Avaliação da produção enzimática por actinobactérias isoladas do intestino do camarão-branco-do-pacífico (Litopenaeus vannamei)

Abstract

The planet has been undergoing increasingly intense environmental changes, affecting terrestrial and aquatic ecosystems at different scales. A large portion of these changes results from human activities, especially those related to the industrial sector, whose expansion and productive demand generate significant impacts on the environment. In this context, the search for more sustainable industrial processes becomes necessary, and the use of microbial enzymes emerges as a promising alternative, capable of reducing costs, optimizing reactions, and minimizing waste generation. Among the microorganisms of greatest biotechnological interest are actinobacteria, a phylum of Gram-positive bacteria widely distributed in environments such as soil, marine habitats, and symbiotic systems. These bacteria are recognized for their high metabolic versatility, which allows them to synthesize bioactive compounds, including antibiotics, pigments, and several enzymes of commercial relevance. In this study, the production of enzymes by 14 strains of actinobacteria isolated from the intestine of the Pacific white shrimp was evaluated. This species represents an importante resource for shrimp farming in the state of Ceará, and this industrial byproduct was used as na alternative source of microorganisms with biotechnological potential. Four enzymes belonging to the hydrolase class were investigated, namely amylases, cellulases, lipases, and proteases, and at least four strains—SGA1, SGA5, SGA6, and SGA8—showedpositive activity for each of them, highlighting the metabolic diversity of this group. In addition, fermentative processes were conducted to quantify the activity of amylases, cellulases, and proteases, allowing the selection of the strain with the highest enzymatic index, which showed intermediate performance for the three enzymes evaluated. For amylase, strain SGA8 showed a production of 3.54 IU/mL (μmol glucose×min−1), while SGA1 presented a value of 0.51 IU/mL (μmol glucose×min−1). Regarding proteases, strain SGA1 showed a value of 138.16 IU/mL (μmol azopeptide×min−1). The results reinforce the potential of these actinobacteria as sources of industrial biocatalysts and indicate the need for further analyses, especially with regard to the specific quantification of lipolytic enzymes, which proved to be particularly promising throughout the study.