Details

Autor(en) / Beteiligte

• Qin, Xiulin
• Lu, Junjie
• Zhang, Yin
• Wu, Xiaole
• Qiao, Xuefeng
• Wang, Zhipeng
• Chu, Ju
• Qian, Jiangchao

Titel

Engineering Pichia pastoris to improve S‐adenosyl‐ l‐methionine production using systems metabolic strategies

Ist Teil von

• Biotechnology and bioengineering, 2020-05, Vol.117 (5), p.1436-1445

Ort / Verlag

United States: Wiley Subscription Services, Inc

Erscheinungsjahr

2020

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• S‐adenosyl‐l‐methionine (SAM) is a highly valued chemical that can be used as a dietary supplement and has been used to treat depression, osteoarthritis, and liver problems as well. We adopted systems metabolic engineering strategies to improve SAM production in a high‐producing strain (GS115/DS56). First, the cystathionine β‐synthase gene CYS4 was downregulated using a weak promoter PG12 to reduce the removal of homocysteine from SAM cycle, thus leading to a 48.8% increase in the SAM titer (1.68 g/L) from the strain G12‐CBS, while preventing cysteine auxotrophy induced by deletion of this essential gene. Subsequently, the SAM titer of G12‐CBS was improved to 13.01 g/L in 15‐L fed‐batch fermentation using the optimal l‐methionine feeding strategy. Finally, based on comparative transcriptomics, five genes were chosen and overexpressed for further enhancement of SAM production. Among them, GDH2 and ACS2 exhibited positive effects, and the additional overexpression of GDH2 led to a 52.3% increase of titer (2.71 g/L) in shake flask culture. Therefore, the engineered Pichia pastoris strains can be utilized in industrial production of SAM using a simple and cost‐effective process, and these approaches could be employed for improving the production of other chemicals by P. pastoris. Systems metabolic strategies were adopted to enhance SAM production in a high‐producing Pichia pastoris strain. The CYS4 gene was downregulated using a weak promoter; the 15‐L fed‐batch fermentation of this newly constructed strain was optimized; additionally, GDH2 or ACS2 gene was overexpressed to further improve SAM production based on comparative transcriptome analysis. By using such strategies, the engineered P. pastoris strains can be utilized in industrial production of SAM using a simple and cost‐effective process.