In this wet lab project, we attempted to engineer Bifidobacterium longum, a probiotic, for synthetic biology. We gathered valuable data on its cultivation and plasmid transformation, and optimized experimental protocols for easier Bifidobacterium synthetic biology operations. Using Bifidobacterium as an engineered strain has clear benefits: it offers a practical solution for treating gastrointestinal diseases, increases patient acceptance, and has potential market value. We hope to reduce challenges in engineering Bifidobacterium longum for future applications. We also developed two innovative systems: an efficient lactose metabolism system and a composite module using the DCA-BreR-MucBP adhesion system. These systems' components and design concepts are pioneering. The efficient lactose metabolism system presents a new synthetic biology engineering approach combining mathematical analysis, protein modification, and multi-pathway integration. We believe this approach is highly referential. In the adhesion system, we turned the MucBP protein into a synthetic biology component and explored new specific expression pathways.

In the dry lab, we established ordinary differential equations for the three systems we designed to better analyze and interpret their behaviors. Moreover, for the first time, we introduced mathematical expressions related to ecological niches to describe the relationship between adhesion systems and population density, offering a new reference for more precise and accurate characterization of relevant behaviors. This approach also mathematically demonstrated the impact of introducing adhesion systems on the survival capacity of bacteria with poor adhesion abilities, such as Bifidobacterium. Additionally, the dry lab conducted molecular dynamics simulations of lactase BgaB, providing further data references for a deeper understanding of its functional mechanisms. Based on this, we carried out exploratory modifications to the BgaB gene and developed a relatively rational optimization cycle to assist other teams in obtaining more efficient lactase—an industrial enzyme that plays a critical role in food and pharmaceutical production. Finally, we attempted to develop a "Web Doctor," utilizing an AI language model to offer reference suggestions for individuals unaware of their lactose intolerance. This initiative aims to help them better address their health concerns.

AOn the social practice front, we primarily engaged in educational activities that were broader and more in-depth compared to previous efforts. "Leaving no one behind"-this United Nations development goal has also been the founding purpose of our educational initiatives. To that end, we participated in a one-month teaching program across six different locations, reaching underdeveloped areas to ignite children's interest in synthetic biology. This is an endeavor rarely undertaken by teams, and we sought to give it a try. In addition, we provided more hands-on experimental opportunities for students who had only studied synthetic biology in theory-one of the key issues we identified-enabling them to experience the subject firsthand in the laboratory. This ensured that knowledge was not confined to textbooks and allowed the seeds of synthetic biology to begin sprouting. Furthermore, we extended our educational outreach to 16 ethnic minority groups, recognizing them as indispensable members of society. To enhance future promotion efforts among these communities, we also prepared corresponding audio clips in ethnic minority languages to facilitate broader dissemination.