The algal beta-carotene hydroxylase gene Crchyb from Chlamydomonas reinhardtii, Czchyb from Chlorella zofingiensis, or Hpchyb from Haematococcus pluvialis and six other carotenoid-synthesis pathway genes were co-integrated into the genome of a yeast host. Each of these three algal genes showed a higher efficiency to convert beta-carotene to downstream carotenoids than the fungal genes from Phaffia rhodozyma. Furthermore, the strain with Hpchyb displayed a higher carotenoid productivity than the strains integrated with Crchyb or Czchyb, indicating that Hpchyb is more efficient than Crchyb and Czchyb. These results suggest that beta-carotene hydroxylase plays a crucial role in the biosynthesis of carotenoids. (C) 2014 Elsevier Ltd. All rights reserved.