Studies on optimization of nitrogen sources for astaxanthin production by Phaffia rhodozyma

Abstract

Fermentation of Phaffia rhodozyma is a major method for producing astaxanthin, an important pigment with industrial and pharmaceutical application. To improve astaxanthin productivity, single factor and mixture design experiments were used to investigate the effects of nitrogen source on Phaffia rhodozyma cultivation and astaxanthin production. Results of single factor experiments showed nitrogen source could significantly affect P. rhodozyma cultivation with respect to carbon source utilization, yeast growth and astaxanthin accumulation. Further studies of mixture design experiments using (NH(4))(2)SO(4), KNO(3) and beef extract as nitrogen sources indicated that the proportion of three nitrogen sources was very important to astaxanthin production. Validation experiments showed that the optimal nitrogen source was composed of 0.28 g/L (NH(4))(2)SO(4), 0.49 g/L KNO(3) and 1.19 g/L beef extract. The kinetic characteristics of batch cultivation were investigated in a 5-L pH-stat fermentor. The maximum amount of biomass and highest astaxanthin yield in terms of volume and in terms of biomass were 7.71 mg/L and 1.00 mg/g, respectively.

Carotenoids from Rhodotorula and Phaffia: yeasts of biotechnological importance

“…The major carotenoid pigments produced by the yeasts Rhodotorula are -carotene, torulene (3Ј,4Ј-didehydro---carotene), and torularhodin (3Ј,4Ј-didehydro---caroten-16Ј-oic acid), in various proportions [9-11, 15, 16, 18, 21, 23, 24, 63-67] and astaxanthin (3,3Ј-dihydroxy-, -carotene-4,4Ј-dione) by PhaYa rhodozyma [20,22,28,31,[68][69][70][71][72][73][74][75][76][77]. The relative share of the three major carotenoid pigments in the total carotenoids is highly variable, and depends on diVerences between strains of the same species and is strongly inXuenced by the cultivation conditions.…”

“…Yeasts can synthesize carotenoids when cultivated in synthetic medium, containing various reWned carbon sources, such as glucose [9,22,23,25,31,[80][81][82][83][84][85][86], xylose [74], cellobiose [85], sucrose [87,88], glycerol [71] and sorbitol [85]. Studies on carotenogenesis have led to a growing interest in using natural substrates as carbon sources: grape juice [72,89]; grape must [11,63]; peat extract and peat hydrolysate [20,21,77,90]; date juice of Yucca Wllifera [76]; hydrolyzed mustard waste isolates [28]; hemicellulosic hydrolysates of eucalyptus globules wood [68,75]; hydrolyzed mung bean waste Xour [91]; sugar cane juice [69,73,78]; sugar cane and sugar-beet molasses [8,10,18,92,93]; corn syrup [18,64]; corn hydrolysate [94,95]; milk whey [15,16,…”

RICE PARBOILING WASTEWATER IN THE MAXIMIZATION OF CAROTENOIDS BIOPRODUCTION BY Phaffia rhodozyma

“…The alga H. pluvialis responded similar to the observations of this work, with nitrogen limitation in the medium culture resulting in the reduction of primary metabolism (synthesis of protein and chlorophyll) and affecting the secondary metabolism and biosynthesis of astaxanthin (Ip;Chen, 2005). However, the C:N ratio alone cannot explain the growth and carotenoid production, as other nutrients such as vitamins, amino acids and minerals as well as the types of carbon and nitrogen sources have a stronger influence on the metabolism of yeasts (Vustin;Belykh;Kishilova, 2004;Dominguez-Bocanegra et al, 2007;Ni et al, 2008).…”

“…Therefore, it was fixed at the central point (5). For other strains of P. rhodozyma, pH 5 was appropriate for cell growth and the production of carotenoids (Liu;Wu, 2007;Ni et al, 2007), similar to the choice in this work.…”

“…A significant increase in carotenoid production by various microorganisms has been observed with the use of the methodology of factorial design to evaluate different means of production, culture conditions, such as pH, temperature, aeration, and inoculum concentration, and recovery of these compounds (Ni et al, 2007;Liu;Wu, 2007;Gu et al, 2008;Ni et al, 2008;Valduga et al, 2011;Cabral et al, 2011;Michelon et al, 2012). In previous work conducted by our research group, the use of a culture medium containing rice parboiling wastewater (15 g L -1…”