of the native microbial biomass in a grassland soil treated with refined glycerol or crude unrefined biodiesel co-product (BCP) with and without ZnCl2. We extracted microbial EPS and more readily soluble microbial products (SMP), and quantified total polysaccharide, uronic acid, and protein content in these respective extracts. Organic addition, especially BCP, significantly stimulated the production of EPS-polysaccharide and protein but had no impact on EPS-uronic acids, while in the SMP-fraction, polysaccharides and uronic acids were both significantly increased. In response to the inclusion of Zn2+, both EPS- and SMP-polysaccharides increased. This implies firstly that a tolerance mechanism of soil microorganisms against Zn2+ toxicity exists through the stimulation of SMP and EPS production, and secondly that co-products of biofuel industries may have value-added use in bioremediation efforts to support in-situ production of microbial biopolymers. Microbial films and mobile polymers are likely to impact a range of soil properties. The recent focus on EPS research in soils is anticipated to help contribute an improved understanding of biofilm dynamics in other complex systems - such as continuously operated bioreactors. Biodiesel co-product (BCP) is demonstrated to support microbial EPS production in acid soil. Contamination of BCP treated soil with zinc (ZnCl2) increased the production of EPS polysaccharides. This increase in EPS was accompanied by an increase in the production of soluble uronic acids. Understanding EPS and SMP dynamics in soils will assist design of engineered bioprocesses in soils. BCP-driven processes in soils and reactors should include Zn as an influential factor in biofilm formation.