Engineering the halophilic bacterium Halomonas elongata to produce beta-carotene

Appl Microbiol Biotechnol. 2007 Dec;77(3):637-43. doi: 10.1007/s00253-007-1195-2. Epub 2007 Sep 27.

Abstract

Engineering halophilic bacteria to produce carotenoids is a subject of great scientific and commercial interest, as carotenoids are desirable products used as additives and colorants in the food industry, with beta-carotene the most prominent. With this target, we expressed the beta-carotene biosynthetic genes crtE, crtY, crtI, and crtB from Pantoea agglomerans and the cDNA encoding isopentenyl pyrophosphate isomerase from Haematococcus pluvialis in the halophilic bacterium Halomonas elongata obtaining a strain able to produce practically pure beta-carotene. Reverse transcription-polymerase chain reaction analysis showed crtY, crtI, and crtB heterologous expression in a selected exconjugant of H. elongata. Biosynthesis of beta-carotene was dependent on NaCl concentration in the culture medium, with the highest production (560 microg per g of dry weight) in 2% NaCl. On the contrary, no beta-carotene was detected in 15% NaCl. Successful construction of the beta-carotene biosynthetic pathway in H. elongata opens the possibility of engineering halophilic bacteria for carotenoid production.

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Gene Expression Regulation, Bacterial
  • Genes, Bacterial
  • Genetic Engineering*
  • Genetic Vectors
  • Halomonas / genetics*
  • Halomonas / metabolism
  • beta Carotene / biosynthesis*
  • beta Carotene / genetics

Substances

  • Bacterial Proteins
  • beta Carotene