title: Biosynthesis of phlorisovalerophenone and 4-hydroxy-6-isobutyl-2-pyrone in Escherichia coli from glucose.
abstract: BACKGROUND
  Type III polyketide synthases (PKSs) contribute to the synthesis of many economically important natural products, which are typically produced by direct extraction from plants or synthesized chemically. For example, humulone and lupulone (Fig. 1a) in hops (Humulus lupulus) account for the characteristic bitter taste of beer and display multiple pharmacological effects. 4-Hydroxy-6-methyl-2-pyrone is a precursor of parasorboside contributing to insect and disease resistance of plant Gerbera hybrida, and was recently demonstrated to be a potential platform chemical. Fig. 1 Examples of phloroglucinols (a) and 2-pyrones (b) synthesized by type III PKS. PIBP phlorisobutyrophenone; PIVP phlorisovalerophenone; TAL 4-hydroxy-6-methyl-2-pyrone (triacetic acid lactone); HIPP 4-hydroxy-6-isopropyl-2-pyrone; HIBP 4-hydroxy-6-isobutyl-2-pyrone
  
  
  RESULTS
  In this study, we achieved simultaneous biosynthesis of phlorisovalerophenone, a key intermediate of humulone biosynthesis and 4-hydroxy-6-isobutyl-2-pyrone in Escherichia coli from glucose. First, we constructed a biosynthetic pathway of isovaleryl-CoA via hydroxy-3-methylglutaryl CoA followed by dehydration, decarboxylation and reduction in E. coli. Subsequently, the type III PKSs valerophenone synthase or chalcone synthase from plants were introduced into the above E. coli strain, to produce phlorisovalerophenone and 4-hydroxy-6-isobutyl-2-pyrone at the highest titers of 6.4 or 66.5 mg/L, respectively.
  
  
  CONCLUSIONS
  The report of biosynthesis of phlorisovalerophenone and 4-hydroxy-6-isobutyl-2-pyrone in E. coli adds a new example to the list of valuable compounds synthesized in E. coli from renewable carbon resources by type III PKSs.
authors: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.|Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.|University of Chinese Academy of Sciences, Beijing, China.
authors: Wei
authors: W
authors: Zhou
authors: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.|Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
authors: Yibin
authors: Y
authors: Zhuang
authors: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.|Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.|University of Chinese Academy of Sciences, Beijing, China.
authors: Yanfen
authors: Y
authors: Bai
authors: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China. bi_hp@tib.cas.cn.|Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China. bi_hp@tib.cas.cn.
authors: Huiping
authors: H
authors: Bi
authors: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China. liu_t@tib.cas.cn.|Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China. liu_t@tib.cas.cn.
authors: Tao
authors: T
authors: Liu
authors: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
authors: Yanhe
authors: Y
authors: Ma
mesh_terms: D000217:Acyltransferases / Q000378:metabolism; D000595:Amino Acid Sequence; D053898:Biosynthetic Pathways / Q000235:genetics*; D053138:Cyclohexenes / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics*; D005947:Glucose / Q000378:metabolism*; D010696:Phloroglucinol / Q000031:analogs & derivatives* / Q000378:metabolism; D048630:Polyketide Synthases / Q000378:metabolism; D011753:Pyrones / Q000378:metabolism*; D013729:Terpenes / Q000378:metabolism
chemical_list: C584017:2-pyrone; D053138:Cyclohexenes; D011753:Pyrones; D013729:Terpenes; C030720:triacetic acid lactone; D048630:Polyketide Synthases; D010696:Phloroglucinol; D000217:Acyltransferases; C020141:flavanone synthetase; D005947:Glucose; C007966:humulon; C525072:4-hydroxy-6-methyl-2-pyrone
keywords: 4-Hydroxy-6-isobutyl-2-pyrone; Escherichia coli; Isovaleryl-CoA; Phlorisovalerophenone; Valerophenone synthase