Проблемы особо опасных инфекций (Feb 2021)
Improvement of Microbial Cell Concentration Technology in the Production of Live Plague Vaccine in the Form of Orodispersible Tablets
Abstract
The aim of the study was to improve the procedure for the Yersinia pestis EV strain cell concentration using the system for tangential flow microfiltration with the ASF-020 filter support unit.Materials and methods. The study used the vaccine Y. pestis EV strain derived from NIIEG cell line. Submerged cultivation of the native culture was performed using BIOR-0.25 reactor with automated control system. Microbial suspension concentrate was produced through microfiltration applying (Adaptive filtration system) AFS-009 and AFS-020 installations. The content of live microbial cells was determined by cytorefractometry. Assessment of the resistance of Y. pestis EV strain cells to technological factors was performed by photometric registration of changes in the optical density of bacterial suspension during the lytic response of cells to sodium dodecyl sulfate. Physical-chemical and immunobiological properties of the dry live plague vaccine were determined in accordance with the pharmacopoeial item.3.3.1.0021.15 of the State Pharmacopoeia of the Russian Federation, 14th edition.Results and discussion. The design features of the equipment introduced made it possible to carry out membrane filtration of microbial suspension, using BIOR-0.25 reactor as an intermediate storage unit, thereby excluding three technological stages. The total concentration of microbes in the suspension obtained by routine and improved methods was more than 150 billion microbial cells per ml. A comparative study of the effect of various hydrodynamic regimes in the working cavities of AFS-009 and AFS-020 filter units did not significantly affect the morphometric properties and resistance of microbial cultures to extreme (technological) factors. Based on the experimental data, the mass balance of the membrane filtration process has been determined. The optimized technology gave 0.13 liter yield of concentrate from 1 liter of native culture, and the process duration was reduced to 5 hours, the yield of the finished product in one production cycle was increased by 3 times. Thus, the process of concentrating Y. pestis EV strain cells during the production of the tablet form of live plague vaccine has been enhanced. A comparative study of the morphometric properties and resistance of plague microbe cultures to technological factors in the process of their concentration using optimized technology did not reveal any significant differences as compared to the routine one. Technological stage of concentrating has been reduced to 5 h term with a three-fold increase in the yield of finished product.
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