Influência do estresse físico-químico e biológico na produção de pigmentos por Penicillium sclerotiorum LM 5679

Abstract

Colorants of natural origin accompanied human development, but with the technological advance synthetic dyes appeared, easier to obtain because they did not depend on the seasonality common to plants, which are still the main sources of natural dyes. Synthetic dyes are not so desired today, some studies point them as causing health problems such as allergies and environmental problems because they are substances of difficult natural degradation, generating a quest for the return to natural. Fungi have a far relation in the production of dyes, this is the case of angkak, a type of rice fermented by fungi of the genus Monascus, a food adopted by some Asian countries. In the search for new colorants of fungal origin, our research group have been working identifying some fungi for this purpose, being Penicillium sclerotiorum LM 5679 one of the most promising, became the focus of this work. A small curiosity observed during the purification of this fungi was that it had a more intense coloration when it was not pure. This work aims to study the influence of abiotic and biotic stresses on dye production. To study the abiotic stresses, a submerged culture was performed with univariate analysis of the factors: pH, temperature, inoculum size, water activity, osmolarity and light exposure. For the biotic stresses, the same bioprocess was carried out by simultaneous inoculation, co-culture, of C. albicans, S. aureus and E. coli with P. sclerotiorum LM 5679. The concentration of pigments was estimated by UV-VIS Spectrophotometry, the biomass of some experiments was also estimated. Among the analyzed factors none exceeded the amount of pigment produced by the standard bioprocess, the highest values were obtained in the tests conducted at pH 3 and inoculum size of 106 cells/mL. The results indicate that there is no relationship between the amount of pigment and the concentration of biomass. This work presents how the stress factors have influence on the bioprocess, it is necessary more to conduct more investigation focusing on the optimization of the bioprocess. The importance of this work was to explain how the stress factors influence the production of pigment by P. sclerotiorum LM 5679 and should be investigated with a focus on the optimization of the bioprocess.