Experimental modeling and optimization of melanin production by Aureobasidium pullulans NBRC 100716 in carrot peel extract

The objective of this study was to optimize the fermentation parameters by using Response Surface Methodology for increasing melanin production in carrot peel extract by Aureobasidium pullulans NBRC 100716. The optimum conditions for melanin production by A. pullulans NBRC 100716 in carrot peel extract were determined as; the initial pH of the fermentation medium: 5.9, temperature: 29.9 degrees C, agitation rate: 120 rpm, and fermentation time: 15 days. The estimated intracellular (Y-1), extracellular (Y-2), and total (Y-3) melanin concentrations in optimum conditions were 2.44 +/- 0.05, 1.95 +/- 0.47, and 4.22 +/- 0.74 g/L, respectively. As a result of confirmation experiments, the observed values of Y-1, Y-2, and Y-3 were 2.23, 1.83, and 4.06 g/L, respectively. The optimization of melanin production conditions by A. pullulans NBRC 100716 caused an almost one-fold increase in total melanin concentration. Besides, using carrot peel extract as an inexpensive substrate source for the production of high value-added melanin, the optimization of the fermentation conditions is beneficial for the production of this product.