RESUMO
Ability to efficiently propagate high quantities of bacteriophages (phages) is of great importance considering higher phage production needs in the future. Continuous production of phages could represent an interesting option. In our study, we tried to elucidate the effect of dilution rate on productivity of continuous production of phages in cellstat. As a model system, a well-studied phage T4 and Escherichia coli K-12 as a host were used. Experiments where physiology of bacteria was changing with dilution rate of cellstat and where bacterial physiology was kept constant were performed. For both setups there exists an optimal dilution rate when maximal productivity is achieved. Experimentally obtained values of phage concentration and corresponding productivity were compared with mathematical model predictions, and good agreement was obtained for both types of experiments. Analysis of mathematical model coefficients revealed that latent period and burst size to dilution rate coefficient mostly affect optimum dilution rate and productivity. Due to high sensitivity, it is important to evaluate phage growth parameters carefully, to run cellstat under optimal productivity.
Assuntos
Bacteriófagos/fisiologia , Reatores Biológicos , Escherichia coli K12/virologia , Cultura de Vírus/métodos , Modelos BiológicosRESUMO
The growing use of bacteriophages in the fields of agriculture, agri-food, veterinary treatments, and medicine involves the quantitative production of these bacteriophages. In this study, we propose a bacteriophage production protocol that can easily be transposed to industry. We used a cellstat production system because the latest studies have shown that it is the most suitable process for the production of phages due to volumetric productivity, safety (limitation of co-evolution), and flexibility (choice of growth rate criteria). Sizing of the assembly used makes it possible to extrapolate the results to industrial production. The production conditions are indicated precisely, which would allow manufacturers to adapt the protocol to their own equipment. We propose experimental conditions in order to obtain a stable Escherichia coli population, qualitatively and over time, and production of high-titer T7 bacteriophages. The optimized production conditions (yield, cost and simplicity of the process) are: a buffered peptone water medium concentration of 11 g L-1 and a dilution rate of 1.6 h-1. Under these conditions, we obtained a production of 7.35×1016 plaque-forming units (PFU) L-1 day-1 with a concentration of 9.8×1012 PFU mL-1. The strength of this work lies in its focus on industrial applicability.