Fungal-Mediated Biomineralization and its Applications in Civil and Environmental Engineering

Abstract

Biomineralization is a common phenomenon in nature and can be categorized into three types based on the mechanisms of mineral formation: microbially induced, microbially influenced, and microbially controlled mineralization. Among these, microbially induced mineralization is widely observed in nature, which occurs outside of the microorganism cells, leading to a larger area of influence compared to other mechanisms. As a result, it holds potential applications in civil and environmental engineering, including carbon dioxide sequestration, repair of building structures, removal of heavy metals, and enhancement of concrete and soil performance.

Ureolytic bacteria have been widely used in the field of geology and environmental engineering. Compared to bacteria, fungi usually possess more tolerance to high salts and heavy metals, enabling MICCP induced by the urease-producing fungi to be applied to harsh environments. Although several fungi have shown promise in biomineralization, there is a shortage of comparative research evaluating the effectiveness of different fungal species in stimulating calcite precipitation.

In this study, the urease-producing fungi were isolated from the concrete walls of Pondicherry University, Kalapet, Puducherry, India. They were tested for their efficacy in improving the durability properties of cementitious materials and for the removal of toxic metals. The techniques involved in this study include isolation of fungi, carbonate precipitation, testing on concrete structures and bioremediation of heavy metals through the mechanism of fungal biomineralization.

The key findings were that fungus selected for all the testing for civil and environmental engineering has a high potential to precipitate CaCO3 through urease hydrolysis and can withstand highly alkaline environments, which makes it a potential candidate for its application in concrete durability as well as in bioremediation of heavy metals.