Fed‐batch cultures ofphaffia rhodozymain xylose‐containing media made from wood hydrolysates

Eucalyptus wood samples were treated with 3% aqueous sulphuric acid to obtain xylose‐containing solutions. The liquors from treatments were neutralized, contacted with charcoal and supplemented with nutrients to obtain culture media suitable for proliferating the carotenoid‐producing yeast, Phaffia rhodozyma NRRL Y‐17268. Two fed‐batch strategies (with continuous or intermittent feeding) were assayed as operational procedures for improving the carotenoid production. Biomass concentration of 10.3 g cells/L and volumetric pigment concentration of 8.15 mg total carotenoids/L (with 7.19 mg astaxanthin/L) were reached with continuous feeding, whereas improved results (30.6 g cells/L and 33.5 mg total carotenoids/L with 30.5 mg astaxanthin/L) were obtained with intermittent feeding.