A novel strategy for reinforcing cementation process coupling microbially induced carbonate precipitation (MICP) with cross-linked silk fibroin

Abstract

Recently, microbially induced carbonate precipitation (MICP) showed potential prospect in civil engineering field. However, the mechanical performance of MICP needs further perfected before they can be put into practice. In this paper, a novel strategy coupling MICP with cross-linked silk fibroin was first proposed to markedly improve the cementation process and mechanical properties of the sand columns. The results showed that addition of 0.05%vt glutaraldehyde, a crosslinking reagent, and 1%wt silk fibroin into loose sand before MICP treatment enhanced up to 2.77-times the unconfined compressive strength and 4.10-times the flexure strength, respectively. The microstructural detection revealed that cross-linked fibroin providing more nucleation sites for calcite precipitation, which not only significantly decreased the porosity of the specimen, but also effectively generated calcite between sand particles, resulting in a significant reinforcement in MICP performance. Meanwhile, by cell viability test and transcriptome analysis, the bacteria’s vitality was also stimulated to some certain extent under a weak poisonous environment from glutaraldehyde, also a cytotoxic reagent, which had never reported before. These findings preliminarily provide theoretical and technical foundation for a potential prospect in civil engineering application of this modified MICP strategy.