EFFECT OF PHOTODYNAMIC THERAPY ON Candida albicans FILAMENTATION

The azo dyes as Congo Red are xenobiotics compounds applied in textile industry. They are highly toxic, recalcitrant for animals and human, and able to cause changes in biological cycles. The fungal diversity in an environment can be interesting for obtaining efficient dye degrading, helping to minimize environmental impacts caused by these compounds. The study of the cultivation conditions is necessary to optimize the microbial degradation process. Therefore, this study aimed to analyze the growth capacity of the fungi species Colletotrichum gloeosporioides and Fusarium sp., in solid medium in the presence of azo dye Congo Red. Inoculum of each fungus was prepared from seven-day old cultures grown on solid minimum salts medium (Vogel, 1956) plus glucose (1%), yeast extract (0,5%) and agar (2%), by taking 7 mm-diameter plugs from the growing edge and transferring them to the centre of Petri dishes with the different culture media used in this study. The experiments were carried out in solid Vogel’s minimal medium according to a factorial experimental design 24, using the variables: carbon source (glucose: 0 and 1 % m/v); nitrogen source (yeast extract: 0 and 0,5 % m/v); cultivation time (days: 5 and 15) and concentration of the dye (0,001% e 0,1% m/v) at two different levels (- or +). Fungal growth was evaluated by measuring the diameters of the growing colonies (cm) at 4-equidistant points taken from the centre of the growing fungal colony on Petri dishes, colony characteristics and the average diameter value were recorded to analyze the aspect and size of the mycelial. Both C. gloeosporioides and Fusarium sp. were able to grow in the presence of Congo Red in the concentrations studied, however, Fusarium sp. mycelium was more abundant and well distributed on the Petri dishes than C. gloeosporioides, suggesting better adaptation to the presence of the dye. The results of the experimental planning also showed that the nitrogen source was more significant for the growth of both fungi in the presence of Congo Red. C. gloeosporioides showed an interaction dependency between the variables of cultivation time and dye concentration. For Fusarium sp. the interaction is more relevant between nitrogen source, cultivation time and dye concentration. Although preliminary, these results suggest with statistical confidence that it can be possible to use these micro-organisms in future studies of the biodegradation of the Congo red dye.