Northern Region Persistent Organic Pollution Control (NRPOP) Laboratory, Faculty of Engineering and Applied Science, Memorial University of Newfoundland, St. John's, NL, A1B 3X5, Canada.
Chemosphere. 2020 Jan;238:124655. doi: 10.1016/j.chemosphere.2019.124655. Epub 2019 Aug 24.
The effectiveness of nitrate-mediated souring control highly depends on the interactions of sulfate reducing bacteria (SRB) and nitrate reducing bacteria (NRB). Biosurfactants produced by natural NRB are promising bio-agents for enhancing NRB competence towards SRB. However, the function of NRB-produced biosurfactants in NRB-SRB interactions remains unexplored due to the rarely successful isolation of natural biosurfactant-producing NRB. Hereby, biosurfactant-aided inhibitory control of SRB strain Desulfomicrobium escambiense ATCC 51164 by biosurfactant-producing NRB strain Pseudomonas stutzeri CX3, reported in our previous work, was investigated. Under non-sour conditions, insufficient nitrate injection resulted in limited SRB inhibition. Phospholipid fatty acid (PLFA) biomarkers traced the overall bacterial responses. Compositional PLFA patterns revealed biosurfactant addition benefitted both SRB and NRB towards stressful conditions. Under sour conditions, nitrite oxidation of sulfide proved to be the primary mechanism for sulfide removal. The subsequent elevation of redox potential and pH inhibited SRB activities. NRB-produced biosurfactants significantly enhanced SRB inhibition by NRB through more efficient sulfide removal and effective duration of nitrate in the microcosms. Biosurfactants specially produced by the NRB strain are for the first time reported to significantly strengthen SRB inhibition by NRB via reduced nitrate usage and prolonged effective duration of nitrate, which has encouraging potential in nitrate-dependent souring control.
硝酸盐介导的酸化控制的有效性高度依赖于硫酸盐还原菌（SRB）和硝酸盐还原菌（NRB）的相互作用。天然 NRB 产生的生物表面活性剂是增强 NRB 对 SRB 竞争力的有前途的生物制剂。然而，由于天然生物表面活性剂产生 NRB 的分离很少成功，因此 NRB 产生的生物表面活性剂在 NRB-SRB 相互作用中的功能仍未得到探索。在此，我们研究了我们之前的工作中报道的，由生物表面活性剂产生 NRB 菌株 Pseudomonas stutzeri CX3 辅助生物表面活性剂抑制 Desulfomicrobium escambiense ATCC 51164 菌株的 SRB 作用。在非酸化条件下，由于硝酸盐注入不足，导致 SRB 抑制作用有限。磷脂脂肪酸（PLFA）生物标志物追踪了细菌的整体反应。组成型 PLFA 模式表明，生物表面活性剂的添加有利于 SRB 和 NRB 适应应激条件。在酸化条件下，证明亚硝酸盐氧化硫化物是去除硫化物的主要机制。随后氧化还原电位和 pH 值的升高抑制了 SRB 活性。NRB 产生的生物表面活性剂通过更有效地去除硫化物和延长硝酸盐在微环境中的有效持续时间，显著增强了 NRB 对 SRB 的抑制作用。NRB 菌株专门产生的生物表面活性剂首次被报道可通过减少硝酸盐的使用和延长硝酸盐的有效持续时间，显著增强 NRB 对 SRB 的抑制作用，这在依赖硝酸盐的酸化控制方面具有令人鼓舞的潜力。
