Anton Perdih

Transformation of Indigo carmine by Phanerochaete chrysosporium ligninolytic enzymes

Abstract The reaction between P. chrysosporium extracellular ligninolytic peroxidases and the dye Indigo carmine was studied. This dye can be successfully decolorized by both manganese (MnP) and lignin (LiP) peroxidases. By using a proper culture medium composition, a growth medium exhibiting high MnP or high LiP activity was obtained. Additionally, some peroxidase isoenzymes were isolated. Although the dye was successfully decolorised by both groups of extracellular peroxidases, the reaction by MnP was faster. Besides a yellow final product, the decolorization of Indigo carmine by MnP resulted in a red product formation that was not observed at the decolorization by LiP. The final concentration of the red product can be influenced by the pH value of the reaction mixture as well as by the initial dye concentration. The maximum formation of the red product was achieved at pH 5 with 60 mg/liter of the Indigo carmine in the reaction mixture. The red product was isolated and partially characterized using UV-VIS and 1 H NMR spectroscopy, and TLC.

Mixed culture of Aspergillus awamori and Trichoderma reesei for bioconversion of apple distillery waste

SummaryAspergillus awamori and Trichoderma reesei were used, separately and in mixed culture, to convert apple distillery waste into microbial biomass. Overall, the use of mixed culture had considerable advantages, the positive properties of each species being retained. The effect of Aspergillus is evident in improved filtration and chemical oxygen demand reduction, as well as in the β-glucosidase synthesis. Trichoderma, on the other hand, contributes to good fibre degradation, protein enrichment of the biomass and cellulolytic, xylanolytic and pectolytic activities in the filtrates.

Decolorization rate of dyes using lignin peroxidases of Phanerochaete chrysosporium

The basidiomycetous fungus Phanerochaete chrysosporium excretes extracellular lignin peroxidases (LiP) which were used in decolorization experiments with different commercial dyes. Very similar patterns in the kinetic curves of decolorization for dyes of different chemical classes and structures were observed. Decolorization is nonspecific, i.e., not dependent on the chromophoric system, slightly dependent on the auxochromic group, and not dependent on the sign and distribution of the charge. It is useful for decolorizing a large number of dyes of diverse structural classes.

Laccase production by Phanerochaete chrysosporium– an artefact caused by Mn(III)?

Aims: The possibility of laccase production by Phanerochaete chrysosporium was studied.

Influence of some oils and surfactants on ligninolytic activity, growth and lipid fatty acids of Phanerochaete chrysosporium

SummaryLigninase production by Phanerochaete chrysosporium MZKIBK-B 186 was increased when the culture medium was supplemented with an emulsion of oleic acid. Addition of linseed oil enhanced fungal biomass synthesis. Under the growth conditions used in our tests, the fungus was capable of accumulating fatty acids from the culture medium into cell lipids. Addition of oleic acid, Tween 80, or 3-[(cholamidopropyl)-dimethylammonio]-1-propanesulphonate (CHAPS), which are known to increase ligninase production by fungi, resulted in oleic acid enrichment of whole cell and polar lipids.

The effect of agitation and nitrogen concentration on lignin peroxidase (LiP) isoform composition during fermentation of Phanerochaete chrysosporium.

Convective Interaction Media (CIM) monolithic columns were applied for the HPLC monitoring of Phanerochaete chrysosporium lignin peroxidase (LiP) isoforms during cultivation. The influence of the agitation mode (circular, elliptic) and rate (130 and 200 rpm), as well as the initial nitrogen concentration (1.6-6 mM) in the growth medium was investigated. Identical rotation rate but different agitation modes resulted in different LiP activities and isoenzyme compositions. On the other hand, at different agitation types and rates, similar LiP activities were obtained at different isoenzyme compositions. Although LiP H2 and LiP H6/H7 were predominant isoenzymes obtained at various cultivation conditions, relative isoenzyme amounts differ considerably when initial nitrogen concentration was changed between 1.6 and 5 mM.

The use of Aspergillus niger for bioconversion of apple distillery waste

SummaryThe bioconversion of waste material remaining after apple brandy distillation was investigated. Different cellulolytic fungi were tested for their ability to convert the waste organic substances into microbial biomass. An Aspergillus niger strain was chosen as the most convenient microorganism. By growing this mold on the apple slop the following results were obtained: filtration time was shortened by 30 times, reduction of the chemical oxygen demand in the liquid phase in the range of 50–80% depending on the substrate dilution and a dry filter cake enriched with fungal biomass to about 12 g/l containing up to 22% raw proteins and certain amounts of cellulolytic enzymes in the filtrate. The influence of the initial pH, the salt addition and the dilution of the substrate were studied as well.

Citric acid production in chemically defined media by Aspergillus niger

SummaryThe effect of changing the composition of a chemically defined medium on citric acid production by Aspergillus niger was investigated. High and reproducible amounts of citric acid were obtained with deionized commercial sugar solutions, proper phosphate concentrations, low initial pH values and suitable amounts of copper as growth inhibiting agent.Comparison of high and low yielding process parameters showed that under high yielding conditions, (deionized sugar, Cu++ addition) besides more citric acid, less mycelium and less mycelial lipids were formed; the consumption of sugar, nitrogen and phosphorus was related to the amount of biomass.

Comparison of different cellulolytic fungi for bioconversion of apple distillery waste

SummaryThe suitability of three ascomycetous fungi, Aspergillus niger, A. awamori and Trichoderma reesei, as well as two basidiomycetes, Pleurotus ostreatus and Phanerochaete chrysosporium, for bioconversion of apple distillery slop was compared. Trichoderma and Phanerochaete degraded raw fiberes by 20%, producing filter cakes with 17% to 22% raw protein contents. Aspergillus spp. were superior in filtration time and COD reduction and were of the same efficiency in protein synthesis as Trichoderma and Phanerochaete, but did not degrade fibres. Pleurotus ostreatus did not degrade lignin under fermentation conditions used and could not compete with other fungi due to its slower growth.

Comparison of different methods for protein determination inAspergillus niger mycelium

SummaryProtein contents were determined in submerged as well as in surface-grown citric acid producingAspergillus niger mycelia. Various methods (Kjeldahl, Biuret, Lowry and Coomassie Blue) for protein determination were compared. The Biuret method seemed to be more suitable than the others for true protein determination in mycelia. The Lowry method gave lower results in all cases. The Coomassie Blue method did not prove suitable for the material used.