IMPROVED ASTAXANTHIN PRODUCTION BY XANTHOPHYLLOMYCES-DENDRORHOUS GROWING ON ENZYMATIC WOOD HYDROLYSATES CONTAINING GLUCOSE AND CELLOBIOSE

Eucalyptus wood samples were treated with NaOH solutions and subjected to enzymatic hydrolysis with a commercial, beta-glucosidase-deficient , cellulase complex or with a mixture of cellulase and beta-glucosidas e. Hydrolysates containing glucose or glucose and cellobiose were supp lemented with KNO3 and nutrients, and used as culture media for the pr oliferation of Xanthophyllomyces dendrorhous (formerly Phaffia rhodozy ma) ATCC 24228. For comparative purposes, similar experiments were car ried out with media made from commercial sugars. All the bioconversion experiments were carried out in a batch fermenter. At selected fermen tation times, the concentrations of substrate (or substrates), biomass and carotenoids were determined. Under the best conditions assayed (h ydrolysates obtained with cellulases supplemented with an inorganic ni trogen source), biomass concentrations in the vicinity of 10 g litre(- 1), with volumetric carotenoid concentration of 2.14 mg litre(-1), wer e reached after 74 h of fermentation. These results compare favourably with those reported for carotenoid production from enzymatic hydrolys ates containing glucose as the sole carbon source. (C) 1998 Elsevier S cience Ltd. All rights reserved.