Biosynthesis of 3‑Hydroxy-3-Methylbutyrate from l‑Leucine by Whole-Cell Catalysis

• Published in: Journal of agricultural and food chemistry Vol. 69; no. 12; pp. 3712 - 3719
• Main Authors: Gao, Ruichen, Li, Zhimin
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 31.03.2021
• Subjects: Biocatalysis; Biotechnology and Biological Transformations; Hemiterpenes; Leucine - metabolism; Pentanoic Acids; Valerates; 4-hydroxyphenylpyruvate dioxygenase (4-HPPD); rational design; whole-cell catalyst; 3-hydroxy-3-methylbutyrate; l-leucine
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/acs.jafc.1c00494

3-Hydroxy-3-methylbutyrate (HMB) is an important compound that can be used for the synthesis of a variety of chemicals in the food and pharmaceutical fields. Here, a biocatalytic method using l-leucine as a substrate was designed and constructed by expressing l-amino acid deaminase (l-AAD) and 4-hydroxyphenylpyruvate dioxygenase (4-HPPD) in Escherichia coli. To reduce the influence of the rate-limiting step on the cascade reaction, two 4-HPPD mutants were screened by rational design and both showed improved catalytic activity. Under optimal reaction conditions, the maximum conversion rate and production rate were 80% and 0.257 g/L·h, respectively. HMB production could be realized with high efficiency without an additional supply of adenosine triphosphate (ATP), which successfully overcomes the shortcomings of chemical production and fermentation methods. This design-based strategy of constructing a whole-cell catalyst system from l-leucine might serve as an alternative route to HMB synthesis.