Garcia-de-Lomas Juan, Corzo Alfonso, Carmen Portillo M, Gonzalez Juan M, Andrades Jose A, Saiz-Jimenez Cesáreo, Garcia-Robledo Emilio
Department of Biology, Faculty of Marine and Environmental Sciences, University of Cádiz, Pol. Río San Pedro s/n, 11510 Puerto Real, Cadiz, Spain.
Water Res. 2007 Jul;41(14):3121-31. doi: 10.1016/j.watres.2007.04.004. Epub 2007 May 23.
The role of the nitrate-reducing, sulfide-oxidising bacteria (NR-SOB) in the nitrate-mediated inhibition of sulfide net production by anaerobic wastewater biofilms was analyzed in two experimental bioreactors, continuously fed with the primary effluent of a wastewater treatment plant, one used as control (BRC) and the other one supplemented with nitrate (BRN). This study integrated information from H(2)S and pH microelectrodes, RNA-based molecular techniques, and the time course of biofilm growth and bioreactors water phase. Biofilms were a net source of sulfide for the water phase (2.01 micromol S(2-)(tot)m(-2)s(-1)) in the absence of nitrate dosing. Nitrate addition effectively led to the cessation of sulfide release from biofilms despite which a low rate of net sulfate reduction activity (0.26 micromol S(2-)(tot)m(-2)s(-1)) persisted at a deep layer within the biofilm. Indigenous NR-SOB including Thiomicrospira denitrificans, Arcobacter sp., and Thiobacillus denitrificans were stimulated by nitrate addition resulting in the elimination of most sulfide from the biofilms. Active sulfate reducing bacteria (SRB) represented comparable fractions of total metabolically active bacteria in the libraries obtained from BRN and BRC. However, we detected changes in the taxonomic composition of the SRB community suggesting its adaptation to a higher level of NR-SOB activity in the presence of nitrate.
在两个实验性生物反应器中分析了硝酸盐还原、硫化物氧化细菌（NR-SOB）在硝酸盐介导的厌氧废水生物膜对硫化物净产生的抑制作用中的作用。这两个生物反应器连续进料污水处理厂的原水，一个用作对照（BRC），另一个添加硝酸盐（BRN）。本研究整合了来自H₂S和pH微电极、基于RNA的分子技术以及生物膜生长和生物反应器水相的时间进程的信息。在不添加硝酸盐的情况下，生物膜是水相中硫化物的净来源（2.01 μmol S₂⁻(tot)m⁻²s⁻¹）。添加硝酸盐有效地导致生物膜停止释放硫化物，尽管如此，在生物膜深层仍存在低速率的净硫酸盐还原活性（0.26 μmol S₂⁻(tot)m⁻²s⁻¹）。添加硝酸盐刺激了包括反硝化硫微螺菌、弓形杆菌属和反硝化硫杆菌在内的本地NR-SOB，从而消除了生物膜中的大部分硫化物。在从BRN和BRC获得的文库中，活性硫酸盐还原细菌（SRB）在总代谢活性细菌中所占比例相当。然而，我们检测到SRB群落的分类组成发生了变化，表明其在硝酸盐存在下适应了更高水平的NR-SOB活性。
