AbstractThe immobilisation of bacteria onto substrates is a common method for using bacteria as biocatalysts via using range of polymers and different strategies that have been used for biotechnological, medical and environmental applications. The research presented here uses this technique to produce a novel macroporous cryogel with sponge-like properties (‘bacterial sponge‘) utilising commercial strains (Pseudomonas mendocina and Rhodococcus koreensis) and indigenous bacteria (Acinetobacter radioresistens isolated from oil contaminated soil) to remedy toxic phenol in aquatic environment. Four different types of crosslinking systems at different concentration were used, i. classic systems: GA 0.5% and PVA 1% + GA 0.5%, ii. modified systems: PVA-al 1% + PEI-al 0.25% and PVA-al 0.5% + PEI-al 0.6%. The CCC samples were able to degrade 50 mg/L of phenol in batch cultures. The CCC samples exhibited good mechanical stability and cell viability that enabled repeated use for phenol degradation for up to five weeks under various conditions. The use of a novel crosslinking system results in a highly permeable and stable bacterial 3D porous structure with pore sizes in the range 10-100 µm, exhibiting low diffusion constraints and a high bacterial content (more than 98% to total polymer content), which led to create monolithic units of macroporous bacterial sponge termed as crosslinked cellscryogels (CCC). Then, CCC produced from modified polymers were developed for use as a bioreactor for water treatment under shaking conditions via placing them into Kaldnes carriers (CCC-KC). An assessment of phenol-degrading efficiency by CCC-KC using environmental and tap water samples spiked with 50 mg/L of phenol was also performed and the results were promising. The novelty of the approach is that a high ratio of bacterial cells to polymer was used to produce 3D bio-cryogel structure. The results of this research suggest that this procedure is a promising tool for developing novel, environmentally-friendly
bioremediation materials based on active bacterial cells.
|Date of Award||2018|
|Supervisor||Jon Caplin (Supervisor), Irina Savina (Supervisor) & Andrew Cundy (Supervisor)|