Potencial biotecnológico de leveduras associadas a filosfera de bromélias da caatinga

Abstract

The Caatinga has a diversified biological heritage, an exclusively Brazilian biome with a high degree of endemisms, but it is a scientifically under-explored environment. Among its vegetation, the Bromeliaceae family attract attention. The plants of this family has several associations with other organisms, including microorganisms, such as yeasts. Yeasts are of great biotechnological interest for the production of extracellular enzymes, as they are produced in a shorter time of cell generation and have greater stability in industrial processes than the enzymes produced by plants and animals. Therefore, enzymes produced by yeasts are a growing and advantageous demand in the industrial processes.Therefore, the present work aimed to test yeast strains for the producing of extracellular enzymes (amylase, caseinase, cellulase, esterase, lipase, pectinase) isolated from phyllosphere (leaves, fruits and flowers) of bromeliads from two locations in the Caatinga of Alagoas: Reserva Private Natural Heritage-Tocaia in the municipality of Santana de Ipanema and Serra Caiçara in the municipality of Maravilha, Alagoas. The yeasts are part of library of the Molecular Diversity Laboratory – LDM of the Federal University of Alagoas. For enzymatic production tests, yeasts were grown on YEPDAgar for 48 hours at 22-25ºC. Subsequently, they were sown in the culture media with the respective enzymatic substrates and incubated for 7 days at 22-25 ºC. After this period, the enzymatic activities were analyzed semi-quantitatively through halos of substrate degradation. In this study, leaf isolates (n = 213), 195 were tested for the enzyme amylase, 166 for caseinase, 186 for cellulase, 197 for esterase and 153 for pectinase. For lipase, isolates positive for esterase were tested (n = 42). All flower isolates (n = 13) were tested for amylase and esterase production, 12 for cellulase and 7 isolates were tested for caseinase and pectinase. All fruit isolates (n = 13) were tested for amylase, 12 were evaluated for cellulase and esterase production, 8 were tested for caseinase, and 6 for pectinase. No isolates from flowers and fruits have been tested for lipase. Among the all isolates tested (239), 58.5% (n = 140) showed strong production (++) for at least one enzyme.The most produced extracellular enzymes in percentage were: lipase (95.2%) followed by esterase (57.3%), caseinase (36.4%), amylase (34.3%), cellulase (31.9%) and pectinase (9.6%).The best producing yeast strains were Rhodosporidiobolus poonsookiae (BMA 56), Pseudozyma hubeiensis (BMA 69), Symmetrospora marina (BMA 83), unidentified (BMA 90), Aureobasidium melanogenum (BMA 94), Phenoliferia sp. nov (BMA 95) and Aureobasidium pullulans (BMA96).With this, it can be concluded that yeasts associated with the Caatinga bromeliad phyllosphere have a great biotechnological potential for the production of interesting extracellular enzymes industrially, considering that yeasts adapted to the northeastern semiarid, undergo variable and stressful conditions and possibly have a high plasticity for settle in the environment and have unique and useful characteristics for applicability in white biotechnology.