RESUMO
Paecilomyces lilacinus (LPS 876) efficiently degraded keratin in chicken feather during submerged cultivation producing extracellular proteases. Characterization of crude protease activity was done including its compatibility in commercial detergents. Optimum pH and temperature were 10.0 and 60 °C, respectively. Protease activity was enhanced by Ca²âº but was strongly inhibited by PMSF and by Hg²âº suggesting the presence of thiol-dependent serine proteases. The crude protease showed extreme stability toward non-ionic (Tween 20, Tween 85, and Triton X-100) and anionic (SDS) surfactants, and relative stability toward oxidizing agent (H2O2 and sodium perborate). In addition, it showed excellent stability and compatibility with various solid and liquid commercial detergents from 30 to 50 °C. The enzyme preparation retained more than 95% of its initial activity with solid detergents (Ariel™ and Drive™) and 97% of its original activity with a liquid detergent (Ace™) after pre-incubation at 40 °C. The protective effect of polyols (propylene glycol, PEG 4000, and glycerol) on the heat inactivation was also examined and the best results were obtained with glycerol from 50 to 60 °C. Considering its promising properties, P. lilacinus enzymatic preparation may be considered as a candidate for use in biotechnological processes (i.e., as detergent additive) and in the processing of keratinous wastes.
Assuntos
Detergentes/farmacologia , Resíduos Industriais , Queratinas/metabolismo , Paecilomyces/metabolismo , Serina Proteases/biossíntese , Serina Proteases/metabolismo , Animais , Galinhas , Misturas Complexas/química , Misturas Complexas/metabolismo , Ativação Enzimática/efeitos dos fármacos , Estabilidade Enzimática/efeitos dos fármacos , Espaço Extracelular/enzimologia , Plumas , Temperatura Alta , Concentração de Íons de Hidrogênio , Metais/farmacologia , Oxidantes/farmacologia , Paecilomyces/citologia , Paecilomyces/enzimologia , Paecilomyces/crescimento & desenvolvimento , Serina Proteases/química , Inibidores de Serina Proteinase/farmacologiaRESUMO
Isogenic strains (with and without dsRNA) of the entomogenous fungi Metarhizium anisopliae var. acridum and Paecilomyces fumosoroseus were investigated for correlation between the presence of dsRNA and the production of cuticle-degrading proteases that play an important role in host parasitism, total secreted protein, and conidia production. Similar levels of cuticle-degrading subtilisin-like (Pr1) protease were observed for isogenic strains of M. anisopliae var. acridum after growth in medium supplemented with the cuticle of the grasshopper Rhammatocerus schistocercoides. Similarly, no statistical differences were observed for protease production, detected using the chromogenic substrate azocasein. For P. fumosoroseus isogenic strains, no significant differences in protease activity were observed after growth in the presence of either Euschistus heros or Nezara viridula (Hemiptera: Pentatomidae) cuticle. Similarly, no statistical differences were observed in virulence against E. heros. A comparison of mean conidia production showed a significantly higher production in the dsRNA-free isogenic strains of M. anisopliae var. acridum. Although, for most of the fungal phenotypes analysed, no overt effects were associated with the presence of these dsRNA infections, the reduction in conidia production by the isogenic strains of M. anisopliae var. acridum with dsRNA suggested that it may not be entirely accurate to describe these infections as latent.