RESUMO
Thermophilic and thermotolerant micro-organisms strains have served as the natural source of industrially relevant and thermostable enzymes. Although some strains of the Trametes genus are thermotolerant, few Trametes strains were studied at the temperature above 30 °C until now. In this paper, the laccase activity and the mycelial growth rate for Trametes trogii LK13 are superior at 37 °C. Thermostability and organic cosolvent tolerance assays of the laccase produced at 37 °C indicated that the enzyme possessed fair thermostability with 50% of its initial activity at 80 °C for 5 min, and could remain 50% enzyme activity treated with organic cosolvent at the concentration range of 25%-50% (v/v). Furthermore, the test on production of laccase and lignocellulolytic enzymes showed the crude enzymes possessed high laccase level (1000 U g (-1) ) along with low cellulose (2 U g (-1) ) and xylanase (140 U g (-1) ) activity. Thus, T. trogii LK13 is a potential strain to be applied in many biotechnological processes.
Assuntos
Lacase/metabolismo , Trametes/enzimologia , Trametes/crescimento & desenvolvimento , Análise por Conglomerados , DNA Fúngico/química , DNA Fúngico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Estabilidade Enzimática , Lacase/química , Microscopia , Dados de Sequência Molecular , Filogenia , Análise de Sequência de DNA , Solventes , Temperatura , Trametes/citologia , Trametes/efeitos da radiaçãoRESUMO
Thermophilic and thermotolerant micro-organisms strains have served as the natural source of industrially relevant and thermostable enzymes. Although some strains of the Trametes genus are thermotolerant, few Trametes strains were studied at the temperature above 30 °C until now. In this paper, the laccase activity and the mycelial growth rate for Trametes trogii LK13 are superior at 37 °C. Thermostability and organic cosolvent tolerance assays of the laccase produced at 37 °C indicated that the enzyme possessed fair thermostability with 50% of its initial activity at 80 °C for 5 min, and could remain 50% enzyme activity treated with organic cosolvent at the concentration range of 25%–50% (v/v). Furthermore, the test on production of laccase and lignocellulolytic enzymes showed the crude enzymes possessed high laccase level (1000 U g−1) along with low cellulose (2 U g−1) and xylanase (140 U g−1) activity. Thus, T. trogii LK13 is a potential strain to be applied in many biotechnological processes.
Assuntos
Lacase/metabolismo , Trametes/enzimologia , Trametes/crescimento & desenvolvimento , Análise por Conglomerados , DNA Fúngico/química , DNA Fúngico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Estabilidade Enzimática , Lacase/química , Microscopia , Dados de Sequência Molecular , Filogenia , Análise de Sequência de DNA , Solventes , Temperatura , Trametes/citologia , Trametes/efeitos da radiaçãoRESUMO
UNLABELLED: Ligninolytic fungi take part in critical processes in ecosystems such as nutrient recycling; however, some fungal species can be pathogenic to forest and urban trees and deteriorate wood products. The tropical flora is an important source of antimicrobial compounds environmentally safer than traditional wood preservatives. Therefore, this study aimed to evaluate the inhibitory activity of ethanol plant extracts of Casearia sylvestris and Casearia decandra on the white-rot wood decay basidiomycetes Trametes villosa and Pycnoporus sanguineus. In addition, the effect of the extracts on the fungal antioxidative metabolism was studied. Among the different substances present in the extracts, the phytochemical analyses identified a clerodane diterpenoid (C. sylvestris) and cinnamic acid, hydroquinone and ß-sitosterol (C. decandra). The extracts inhibited the fungi up to 70% and caused hyphal morphology changes. The extracts triggered oxidative stress process as indicated by the increased levels of the antioxidant enzymes catalase and glutathione reductase. Therefore, the Casearia extracts are a potential source of natural biocides to control wood decay fungi, and one of the mechanisms of action is the oxidative stress. SIGNIFICANCE AND IMPACT OF THE STUDY: The Casearia plant extracts exhibited important antifungal activity on wood decay fungi and triggered oxidative stress process, an inhibitory mechanism rarely studied in filamentous fungi exposed to plant extracts. Therefore, a starting point was provided for the development of natural compounds-based products as an alternative to chemical fungicides. In addition, subsidies were given to further studies in order to elucidate in more detail how compounds present in extracts of native tropical plants affect the physiology of fungi.