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Enhancing desulphurization by engineering a flavin reductase‐encoding gene cassette in recombinant biocatalysts
Author(s) -
Galán Beatriz,
Díaz Eduardo,
García José L.
Publication year - 2000
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1046/j.1462-2920.2000.00151.x
Subject(s) - biology , dibenzothiophene , heterologous expression , rhodococcus , expression cassette , escherichia coli , gene , monooxygenase , recombinant dna , biochemistry , bacteria , genetics , enzyme , vector (molecular biology) , cytochrome p450 , catalysis
Biological desulphurization of petroleum feedstocks and products may offer an attractive alternative to reduce sulphur oxide emissions that cause serious environmental pollution. Dibenzothiophene (DBT) desulphurization via the Dsz pathway of Rhodococcus erythropolis IGTS8 is an energetically expensive process that consumes reducing equivalents. We have shown in this work that the HpaC oxidoreductase from Escherichia coli W is able to supply the required FMNH 2 to the Dsz monooxygenases. The cloning and expression of the hpaC gene in Pseudomonas strains bearing the dszABC gene cluster significantly enhanced DBT desulphurization efficacy of the recombinant biocatalysts in a resting‐cell process, thus indicating that overexpression of a heterologous flavin reductase in the host cell is critical for a high rate of sulphur removal in vivo . The hpaC and dszABC genes have been engineered as a single transcription unit under control of broad‐host‐range regulatory signals in a mobilizable DNA cassette that can be used to confer a DBT desulphurization phenotype to a wide variety of bacteria regardless of the expression of putative housekeeping flavin reductases within the host cells. This cassette will be very useful in exploring the biotechnological potential of novel biocatalysts for developing an efficient desulphurization process.