Expression of POX2 gene and disruption of POX3 genes in the industrial Yarrowia lipolytica on the γ-decalactone production

The yeast Yarrowia lipolytica growing on methyl ricinoleate can produce gamma-decalactone, the worthy aroma compound, which can exhibit fruity and creamy sensorial notes. and recognized internationally as a safe food additive. Unfortunately, the yield is poor because of lactone degradation by enzyme Aox3 (POX3 gene encoded), which was responsible for continuation of oxidation after C-10 level and lactone reconsumption. In this paper, we chose the industrial Y. lipolytica (CGMCC accession number 2.1405), which is the diploid strain as the starting strain and constructed the recombinant strain Tp-12 by targeting the POX3 locus of the wild type, one copy of POX3 was deleted by CRF1 + PDX2 insertion. The other recombinant strain Tpp-11, which was a null mutant possessing multiple copies of PDX2 and disrupted PDX3 genes on two chromosomes, was constructed by inserting XPR2 + hpt into the other copy of PDX3 of Tp-12. The growth ability of the recombinants was changed after genetic modification in the fermentation medium. The production of gamma-decalactone was increased, resulting from blocking beta-oxidation at the C-10 Aox level and POX2 overexpression. The recombinant strain Tpp-11 was stable. Because there was no reconsumption of gamma-decalactone, the mutant strain could be grown in continuous fermentation of methyl ricinoleate to produce gamma-decalactone. (C) 2011 Elsevier GmbH. All rights reserved.