Identificação e análise do potencial enzimático de leveduras isoladas do afloramento rochoso do Morro da Pioneira - Bahia

Abstract

Yeasts are unicellular micro-organisms that have extensive biochemical and morphological diversity present in various habitats on Earth, with high biotechnological potential. The study of biodiversity and bioprospecting of new microbial sources of unexplored environments are essential for the use of these micro-organisms in various economic sectors, especially in the production of economic value added biocompostos. Thus, this study aimed to identify the yeasts isolated from the rocky outcrop of Morro da Pioneira located in the Serra da Jiboia, the city of Santa Terezinha, and analyze the potential of biotechnology in the production of enzymes of industrial interest, as well as observe the growth in media with high concentration of salt and sugar. The yeasts were isolated from flowers and water tanks of bromeliads, using classical techniques, with the use of selective medium. The isolates were studied for the production of cellulase enzymes, amylase, protease and inulinase. For the analysis of amylolytic activity, cellulolytic and proteolytic yeast cells were plated in YP medium containing 1% of starch, carboxymethyl cellulose and milk powder (casein), respectively, as sole source of carbon and protein. The production capacity of these enzymes was evaluated by measuring the hydrolysis halo on the surface of the media. Inulinase production was evaluated by plating the yeast in YNB medium containing inulin as sole carbon source and maintained the growth of colonies. To examine the growth in medium hypertonic, yeast cells were plated on YNB medium containing 10% NaCl and 5% glucose and medium containing 50% glucose. For species identification we used traditional methods, through the colonial and cellular morphology and assimilation tests of compounds of carbon and nitrogen as well as the yeast identification system API 20 C AUX. We used the MSP-PCR method for grouping the strains through the banding pattern. According to the capacity provided by the enzymatic morphotypes 75% of yeast were capable of growing in inulin, 58% were able to produce the enzyme amylase, protease and 42% produced no yeast isolates were capable of producing the cellulase enzyme. To 83% osmophilic tolerance grew in the media composed of 50% glucose and 64% grew in the media whit 10% NaCl 5% glucose. The methods used for identification of yeasts identified five species (Candida lusitaniae, Candida guillermondi, Rhodotorula mucilaginosa, Rhodotorula glutinis and Cryptococcus Laurenti) and only three isolates to genus (Candida sp., Rhodotorula sp. and Cryptococcus sp.) may represent potential new biotypes or new species.