OVERVIEW

As the project progressed, we became increasingly aware of the limitations in our initial design and proactively sought external input to explore new perspectives.

During experiments, we observed that engineered bacteria carrying the recombinant plasmid showed a slightly lower growth curve in population density—as indicated by absorbance measurements—compared to the wild-type strain. Despite repeated attempts to optimize culture conditions, improvements were minimal. Professor Dai Junbiao from Shenzhen, an experienced researcher in synthetic biology, pointed out the underlying issue: our engineered plasmids were relatively large and numerous, imposing a significant metabolic burden on the host Bifidobacterium.

Following in-depth discussions, we planned to reanalyze the plasmid design, remove non-essential regions, and consolidate functional modules to reduce this metabolic burden.

For the core module of Lacbutler responsible for lactose uptake—the lactase enzyme activity modification block—Professor Liu Zhijian from our institution provided an alternative approach beyond our original modeling work. He suggested modifying the codon usage of the lactase gene to facilitate more efficient expression in Bifidobacterium, thereby reducing metabolic load and increasing protein yield. Additionally, he recommended simulating the response threshold of the plsrA promoter—which regulates the ccdB gene in the population density control system—to deoxycholic acid, in order to reduce the workload in wet-lab experiments.

After learning about our challenges, Professor Gong Lei encouraged us to consult scholars from other disciplines for fresh insights. Three professors from Moscow State University, though specializing in fields not directly related—such as geography and botany—offered unexpected inspiration:

Professor Dmitry Orlov, from a human ecology perspective, noted that "differences in gut microbiomes across regional populations may affect the colonization efficiency of engineered bacteria." This prompted us to include simulated gut metabolite conditions representing different regional characteristics in subsequent experiments.

Professor Bocharnikov Maxim, an expert in remote sensing and spatial data visualization, saw our scattered enzyme activity and growth curve data and suggested applying a "time-space heatmap logic, similar to that used in remote sensing imagery." We accordingly transformed fluorescence intensity data into heatmaps with horizontal axes showing zones, vertical axes showing time, and color indicating bacterial density—making results immediately clear.

Based on his experience in plant-microbe interactions, Professor Vladimir Grinkov proposed adding 0.1% plant-derived pectin to the agarose to improve both air permeability and biocompatibility of the material.

While continuing to improve Lacbutler in the wet lab, we began contemplating a deeper question: What can Lacbutler truly offer society? Can it genuinely integrate into the daily lives of those with lactose intolerance? To find answers, we proactively engaged with representatives from Adopt a Cow, Professor Meng Yue from the School of Life Sciences at Northeast Normal University, Dr. Shi Ying, and a nutritionist—evaluating the project’s value and future potential from industrial, clinical, and nutritional perspectives.

During our visit to Adopt a Cow, we discussed Lacbutler with their team. They affirmed the rationality of our technical approach: “The use of Bifidobacterium longum offers intestinal colonization benefits, and the modular plasmid design provides strong extensibility—in the future, it could address not only lactose intolerance but also other gut-related issues by replacing functional genes. This gives it greater potential than single-function probiotic products.” Through observing their production processes, we also realized that “our current reliance on an anaerobic culture system would entail high costs in scaled production. We should consider simplifying anaerobic conditions or collaborating with dairy enterprises to leverage existing fermentation equipment for cost efficiency.”

After returning to the university, we shared these concerns with Professor Meng Yue. She advised that, based on our earlier experiments with miniature fermenters, we could develop small batches of bacterial powder samples to accumulate experience for future human trials and product development.

Dr. Shi Ying, who has extensive clinical experience, noted: “If your engineered bacteria can achieve 'one-time supplementation, long-term colonization,' it would indeed address a core concern for patients.” At the same time, she emphasized stricter safety requirements: “Especially for sensitive groups such as children and the elderly, indicators like bowel movement frequency and bloating scores should be closely monitored—these clinical data are more convincing than laboratory results.” She added that, if proven effective, such engineered bacteria could complement existing treatments and would be particularly suitable for daily management of mild lactose intolerance.

The nutritionist focused on the fundamental need for “nutritional balance.” Citing recommendations from the Chinese Dietary Guidelines, she pointed out that “currently, fewer than 45% of lactose-intolerant individuals meet the recommended calcium intake. Your project, if successful, could directly help bridge this nutritional gap.” She proposed specific usage scenarios for different groups: children could take it with breakfast milk, the elderly with meals, and future community-based dietary guidance could be introduced to enhance practical value. She also highlighted potential public perception barriers: “Many parents associate the term 'engineered bacteria' with 'artificial modification,' which raises concerns. It is essential to strengthen science communication and clarify misconceptions with reliable experimental data.”

As we reflected on how our project could better serve the community, we came to recognize a crucial reality: for synthetic biology to genuinely contribute to public health, it must bridge the gap between the laboratory and public understanding. As a team from a normal university, we deeply believe that education is the vital link connecting scientific research with society, and an essential pathway to help more people understand and engage with science.

Guided by this conviction, we consulted Professor Huang He from the University Teacher Development Center. Professor Huang emphasized that our primary task was to address the comprehension barriers different groups face regarding synthetic biology. We subsequently conducted an internal survey within our university, which revealed that nearly 80% of non-biology majors found the concept of "engineering bacteria" difficult to understand, with some students even developing misconceptions due to a lack of specialized knowledge. These findings clearly indicated our next step: building professional and effective channels for science communication.

A high school biology teacher also advised us to expand our outreach to the broader public—only by helping society understand our work can we attract more people to join our efforts and lay the groundwork for future commercialization. In response, we have launched a range of educational activities tailored to different age groups and society at large. You can find detailed descriptions of these initiatives in the Education section of our presentation.

Promoting understanding through education, and earning support through understanding—this has been our consistent principle as a team from a teacher-training institution. Only when scientific achievements are truly comprehended and accepted by society can research innovation realize its fullest potential. We will continue to refine this education and outreach framework, inviting more people to join us on this journey of advancing health through science.