Bioscience Evidence 2024, Vol.14, No.2, 81-92 http://bioscipublisher.com/index.php/be 89 6.4 Case studies highlighting significant progress Recent advances in genetic engineering, synthetic biology, and omics technologies have significantly enhanced our ability to engineer anaerobic bacteria for improved biohydrogen production. These breakthroughs are paving the way for more sustainable and economically viable hydrogen production technologies, with the potential to contribute significantly to the global transition to renewable energy sources. Enhanced Hydrogen Production in Clostridium acetobutylicum: Through a combination of CRISPR-Cas9-based gene editing and synthetic biology, researchers developed a strain of C. acetobutylicum that overexpresses a synthetic operon for [FeFe]-hydrogenase, leading to a threefold increase in hydrogen yield compared to wild-type strains (Yu et al., 2019). Optimization of Thermotoga maritima for Industrial Hydrogen Production: By integrating genomic and metabolomic data, scientists were able to engineer T. maritima to produce hydrogen more efficiently at high temperatures, making it a viable candidate for industrial-scale hydrogen production from lignocellulosic biomass (Ben Gaida et al., 2022). Directed Evolution of Enterobacter cloacae for Oxygen Tolerance: Using directed evolution, a strain of E. cloacae was developed that exhibits enhanced hydrogen production under less stringent anaerobic conditions, thanks to the evolution of a more robust hydrogenase enzyme (Lee et al., 2019). These case studies underscore the potential of advanced genetic and synthetic biology techniques to overcome the limitations of traditional biohydrogen production methods and to create more efficient, scalable systems. 7 Challenges and Future Directions The field of biohydrogen production through the genetic engineering of anaerobic bacteria holds great promise but also faces significant challenges. These challenges span technical, economic, and environmental domains, each presenting obstacles that must be addressed to fully realize the potential of biohydrogen as a sustainable energy source. 7.1 Technical challenges in genetic engineering One of the primary technical challenges in the genetic engineering of anaerobic bacteria for biohydrogen production is the complexity of metabolic networks. Genetic modifications often lead to unintended consequences, such as the accumulation of toxic intermediates or the disruption of cellular homeostasis, which can reduce the efficiency of hydrogen production. Additionally, the stability of engineered traits over time and under industrial conditions remains a significant hurdle. Maintaining the functionality of genetically modified pathways in the face of fluctuating environmental factors, such as pH, temperature, and substrate availability, is crucial for the success of biohydrogen production on a commercial scale (Tang et al., 2021). Another challenge is the difficulty in achieving high levels of gene expression without triggering metabolic burden or toxic effects. Overexpression of hydrogenase genes or other key enzymes can lead to the depletion of essential cellular resources, negatively impacting overall cell growth and viability. Balancing the need for high enzyme activity with the health of the host organism is a delicate task that requires careful optimization of genetic constructs and regulatory elements (Jia et al., 2021). 7.2 Economic and Scalability Considerations The economic viability and scalability of biohydrogen production are major considerations that will determine the feasibility of this technology in real-world applications. One of the significant economic challenges is the cost of genetic engineering itself, which includes the development and optimization of engineered strains, as well as the necessary infrastructure for large-scale production. The use of specialized bioreactors, stringent anaerobic conditions, and precise control of environmental variables can drive up costs, making it difficult for biohydrogen to compete with more established methods of hydrogen production, such as steam methane reforming or electrolysis (Saidi et al., 2018).
RkJQdWJsaXNoZXIy MjQ4ODYzMg==