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Abstract：
Monitoring the dynamics of bacteria in porous media is of great significance to understand the bacterial transport and the interplay between bacteria and environmental factors. In this study, we reported a non-invasive, real-time, and efficient method to quantify bioluminescent bacterial concentration in water and sand media during flow-through experiments. First, 27 column experiments were conducted, and the bacterial transport was monitored using a real-time bioluminescent imaging system. Next, we quantified the bacterial concentration in water and sand media using two methods-viable count and bioluminescent count. The principle of the bioluminescent count in sand media was, for a given bioluminescence image, the total number of bacteria was proportionally allocated to each segment according to its bioluminescence intensity. We then compared the bacterial concentration for the two methods and found a good linear correlation between the bioluminescent count and viable count. Finally, the effects of porous media surface coating, pore water velocity, and ionic strength on the bioluminescent count in sand media were investigated, and the results showed that the bioluminescence counting accuracy was most affected by surface coating, followed by ionic strength, and was hardly affected by pore water velocity. Overall, the study proved that the bioluminescent count was a reliable method to quantify bacterial concentration in water (106 to 2 × 108 cell mL-1) or sand media (5 × 106-5 × 108 cell cm-3). This approach also offers a new way of thinking for in situ bacterial enumeration in two-dimensional devices such as 2D flow cells, microfluidic devices, and rhizoboxes.
摘要：
监测多孔介质中细菌的动态对了解细菌的运输以及细菌与环境因素之间的相互作用具有重要意义。在这项研究中,我们报告了一种非侵入性的，实时,和有效的方法来量化生物发光细菌浓度在水和砂介质中的流动实验。首先,进行了27个柱实验，使用实时生物发光成像系统监测细菌的运输。接下来,我们使用两种方法-活菌计数和生物发光计数定量水和砂介质中的细菌浓度。沙介质中生物发光计数的原理是，对于给定的生物发光图像，细菌总数根据其生物发光强度按比例分配给每个片段。然后，我们比较了两种方法的细菌浓度，发现生物发光计数和活菌计数之间存在良好的线性相关性。最后,多孔介质表面涂层的影响，孔隙水速度,并研究了砂介质中生物发光计数的离子强度，结果表明，生物发光计数精度受表面涂层的影响最大，其次是离子强度，几乎不受孔隙水速度的影响。总的来说,该研究证明，生物发光计数是定量水（106至2×108细胞mL-1）或砂培养基（5×106-5×108细胞cm-3）中细菌浓度的可靠方法。这种方法也为二维设备（如2D流动池）中的原位细菌计数提供了一种新的思路，微流体装置，和根茎盒。
