PRODUCTION OF ASTAXANTHIN BY PHAFFIA-RHODOZYMA USING PEAT HYDROLYSATES AS SUBSTRATE

Peat hydrolysates prepared with and without acid and under various tem peratures were tested in the growth of the yeast Phaffia rhodozyma ATC C 24202, which synthesizes carotenoids, including astaxanthin. The hyd rolysate that resulted in the best growth of P. rhodozyma biomass was subsequently used as substrate for the submerged culture of the yeast, and the growth conditions were optimized. Those studied included init ial substrate concentration, initial pH, incubation temperature, ferme ntation time and agitation rate. The optimum growth conditions produce d approximately 4.6 g dm-3 of dry biomass with a crude protein content of 47% (dry weight basis). The mean astaxanthin content of the yeast cultivated under these conditions, 1567 mug g-1 dry yeast, was also th e highest produced in this work, and compares favourably with other re sults reported in the literature.