Biocoating boosts bacterial viability for wastewater treatment


A porous biocoating synthesized with a permeable structure might find use in encapsulating and corralling bacteria for wastewater treatment functions.

The permeability of the material, composed of rigid tubular nanoclays and latex particles, can be tuned to support a high rate of nutrient and metabolic product transport sufficient for bacterial viability. The biocoating was tested with Escherichia coli as a model organism, using the expression of a yellow fluorescent protein as an indicator of metabolic activity. Single-cell observations using confocal laser scanning microscopy provided evidence of these biological mechanisms.

A custom-built apparatus based on a resazurin reduction assay indicated no measurable permeability in a coating made from only latex particles. The permeability coefficient of composite biocoatings increased up to a halloysite nanoclay content of 29%. Bacteria encapsulated in halloysite composite biocoatings had statistically significant higher metabolic activities in comparison to bacteria encapsulated in a nanoptimized coating made from latex particles alone.

The biocoatings were demonstrated by researchers from University of Surrey and University of Warwick, U.K., to maintain bacterial viability for extended time periods, enhancing their potential application in water pollutant degradation and removal., 9 September 2020