P12: Determination of Bacterial Cell Viability in 3D-scaffold

Bacteria interface oil droplet has been firstly developed using bacteria-chitosan network. Since, this type of 3D-scaffold allows the bacterial cells to contact closely with solvent phase, it is expected be applicable for several biotechnological applications such as bioconversion and bioremediation. In such applications, the bacterial cell viability is an important parameter that must be monitored during the process. In this study, several techniques including gas chromatography (GC), indirect conductivity measurement and acid-base titration were evaluated and compared with viable cell count technique. GC was the most sensitive technique when tested with model experiment using toluene-treated cells. GC technique not only could distinguish dead cell, damaged cell and viable cell but the result could be observed earlier than other techniques. Therefore, GC technique was employed for bacterial cell viability determination in Pickering emulsion composing of E. coli DH5α, 0.3% chitosan and solvent phase (soybean oil, n-tetradecane, squalene, silicone oil, hexane and toluene). Comparison of the CO₂ area obtained from each emulsion with the positive control (bacterial cell suspension) and negative control (buffer) allows us to effectively monitor the cell viability in the 3D-scaffold of bacteria interface oil droplet.