Avaliação da viabilidade de fungos encapsulados e armazenados em diferentes temperaturas

Abstract

Cellular immobilization represents an alternative for the bioprocess conduction, where the cells are kept in a matrix and can be used over long periods. This work was conducted with the objective to test a fungi immobilization methodology with reduced cost, to evaluate the viability of these fungi when submitted to the new encapsulation method, and to determine the ideal temperature to store the immobilized fungi. The mycelium of the fungi Aspergillus niger, Cladosporium cladosporioides and Penicillium solitum were mixed with 15gr of titrated rice and 3gr of sodium alginate, which was dripped in a 0.25M calcium chloride solution for formation of the pellets. After drying in an oven at 26ºC, the granules were stored at three temperatures: room ( 18 - 27 °C ) refrigerator (4 a 7 °C) and freezer (-3 a -6 °C). The platings were carried out every 15 days in BDA culture medium (potato-dextrose-agar). The evaluations of the colony size and sporulation were carried out after 7, 14 and 12 days of plating, during 195 days for A.niger, 225 days for C. cladosporioides, and 210 days for P.Solitum. Scanning Electronic Microscopy (SEM) analysis also took place seeking to verify the security of the encapsulated mycelium. The storage temperature did not affect the mycelial development of A.niger and P.solitum. However the sporulation was reduced for the granules stored in the freezer. The mycelial development of Cladosporium cladosporioides was influenced by the temperature. The granules conserved at room temperature had lower viability than those refrigerator and freezer stored. In the SEM analysis it was observed that the immobilization is a safe method where the fungus mycelium remains inside the granule, facilitating transport, storage and application of microorganisms.