Encapsulation of Lactobacillus acidophilus and Lactobacillus casei to Determine Cell Viability in a Hydrogel Biobead Matrix
Additional Funding Sources
The project described was supported by a student grant from the UI Office of Undergraduate Research. This research was funded in part by National Science Foundation Award No. 1805358.
Abstract
Trichloroethylene (TCE), a commonly used industrial solvent, is a widespread, persistent, and carcinogenic groundwater pollutant. An effective treatment strategy for TCE contamination is bioremediation using reductively dechlorinating bacteria. However, during bioremediation changing pH levels can harm these degrading microbes. By incorporating the microbes into a polymer matrix, pH is buffered, and the microbes are protected. This study assessed the viability of model microorganisms (Lactobacillus casei and Lactobacillus acidophilus) in various compositions and molecular weights of polyvinyl alcohol (PVA) and sodium alginate (SA) hydrogels. A method to measure viability of bacterial cells in biobeads was developed. Viability was characterized using plate counts and optical density measurements. We have observed increased viability in beads composed of higher molecular weight PVA. A second goal of the project was to determine if polymer modifications impact diffusion rates. Similarly sized ionic (methylene blue, metanil yellow) and neutral (caffeine) model compounds were used to investigate the effect of charge on diffusion. Diffusion of caffeine through hydrogel membranes was determined to be 40% slower in hydrogels containing bacterial cells than without biomass. Determination of encapsulated microbe viability assists in optimization of polymer formulations to better protect microbial consortia and improve degradation of contaminants.
Encapsulation of Lactobacillus acidophilus and Lactobacillus casei to Determine Cell Viability in a Hydrogel Biobead Matrix
Trichloroethylene (TCE), a commonly used industrial solvent, is a widespread, persistent, and carcinogenic groundwater pollutant. An effective treatment strategy for TCE contamination is bioremediation using reductively dechlorinating bacteria. However, during bioremediation changing pH levels can harm these degrading microbes. By incorporating the microbes into a polymer matrix, pH is buffered, and the microbes are protected. This study assessed the viability of model microorganisms (Lactobacillus casei and Lactobacillus acidophilus) in various compositions and molecular weights of polyvinyl alcohol (PVA) and sodium alginate (SA) hydrogels. A method to measure viability of bacterial cells in biobeads was developed. Viability was characterized using plate counts and optical density measurements. We have observed increased viability in beads composed of higher molecular weight PVA. A second goal of the project was to determine if polymer modifications impact diffusion rates. Similarly sized ionic (methylene blue, metanil yellow) and neutral (caffeine) model compounds were used to investigate the effect of charge on diffusion. Diffusion of caffeine through hydrogel membranes was determined to be 40% slower in hydrogels containing bacterial cells than without biomass. Determination of encapsulated microbe viability assists in optimization of polymer formulations to better protect microbial consortia and improve degradation of contaminants.