Document Detail

Efficient polycyclic aromatic hydrocarbons dihydroxylation in direct micellar systems.
MedLine Citation:
PMID:  11400097     Owner:  NLM     Status:  MEDLINE    
Optimization of whole-cell bioconversion of the polycyclic aromatic hydrocarbons (PAHs) anthracene, phenanthrene, and naphthalene to the enantiomerically pure corresponding cis-dihydroxydihydro derivatives by the Escherichia coli JM109 (pPS1778) recombinant strain, carrying the naphthalene dioxygenase and corresponding regulatory genes cloned from Pseudomonas fluorescens N3, in micellar systems, is presented. We show that direct microemulsion systems, where a nonionic surfactant such as 1.5% (v/v) Triton X-100 plus 0.6% to 1.0% (v/v) selected oils are able to solubilize the PAHs tested at relatively high concentrations (initial concentrations in the reaction medium > or =10 mM for naphthalene and phenanthrene and > or =2 mM for anthracene), and allow for more efficient substrate bioconversion. These media, while not affecting bacteria viability and performance, provide increased efficiency and final product yields (100% for naphthalene, >30% for anthracene, >60% for phenanthrene). The phase behavior of the direct microemulsion systems for the different substrates and oils utilized was monitored as a function of their volume fraction by light scattering experiments, and related to the bioconversion results. For anthracene and phenanthrene, the dihydroxylated products have an inhibitory effect on the conversion reactions, thus hindering complete turnover of the substrates. We ascertain that such inhibition is reversible because removal of the products formed allowed the process to start over at rates comparable to initial rates. To allow for complete conversion of the PAHs tested a stepwise or continuous separation of the product formed from the micellar reaction environment is being developed.
D Randazzo; D Berti; F Briganti; P Baglioni; A Scozzafava; P Di Gennaro; E Galli; G Bestetti
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biotechnology and bioengineering     Volume:  74     ISSN:  0006-3592     ISO Abbreviation:  Biotechnol. Bioeng.     Publication Date:  2001 Aug 
Date Detail:
Created Date:  2001-06-11     Completed Date:  2001-10-04     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7502021     Medline TA:  Biotechnol Bioeng     Country:  United States    
Other Details:
Languages:  eng     Pagination:  240-8     Citation Subset:  IM    
Copyright Information:
Copyright 2001 John Wiley & Sons, Inc.
Laboratorio di Chimica Bioinorganica, Dipartimento di Chimica, Università di Firenze, Via Della Lastruccia 5, 50019 Florence, Italy.
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MeSH Terms
Anthracenes / chemistry,  metabolism
Escherichia coli / genetics,  metabolism*
Industrial Microbiology / methods*
Octoxynol / chemistry
Oils / chemistry
Phenanthrenes / chemistry,  metabolism
Polycyclic Hydrocarbons, Aromatic / chemistry*,  metabolism*
Surface-Active Agents / chemistry
Reg. No./Substance:
0/Anthracenes; 0/Micelles; 0/Oils; 0/Phenanthrenes; 0/Polycyclic Hydrocarbons, Aromatic; 0/Surface-Active Agents; 120-12-7/anthracene; 85-01-8/phenanthrene; 9002-93-1/Octoxynol

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