(562w) Bacteriophage Recovery from Environmental Samples Using Functionalized Silica

Authors: 
Montealegre, C., University of the Philippines Diliman
Han, W., The Hong Kong University of Science and Technology
Yeung, K. L., The Hong Kong University of Science and Technology
The prevalence of antibiotic resistant bacteria is driving attention to alternative antimicrobials including bacteriophages. Bacteriophages are bacterial viruses which are specific to bacteria and abundant in nature. A typically used method for isolation is by membrane filtration which can separate viruses from a large amount of liquid sample and backwash them as a concentrate. However, this method has limited scalability. Previous studies showed that bacteriophages are capable of adsorption into solids. In this study, silica and aluminum hydroxide functionalized silica were used as the column material for the adsorption of bacteriophages from environmental samples. Using this unit operation allows possible scale up of the process provided that the effect of various factors on the efficiency of the process is determined. Samples with high solid content were pretreated by centrifugation at 5,000×g for 10 minutes, followed by pretreatment of solids by washing and finally, dilution. The dilute sample was then passed through a bed of solids. Solids to fluid ratio and number of passes were kept constant while varying column parameters and configuration. The solid used and pretreatment method highly influenced the performance of the column. Pretreatment using a solution of glycine, broth and tryptone was very effective in solids removal but greatly increases the pressure drop across the column. This limits the flowrate through the bed, beyond the capability of the pump used. Bacteriophage recovery was determined using plaque assay. Aluminum hydroxide functionalized silica performed better in adsorbing phages relative to silica. However, in a fixed bed of solids the combination of silica with glycine-tryptone-broth solution resulted into better overall recovery relative to aluminum hydroxide functionalized silica and water.
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