Weithmann Nicolas, Mlinar Stanislava, Hilbrig Frank, Bachmaf Samer, Arndt Julia, Planer-Friedrich Britta, Weig Alfons R, Freitag Ruth
Process Biotechnology and Centre for Energy Technology (ZET), University of Bayreuth, Bayreuth, Germany.
Department of Environmental Geochemistry, Bayreuth Centre for Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany.
AMB Express. 2019 Nov 28;9(1):190. doi: 10.1186/s13568-019-0902-6.
The metal(loid) and in particular the Arsenic (As) burden of thirteen agricultural biogas plants and two sewage sludge digesters were investigated together with the corresponding microbial consortia. The latter were characterized by ARISA (automated ribosomal intergenetic spacer analysis) and next generation sequencing. The consortia were found to cluster according to digester type rather than substrate or metal(loid) composition. For selected plants, individual As species in the liquid and gaseous phases were quantified, showing that the microorganisms actively metabolize and thereby remove the As from their environment via the formation of (methylated) volatile species. The As metabolites showed some dependency on the microbial consortia, while there was no statistical correlation with the substrate mix. Finally, slurry from one agricultural biogas plant and one sewage sludge digester was transferred into laboratory scale reactors ("satellite reactors") and the response to a defined addition of As (30 and 60 µM sodium arsenite) was studied. The results corroborate the hypothesis of a rapid conversion of dissolved As species into volatile ones. Methanogenesis was reduced during that time, while there was no discernable toxic effect on the microbial population. However, the utilization of the produced biogas as replacement for natural gas, e.g. as fuel, may be problematic, as catalysts and machinery are known to suffer from prolonged exposure even to low As concentrations.
对13个农业沼气厂和2个污水污泥消化器的金属（类金属），特别是砷（As）负荷，以及相应的微生物群落进行了研究。后者通过自动核糖体基因间隔区分析（ARISA）和下一代测序进行表征。发现这些群落根据消化器类型聚类，而不是根据底物或金属（类金属）组成聚类。对于选定的工厂，对液相和气态中的个别砷物种进行了定量，结果表明微生物通过形成（甲基化）挥发性物种来积极代谢并从而从其环境中去除砷。砷代谢物显示出对微生物群落有一定依赖性，而与底物混合物没有统计相关性。最后，将一个农业沼气厂和一个污水污泥消化器的浆液转移到实验室规模的反应器（“卫星反应器”）中，研究了对特定添加量砷（30和60 μM亚砷酸钠）的响应。结果证实了溶解态砷物种快速转化为挥发性物种的假设。在此期间甲烷生成减少，而对微生物种群没有明显的毒性作用。然而，将产生的沼气用作天然气替代品（例如作为燃料）可能存在问题，因为已知催化剂和机械设备即使长时间暴露于低浓度砷也会受到影响。
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