Influence of carbon and nitrogen sources on Flavobacterium growth and zeaxanthin biosynthesis

Growth and production of zeaxanthin by Flavobacterium sp were studied using different carbon and nitrogen sources in a chemically defined medium. The best growth was supported by sucrose, but glucose yielded similar carotenoi d concentrations, Both asparagine and glutamine stimulated growth and pigme nt formation, Carotenoid production and glucose consumption increased as a function of asparagine concentration. In the presence of asparagine, high g lucose concentrations decreased pigment production without affecting biomas s formation, In the absence of glucose, asparagine could not support growth and zeaxanthin production, When compared to the effect of 55 mM glucose, 1 0 mM oxaloacetate increased growth and carotenoid production, Pyruvate and other intermediates of the citric acid cycle showed a similar stimulatory e ffect. The intermediates of glycolysis: glucose g-phosphate and fructose 1, 6-diphosphate did not support growth. These results suggest that Flavobacte rium sp utilizes asparagine primarily as a nitrogen source for growth and p roduction of zeaxanthin.