PiLacto - Methylotrophe Hefe Pichia pastoris als Plattform für die Produktion von Aromalactonen
Objective
The global energy demand and increased environmental and climate issues enhance the need for renewable feedstocks like biomass. However, intensive biomass use will compete for food crops and land usage. This competition can be mitigated by using CO2 and C1-derived molecules to produce high-value chemicals. Methanol is one promising feedstock linking effective storage and CO2 capture. In this regard, methylotrophic microorganisms like the yeast Pichia pastoris attract attention due to their ability to grow on methanol as sole energy and carbon source. In this context, the bilateral German-South African project PiLacto will engineer P. pastoris as a microbial cell factory to produce γ- and δ-lactones.
These lactones have diverse commercial applications as flavorings and fragrances. Extraction from exotic plants raises environmental concerns, and their chemical synthesis requires transition-metal catalysts peroxyacids. Thus, direct hydroxylation of bioavailable fatty acids at suitable positions offers an attractive alternative to access lactones. The South African project partners recently reported a biocatalytic route towards δ-dodecalactone. The cytochrome P450 monooxygenase CYP505E3 from Aspergillus terreus catalyzes hydroxylation of dodecanoic acid (C12) at the ω-7 position to the 5-hydroxy fatty acid, which is lactonized to δ-dodecalactone by lowering pH. Hydroxylation of dodecanoic acid at the ω-8 position for γ-dodecalactone formation was, however, low.
Within PiLacto, P450 fatty acid hydroxylases with increased activity and suitable regioselectivity will be designed and introduced into P. pastoris strains with engineered β-oxidation and fatty acid accumulation for the production of γ- and δ-(do)-decalactones from methanol. The constructed P. pastoris strains can also serve as a generic platform for the synthesis of C10 - C12 fatty acids-derived chemicals like dicarboxylic acids or diamines.
Funding
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Bundesministerium für Bildung und Forschung (BMBF)
Project partners
- Prof. Martha Sophia Smit, Department of Microbiology, University of the Free State, Bloemfontein, South Africa (https://www.ufs.ac.za/natagri/departments-and-divisions/microbiology-and-biochemistry-home/departmental-divisions/green-chemistry)
- Prof. Diederik J. Opperman, Department of Microbiology, University of the Free State, Bloemfontein, South Africa (https://www.ufs.ac.za/natagri/departments-and-divisions/microbiology-and-biochemistry-home/departmental-divisions/green-chemistry)