Process intensification of hydrogen production in recombinant Escherichia coli Via low pH and fed-batch
- 발행기관 서강대학교 일반대학원
- 지도교수 나정걸
- 발행년도 2026
- 학위수여년월 2026. 2
- 학위명 석사
- 학과 및 전공 일반대학원 화공생명공학과
- 실제URI http://www.dcollection.net/handler/sogang/000000082212
- UCI I804:11029-000000082212
- 본문언어 영어
- 저작권 논문은 저작권에 의해 보호받습니다.
초록(요약문)
In the Persistent climate change and greenhouse gas emissions have made the realization of carbon neutrality (net zero) a global priority, drawing increasing attention to hydrogen as a carbon-free energy carrier. However, most hydrogen is still produced via fossil fuel–based, high-temperature and high-pressure processes (grey hydrogen), highlighting the need for more sustainable and cost-effective alternatives such as biological hydrogen production. In this study, we optimized fermenter operating conditions for an Escherichia coli strain overexpressing a recombinant enzyme (HyaB–Rf) designed to accept electrons directly from intracellular NADH and enable efficient hydrogen generation without complex membrane-associated electron-transfer systems. Using vial- scale results as a baseline, key operational variables—including pH, average specific glucose uptake rate (qₛ), and cell density at the aerobic-to-anaerobic shift—were systematically screened in a fermenter. The results showed that a lower pH (5.5) improved hydrogen productivity and yield compared with the conventional cultivation pH of 6.8. Moreover, implementing a fed-batch strategy to maintain lower qₛ values increased the hydrogen-to-lactate production ratio, suggesting that reducing equivalents were preferentially redirected toward the hydrogen-producing pathway rather than byproduct formation. Further improvements in productivity were achieved by increasing the cell density at the anaerobic shift to OD₆₀₀ = 10. Under optimized conditions, hydrogen productivity and yield were enhanced by up to 37.78-fold and 7.13-fold, respectively, relative to vial cultures. These findings demonstrate that substantial gains in yield and productivity can be achieved through optimization of cultivation and operating conditions alone in recombinant enzyme–based bioprocesses, providing practical guidance for setting culture conditions, particularly for microbial hydrogen production.
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Contents 6
Abstract 7
List of figures 9
List of tables 10
1. Introduction 11
2. Material and Methods 15
2.1. Strain and Media 15
2.2. Seed culture 16
2.3. Vial culture 17
2.4. Fermenter culture 17
2.4.1. pH control Batch culture 18
2.4.2. Fed-batch culture 18
2.4.3. High cell density fed-batch culture 19
2.5. Analytical methods 19
3. Results and Discussion 20
3.1. Baseline culture in vial and fermenter 20
3.2. Effect of pH on hydrogen production in batch culture 22
3.3. Fed-batch culture 23
3.4. High cell density fed-batch culture 25
4. Conclusion 28
5. References 29
