Team:Wageningen UR/Applications

From 2013.igem.org

Summary

Subtitle


Concluding our iGEM project in 2013, we introduced Aspergillu Niger as a potential host into iGEM. It is an industrially relevant organism, deserving a place in iGEM as a standard synthetic biological chassis. With the host engineering, we stepped further to the next level of synthetic biology.

In this GRAS organism, we established a modular system of domain shuffling in order to express a variety of secondary metabolites. We focused on the production of a medically relevant compound, lovastatin, which has never been produced in A. niger. By synthesizing a range of modules for the main multi-domain enzyme in the lovastatin pathway, a new frame shiftless assembly protocol was developed to design the complexes, and bricked these parts for future teams. Furthermore, the metabolic models we developed to pre-emptively assess the production conditions, and potentially the optimization of production, has hinted at future improvements for A. niger lovastatin production and comply the need of industry.

Additionally, to target the production of specific compartment, a toolkit including a promoter , terminator , biosensors for pH , ATP , and chromogenic biomarkers , chromogenic biomarkers as well as a marker for the cytoskeleton was created successfully. It accelerated the exploration of more potentiality and paved the way for future teams to further exploit this beautiful bug.

Finally, we modified the host by directed evolution. Filamentous fungi are pretty organisms, but multicellularity is not always wanted in fermentations. We set out to solve this defect by evolving mutants with a reduced mycelial cohesiveness. Microscopic analyses have shown that Aspergillus is conditionally dimorphic, and both viable and metabolically active in a single cell morphotype. The causes of multicellularity was further unravelled.

We learned a lot, we made mistakes, and though this whole endeavor was incredibly ambitious, it was inspiring, educational, and totally worthwhile. And nothing beats the excitement of positive results. –Wageningen iGemers