Blocking consumption pathway increases production of S-adenosyl-l-methionine by Pichia pastoris

Abstract:

[Background] S-Adenosyl-l-methionine (SAM) is an important intracellular metabolite that can be used as a dietary supplement and to treat a variety of diseases. [Objective] To enhance SAM production for industrial application by blocking SAM consumption pathways in the recombinant Pichia pastoris strain GS115/DS16. [Methods] The genes associated with the metabolism of SAM, sah1 (encoding S-adenosyl-l-homocysteine hydrolase), spe2 (encoding S-adenosylmethionine decarboxylase), and msm1 (encoding mitochondrial methylthio-tRNA synthase), were knocked out in SAM-producing strain GS115/DS16. Accordingly, the engineered strains G/Dsah, G/Dspe, and G/Dmsm were constructed. The cell growth and SAM production of the three engineered strains were investigated. Additionally, the effect of methionine addition on SAM accumulation was studied. [Results] The knock-out did not affect cell growth, whereas it increased SAM production by 29.3%, 55.6%, and 24.8% in G/Dsah, G/Dspe, and G/Dmsm, respectively, compared with the parental strain GS115/DS16. When l-Met addition was decreased from 0.10% to 0.06%, the SAM production increased by 26.4% and 28.9% in G/Dsah and G/Dmsm, respectively. [Conclusion] Therefore, the engineered P. pastoris strains can be utilized in industrial production of SAM in a cost-effective manner, and the strategy can also be employed for improving the production of other chemicals.