Southwest University has a bacterial strain library?! The probiotics you drink may come from it →

"The microscope focuses on everything, the incubator gives birth to new life" is posted in Room 610 of the 39th Teaching Building of the School of Food Science of Southwest University. In the laboratory, six or seven graduate students and doctoral students are busy with related experimental research based on research models such as asthma, diabetes, and obesity. In the next laboratory, a small medicine cool cabinet is running, and it stores more than 3,000 strains of lactic acid bacteria, acetic acid bacteria, yeast, and filamentous fungi. This is the "home" of the strain samples.

Looking for fungi

The microbial strains mainly come from traditional Chinese fermented foods such as liquor, fermented tea, fermented bean curd, soy sauce, pickles, vinegar, etc. The southwest region, due to its natural and cultural factors, has produced many fermented foods with local characteristics.

More than 10 years ago, Professor Suo Huayi from the School of Food Science of Southwest University led his team - the special food quality control and strain resource development team to travel to Chongqing, Sichuan, Yunnan, Gansu, Tibet, Qinghai, Xinjiang and other places, collecting more than 500 samples of traditional fermented food.

Professor Suo Huayi led the team to collect bacterial samples from various places (Photo provided by the interviewee)

"It took the efforts of many people!" Professor Suo said with emotion. Collecting samples is time-consuming and laborious. The teachers and students of the team, whether they are on vacation back home or on business trips, volunteer to collect strains for the team wherever they go.

Lactobacillus casei, Lactobacillus plantarum, Lactobacillus fermentum... With the continuous enrichment of bacterial species in the bacterial library, a bacterial species information management system has been developed based on this. The system realizes the management of the entire process including the sampling source, functional properties, storage location, and freeze-dried tube quantity alarm of bacterial species resources.

Thanks to the long-term experience in building strain banks, the team also established a basic strain bank and a strain bank management system for Chongqing Tianyou Dairy.

Research and Development

With the foundation of the bacteria library, the team develops and acquires functional bacteria based on market research and product demand, and the launch of each functional probiotic is not an easy task.

Professor Suo said that isolating the strains from the samples is the first step, and then the physiological characteristics and functions of each strain need to be scientifically verified. The research of a strain, from genetic background to physiological and biochemical characteristics to probiotic effects, takes at least 2 years and at most 6 to 7 years.

Professor Suo Huayi (Photo provided by the interviewee)

The birth of Lactobacillus plantarum S58, a "patented bacterium", went through such a process. "This probiotic was isolated from pickled vegetables grown in Shizhu County, Chongqing, and can relieve obesity and capsaicin-induced damage to the digestive tract." Professor Suo said that Lactobacillus plantarum S58 precisely addresses the pain points of Chongqing hotpot, which is high in oil and spicy, and can be called a "hotpot companion probiotic."

Introduction to Lactobacillus plantarum S58 (Photo provided by the interviewee)

“No one knows it in the kimchi jar, but once it is developed, it becomes known to the world.” The advent of Lactobacillus plantarum S58 has led many companies to find the Suo Huayi team, purchase its patent implementation license, and produce related probiotic products - "Shuhechang" simple life series probiotics, Troye small orange bar "light body probiotics", Delinfig instant probiotic powder, and Baodikel high-activity probiotic powder, achieving a production value of 200 million yuan.

Empowerment

Yongchuan fermented black beans, as a specialty fermented condiment in the southwest region, are characterized by loose seeds, shiny black color, delicious taste, and a refreshing sweet aftertaste. There are two main production processes.

One is the production process of Mucor type fermented black beans, which uses natural koji made by Mucor racemosus, high salt (11%) and room temperature post-fermentation, which takes 9-12 months. Due to the low growth temperature of Mucor, it is only produced from November to February of the following year.

The publication of probiotics-related papers and patents obtained by the Suo Huayi team (Photo provided by the interviewee)

A production cycle as long as one year can easily cause difficulties in capital turnover for enterprises and idle factories and production equipment.

Another low-salt quick-made fermented black beans production process uses pure Aspergillus oryzae to make koji, which can be made most of the year. In comparison, the production cycle is shorter, which improves the utilization rate of enterprise funds and plant equipment. However, the flavor of the fermented black beans is difficult to guarantee, which conflicts with consumers' demand for high-quality fermented black beans.

Professor Suo Huayi is collecting bacterial samples (Photo provided by the interviewee)

In response to this problem, Chongqing Yongchuan Douchi Food Co., Ltd. found Professor Suo Huayi's team. After a series of experimental adjustments, the team found that the lack of flavor-enhancing strains in fermentation may be an important factor leading to the poor flavor of Douchi.

After finding the key to solving the problem, the team used high-salt culture medium to isolate, culture and identify salt-tolerant microorganisms in traditional fermented black beans, and then carried out single-strain solid-state fermentation for flavor enhancement of low-salt quick-made black bean products. Relying on the sensory evaluation team and black bean craft inheritors, the team analyzed the black bean flavor and obtained a salt-loving flavor enhancement yeast fermentation combination of Zygosaccharomyces rouxii and Torulopsis saccharomyces.

This combination significantly increases the black bean flavor of the instant fermented black beans and reduces the bitterness, effectively solving the industry problem that has plagued the company's low-salt instant fermented black beans with poor flavor.

It is worth mentioning that this discovery also has important guiding significance and theoretical value for enriching the theory of flavor substance composition and aroma characteristics of traditional Chinese fermented condiments, and innovating the theory of flavor enhancement and aroma regulation, and provides new ideas for improving traditional processes.

The development of bacterial resources is a long journey. For a long time, Professor Suo's team has been adhering to the concept of "the local water and soil nurture the local people, and Chinese people are more suitable for eating Chinese probiotics", and is committed to customizing "Chinese bacteria" that are exclusive to the Chinese physique. He said that at present, the team is conducting research and development of mental probiotics, sports probiotics, oral probiotics, and probiotics to relieve alcoholic liver damage. In the next step, it will cooperate with enterprises to produce probiotic solid beverages, probiotic toothpaste, etc., to realize the product application of probiotics.

"Zhegui·Osmanthus Fragrance Wheat Ale" and "Hejiu·Dihe" developed by Professor Suo Huayi's team (Photo provided by the interviewee)

"Zhegui·Osmanthus Fragrance Wheat Ale" and "Hejiu·Dihe" developed by Professor Suo Huayi's team (Photo provided by the interviewee)

Text: Yang Fan