No abstract

Microbial pigments are an important alternative to potentially harmful synthetic dyes. An extracellular red pigment producing fungus, Penicillium purpurogenum was isolated from soil and its optimal submerged fermentation parameters were evaluated. The optimal process conditions for maximum red pigment production were as follows: Starch (33.41 CVU mL -1 ), peptone (34.5 CVU mL -1 ) ammonium nitrate (32.8 CVU mL -1 ) and incubated under darkness (34.5 CVU mL -1 ). Addition of the ferrous sulphate gave significant yield (29.4 CVU mL -1 ) on red pigment production. These results suggest the red pigment from P. purpurogenum with potential application in food colouring and textile industries.

The fungal pigments are a good alternative to currently used synthetic colourants and / or natural colourants derived from plant materials. The aim of the present study was to investigate the feasibility of cassava processing waste as a substrate for production of pigments by Penicillium Purpurogenum in solid state fermentation (SSF). A pigment yield of 40.13 Colour Value Units (CVU) / g of dry fermented substrate was achieved by using cassava processing waste with optimized process parameters such as 50 % initial moisture content, inoculation with 4.0 ml of spores (25×10 5 spores) / gram of dry substrate and an incubation period of 15 days with 1 % peptone at 30°C,. Thus, utilization of cassava processing waste for red pigment production in this study could provide the most effective use of natural resources and lead to technology development for further cost reduction.

Pencillium purpurogenum 8904.12, a red pigment producer, was isolated from soil screened and selected based on the pigment production. The pigment production by P.purpurogenum was optimizedby using factorial design and Response Surface Methodology (RSM) in SSF. Cassava waste is a low cost and nutrient rich substrate used in this study as a substrate. RSM based central composite design was employed to obtain best combination of substrate concentration, inoculum volume, incubation time, initial moisture and initial pH. By the point prediction tool of Design-Expert 8.0, the optimum values of the factors for maximum red pigment production were determined. Under the optimized conditions (substrate concentration 10 g, inoculum volume 5 ml, 15 days incubation time, 50 % initial moisture and initial pH of 6), the red pigment yield was 28.33 colour value units / g of dry fermented substrate which agreed closely with the predicted yield. The model showed that the value of R2 (0.9936) was high and pvalue of interaction of variance was <0.0001. Hence the model can be said to be of highly significant. A significant Increase in red pigment production was achieved using RSM. Thus, utilization of cassava waste for red pigment production in this study could provide the most effective use of cassava resource, and lead to technology of development for its further utilization and value addition.