Relationship between production of 3-indoleacetic acid and peroxidase-laccase activities depending on the culture periods in Funalia trogii (Trametes trogii)

Transcriptome profiling of peanut (Arachis hypogaea) gynophores in gravitropic response

Peanut (Arachis hypogaea L.) produces flowers aerially, but the fruit develops underground. This process is mediated by the gynophore, which always grows vertically downwards. The genetic basis underlying gravitropic bending of gynophores is not well understood. To identify genes related to gynophore gravitropism, gene expression profiles of gynophores cultured in vitro with tip pointing upward (gravitropic stimulation sample) and downward (control) at both 6 and 12h were compared through a high-density peanut microarray. After gravitropic stimulation, there were 174 differentially expressed genes, including 91 upregulated and 83 downregulated genes at 6h, and 491 differentially expressed genes including 129 upregulated and 362 downregulated genes at 12h. The differentially expressed genes identified were assigned to 24 functional categories. Twenty pathways including carbon fixation, aminoacyl-tRNA biosynthesis, pentose phosphate pathway, starch and sucrose metabolism were identified. The quantitative real-time PCR analysis was performed for validation of microarray results. Our study paves the way to better understand the molecular mechanisms underlying the peanut gynophore gravitropism.

Extracellular laccases in ascomycetes Trichoderma atroviride and Trichoderma harzianum

Laccase activity in Trichoderma harzianum and in our own isolate Trichoderma atroviride was correlated with the production of the green pigment in conidial spores. The laccases of the two fungal species exhibit comparable kinetic parameters, pH optima and thermal sensitivity but differed in physiological properties, such as their catalytic activity during growth.

Decolorization of synthetic textile dyes by lignin peroxidase of Phanerochaete chrysosporium

Neem hull waste (containing a high amount of lignin and other phenolic compounds) was used for lignin peroxidase production by Phanerochaete chrysosporum under solid-state fermentation conditions. Maximum decolorization achieved by partially purified lignin peroxidase was 80% for Porocion Brilliant Blue HGR, 83 for Ranocid Fast Blue, 70 for Acid Red 119 and 61 for Navidol Fast Black MSRL. The effects of different concentrations of veratryl alcohol, hydrogen peroxide, enzyme and dye on the efficiency of decolorization have been investigated. Maximum decolorization efficiency was observed at 0.2 and 0.4 mmol/L hydrogen peroxide, 2.5 mmol/L veratryl alcohol and pH 5.0 after a 1-h reaction, using 50 ppm of dyes and 9.96 mkat/L of enzyme.

Decolorization of industrial dyes by a Brazilian strain of Pleurotus pulmonarius producing laccase as the sole phenol-oxidizing enzyme

The ability of a Brazilian strain of Pleurotus pulmonarius to decolorize structurally different synthetic dyes (including azo, triphenylmethane, heterocyclic and polymeric dyes) was investigated in solid and submerged cultures. Both were able to decolorize completely or partially 8 of 10 dyes (Amido Black, Congo Red, Trypan Blue, Methyl Green, Remazol Brilliant Blue R, Methyl Violet, Ethyl Violet, Brilliant Cresyl Blue). No decolorization of Methylene Blue and Poly R 478 was observed. Of the four phenol-oxidizing enzymes tested in culture filtrates (lignin peroxidase, manganese peroxidase, aryl alcohol oxidase, laccase), P. pulmonarius produced only laccase. Both laccase activity and dye decolorization were related to glucose and ammonium starvation or to induction by ferulic acid. The decolorization in vivo was tested using three dyes--Remazol Brilliant Blue R, Trypan Blue and Methyl Green. All of them were completely decolorized by crude extracellular extracts. Decolorization and laccase activity were equally affected by pH and temperature. Laccase can thus be considered to be the major enzyme involved in the ability of P. pulmonarius to decolorize industrial dyes.