Whole-cell fungal transformation of precursors into dyes

<p>Abstract</p> <p>Background</p> <p>Chemical methods of producing dyes involve extreme temperatures and unsafe toxic compounds. Application of oxidizing enzymes obtained from fungal species, for example laccase, is an alternative to chemical synthesis of dyes. Laccase can be replaced by fungal biomass acting as a whole-cell biocatalyst with properties comparable to the isolated form of the enzyme. The application of the whole-cell system simplifies the transformation process and reduces the time required for its completion. In the present work, four fungal strains with a well-known ability to produce laccase were tested for oxidation of 17 phenolic and non-phenolic precursors into stable and non-toxic dyes.</p> <p>Results</p> <p>An agar-plate screening test of the organic precursors was carried out using four fungal strains: <it>Trametes versicolor</it>, <it>Fomes fomentarius</it>, <it>Abortiporus biennis</it>, and <it>Cerrena unicolor</it>. Out of 17 precursors, nine were transformed into coloured substances in the presence of actively growing fungal mycelium. The immobilized fungal biomass catalyzed the transformation of 1 mM benzene and naphthalene derivatives in liquid cultures yielding stable and non-toxic products with good dyeing properties. The type of fungal strain had a large influence on the absorbance of the coloured products obtained after 48-hour transformation of the selected precursors, and the most effective was <it>Fomes fomentarius </it>(<it>FF25</it>). Whole-cell transformation of AHBS (3-amino-4-hydroxybenzenesulfonic acid) into a phenoxazinone dye was carried out in four different systems: in aqueous media comprising low amounts of carbon and nitrogen source, in buffer, and in distilled water.</p> <p>Conclusions</p> <p>This study demonstrated the ability of four fungal strains belonging to the ecological type of white rot fungi to transform precursors into dyes. This paper highlights the potential of fungal biomass for replacing isolated enzymes as a cheaper industrial-grade biocatalyst for the synthesis of dyes and other commercially important products. The use of immobilized fungal biomass limits free migration of cells and facilitates their reuse in a continuous system for precursor transformation.</p

Oxalic acid, versatile peroxidase secretion and chelating ability of Bjerkandera fumosa in rich and limited culture conditions

Efficient ligninolytic systems of wood-degrading fungi include not only oxidizing enzymes, but also low-molecular-weight effectors. The ability of Bjerkandera fumosa to secrete oxalic acid and versatile peroxidase (VP) in nitrogen-rich and nitrogen-limited media was studied. Higher activity of VP was determined in the nitrogen-limited media but greater concentration of oxalic acid was observed in the cultures of B. fumosa without nitrogen limitation. Ferric ions chelating ability of Bjerkandera fumosa studied in ferric ions limited media was correlated with the increased level of oxalic acid. The presence of hydroxamate-type siderophores in B. fumosa media were also detected. Oxalate decarboxylase was found to be responsible for regulation of oxalic acid concentration in the tested B. fumosa cultures

Nonlinear changes in the activity of the oxygen-dependent demethylase system in Rhodococcus erythropolis cells in the presence of low and very low doses of formaldehyde

The effect of exogenous, highly diluted formaldehyde on the rate of demethylation/re-methylation of veratric acid by the bacteria Rhodococcus erythropolis was studied using electrophoretic and microscopic techniques. The activity of 4-O-demethylase, responsible for accumulation of vanillic acid, and the levels of veratric and vanillic acids were determined using capillary electrophoresis. Formaldehyde was serially diluted at 1:100 ratios, and the total number of iterations was 20. After incubation of the successive dilutions of formaldehyde with the bacteria, demethylase activity oscillated in a sinusoidal manner. It was established using capillary electrophoresis that methylation of vanillic acid to veratric acid occurred at a double rate, as shown by the doubled fluctuation in the concentration of veratrate. There were also changes in the NADH oxidase activity, which is associated with methylation processes. Microscopic observations revealed the presence of numerous enlarged vacuoles in bacterial cells during the accumulation of large amounts of vanillic acid, and their disappearance together with a decrease in 4-O-demethylase activity. The presented results give evidence for the ability of living cells to detect the presence of submolecular concentrations of biological effectors in their environment and provide a basis for a scientific explanation of the law of hormesis and the therapeutic effect of homeopathic dilutions

Synthesis of dyes using immobilized fungal biomass

Grzyby białej zgnilizny drewna cechuje naturalna zdolność wydzielania zewnątrzkomórkowych oksydoreduktaz o właściwościach lignino-litycznych. Do nich należy lakaza, enzym katalizujący syntezę różnego typu związków. Celem pracy było zastosowanie unieruchomionej biomasy grzybów wydzielających lakazę do syntezy barwników.Application of whole-cell-mediated reactions in white biotechnology represents a promising alternative to chemical synthesis of products of commercial importance. The goal of this paper was to present potential application of fungal biomass, focusing specifically on their use as biocatalysts in environmental friendly synthesis of new molecules

Immobilized fungal biomass as biocatalyst for the synthesis of textile dyes

Hodowle grzybów ligninolitycznych, o naturalnej zdolności wydzielania lakazy wykazują ogromny potencjał aplikacyjny w syntezie m.in. barwników tekstylnych. Biotransformacja związków przez grzyby zachodzi in situ, nie wymaga kosztownego i czasochłonnego procesu pozyskiwania i oczyszczania enzymu. Dodatkowe związanie biomasy na trwałym nośniku wykonanym np. z żyłki polipropylenowej, ogranicza swobodną migrację komórek i umożliwia działanie układu w systemie ciągłej syntezy.White rot fungal cultures, with natural capacity of laccase secretion, have a great potential application in the synthesis of textile dyes. The biotransformation of compounds by fungal biomass occurs in situ and does not require expensive and time-consuming process of enzyme purification. Additional immobilization of biomass on a plastic mesh scourer limited free migration of cells and allows the operation of this system during continuous synthesis

Purification of fungal polysaccharides using chromatographic methods

Celem pracy było opracowanie metody pozyskiwania i oczyszczania zewnątrzkomórkowych polisacharydów ze szczepu Ganoderma applanatum z wykorzystaniem metod chromatograficznych. Surowy preparat polisacharydu poddawano analizie chromatograficznej z wykorzystaniem nośników Sepharose 6B lub Sepharose CI-4B uzyskując trzy symetryczne piki elucji. Frakcje polisacharydowe nie wykazywały absorbancji przy długości fali 280 i 260 nm co świadczy o braku białek i kwasów nukleinowych w badanych substancjach.The aim of this work was to study the production of exopolysaccharides from Ganoderma applanatum and the description of chromatographic methoc purification of fungal polysaccharides. Crude polysaccharides were fractionated using preparative Sepharose 6B or Sepharose CI-4B chromatography obtain three fractions, which were selected on the total carbohydrate elution profile. Polysaccharides fractions had no absorbance at 280 and 260 nm UV spectrum, indicating the absence of proteins and nucleic acids