摘要
Malonate is a high-value chemical that can be used to produce value-added compounds.Due to the toxic by-products and low product yield for malonate production through hydrolysis of cyanoacetic acid,microbial production methods have attracted significant attention.Previously,theβ-alanine pathway has been engineered in Escherichia coli for malonate production.In this study,theβ-alanine pathway was constructed in Saccharomyces cerevisiae by introducing the heterologous genes of BcBAPAT and TcPAND to convert l-aspartate to malonic semialdehyde,combining with co-expression genes of AAT2 and UGA2 to improve precursor supply and malonate producing.Through delta sequence-based integration of the two heterologous genes,the engineered strain produced with 7.21 mg/L malonate was screened.Further,replaced the succinic semialdehyde dehydrogenase gene UGA2 with yneI from E.coli which was utilized to produce malonate in previous study,increased the malonate titer to 7.96 mg/L in flask culture.Following optimization,fermentation of the final engineered strain in shake flasks yielded a maximum malonate titer of 12.83 mg/L,and this was increased to 91.53 mg/L during fed-batch fermentation in a 5 L bioreactor which increased by two-fold compared with that of the engineered strain overexpressing UGA2.
基金
supported by the National Key R&D Program of China(2019YFA0905502)
the National Natural Science Foundation of China(21877053)
Tianjin Synthetic Biotechnology Innovation Capacity Improvement Project(TSBICIP-KJGG-015)
the Open Foundation of Jiangsu Key Laboratory of Industrial Biotechnology(KLIB-KF201807).
