BIT Has Made Research Achievements in Boosting the Ethanol Production Capacity of Saccharomyces Cerevisiae with the Multiple Defense Systems (MDS)

  Beijing Institute of Technology, March 25, 2020: Recently, Professor Li Chun's research group, Department of Biochemical Engineering of the School of Chemistry and Chemical Engineering, Beijing Institute of Technology(BIT) / Institute of Synthetic Biosystems, has taken industrial S. cerevisiae strains as research objects, using metabolic engineering, synthetic biology, and high-throughput screening technologies to build a multiple defense system at the molecular level and conduct research on its suitability with host cells, conducting industrial pilot tests on the obtained high-performance multiple resistance saccharomyces cerevisiae, and provide new ideas and methods for constructing multiple stress-resistant industrial microbial chassis cells. The research result was published online in the top international journal of energy, ACS Energy letters, with the title of "Multilevel Defense System (MDS) Relieves Multiple Stresses for Economically Boosting Ethanol Production of Industrial Saccharomyces cerevisiae" (Factor 16.331). The corresponding author of this article is Professor Li Chun, and the co-first author is Qin Lei, a Ph.D. student and postdoctoral fellow at the School of Chemistry and Chemical Engineering, BIT.

  The lack of petroleum resources in today's society and the increasingly prominent environmental problems in the context of petroleum refining have prompted mankind to develop new energy sources. Fuel ethanol is currently the world's most important liquid renewable fuel, and saccharomyces cerevisiae is the core strain for producing fuel ethanol presently. The dynamic disturbance of the industrial fermentation environment seriously affects the cost and green index of the fuel ethanol production process. Among them, high sugar mash, high temperature, high ethanol concentration and other stresses lead to a decline in Saccharomyces cerevisiae production performance. Using engineering thinking and synthetic biological techniques can effectively improve the resistance of Saccharomyces cerevisiae strains to stress and improve their ability to survive under adverse environmental conditions. However, the research in this field is still in the initial stage, limited to the transformation of yeast strains in the laboratory, and there is no report on the application of multiple anti-stress industrial yeast in the production of fuel ethanol fermentation. 

  In this paper, by analyzing the omics data of the stress process, a stress signal cascade conduction model of industrial Saccharomyces cerevisiae is established; according to this, the anti-stress gene elements from different sources are excavated, and multiple anti-stress defense systems are constructed using synthetic biotechnology and integrated into the industrial Saccharomyces cerevisiae genome. By combining with ARTP evolution and high-throughput screening methods, strains with high ethanol production in industrial liquefied mash were obtained. The detection and analysis of cell damage, genome and transcriptome of the strains revealed that the apoptosis rate and intracellular reactive oxygen level of the engineering strains in the late stage of fermentation were much lower than those of the original strains, reflecting the role of multiple anti-stress defense systems.

  It can be seen from the results of the pilot fermentation experiment conducted by COFCO Bio-chemical Energy Co., Ltd. that the ethanol production of the engineering bacteria was increased by 7.09% compared with the control group, and the residual sugar content was only 34.9% of the control group. Engineering strains are superior to existing industrial strains in ethanol yield, sugar alcohol conversion rate, high temperature resistance, and high concentration ethanol tolerance. Various indexes of 37℃ high temperature fermentation to produce ethanol achieve or even better than the existing strain 32℃ fermentation results. The company's current scale is more than 12 million Yuan in annual increase only in ethanol production value, while reducing energy consumption by 3 million Yuan in the process. After reducing the residual sugar in the liquefied mash, it will also greatly help the production of DDGS in the later period.

  This work effectively improved the production efficiency of bio-ethanol, reduced fermentation energy consumption and production costs, and realized the high efficiency of the microbial manufacturing system. While establishing new methods and obtaining new strains, it actively promoted the application of its results and effectively improved bio-fuel enterprise technical level and economic benefits.


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​News Source: School of Chemistry and Chemical Engineering
Editor: News Agency of BIT
Translation:BIT News Agency, Han Yu