Glucoamylase-in Saccharomyces cerevisiae

After the outburst of Covid-19, the demand for ethanol has surged. In China, the factory price of ethanol reached a historical high level of 7500 RMB/ton. Meanwhile, as a renewable fuel, ethanol has been added to gasoline. The E10 petrol has been widely used in the U.S., China, U.K. and other European nations. In 2021, Mohammed, Balla, Al-Dulaimi, Kareem, Al-Zuhairy concluded that “adding ethanol reduce harmful exhaust gasses. It is found that more ethanol is an accompanied with less exhaust gasses.”

In the context of global pandemic and demand for environmental-friendly energy, it is expected that production of ethanol may become a profitable business opportunity.

The traditional production of ethanol starts from starch raw materials, such as cassava, wheat, corn, etc.

After being saccharified with glucoamylase, it is then fermented with glucose to produce ethanol. However, it requires the artificial addition of glucoamylase leading to additional costs. (For production of 1 ton of ethanol, it costs approximately 100 RMB to add sufficient glucoamylase)

To lower the costs of ethanol production, we decide to design a novel Saccharomyces cerevisiae, which can produce glucoamylase by itself while keeping original fermentation. We call our Saccharomyces cerevisiae by Glucoamylase-in Saccharomyces cerevisiae.

We intercepted the gene fragment responsible for the autocrine glucoamylase in the organism, optimized the codon, and inserted it into the plasmid vector as the target gene. Then we isolated the plasmids, and eventually transferred them into the yeast to produce alcohol through fermentation. After that, several function tests would be conducted to analyze the performance of our engineered yeast.

Our experiment results (for details please refer to our results page) indicate an initial success of our Glucoamylase-in Saccharomyces cerevisiae, which self-secretes Glucoamylase without lowering fermentation.

The following figure listed the Glucoamylase activity assay results of our experiments.

The GA activity of S. cerevisiae strains harboring various plasmids was determined using the glucoamylase activity assay kit. As shown in Figure above, the control stain (left column) exhibited no GA activity. To the contrast, the strains harboring pYES2-TGC and pYES2-HGC plasmids, which means the GA’s expression was driven by the constitutive promoter TEF1 and glucose inducible promoter HXT7, showed almost the same and high GA activity.

Potential End Users

Currently, we are planning to locate the end users of Glucoamylase-in Saccharomyces cerevisiae as ethanol production companies or energy firms, such as SDIC Biotech Investment Co.,Ltd, COFCO Biotechnology Co., Ltd, CNPC and etc.

With our Glucoamylase-in Saccharomyces cerevisiae, they can produce the same amount of ethanol at a lower cost. We believe that this ethanol production giants may use our product efficiently because of their scale economics, talent reserve and willingness to innovate.

If our Glucoamylase-in Saccharomyces cerevisiae is used in the real world, the production costs will be lowered, and supply of ethanol will be stable. In the future, even if there is a similar epidemic, people can have enough ethanol reserves to prepare. Also, with more and more supply of ethanol in the market, the renewable fuel will also be gradually popular, contributing to a better environment.

Safety Concerns and Challenges

• The significant problems that genetically modified products face are the public's concerns about their safety and how they affect health. However, since our current project does not envisage the consumption business, such as wineries and breweries, those concerns do not affect our implementation.

  Our team did not test or have trials of the human body's reaction, consuming alcohol made with this new yeast; thus, our product will only be limited to industrial and medical use.

• Obstacles in developing business cooperation with end users (ethanol production companies or energy firms

  We may look deeper into policies of different countries and contact organizations such as the Chinese Academy of Sciences, fuel processing companies, and the government to obtain a production license.

  We have already developed an attractive and realistic business plan, please refer to our entrepreneurship page.

  We may also try to seek potential investors and present our plan with all types of investors, including bankers, venture capitalists, specialty funds, and other biotech and pharmaceutical companies.

  We may also improve safety precautions, test more to ensure that the products are entirely eligible to use for biofuels, for medical-related products.