Atlantic Forest's and Caatinga's semiarid soils and their potential as a source for halothermotolerant actinomycetes and proteolytic enzymes

• Published in: Environmental technology Vol. 44; no. 11; pp. 1566 - 1578
• Main Authors: Silveira, Marghuel A. Vieira, Batista dos Santos, Saara M., Okamoto, Débora Noma, de Melo, Itamar Soares, Juliano, Maria A., Ribeiro Chagas, Jair, Vasconcellos, Suzan P.
• Format: Journal Article
• Language: English; French
• Published: England Taylor & Francis 12.05.2023; Taylor & Francis Ltd
• Subjects: Acetic acid; Actinobacteria; Actinomyces; Actinomycetes; Agar - metabolism; Bioactive compounds; Bioconversion; Casein; Culture media; Culture Media - metabolism; Dextrose; Edetic acid; Energy transfer; Enzymes; Fluorescence; Fluorescence resonance energy transfer; Fluorides; Food processing; FRET peptide; Industrial applications; Libraries; Metabolism; Metabolites; metalloprotease; Microorganisms; Peptide Hydrolases - metabolism; Peptide libraries; Peptides; Phenylmethylsulfonyl fluoride; Potatoes; Proteolysis; proteolytic ability; Proteolytic enzymes; Rhizosphere; serine; Sodium chloride; Soil; Strains (organisms); Waste management; Atlantic Forest; FRET peptide; serine; proteolytic ability; metalloprotease; rhizosphere
• ISSN: 0959-3330; 1479-487X
• DOI: 10.1080/09593330.2021.2008015

Actinomycetes are versatile about their metabolism, displaying high capacity to produce bioactive metabolites. Enzymes from actinomycetes represent new opportunities for industrial applications. However, proteases from actinomycetes are poorly described by literature. Thereby, to verify proteolytic potential of actinomycetes, the present study aimed the investigation of bacterial isolates from Caatinga and Atlantic Forest rhizosphere. Fluorescence resonance energy transfer (FRET) peptide libraries were adopted for the evaluations, since they are faster and more qualitative methods, if compared with others described by most reports. A total of 52 microorganisms were inoculated in different culture media (PMB, potato dextrose agar, brain heart infusion agar, Starch Casein Agar and Reasoner's 2A agar), temperatures (12, 20, 30, 37, 45 and 60°C), and saline conditions (0-4 M NaCl), during 7 days. The actinomycetes named as AC 01, 02 and 52 were selected and showed enzymatic abilities under the peptide probes Abz-KLRSSKQ-EDDnp and Abz-KLYSSKQ-EDDnp, achieving enhanced performance at 30 °C. Biochemical parameters were established, showing a predominance of alkaline proteases with activity under saline conditions. Secreted proteases hydrolysed preferentially polar uncharged residues (Y and N) and positively charged groups (R). Phenylmethylsulfonyl fluoride and ethylenediaminetetraacetic acid inhibited the proteins, a characteristic of serine (AC 01 e 02) and metalloproteases (AC 52). All selected strains belonged to Streptomyces genera. In summary, actinomycete strains with halophilic proteolytic abilities were selected, which improve possibilities for their use in detergent formulations, food processing, waste management and industrial bioconversion. It is important to highlight that this is the first report using FRET libraries for proteolytic screening from Caatinga and Atlantic Forest actinobacteria.