posted on 2021-04-26, 16:36authored byMingtao Zhao, Yankai Tao, Xiaofeng Wu, Yi Xiao
4-Hydroxyphenylacetic,
homovanillic, and 3,4-dihydroxyphenylacetic
acids are phenolic acids with various attractive bioactivities, such
as antioxidative, anti-inflammatory, and antiobesity effects. However,
powerful strategies for the efficient and sustainable synthesis of
hydroxyphenylacetic acids are lacking. In this work, to promote the
synthesis of hydroxyphenylacetic acids, we first engineered an Escherichia coli BL21 (DE3)-reduced aromatic aldehyde
reduction strain to accumulate their aromatic aldehyde precursors.
Then, we developed a one-pot bioconversion strategy using lignin-related p-coumaric and ferulic acids as starting materials for the
abovementioned synthesis. The bioconversions comprise two artificial
routes: decarboxylation-epoxidation-isomerization-oxidation for the
synthesis of 4-hydroxyphenylacetic and homovanillic acids and decarboxylation-epoxidation-isomerization-oxidation-hydroxylation
for the synthesis of 3,4-dihydroxyphenylacetic acid. This enabled
efficient biosynthesis of 4-hydroxyphenylacetic acid (13.7 mM, 91.3%
yield, 1041 mg/L/h productivity), homovanillic acid (3.8 mM, 76.2%
yield, 115.6 mg/L/h productivity), and 3,4-dihydroxyphenylacetic acid
(13.5 mM, 90% yield, 907 mg/L/h productivity). Moreover, we made an
example to investigate the synthesis of hydroxyphenylacetic acids
from the lignocellulosic biomass hydrolysate, in which 5.2 mM 4-hydroxyphenylacetic
acid in 57.8% conversion and 2.2 mM 3,4-dihydroxyphenylacetic acid
in 55% conversion were produced from 9 and 4 mM p-coumaric acid, respectively. This study provides not only a new
strategy to enable the efficient and sustainable synthesis of hydroxyphenylacetic
acids but also new insights into the utilization of lignocellulosic
biomass in the synthesis of high-value compounds.