| Congresso Brasileiro de Microbiologia 2023 | Resumo: 212-2 | ||||
Resumo:Creation of Protected Areas is an effective strategy to conserve biodiversity. In those areas, microorganisms represent most of the biodiversity, and, among several bacterial groups found in soil, actinobacteria stands out. This bacterial phylum presents a source of many metabolites, including degradative enzymes of commercial interest like amylases. The present study aimed to quantify and determine the amylolytic enzymatic activity of actinobacteria strains isolated from soil of Preserved Areas from the Brazilian semi-arid region. The strains used in the experiments were obtained from the collection of microorganisms of the Laboratory of Environmental Microbiology at the Federal University of Ceará. Strains SN03, SN17, SN27, SN35 were selected based on a qualitative test for the presence of amylase previously performed in Petri plates. The strains were transferred to plates containing Casein Dextrose Agar (CDA) medium and were incubated in B.O.D. at 28°C for 6 days. Spore suspension technique was performed at the end of incubation period, where 3 mL of distilled water and a drop of Tween 80 reagent were added to all plates. Solutions were read at 625 nm in triplicate and the mean absorbances were diluted and standardized at 0.1. After that, 1 mL of each solution was inoculated into Erlenmeyer flasks containing 50 mL of Starch Casein Broth (SCB) to prepare the pre-inoculum, which was cultivated at 28ºC for 6 days. At the end of cultivation period, 10.0 mL of pre-inoculum was added to 90.0 mL of SCB. Cultivation was carried out at 28 ºC for 14 days at 160 rpm. Media were centrifuged at 4°C, 10000 g, 10 min. The supernatant obtained was used for a quantitative test of amylolytic activity using 3,5-dinitrosalicylic acid (DNS) method. Samples were read in a spectrophotometer at 540 nm and the reducing sugar concentration was calculated from a glucose standard curve. Enzyme activity was described by International Unit (IU), which can be defined by the amount of enzyme required for the liberation of 1 µmol of reducing sugar as glucose per minute under assay
condition. All strains produced amylases in detectable amounts in centrifuged extracts after fermentation. The fermented extracts of the strains SN03, SN17, SN27 and SN35 showed amylolytic activity of, respectively, 34.074,07 IU/mL.min, 53.333,33 IU/mL.min, 80.370,37 IU/mL.min and 66.296,30 IU/mL.min under assay condition. Among the studied strains, SN27 strain showed the highest amylolytic activity. These results show that strains of actinobacteria isolated from preserved areas have a potential that can be used in studies that aim to produce
microbial molecules of commercial interest. Palavras-chave: Biodiversity, Metabolites, Amylase, Reducing Sugar Agência de fomento:Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) | |||||