When it comes to PHA, you may feel unfamiliar. But if I tell you that PHA has started to be applied in many fields such as tableware, food packaging, 3D printing, textile fibers, medical devices, etc., you will feel that it is not far from our lives. PHA, also known as polyhydroxyalkanoate material family, is a new material that grows from cells. It can be completely degraded in nature, non-toxic and harmless In a recent interview with Science and Technology Daily, Chen Guoqiang, a professor at the School of Life Sciences and director of the Center for Synthesis and Systems Biology at Tsinghua University, introduced it as follows. As early as 30 years ago, Chen Guoqiang recognized PHA as the direction of future green materials and embarked on the research and development of bio manufactured PHA without hesitation. This is a process of constant trial and error, we hit walls time and time again, and broke through again and again, "he said. In order to reduce the use of petroleum based plastics and avoid causing more white pollution, researchers have been searching for biodegradable alternative materials to solve the pain of "bacterial contamination". Biological manufacturing is one of the recognized alternative material production pathways. Biomanufacturing, as the name suggests, is the process of redesigning and modifying living organisms to obtain high-performance chassis cells, which are then used as factories to manufacture various materials needed by humans Chen Guoqiang told reporters. Among various biomaterials, PHA has advantages such as biocompatibility, thermoplasticity, and degradability. Based on years of exploration and practice, in 1994, Chen Guoqiang, who had completed his postdoctoral research abroad, came to Tsinghua University to form a team and devoted himself to researching how to achieve PHA mass production. In the laboratory, many problems are not easily exposed. In the factory, as soon as the scale is enlarged, problems arise Chen Guoqiang discovered that the first and foremost challenge is "bacterial contamination" - during the cultivation of microbial cells, other microbial species will grow together with them. Once microbial cells become infected, the entire fermentation process has to start from scratch, resulting in significant losses. To prevent cells from being infected, strict aseptic procedures must be carried out, with strict requirements for equipment and personnel, and high energy consumption. We have tried many types of microorganisms, but none of them have been able to solve this problem Chen Guoqiang recalled that it was not until a chance encounter that he thought of extreme microorganisms. Extreme microorganisms generally grow in extreme environments where ordinary microorganisms find it difficult to survive and are not easily infected by other microorganisms. With it, the PHA production process can be relatively open without the need for complex and cumbersome sterilization operations. So, Chen Guoqiang turned his attention to halophilic microorganisms that were difficult to "infect". Unfortunately, the team members searched multiple places without success. Until 2006, from soil samples retrieved from a salt lake with low latitude, large temperature difference between day and night, and higher salinity than seawater, they finally isolated a strain with both salt tolerance and rapid growth characteristics, which is halophilic bacteria. With suitable strains of bacteria as the basis for constructing the 'chassis', constructing chassis cells becomes the key to achieving biomanufacturing. During the fermentation process, chassis cells can convert renewable biomass such as glucose, starch, and vegetable oil into PHA Chen Guoqiang made an analogy, saying, "They are like machines in a factory, which can continuously produce the polymer materials we need." To obtain chassis cells, it is necessary to disassemble and assemble the genes of halophilic bacteria. A new problem arises - halophilic bacteria are too unique and lack readily available molecular manipulation tools. Molecular surgical knives, molecular suture needles, and molecular transport vehicles are all essential tools Chen Guoqiang explained, 'They are responsible for cutting, recombining, and transporting microbial genes.' Without tools, halophilic bacteria are like a 'black box' that can be seen but cannot be used. Plasmid vectors are commonly used "molecular transport vehicles" responsible for introducing recombinant genes into recipient cells. Just this one tool has consumed a lot of our energy, "Chen Guoqiang told reporters. The team has tried hundreds of existing plasmids, but none of them have been successful. What should I do? Only by expanding the scope and searching for new plasmids. After unremitting efforts, more than 200 plasmids with potential were screened and tested one by one, finally ushering in a turning point - three of them can be used! With plasmids, the "black box" of microbial genetic modification has been opened. On this basis, the team has developed a series of tools for gene editing, metabolic regulation, and network optimization, which can modify and regulate the performance of chassis cells from different levels. The R&D team spent a full decade developing molecular manipulation tools. This process is very painful, "Chen Guoqiang admitted," The secret to success is faith and persistence. Finally, the chassis cells were constructed by the team. The next step is production validation. We spent another seven to eight years, overcoming difficulties such as fermentation process improvement, bacterial morphology transformation, material separation and extraction, and crossing the industrial scale 'death valley' Team member and Associate Researcher at the School of Life Sciences, Tsinghua University, Wu Renqing, introduced. During the industrial scaling up campaign, Chen Guoqiang first proposed the "next-generation industrial biotechnology" internationally in 2018, which was validated in "small-scale", "pilot" and large-scale production. But this does not mean that this technology can gain recognition from enterprises. The team is facing a new challenge - the transformation of achievements. The 'next-generation industrial biotechnology' utilizes a continuous fermentation system that does not require sterilization for production, and has the advantages of openness, high efficiency, low energy consumption, and water resource conservation. It is a 2.0 upgraded version of traditional biomanufacturing technology Wu Renqing said that these disruptive characteristics have actually caused traditional fermentation enterprises to have many concerns. All along, strict sealing and high-temperature sterilization have been required. If you say you don't need it, then you don't need it Some companies even feel that their R&D teams are "fooling" them. After many twists and turns, the team finally found a large fermentation enterprise willing to try. In order to dispel the other party's concerns, the fermentation test was conducted on-site at the enterprise. 200 cubic fermentation tank, first test, successful! The opposing engineer suspects: Is there a "luck" factor? Let's do it again, it's still successful! The cooperation was successfully achieved. In 2021, the achievement transformation enterprise - Beijing Micro Structure Workshop Biotechnology Co., Ltd. (hereinafter referred to as "Micro Structure Workshop") was established, and industrialization entered the fast lane. After the establishment of the company, under the guidance of the market, the progress of laboratory research has been comprehensively accelerated Ouyang Pengfei, Vice President of Micro Structure Factory, said, "In the past, strains were iterated for 3 generations in 9 years; in recent years, 3 generations have been iterated in 1 year; this year, it is expected to iterate for 4 to 5 generations. Iterations have improved the performance of strains and provided a more solid foundation for industrialization. The intelligent production demonstration line with an annual output of thousands of tons has been built in Shunyi, Beijing, and the production base with an annual output of 30000 tons has been established in Yichang, Hubei... "We have also partnered with Chuanning Biotechnology to promote the application of medical grade PHA industry, and explored various application scenarios by building a 'lighthouse factory' in Hefei, Anhui," Ouyang Pengfei introduced. In 2023, based on the development and utilization of halophilic bacteria and the contribution of "next-generation industrial biotechnology" to the industry, the International Society of Metabolic Engineering awarded Chen Guoqiang the "International Metabolic Engineering Award". Nowadays, related technologies have been widely applied in open production of biomanufacturing. Looking towards the future, Chen Guoqiang is full of confidence: "We will solidly promote the deep integration of technological innovation and industrial innovation, continuously improve the level of PHA industrialization, and contribute to China's achievement of the 'dual carbon' goal and green development!" (Xinhua News Agency)