RESUMO
Background: Hydrophobins are small proteins secreted by filamentous fungi, which show a highly surface activity. Because of the signally self-assembling abilities and surface activities, hydrophobins were considered as candidates in many aspects, for example, stabilizing foams and emulsions in food products. Lentinus tuber-regium, known as tiger milk mushroom, is both an edible and medicinal sclerotium-producing mushroom. Up to now, the hydrophobins of L. tuber-regium have not been identified. Results: In this paper, a Class I hydrophobin gene, Ltr.hyd, was cloned from L. tuber-regium and expressed in the yeast-like cells of Tremella fuciformis mediated by Agrobacterium tumefaciens. The expression vector pGEH-GH was under the control of T. fuciformis glyceraldehyde-3-phosphate dehydrogenase gene (gpd) promoter. The integration of Ltr.hyd into the genome of T. fuciformis was confirmed by PCR, Southern blot, fluorescence observation and quantitative real-time PCR (qRT-PCR). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that recombinant hydrophobin rLtr.HYD with an expected molecular mass of 13 kDa was extracted. The yield of rLtr.HYD was 0.66 mg/g dry weight. The emulsifying activity of rLtr.HYD was better than the typical food emulsifiers sodium caseinate and Tween 20. Conclusions: We evaluated the emulsifying property of hydrophobin Ltr.HYD, which can be potentially used as a food emulsifier.
Assuntos
Basidiomycota/metabolismo , Proteínas Fúngicas/genética , Lentinula/genética , Lentinula/metabolismo , Transformação Genética , Basidiomycota/enzimologia , Leveduras , Proteínas Fúngicas/metabolismo , Southern Blotting , Clonagem Molecular , Agrobacterium tumefaciens/metabolismo , Análise de Sequência , Emulsificantes , Eletroforese em Gel de Poliacrilamida , Reação em Cadeia da Polimerase em Tempo Real , Gliceraldeído-3-Fosfato Desidrogenases/metabolismo , Microscopia de FluorescênciaRESUMO
Lentinus tigrinus is a species with a fleshy pileus, strong odor and agreeable taste. In order to determine the optimal conditions for the production of this species, three substrates based on Salix sp. sawdust, wheat straw and supplements were tested in 500g dry weight bags at two different fruiting temperatures. Naturally occurring strains of this species were incubated at 30 degrees C. Primordium initiation could be observed 11-16 days after induction conditions began. This species produced highest yields with biological efficiency (BE) of 62% with supplemented sawdust at 25 degrees C. When bags were reduced to 100g dry weight, spawning run time was reduced from 28 to 30 to 10 to 14 days and BE increased more than 100%. L. tigrinus is a promising species with possibilities for commercial production.