Multistep conversion of cresols by phenol hydroxylase and 2,3-dihydroxy-biphenyl 1,2-dioxygenase
Shengnan SHI,Fang MA,Tieheng SUN,Ang LI,Jiti ZHOU,Yuanyuan QU
《环境科学与工程前沿（英文）》
2014年
第8卷
第4期
页码 539-546
doi:
10.1007/s11783-013-0616-y
摘要：
A multistep conversion system composed of phenol hydroxylase (PH ) and 2,3-dihydroxy-biphenyl 1,2-dioxygenase (BphC ) was used to synthesize methylcatechols and semialdehydes from - and -cresol for the first time. Docking studies displayed by PyMOL predicted that cresols and methylcatechols could be theoretically transformed by this multistep conversion system. High performance liquid chromatography mass spectrometry (HPLC-MS) analysis also indicated that the products formed from multistep conversion were the corresponding 3-methylcatechol, 4-methylcatechol, 2-hydroxy-3-methyl-6-oxohexa-2,4-dienoic acid (2-hydroxy-3-methyl-ODA) and 2-hydroxy-5-methyl-6-oxohexa-2,4-dienoic acid (2-hydroxy-5-methyl-ODA). The optimal cell concentrations of the recombinant strain BL21 (DE3) expressing phenol hydroxylase (PH ) and 2,3-dihydroxy-biphenyl 1,2-dioxygenase (BphC ) and pH for the multistep conversion of - and -cresol were 4.0 (g·L cell dry weight) and pH 8.0, respectively. For the first step conversion, the formation rate of 3-methylcatechol (0.29 μmol·L ·min ·mg cell dry weight) from -cresol was similarly with that of methylcatechols (0.28 μmol·L ·min ·mg cell dry weight) from -cresol by strain PH . For the second step conversion, strain BphC showed higher formation rate (0.83 μmol·L ·min ·mg cell dry weight) for 2-hydroxy-3-methyl-ODA and 2-hydroxy-5-methyl-ODA from -cresol, which was 1.1-fold higher than that for 2-hydroxy-3-methyl-ODA (0.77 μmol·L ·min ·mg cell dry weight) from -cresol. The present study suggested the potential application of the multistep conversion system for the production of chemical synthons and high-value products.
关键词：
multistep conversion
cresols
phenol hydroxylase
2
3-dihydroxybiphenyl 1
2-dioxygenase
methylcatechols
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