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The Methanol Converter

Pichia pastoris GS115: From methanol to medicine, how to do it better?

Methanol is a major byproduct of the coal industry, and engineered Pichia pastoris GS115 can convert methanol into medical compounds such as the insulin precursor and lovastatin. However, this pathway results in significant oxygen consumption and heat generation, limiting its industrial applications. We improved the methanol conversion rate in P. pastoris by rewiring its homogeneous regulatory circuits to up-regulate the expression of alcohol oxidase 1, the protein that allows it to metabolize methanol. Improving the conversion efficiency lowers heat generation as all heat comes from methanol metabolism. Through multiple rounds of experiments, we acquired strains that are able to yield an up to 20% increase in methanol conversion rate compared to the wildtype.

Design Experiment Results Parts

About us

We are a diverse group of high school students from China, studying in Beijing, Tianjin, the United States or Switzerland, as well as in Shanghai Foreign Language School. We have different hobbies, ambitions, and views towards bioengineering. We also have different roles to play this fascinating project. For more information about us, please check the links below:

Team Members Attributions

Outside the Lab

Model

Before we got into the lab, we wanted to get an idea of how much more efficient our constructs will be compared with the wild-type P. pastoris. So we modeled our constructs based on various statistics published in Wang et al., 2016, Shi et al., 2019 and Liang et al., 2012, and calculated basic parameters for each promoter and transcription factor in our three constructs. Specifically, we modulated the activity of one promoter under the effect of one unit transcription factor, and used it to calculate the overall expression efficiency of our constructs. As it turned out, the results looked pretty encouraging, and so we proceeded with our experiment.

Demonstrate

In our project, we rewired the homogeneous regulatory pathways of Pichia pastoris GS115 to improve its methanol metabolizing capabilities. When we consulted research professionals and industry leaders regarding the feasibility of our approach in industrial settings, most were not optimistic. To address this doubt, we constructed a model calculating the oxygen consumption and heat generation of our yeast strains, two main factors to be considered in industrial processes. We based our models on validated and published equations and data from our experiments. The results of our calculations confirm the potential industrial applications of our modified P. pastoris GS115 strains.

Human Practices

From the start of our project, we actively consulted peers, research professionals, industry experts, and the general public for advice and guidance. We first met up with Dr. Cai from ECUST, who introduced us to Pichia pastoris GS115, which we decided to base our project upon. We also interviewed two industry leaders. One of them, Dr. Hu, CEO of GTL Biotech, illustrated to us the great potential of methanol as a carbon source, which happens to be what P. pastoris is tailored to metabolize. After designing our experiments, we referred to the opinion of the public for evaluations of acceptability, feasibility and general impact via a questionnaire. We also became aware that industrializing our design might be difficult and altered our experiments to provide data for a demonstration model constructed afterwards.