Potencial biotecnológico de fungos de ecossistema manguezal

Abstract

The mangrove is an estuarine ecosystem delimited by the line of the greater tide of syzygy that occurs in tropical and subtropical regions. In this environment microorganisms are involved in a series of transformations and nutrient cycling. Thus, the object of the present study was to evaluate the biotechnological potential of fungi isolated from mangrove ecosystem. Samples were collected at Paranaguá Estuary Complex (CEP) in two points equidistant from a parallel line. From sampling and isolation procedures, 40 fungal isolates were obtained, which were qualitatively evaluated for hydrolytic and ligninolytic enzymatic activity. Screening results showed a predominance of hydrolytic enzyme activity among isolates. In addition, the fungi presented tolerance towards the concentration ≤ 5% of sodium chloride (NaCl) in culture medium, indicating adaptive halofilia. By means of morphological and molecular analyzes the selected isolates were identified as: Trichoderma atroveride, Trichoderma harzianum, Microsphaeropsis arudinis, Epicoccum sp., Trichoderma sp., Gliocladium sp., Geotrichum sp. and Cryphonectria sp. These fungi were evaluated for their ligninolytic enzyme production by static liquid cultivation in the presence and absence of sea water. The results demonstrated a main production of laccases by the isolates, with Microsphaeropsis arudinis (LB07) presenting 1,037 U/L of enzyme activity, which is a data that has not been reported so far in scientific literature. When fungi were cultured in the presence of sea water, higher values of laccase enzyme were observed. In order to evaluate the biodegradation of a real textile effluent, the enzyme crude extracts containing laccase from the fungi Microsphaeropsis arudinis (LB07) and Trametes villosa, was applied in the presence and absence of chemical mediators. The highest rate of discoloration was achieved by the application of 100 U/L of laccase in the crude extract from Microsphaeropsis arudinis (LB07), which is also new in the literature. As for the Trametes villosa the best percentage of discoloration was observed with 500 U/L of laccase enzyme. Considering that the fungi from mangrove are practically unexplored, most of the results obtained in this work are novel. The data obtained in the present study emphasize the importance of microorganisms in the mangrove, their diversity, adaptation to saline conditions, enzymatic potential (hydrolytic and ligninolytic), and the ability to biodegrade pollutants, which make them promising in biotechnological processes.