Atividade enzimática de actinobactérias do semiárido

Abstract

Actinobacterias are Gram-positive bacterias found in soil and are distinguished by their production of hydrolytic enzymes, such as amylase and cellulase. These enzymes degrade starch and cellulose, respectively, which are abundant substrates in soil, but that are unavailable for use by other organisms due to their chemical complexity. These bacteria grow in extreme conditions, such as those prevalent in the Brazilian semi-arid northeast, where there are also few studies about this microbial group. Thus, due to the growing interest in the biological functioning of the soil, together with the biotechnology aspect, this work aimed to evaluate the enzymatic activity of twenty eight strains of actinobacteria of the genus Streptomyces, Terrabacter, Nocardia, and Micromonospora obtained from the soil samples of the Ubajara National Park in the state of Ceará. The amylolytic and cellulolytic activities were determined by the enzymatic index corresponding to the relation between the diameter of hydrolysis halo, in millimeters, and the diameter in millimeters of the colony of each strain. The cellulolytic and amylolytic indexes were detected in 75% and 85% of the evaluated strains, respectively. One of the strains evaluated stood out with an enzyme cellulase index equal to 6.90 while the highest rate for amylase was 6.23. The results indicated the ecological and biotechnological potential of actinobacteria from the soil of analyzed region