硝基螺
硝化细菌
恒化器
亚硝酸盐
硝化作用
活性污泥
生物
人口
生物反应器
化学
食品科学
环境化学
微生物学
细菌
植物
环境工程
生态学
氮气
污水处理
硝酸盐
环境科学
社会学
人口学
有机化学
遗传学
作者
R. Nogueira,L. F. Melo
摘要
Abstract In this work the question was addressed if in nitrite‐oxidizing activated sludge systems the environmental competition between Nitrobacter spp. and Nitrospira spp., which only recently has been discovered to play a role in these systems, is affected by the nitrite concentrations. Two parallel chemostats were inoculated with nitrifying‐activated sludge containing Nitrospira and operated under identical conditions. After addition of Nitrobacter to both chemostats, the nitrite concentration in the influent of one of the chemostats was increased such that nitrite peaks in the bulk liquid of this reactor were detected. The other chemostat served as control reactor, which always had a constant nitrite influent concentration. The relative cellular area (RCA) of Nitrospira and Nitrobacter was determined by quantitative fluorescence in situ hybridization (FISH). The nitrite perturbation stimulated the growth of Nitrobacter while in the undisturbed control chemostat Nitrospira dominated. Overall, the results of this experimental study support the hypothesis that Nitrobacter is a superior competitor when resources are abundant, while Nitrospira thrive under conditions of resource scarcity. Interestingly, the dominance of Nitrobacter over Nitrospira , caused by the elevated nitrite concentrations, could not be reverted by lowering the available nitrite concentration to the original level. One possible explanation for this result is that when Nitrobacter is present at a certain cell density it is able to inhibit the growth of Nitrospira. An alternative explanation would be that the length of the experimental period was not long enough to observe an increase of the Nitrospira population. © 2006 Wiley Periodicals, Inc.
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