Department of Civil and Environmental Engineering, University of Utah, Salt Lake City, UT, USA.
Water Res. 2011 Jan;45(2):694-704. doi: 10.1016/j.watres.2010.08.038. Epub 2010 Aug 27.
This research demonstrates the first ever application of lytic bacteriophage (virus) mediated biocontrol of biomass bulking in the activated sludge process using Haliscomenobacter hydrossis as a model filamentous bacterium. Bacteriophages are viruses that specifically infect bacteria only. The lytic phage specifically infecting H. hydrossis was isolated from the mixed liquor of a local wastewater treatment plant. The isolated bacteriophage belongs to the Myoviridae family with a contractile tail (length-126 nm; diameter-18 nm) and icosahedral head (diameter-81 nm). Titer of the isolated phage with H. hydrossis was calculated to be 5.2 ± 0.3 × 10(5) PFU/mL and burst size was found to be 105 ± 7 PFU/infected cell. The phage was considerably stable after exposure to high temperature (42 °C) and pH between 5 and 8, emphasizing that it can withstand the seasonal/operational fluctuations under real-time applications. Phage to host (bacteria) ratio for the optimal infection was found to be 1:1000 with ∼54% host death. The isolated phage showed no cross infectivity with other bacteria most commonly found in activated sludge systems, thus validating its suitability for biocontrol of filamentous bulking caused by H. hydrossis. Following the phage application, successful reduction in sludge volume index (SVI) from 155 to 105 was achieved, indicating improved biomass settling. The application of phage did not affect nutrient removal efficiency of the biomass, suggesting no collateral damage. Similar to phage therapy in medical applications, phage-mediated biocontrol holds a great potentiality for large-scale applications as economic agent in the mitigation of several water, wastewater and environmental problems. Present study in this direction is a novel effort.
本研究首次应用裂解噬菌体（病毒）介导的生物控制，利用 Haliscomenobacter hydrossis 作为模型丝状菌，控制活性污泥工艺中的生物量膨胀。噬菌体是专门感染细菌的病毒。从当地污水处理厂的混合液中分离出专门感染 H. hydrossis 的裂解噬菌体。分离出的噬菌体属于肌病毒科，具有收缩尾（长度 126nm；直径 18nm）和二十面体头部（直径 81nm）。分离噬菌体与 H. hydrossis 的效价计算为 5.2±0.3×10(5)PFU/mL，爆发量为 105±7PFU/感染细胞。噬菌体在暴露于高温（42°C）和 pH 值在 5 到 8 之间时相当稳定，这强调了它可以承受实时应用中的季节性/操作波动。最佳感染的噬菌体与宿主（细菌）的比例被发现为 1:1000，导致约 54%的宿主死亡。分离的噬菌体与其他常见于活性污泥系统中的细菌没有交叉感染性，从而验证了其对 H. hydrossis 引起的丝状膨胀的生物控制的适用性。噬菌体应用后，污泥体积指数（SVI）从 155 成功降低到 105，表明生物量沉降得到改善。噬菌体的应用并未影响生物量的养分去除效率，表明没有附带损害。与医疗应用中的噬菌体治疗类似，噬菌体介导的生物控制作为减轻水、废水和环境问题的经济手段，具有很大的大规模应用潜力。目前在这方面的研究是一项新的努力。
