Estudo da produção de pigmento por linhagem endofítica de Talaromyces minioluteus / Penicillium minioluteum em diferentes temperaturas

Abstract

In view of the risks offered by synthetic pigments to humans and the environment, as well as the growing global interest in healthier and more natural products, the study and interest in the production and use of natural pigments has become increasingly attractive due to less harmful to human health and nature. A promising alternative source for obtaining natural pigments are microorganisms, among them are filamentous fungi, since they have a high productivity and are capable of synthesizing compounds with a wide range of colors. In this context, the present work aimed to evaluate the production of red pigment by the fungus Talaromyces minioluteus/Penicillium minioluteum in submerged cultures under different temperatures. Initially, a microbiological screening of fungal colonies was carried out using a plating methodology, in order to isolate the endophytic strain of Talaromyces minioluteus/Penicillium minioluteum. After obtaining and isolating the species in question, 8 different culture media were analyzed in order to obtain the most favorable for the red pigment production. Submerged cultures in shaken flasks conducted at 28 °C, 250 rpm for 120 hours, showed that the most successful medium to obtain a high production of red pigment was SABORAUD medium (medium 4) with a final pigment concentration of approximately 23.07 AU (Absorbance Unities) for a wavelength of 500 nm. Submerged fermentations using the SABORAUD medium were carried out in a rotating incubator at 250 rpm at temperatures of 20, 24, 28 and 32 °C. Subsequently, cultures were carried out in 4 L benchtop bioreactors of useful capacity at 400 rpm and 0.5 vvm under the same temperature conditions in order to validate the results obtained in a rotary incubator. As a result, the highest red pigment yields were observed at 24 °C, with absorbance values at 500 nm (ABS500) and approximate red pigment concentration of 41.40 AU and 8.07 gpigment/L, respectively. Evaluated the effect of temperature on the red pigment synthesis process, three extraction routines were performed, which routine 3 was used in samples of 20, 24 and 28°C in order to obtain a ratio between absorbance (ABS500) and pigment concentration (gpigment/L). Finally, using the Contois cell growth model, two kinetic modeling of the process was proposed, Modeling A being characterized by assuming glucose as the only limiting substrate and the pigment as a product not associated with growth, and Modeling B characterized for presuming the production of pigment via a precursor from the consumption of the nitrogen source. Both presented satisfactory results, however, Modeling B was the most adequate to describe the behavior of the bioprocess. Thus, the results obtained in this work show the potential of the endophytic fungus Talaromyces minioluteus / Penicillium minioluteum to obtain the red pigment via cultures submerged at different temperatures.