Abstract: The culture medium serves as the fundamental basis for recombinant Escherichia coli (E. coli) fermentation, where its composition and formulation critically govern cellular growth, the expression efficiency of target proteins (e.g., collagen), and the cost-effectiveness of industrial-scale production. This study aimed to optimize the culture medium for recombinant E. coli fermentation to improve collagen production efficiency while reducing costs. By conducting single-factor experiments, the key medium components were systematically refined, followed by the application of response surface methodology (RSM) to refine the composition of the culture medium, aiming to enhance production efficiency while reducing costs. The optimized fermentation medium formula obtained was composed of 2.85 g/L glucose, 53.85 g/L complex nitrogen source, and 64.63 mmol/L phosphate buffer. Validation experiments based on this refined formulation demonstrated that the collagen yield reached an impressive 8.62 mg/50 mL, matching that of conventional TB medium while reducing production costs by 30%, highlighting significant economic advantages. A critical innovation was the complete replacement of glucose with straw hydrolysate, which achieved 93% of the original yield, not only confirming the practicality and cost-effectiveness of utilizing agricultural waste as a sustainable feedstock but also providing robust empirical evidence to support the broader adoption of lignocellulosic biomass as a sustainable substitute for starch-derived sugars in microbial fermentation processes. Additionally, scale-up studies conducted at the 5 L bioreactor level unequivocally validated the excellent stability and scalability of the optimized medium, as both bacterial growth kinetics and collagen expression profiles remained consistently unaffected, indicating seamless transition from laboratory to pilot-scale operations. Collectively, these findings establish a solid technical foundation for the high-efficiency, low-cost biological manufacturing of collagen using recombinant E. coli as the host system, offering a transformative pathway toward more sustainable, resource-efficient bioproduction that aligns with circular economy principles while significantly advancing industrial applications in the field of recombinant protein synthesis.

Key words: collagen, recombinant Escherichia coli, fermentation, medium, straw saccharification liquid

摘要： 培养基是重组大肠杆菌(Escherichia coli)发酵的核心基础，其成分和配比直接影响菌体生长、目标蛋白(如胶原蛋白)的表达效率及工业化生产的成本效益。本研究聚焦于重组大肠杆菌发酵产胶原蛋白的培养基优化问题，通过单因素研究初步筛选出关键影响因素，并采用响应面优化策略对培养基组分进行精化调整，旨在提升产量并降低成本。优化后得到的发酵培养基配方为：葡萄糖2.85 g/L、复合氮源53.85 g/L、磷酸缓冲液64.63 mmol/L。基于该配方进行发酵验证研究，结果发现胶原蛋白产量达8.62 mg/50 mL，与商用TB培养基的产能相当，但生产成本显著降低30%。进一步的替代试验中，以秸秆糖化液完全替代葡萄糖组分后，胶原蛋白表达量达到原葡萄糖培养基的93%。这一成果不仅验证了秸秆资源的经济性与可行性，还为推动秸秆综纤维素全面替代淀粉糖在大肠杆菌发酵领域的应用提供了重要依据。5 L发酵罐规模的放大研究证实了优化培养基的良好稳定性和可放大性，菌体生长与产物表达未受显著影响。本研究为以大肠杆菌为宿主的高效、低成本胶原蛋白生物制造提供了坚实的技术支撑。

关键词: 胶原蛋白, 重组大肠杆菌, 发酵, 培养基, 秸秆糖化液