Evaluating the Potential of OmpC and YiaT for Cobalt Binding Peptide Cell Surface Display and Applications of Adsorbed Cobalt

Abstract

Cobalt, a highly adaptable transition metal found in the d-block of the periodic table, plays a crucial role in the manufacturing of acrylic and ceramic materials. It is a critical electrocatalyst in various industrial processes, including hydroformylation, gasification, and thermal degradation. The extensive use of cobalt may be found in several industries, such as metallurgy, paints, batteries, electroplating, and electronics. The growing demand in the battery industry has led to a significant increase in worldwide cobalt consumption. The increasing demand for cobalt has caused the yearly mining output to rise from 700 to 1200 tonnes between 1995 and 2005, and this upward trend has continued without any decline. As a result, a wide range of recycling methods that involve physical, chemical, physiochemical, and biological processes have been developed to address this urgent need. In this context, nanotechnology has significantly transformed the sector by demonstrating the production of nanocrystalline cobalt oxide materials by various methods, particularly the microemulsion technique, which is known for precisely adjusting the characteristics of nanoparticles. Although cobalt nanoparticles obtained from botanical and microbial sources are stable, there has been limited focus on synthesizing cobalt oxide nanoparticles using microbes. This work explores the utilisation of metal binding peptides (MBP) in the microbial cell surface display (CSD) technique for cobalt recovery. The inquiry reveals the exhibition of cobalt MBP (Metal Binding Protein) on E. coli, a crucial milestone in developing a sustainable method for extracting cobalt from diverse sources. Research efforts have explored innovative approaches for displaying cells on the surface, specifically focusing on utilising the outer membrane proteins of Escherichia coli, namely OmpC and YiaT. These proteins act as structural frameworks for binding peptides that can capture heavy metals. This leads to the creation of a new type of biosorbent, which involves using cells that produce peptides capable of binding to cobalt. This allows for the extraction of cobalt from polluted water sources. The study thoroughly assesses four cobalt binding peptide fragments derived from CP1 and CP2, expressed on the cell surface. The fusion protein-based method using OmpC as the anchor shows promising rates of cobalt recovery. This is highlighted by the excellent performance of specific peptide fragments such as CF4 and CF2, evident in different medium compositions. Furthermore, the examination explores the use of thermal treatments to reveal the structure and characteristics of cobalt oxide nanoparticles obtained from cobalt that have been adsorbed by biological means. This study highlights the potential of these nanoparticles in several applications, including anticancer research, dye photocatalytic degradation, and drug decomposition. This research introduces a new approach to using microorganisms to produce metal nanoparticles and remediate wastewater. It achieves this by utilizing synthetic peptides that are produced by the bacteria. The results provide insight into the effectiveness of peptide-cobalt interactions, their ability to selectively bind, and the diverse possibilities of cobalt-binding peptides and nanoparticles in tackling industrial and environmental issues. These discoveries enhance our understanding of how peptides interact with metals, leading to significant advancements in several fields.