Efeitos de fatores físico-químicos na produção de biomassa, colorantes e antibióticos por fungos Trichoderma spp.

Abstract

Consumers are increasingly demanding from industries the use of natural dyes beneficial to the human body and the environment. Colorants of microbial origin have the advantage of not being seasonal and of a faster production. Another problem faced by society is the problem of bacterial resistance. Despite the lack of profit desired by the industry when antibiotics are launched, the population calls for new therapeutic options, in the same way that behavioral changes regarding the use of antibiotics are necessary. In view of this scenario, research directed to the investigation of possible dyes and antibiotics, mainly of microbial origin, becomes extremely important. Thus, five strains of Trichoderma spp. in submerged crops, with univariate variation in cultivation conditions, with subsequent filtration. Then, the analysis of biomass production (dry mass weight) and colorant was performed using a spectrophotometer. Subsequently, the antibacterial activity of these strains was evaluated against E. coli CBAM 0001, B. cereus CBAM 0549, K. pneumoniae CBAM 0672 and P. aeruginosa CBAM 0665. Initially, the Gelose Method was applied in the selection of fungi. From the filtrates of the strain selected in the previous test, a method adapted in a 96-well microplate was used, in order to select four filtrates to proceed with the analysis of the Minimum Inhibitory Concentration (CMI). Alluding to the biomass production, the temperature, the temperature that most stimulated the production was 27ºC, with an average dry mass weight of 0.66 g / 100 ml, as for the pH it was pH 5.5, with 0.71 g / 100ml, and regarding the level of exposure to light classified as very light, with 0.74 g / 100ml. Regarding the production of colorants, the temperature that stimulated the most was also 27ºC, with an average of 4.48 AU, and the level of exposure to light was also a lot of light, with an average of 5.07 AU. pHs 6.5 and 7.5, with averages of 5.21 AU and 4.93UA. Regarding antimicrobial activity, in the screening stage, Trichoderma virens CFAM 1144 showed activity against three of the pathogens tested: Escherichia coli CBAM 0001, Bacillus cereus CBAM 0549 and Pseudomonas aeruginosa CBAM 0665, while Trichoderma sp. CFAM 1162 showed activity for two of these bacteria: CBAM 0001 e CBAM 0549. Thus, CFAM 1144 was selected. They proceeded to analyze the filtrates in the microplates, when 4 of the filtrates were chosen: 37ºC, Too much light, too little light and pH 6.5. However, when the IMC was performed, the filtrates were shown to have no antibacterial activity, since all the bacteria were resistant. The results obtained indicate that the culture conditions need to be adapted to the objective of the work and the microorganisms to be used. None of the strains managed to grow or produce colorant at 47ºC. Regarding antibacterial activity, Trichoderma virens CFAM 1144 was the most promising fungus.