TY - JOUR
T1 - Establishing an Artificial Pathway for Efficient Biosynthesis of Hydroxytyrosol
AU - Li, Xianglai
AU - Chen, Zhenya
AU - Wu, Yifei
AU - Yan, Yajun
AU - Sun, Xinxiao
AU - Yuan, Qipeng
N1 - Publisher Copyright:
© 2017 American Chemical Society.
PY - 2018/2/16
Y1 - 2018/2/16
N2 - Hydroxytyrosol (HT) is a valuable natural phenolic compound with strong antioxidant activity and various physiological and pharmaceutical functions. In this study, we established an artificial pathway for HT biosynthesis. First, efficient enzymes were selected to construct a tyrosol biosynthetic pathway. Aro10 from Saccharomyces cerevisiae was shown to be a better ketoacid decarboxylase than Kivd from Lactococcus lactis for tyrosol production. While knockout of feaB significantly decreased accumulation of the byproduct 4-hydroxyphenylacetic acid, overexpression of alcohol dehydrogenase ADH6 further improved tyrosol production. The titers of tyrosol reached 1469 ± 56 mg/L from tyrosine and 620 ± 23 mg/L from simple carbon sources, respectively. The pathway was further extended for HT production by overexpressing Escherichia coli native hydroxylase HpaBC. To enhance transamination of tyrosine to 4-hydroxyphenylpyruvate, NH4Cl was removed from the culture media. To decrease oxidation of HT, ascorbic acid was added to the cell culture. To reduce the toxicity of HT, 1-dodecanol was selected as the extractant for in situ removal of HT. These efforts led to an additive increase in HT titer to 1243 ± 165 mg/L in the feeding experiment. Assembly of the full pathway resulted in 647 ± 35 mg/L of HT from simple carbon sources. This work provides a promising alternative for sustainable production of HT, which shows scale-up potential.
AB - Hydroxytyrosol (HT) is a valuable natural phenolic compound with strong antioxidant activity and various physiological and pharmaceutical functions. In this study, we established an artificial pathway for HT biosynthesis. First, efficient enzymes were selected to construct a tyrosol biosynthetic pathway. Aro10 from Saccharomyces cerevisiae was shown to be a better ketoacid decarboxylase than Kivd from Lactococcus lactis for tyrosol production. While knockout of feaB significantly decreased accumulation of the byproduct 4-hydroxyphenylacetic acid, overexpression of alcohol dehydrogenase ADH6 further improved tyrosol production. The titers of tyrosol reached 1469 ± 56 mg/L from tyrosine and 620 ± 23 mg/L from simple carbon sources, respectively. The pathway was further extended for HT production by overexpressing Escherichia coli native hydroxylase HpaBC. To enhance transamination of tyrosine to 4-hydroxyphenylpyruvate, NH4Cl was removed from the culture media. To decrease oxidation of HT, ascorbic acid was added to the cell culture. To reduce the toxicity of HT, 1-dodecanol was selected as the extractant for in situ removal of HT. These efforts led to an additive increase in HT titer to 1243 ± 165 mg/L in the feeding experiment. Assembly of the full pathway resulted in 647 ± 35 mg/L of HT from simple carbon sources. This work provides a promising alternative for sustainable production of HT, which shows scale-up potential.
KW - 4-hydroxyphenylacetic acid 3-hydroxylase
KW - biphasic cultivation
KW - hydroxytyrosol
KW - microbial synthesis
KW - shikimate pathway
UR - http://www.scopus.com/inward/record.url?scp=85042192803&partnerID=8YFLogxK
U2 - 10.1021/acssynbio.7b00385
DO - 10.1021/acssynbio.7b00385
M3 - Article
C2 - 29281883
AN - SCOPUS:85042192803
SN - 2161-5063
VL - 7
SP - 647
EP - 654
JO - ACS Synthetic Biology
JF - ACS Synthetic Biology
IS - 2
ER -