(1) It has the promoter of the alcohol oxidase AOX1 gene, which is one of the strongest promoters with the strictest regulation mechanism. (2) The expression plasmid can be stably integrated in the form of single copy or multiple copies at a specific site in the genome. (3) The strain is easy to carry out high-density fermentation, and the exogenous protein expression is high. (4) Peroxisome exists in Pichia pastoris, and the expressed protein is stored in it, which can be protected from protease degradation and reduce the toxicity to cells.
After nearly ten years of development, the Pichia.pastoris gene expression system has basically become a relatively complete exogenous gene expression system. It is easy to high-density fermentation, and the expressed gene is stably integrated into the host genome, enabling the product to be effectively secreted and properly glycosylated. Cultivate the characteristics of convenience and economy. Using the potent regulatable promoter AOX1, a variety of exogenous genes such as HBsAg, TNF, EGF, tetanus toxin C fragment, and genetically engineered antibodies have been efficiently expressed, which proves that the system is efficient, practical and simple. It is an exogenous gene expression system that maintains the biological activity of the product as a prominent feature, and is very suitable for scaling up to an industrial scale. At present, the US FDA has been able to evaluate genetically engineered products from this system, and the Cephelon preparation from this system has recently been approved by the FDA, so the system is considered safe. The Pichia.pastoris expression system will play an increasingly important role in the field of bioengineering, promoting the efficient expression of more exogenous genes in the system and providing a wider range of genetic engineering products.
Researchers at Johns Hopkins University have successfully used a new technique to identify genes from the yeast genome that are involved in the aggregation of chromosomes that replicate during yeast cell division to protect the yeast’s genetic integrity during cell division.
The history of industrial development
As early as 3000 AD, humans began to use yeast to make fermented products. The earliest product sold in the market was yeast puree. This product is characterized by fast fermentation, but inconvenient transportation and use, and the commercialization of the product has been limited to a certain extent. The yeast industry has a history of more than 200 years, starting from the sale of yeast paste and the manufacture of yeast as an industry. Yeast has become one of the most studied microorganisms in the world, a hot spot in the research and development of biotechnology products and a model system for modern biotechnology development and genome research. At present, the total global yeast production capacity (in terms of dry yeast) exceeds 1 million tons, and the annual sales revenue exceeds 2.5 billion US dollars. Since the 1980s, China’s yeast industry has achieved leapfrog development and has owned independent innovative brands that sell well all over the world. The research, production and application of yeast products have reached the international advanced level.