Maria Wojtas-Wasilewska

Fungal laccase: properties and activity on lignin

The sources of ligninocellulose that occur in various forms in nature are so vast that they can only be compared to those of water. The results of several, more recent experiments showed that laccase probably possesses the big ability for “lignin‐barrier” breakdown of ligninocellulose. The degradation of this compound is currently understood as an enzymatic process mediated by small molecules, therefore, this review will focus on the role of these mediators and radicals working in concert with enzymes. The fungi having a versatile machinery of enzymes are able to attack directly the “lignin‐barrier” or can use a multienzyme system including “feed‐back” type enzymes allowing for simultaneous transformation of lignin and carbohydrate compounds.

Cooperation of fungal laccase and glucose 1-oxidase in transformation of Björkman lignin and some phenolic compounds

Summary A screening of wood-rotting basidiomycete fungi was conducted for glucose 1-oxidase (GOD) and laccase (LAC) production as well as for ligninolytic activity measured by a Rhemazol reaction. The results showed that genera rich in GOD are lignin degraders as well as effective producers of extracellular LAC. The fungi poor in GOD neither showed LAC, nor ligninolytic activity. The Björkman lignin and 3 phenolic compounds, hydroquinone and syringic and vanillic acids, were tested on the sequential activity of LAC and GOD. In the presence of LAC, quinoid intermediates formed from Björkman lignin and phenolic compounds were observed. The addition of GOD caused a diminution of the quinone level. During incubation of Björkman lignin with LAC and GOD depolymerization occurred, and in the experiments omitting GOD the quantities of low molecular products were markedly lower. Consequently, the consecutive ping-pong activity of LAC and GOD reduced the polymerization and improved the efficiency of depolymerization processes.

Effect of coniferyl alcohol addition on removal of chlorophenols from water effluent by fungal laccase

The effect of coniferyl alcohol on removal of chlorinated phenols from a water environment byRhizoctonia praticola andCerrena unicolor laccases was studied. At optimal conditions in which 7 mM coniferyl alcohol and laccase were added to chlorinated phenols over 20h, about 34% of the radioactivity of 4-chlorophenol, 57% of 2,4-dichlorophenol, 66% of 2,4,5-trichlorophenol, and 85% of pentachlorophenol were removed from the supernatants, compared to the level without laccase activity. After 12-h incubation periods at the optimal concentrations of coniferyl alcohol and laccase (added simultaneously), the fast first phase of chlorophenol removal was complete in 1 h, and eventually coniferyl alcohol enhanced the removal of 4-chlorophenol by 40%, 2,4-dichlorophenol by 54%, 2,4,5-trichlorophenol by 60%, and pentachlorophenol by 76%.

Higher fungi as a potential feed and food source from lignocellulosic wastes.

Publisher Summary This chapter describes higher fungi as a potential feed and food source from lignocellulosic wastes. The idea of feed or food biomass production by the submerged culture in the agitated and aerated baffle tanks results from the experiments carried out on penicillin and other antibiotic fermentation processes. In this case, low-cost materials might be used as substrates for fungal mycelium production, and at the same time, the reduction of the biological oxygen requirement by waste by products to an acceptable level could be achieved. It results from the fact that higher fungi are equipped with efficient enzymatic apparatus, which can attack the substrates not acceptable for yeast and bacteria. Solid-stationary or submerged and agitated cultures have been carried to obtain either biomass or some nutritive substances, such as vitamins, amino acids or monosaccharides. The efficiency and quality of biomass depends on the fungal species and methods of culture growth. There are two known kinds of cultures: shallow stationary and submerged, mixed and aerated in the liquid phase.

The Detoxifying Role of Ferro-Phenolic Complexes Produced by Nocardia

Summary The possibility of recultivation of soil contaminated with the excess of phenol substances or iron by some species of Nocardia was studied. A complex of the properties close to natural siderophore was formed under the model conditions in the barren soil contaminated with the addition of p-hydroxybenzoic acid in the presence of cells. It was stated that the process protected vegetation, as could be seen in the case of the better oat growth in the soil.