A pigment producing fungus was isolated from soil collected from cassava processing site in Ebonyi State. The effects of carbon sources on pigment production by the isolate in liquid surface cultures were studied. Pigment production in a basal medium composed of (in g/L) MgSO4, 0.4; NaNO3, 0.8; peptone, 15 mixed with 12g/L of one of the following carbon sources: glucose, Ipomea batatas, Dioscorea alata, Manihot esculenta cratz, Colocasia esculenta flour or soluble starch, was investigated. The highest red, orange and yellow pigment concentrations were obtained with sweet potato and water yam flour, followed by soluble starch while the least pigment concentrations were obtained with glucose. Unit optical densities of red (13), orange (9.5) and yellow (11) pigments were produced by the fungus using Ipomea batatas flour. These were higher than the concentrations of red (9), orange (7) and yellow (10.5) produced from Hajjaj medium composed of (in g/L) Glucose, 50; monosodium glutamate, 12; K2HPO4, 2.5; KH2PO4, 2.5; MgSO4, 1; KCl, 0.5; ZnSO4, 0.001; FeSO4, 0.001; and MnSO4, 0.001. The results indicate that Ipomea batatas flour is a better carbon source than glucose for pigment production by T. purpurogenus and thus has a very high potential for commercial production of pigments.
Christiana N. Ogbonna
