Bioprospecção de fungos produtores de fitase em solo e serrapilheira da Floresta Estacional Semidecídua no Bioma Cerrado, Sete Lagoas, MG

Abstract

In Brazil most of the agricultural soils have low availability of phosphorus , a nutrient limiting for several crops in Brazilian soils . The ability of filamentous fungi in solubilizing the phosphorus from various sources, has been considered as a desirable characteristic for various uses. Brazil has a huge biodiversity , and one way of extracting economic value of it, is bioprospecting, which presents a systematic search for organisms , genes , enzymes , compounds , processes and parts from living beings in general, which may eventually lead to the development of a product. The goal was the isolation of filamentous fungi solubilizing phosphorus of soil and litter, and quantification of fungal mycoflora. The study was conducted in one Semi-deciduous forest biome Cerrado of Sete Lagoas, MG city, in which soil samples were collected from eight distinct forest fragments , two collection periods , and 2 depths , layer 0 - 5cm, 5 -10cm and litter, for the isolation of mycobiota , and subsequent evaluation of the ability to solubilize phosphate . The soils were classified according to the Brazilian System of Soil Classification . The mycoflora was quantified using the methodology of colony-forming unit and identified based on morphological study. Soil fertility and nutrient content were evaluated for exchangeable nutrients, for the 0-10 cm layer of soil. The identification of isolates capable of solubilizing phosphorus was made by plating in the same culture medium Pikovskaya . The litter showed higher CFU in samples collected during the rainy season (C1) compared to the dry season (C2) , and for both periods of collect, the litter had a higher number of UFC the other two depths . In the collection C1 , held in late January 2012, 907 fungi were isolated , of these, 103 (11.35%) were filamentous had capacity to solubilize phosphorus In the collection C2 , held in early September 2012 , 947 fungi were isolated , 152 (16,76%) were filamentous had the capacity to solubilize phosphorus. The C2 showed higher percentage of phytase - producing species belonging to the genus Penicillium, while C1 showed higher percentage of fungi belonging to the genus Aspergillus section Nigri with production capacity of phytase . The total number of fungal isolates producing phytase was higher in C2. It was concluded that the soil in the area in the study have high mycobiota diversity and high number of phosphorus solubilizing fungi, and are potentially exploitable with respect to obtaining these .