Production of enterodiol from defatted flaxseeds through biotransformation by human intestinal bacteria.
BACKGROUND
The effects of enterolignans, e.g., enterodiol (END) and particularly its oxidation product, enterolactone (ENL), on prevention of hormone-dependent diseases, such as osteoporosis, cardiovascular diseases, hyperlipemia, breast cancer, colon cancer, prostate cancer and menopausal syndrome, have attracted much attention. To date, the main way to obtain END and ENL is chemical synthesis, which is expensive and inevitably leads to environmental pollution. To explore a more economic and eco-friendly production method, we explored biotransformation of enterolignans from precursors contained in defatted flaxseeds by human intestinal bacteria.


RESULTS
We cultured fecal specimens from healthy young adults in media containing defatted flaxseeds and detected END from the culture supernatant. Following selection through successive subcultures of the fecal microbiota with defatted flaxseeds as the only carbon source, we obtained a bacterial consortium, designated as END-49, which contained the smallest number of bacterial types still capable of metabolizing defatted flaxseeds to produce END. Based on analysis with pulsed field gel electrophoresis, END-49 was found to consist of five genomically distinct bacterial lineages, designated Group I-V, with Group I strains dominating the culture. None of the individual Group I-V strains produced END, demonstrating that the biotransformation of substrates in defatted flaxseeds into END is a joint work by different members of the END-49 bacterial consortium. Interestingly, Group I strains produced secoisolariciresinol, an important intermediate of END production; 16S rRNA analysis of one Group I strain established its close relatedness with Klebsiella. Genomic analysis is under way to identify all members in END-49 involved in the biotransformation and the actual pathway leading to END-production.


CONCLUSIONS
Biotransformation is a very economic, efficient and environmentally friendly way of mass-producing enterodiol from defatted flaxseeds.
Wang
Cheng-Zhi
CZ
Department of Microbiology, Peking University Health Science Center, Beijing 100191, China.
Ma
Xiao-Qing
XQ
Yang
Dong-Hui
DH
Guo
Zhi-Rong
ZR
Liu
Gui-Rong
GR
Zhao
Ge-Xin
GX
Tang
Jie
J
Zhang
Ya-Nan
YN
Ma
Miao
M
Cai
Shao-Qing
SQ
Ku
Bao-Shan
BS
Liu
Shu-Lin
SL
D001711:Biotransformation; D002072:Butylene Glycols / Q000378:metabolism; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D004755:Enterobacteriaceae / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D005243:Feces / Q000382:microbiology; D005260:Female; D019597:Flax / Q000378:metabolism*; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006801:Humans; D017705:Lignans / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D055815:Young Adult
D002072:Butylene Glycols; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D017705:Lignans; D012336:RNA, Ribosomal, 16S; C029498:2,3-bis(3'-hydroxybenzyl)butane-1,4-diol; C060283:secoisolariciresinol
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