Team:OUC-China
This year,we have done a lot of works that make useful contribution for future iGEM teams.
Aureobasidium melanogenum is a kind of multi-morphological fungus. Its cell morphology and some physiological characteristics are similar to those of yeast. It can produce a variety of products in the process of fermentation and culture, mainly pullulan polysaccharide, poly malic acid and a variety of enzymes, which has great fermentation potential. However, the development is late and the application of biological elements is less. This year, OUC-China is committed to developing the Disp platform of Aureobasidium melanogenum. In order to select suitable promoters, we learned the promoters of Aureobasidium melanogenum in various fermentation stages, and established a platform that can independently design the required promoters as a part of our software. In the future, iGEM teams can obtain the components they need from the parts and software we develop. Secondly, because there is less fungal quorum sensing, we found signal paths that can be used in the engineering bacterial quorum sensing system from Arabidopsis and optimized relevant parts for our platform construction. These new parts can provide new ideas for the team to introduce quorum sensing circuits. During the characterization process, we were surprised to find that there is an enzyme protein that can catalyze ATP to generate IP in the genome of Aureobasidium melanogenum. Through protein sequence alignment, we found that it is similar to the AtIPT4 enzyme protein molecule of Arabidopsis, which also provided a new idea for the iGEM team to construct the quorum sensing of Aureobasidium melanogenum.It is worth mentioning that, in order to better characterize the SSRE promoter, we optimized the codon of the part BBa_E0040 and expressed it in Aureobasidium melanogenum, expanding the application chassis range of this part. The sequence optimized of the codon also can be a suitable part for the team committed to developing the potential of Aureobasidium melanogenum
Development of a new chassis strain—Aureobasidium melanogenum
Innovative application of aptamer transport RNA
We chose to use adaptors with different affinity for products as a highlight of our platform, such as the modification of riboswitch and transport products,which also inspired the later teams to apply the adaptors to more aspects. Among them, in order to transport the products out of the engineering bacteria in time and break through the limitation of limited types of protein transporters, OUC-China decided to apply the aptamer to the transmembrane transport of products. This RNA molecule with transporter function consists of three strands of two different RNA. Among them, one RNA is responsible for targeting the cell membrane structure, and one RNA is responsible for specifically binding products. After they are self-assembled , the bound product molecules can be transported out of the membrane. This innovative application can also be applied to drug targeted delivery and other fields, which also inspired the later teams to apply the adapters to more aspects.
Develop Disp software platform
We are trying to develop software to help more teams design their own fermentation schemes. The functions of the software include setting your login account, helping you use the software, and collecting personal history records. After the team obtains its login account, it can log into our system. Then we will judge whether the scheme is feasible through our algorithm according to the team's selected bacteria species, existing pathways, current yield, target yield, expected yield, suicide yield and other data. We hope to improve the function of our fermentation platform through this software and make it more in line with the fermentation schemes of different teams. Due to the epidemic, some algorithms of this software have not been improved yet, but after improving our algorithm, we believe that it will be of great help to the fermentation project of iGEM team in the future.
Hardware for automatic regulation of purified products
We intend to design an automated fermentation and product screening device. We can ferment strains in fermenters and use expansion bed adsorption to isolate and purify the products. We selected CroCD-TuC3 as our adsorbent. Through the design of infrared sensors and computational processor, the speed of fermentation liquid outflow can be kept constant, achieving the long-term continuous use of our designed device. Although we don’t show it completely in a physical form due to the impact of the epidemic, our design provides a new idea for the screening of fermentation products. And in the actual production practice, the existing fermentation device is transformed into our design, which is also relatively economical and simple. What's more, our hardware design can help the teams who want to do fermentation in the iGEM competition in the future to obtain their products.
