ASSESSMENT OF DECAPSULATION METHOD AND THE EFFECT OF ALGINATE ENCAPSULATION ON E. Coli CELL VIABILITY

Alginate-encapsulation of bacterial cells is a cell immobilisation technique used in various biotechnology fields due to its numerous benefits. One of its cited benefit is the increased preservation of bacterial cell viability post-encapsulation. However, the process of encapsulation may inherently negatively affect cell viability. This study explores changes in cell viability after subjecting E. coli BL21 DE3 cells to alginate encapsulation. Cell viability of free cells is compared with cells that have undergone alginate encapsulation, and cell viability is measured using the resazurin microtitre assay (REMA) and viability-PCR (vPCR). A decapsulation step is designed to reliably assess the viability of the encapsulated cells, which involves an enzymatic approach using alginate lyase in combination with a chemical sequestration approach using sodium citrate. The optimum decapsulation condition is determined to be a two-hour incubation at 37°C in a solution of 50 mM sodium citrate and 500 μg/μL alginate lyase. The study also found that cell viability decreased following alginate encapsulation, with both REMA and vPCR showing a mean reduction of 14.43% and, 31.54%, respectively. This decrease in cell viability is synonymous with other cited studies. However, the magnitude of the decrease varied due to the use of different experimental parameters.