A novel nicotinamide adenine dinucleotide control strategy for increasing the cell density of Haemophilus parasuis |
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Authors: | Likun Cheng Feng Li Shuguang Li Chuwen Lin Qiang Fu Huanhuan Yin Fengrong Tian Guanggang Qu Jiaqiang Wu Zhiqiang Shen |
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Affiliation: | 1. Post-doctoral Scientific Research Workstation, Shandong Binzhou Animal Science and Veterinary Medicine Academy, Binzhou, China;2. Post-doctoral Scientific Research Workstation, Shandong Binzhou Animal Science and Veterinary Medicine Academy, Binzhou, China Key Laboratory of Binzhou High Cell Density Fermentation, Shandong Lvdu Bio-science and Technology Co. Ltd., Binzhou, China;3. Institution of Poultry, Shandong Academy of Agricultural Science, Jinan, China |
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Abstract: | Haemophilus parasuis is the causative agent of Glässer's disease and is a major source of economic losses in the swine industry each year. To enhance the production of an inactivated vaccine against H. parasuis, the availability of nicotinamide adenine dinucleotide (NAD) must be carefully controlled to ensure a sufficiently high cell density of H. parasuis. In the present study, the real-time viable cell density of H. parasuis was calculated based on the capacitance of the culture. By assessing the relationship between capacitance and viable cell density/NAD concentration, the NAD supply rate could be adjusted in real time to maintain the NAD concentration at a set value based on the linear relationship between capacitance and NAD consumption. The linear relationship between cell density and addition of NAD indicated that 7.138 × 109 NAD molecules were required to satisfy per cell growth. Five types of NAD supply strategy were used to maintain different NAD concentration for H. parasuis cultivation, and the results revealed that the highest viable cell density (8.57, OD600) and cell count (1.57 × 1010 CFU/mL) were obtained with strategy III (NAD concentration maintained at 30 mg/L), which were 1.46- and 1.45- times more, respectively, than cultures with using NAD supply strategy I (NAD concentration maintained at 10 mg/L). An extremely high cell density of H. parasuis was achieved using this NAD supply strategy, and the results demonstrated a convenient and reliable method for determining the real-time viable cell density relative to NAD concentration. Moreover, this method provides a theoretical foundation and an efficient approach for high cell density cultivation of other auxotroph bacteria. |
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Keywords: | control strategy Haemophilus parasuis linear relationship nicotinamide adenine dinucleotide real-time monitoring |
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