Turbidity Sensor for Bacterial Growth Measurements in Spaceflight and Simulated Micro-gravity
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- 作者：Roel van Benthem (1) benthem@nlr.nl
Wubbo de Grave (1) grave@nlr.nl - 关键词：Turbidity sensor ; Bacterial growth measurements ; BIOFILTER ; FOTON M2 space flight ; Bacteriological air filter ; Ground reference experiment ; Random positioning machine
- 刊名：Microgravity Science and Technology
- 出版时间：November 2009
- 出版年：2009
- 期刊代码：116_1875-0494
- 类别：et
- 卷：21
- 期：4
- 页码：349-356
- 数据来源：sp
摘要
For the BIOFILTER flight experiment a set of turbidity sensors was developed for the measurement of the growth rate of the bacteria Xanthobacter autrophicus GJ10 in a fluid medium. During the flight experiment on FOTON M2 in 2005, bacterial growth was measured revealing growth rates between 0.046–0.077 h − 1 in microgravity, i.e. approximately 1.5–2.5 times slower than routinely measured under optimal laboratory conditions on earth. To increase confidence in the equipment and for comparison of the results, a ground-reference experiment was carried out in 2006, using BIOFILTER hardware mounted on a random positioning machine (RPM). The RPM performed random rotations at 0.5掳/min (for settling compensation) and 90掳/min (for simulated microgravity) while the environment was controlled, accurately repeating the BIOFILTER flight temperature conditions. Despite the rotations of the RPM, a normal growth rate of 0.115 h − 1 was confirmed in both cases. The operation of the turbidity sensor was verified. Biological interpretation of the measurements is however compromised due to poor mixing and other unknown physical and biological phenomena that need to be addressed for further space experiments using these kinds of systems.