Microbial influenced corrosion (MIC) stands as a unique and intricate phenomenon where microorganisms, particularly bacteria, impact the corrosion processes of various materials. This review delves into the complexities of MIC, examining its mechanisms, environmental factors, detection methods, and implications for industries where corrosion poses a significant threat.

Microbial Corrosion Mechanisms
MIC involves the interaction between microorganisms and metallic surfaces, leading to accelerated corrosion. Bacteria such as sulfate-reducing bacteria (SRB), acid-producing bacteria, and iron-oxidizing bacteria play pivotal roles in MIC. Their metabolic activities often result in the production of corrosive byproducts, altering the local environment and promoting the corrosion of susceptible materials.

Environmental Factors
The occurrence and severity of MIC are influenced by a myriad of environmental factors. These include temperature, pH, oxygen levels, and the availability of nutrients. The interplay of these factors in different industrial settings, such as pipelines, marine structures, and oil and gas facilities, contributes to the varying degrees of MIC observed in diverse environments.

Detection and Monitoring
Detecting MIC in its early stages is crucial for preventing material degradation and avoiding costly repairs. Advances in molecular biology techniques, including DNA-based methods and high-throughput sequencing, have enhanced our ability to identify and quantify microbial communities associated with corrosion. In-situ monitoring tools, electrochemical techniques, and corrosion sensors also aid in real-time detection and assessment of MIC, allowing for timely intervention.

Industrial Implications
MIC poses significant challenges to industries reliant on metal structures and pipelines. Oil and gas pipelines, marine infrastructure, and aviation components are particularly vulnerable. The economic impact of MIC includes maintenance costs, repair expenses, and potential safety risks associated with compromised structural integrity. Understanding the microbial communities involved and implementing preventive measures are crucial for mitigating the impact of MIC on infrastructure.

Preventive Strategies
Several strategies have been employed to mitigate MIC and protect against material deterioration. These include the use of corrosion-resistant materials, biocides to control microbial growth, and the implementation of cathodic protection systems. Additionally, comprehensive monitoring and regular inspections are essential components of effective MIC prevention strategies.

Challenges and Future Directions
Despite significant strides in understanding MIC, challenges persist. The complex interactions between microorganisms and metals, the influence of biofilm formation, and the variability in environmental conditions make predicting and preventing MIC a continuing challenge. Future research should focus on developing more accurate predictive models, innovative preventive technologies, and sustainable management practices to address MIC in diverse industrial contexts.

Metagenomics in MIC Diagnosis 

Metagenomics has revolutionized the field MIC diagnosis. By analyzing the entire genetic content of microbial communities associated with corroded surfaces, metagenomics provides a holistic view of the diverse microbiota involved in corrosion processes. This approach offers a significant advantage over traditional culture-based methods by capturing the full spectrum of microbial diversity.

Strengths of Metagenomics

• Unbiased Community Profiling: Metagenomics allows for unbiased profiling of microbial communities, revealing the full diversity of microorganisms present, including non-culturable species that may play crucial roles in MIC.
• Functional Gene Analysis: Beyond taxonomy, metagenomics enables the identification of functional genes associated with corrosion processes, shedding light on the mechanisms by which microorganisms contribute to material degradation.
• High Resolution and Sensitivity: Metagenomic analyses provide high resolution, enabling the detection of low-abundance or slow-growing microbial populations that may have a significant impact on corrosion but could be overlooked by traditional methods.
• Longitudinal Studies: Metagenomics facilitates longitudinal studies, allowing researchers to track changes in microbial communities over time, which is essential for understanding the dynamic nature of MIC.

Microbial influenced corrosion represents a dynamic interplay between microorganisms and materials, with profound implications for the integrity and durability of industrial infrastructure. As our understanding of MIC mechanisms deepens, the development of effective preventive strategies becomes increasingly crucial. This review underscores the interdisciplinary nature of MIC research, calling for collaborative efforts between microbiologists, corrosion scientists, and engineers to address the multifaceted challenges posed by microbial influenced corrosion and ensure the resilience of critical infrastructure.