Wang Hongwei, Gu Carina M, Xu Sujuan, Wang Hongfeng, Zhao Xiaomin, Gu Lichuan
State Key Laboratory of Microbial Technology Shandong University Qingdao China.
The Faculty of Science University of British Columbia Vancouver British Columbia Canada.
mLife. 2024 Dec 1;3(4):565-572. doi: 10.1002/mlf2.12147. eCollection 2024 Dec.
Optical density (OD) is an important indicator of microbial density, and a commonly used variable in growth curves to express the growth of microbial culture. However, OD values show a linear relationship with bacterial concentration only at low concentrations. When the cell density is high, the relationship loses linearity, and serial dilution is needed to obtain readings of better accuracy. Here, we show that measuring OD values using shorter light paths is in close equivalence to measuring OD values of the cell culture with corresponding dilution. By measuring three different light paths simultaneously, accurate OD values can be easily obtained from low to high cell density. Using this method, growth curves of , , and are measured with higher accuracy. To further simplify the process, an l-shaped cuvette and a corresponding turbidimeter are designed specifically for OD value measurement based on the multi-light path transmission method.
光密度（OD）是微生物密度的重要指标，也是生长曲线中用于表达微生物培养物生长情况的常用变量。然而，OD值仅在低浓度时与细菌浓度呈线性关系。当细胞密度较高时，这种关系失去线性，需要进行系列稀释以获得更准确的读数。在此，我们表明使用较短光路测量OD值与测量相应稀释度的细胞培养物的OD值非常等效。通过同时测量三种不同的光路，可以轻松地从低细胞密度到高细胞密度获得准确的OD值。使用这种方法，可以更准确地测量大肠杆菌、枯草芽孢杆菌和酿酒酵母的生长曲线。为了进一步简化该过程，基于多光路传输方法专门设计了一种用于测量OD值的L形比色皿和相应的浊度计。
