Microbiome analysis of novel cement composites admixed with biopolymer and silver nanoparticles

This study analyses the effect of cement composites containing natural plastificator - silver nanosized particles (AgNPs) stabilised with biopolymer (starch derivative – dextrin) on the spatial, taxonomic, and functional structure of the bacterial metabiome in the context of their potential to deteriorate the wastewater infrastructure (in-situ testing). The obtained results showed that the presence of AgNPs inhibited the formation of the complex spatial structure of the biofilm and contributed to significant changes in the structure of bacterial metapopulation. The highest sensitivity to the presence of nanoparticles was demonstrated by microorganisms categorised into the order Caulobacterales, the genera Caulobacter and Mycoplana, and among the taxa responsible for sulphur metabolism – the genera Thiovirga, Thiofaba and Thiothrix. On the surface of nanocomposites were found nanoparticle-resistant groups from the families Rhodobacteraceae, Porhyromonadaceae, Campylobacteriaceae and the genera Bacillus, Pseudomonas, Sulfurospirillum, Microvulga, Dysgonomonas, Propionobacterium, Ralstonia, Renibacterium, Desulfosporosinus, Metylobacterium and Anoxybacillus, all playing a potential role in the deterioration of concrete structures. Despite this, relative to the reference sample, the total predicted thiosulfate oxidation potential was lower in the variants with nanocomposite and the nanocomposite with nano-coating by 52 % and 29 %, respectively. The integration of plasticizers and nanosized silver resulted in the development of a multifunctional preparation that exhibits bactericidal efficiency and enhances the workability, durability, and compressive strength of cement composites. This innovative formulation has the potential to be applied in a wide range of contexts, including the construction of wastewater wells.