Effects of manganese, 2,5-xylidine, veratryl alcohol and tween 80 on the production of ligninolytic enzymes by Ceriporiopsis subvermispora

The effects of adding manganese, 2,5-xylidine, veratryl alcohol and Tween 80 in a culture medium used for the production of ligninolytic enzymes by polyurethane foam-immobilized Ceriporiopsis subvermispora were studied. While 11 ppm Mn2+ promoted the highest maximum activity of  manganese peroxidase (108.0 ± 43.3 U/L, in the 6th day of cultivation), the medium without manganese led to the highest maximum activity of laccase (15.5 ± 2.1 U/L, in the 12th day of cultivation). By supplementing the medium containing 11 ppm Mn2+ with 1.0 mM 2,5-xylidine, it was possible to improve the maximum activity of laccase to 21.5 ± 4.9 U/L. The supplementation of the medium containing 11 ppm Mn2+ with 1.0mM veratryl alcohol, in turn, led to an apparent second peak of MnP activity (110.0 ± 1.4 U/L, in the 24th day of cultivation; compared to 147.5 ± 60.1 U/L, in the 9th day of cultivation). When the medium containing 11 ppm Mn2+ and 1.0 mM 2,5-xylidine was supplemented with 0.05% (v/v) Tween 80, the maximum activities of Lac and MnP reached 53.3 ± 17.7 U/L (21st day of cultivation) and 174.8 ± 1.4 U/L (9th day of cultivation),  respectively. During the cultivations, the exhaustion of glucose in the medium promoted nutritional stress, which, in turn, led to cell autolysis; reflected by an apparent reduction in the concentration of mycelium, and by an increase in the concentration of ammonium. The concentrations of extracellular proteins increased throughout the cultivations; such  concentrations, however, did not generally exhibit good correlations with the measured enzyme activities.Key words: Ceriporiopsis subvermispora, manganese, 2,5-xylidine, veratryl alcohol, Tween 80; manganese peroxidase, laccase

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

Proteomic and Physiological Responses of Kineococcus radiotolerans to Copper

Copper is a highly reactive, toxic metal; consequently, transport of this metal within the cell is tightly regulated. Intriguingly, the actinobacterium Kineococcus radiotolerans has been shown to not only accumulate soluble copper to high levels within the cytoplasm, but the phenotype also correlated with enhanced cell growth during chronic exposure to ionizing radiation. This study offers a first glimpse into the physiological and proteomic responses of K. radiotolerans to copper at increasing concentration and distinct growth phases. Aerobic growth rates and biomass yields were similar over a range of Cu(II) concentrations (0–1.5 mM) in complex medium. Copper uptake coincided with active cell growth and intracellular accumulation was positively correlated with Cu(II) concentration in the growth medium (R2 = 0.7). Approximately 40% of protein coding ORFs on the K. radiotolerans genome were differentially expressed in response to the copper treatments imposed. Copper accumulation coincided with increased abundance of proteins involved in oxidative stress and defense, DNA stabilization and repair, and protein turnover. Interestingly, the specific activity of superoxide dismutase was repressed by low to moderate concentrations of copper during exponential growth, and activity was unresponsive to perturbation with paraquot. The biochemical response pathways invoked by sub-lethal copper concentrations are exceptionally complex; though integral cellular functions are preserved, in part, through the coordination of defense enzymes, chaperones, antioxidants and protective osmolytes that likely help maintain cellular redox. This study extends our understanding of the ecology and physiology of this unique actinobacterium that could potentially inspire new biotechnologies in metal recovery and sequestration, and environmental restoration

Induction of cellulase and hemicellulase activities of <I>Thermoascus aurantiacus </I>by xylan hydolyzed products

IngenieursweseProsesingenieurswesePlease help us populate SUNScholar with the post print version of this article. It can be e-mailed to: [email protected]

PRODUCTION OF EXTRACELLULAR XYLANASES BY PENICILLIUM-JANTHINELLUM - EFFECT OF SELECTED GROWTH-CONDITIONS

Xylanase production by Penicillium janthinellum using 10-100 mM of 2,2-dimethylsuccinate (DMS) buffer, in a range of PH 4.5-6.0 was studied. The enzyme activity was enhanced using oat xylan as the carbon source. Under these conditions a culture produced 1.14 mu mol/min (11.4 U/mL or 84.4 U/mg) of beta-xylanase after 5 d of growth in a 10-mM buffer solution at PH 4.5. Protease was absent in the DMS buffer except when 100 mM phosphate buffer at PH 6.0 was used (4 U/mL). beta-Xylosidase was only found at a PH of 4.5 in all the buffer concentrations. At a 50 mM DMS buffer concentration at pH 4.5 beta-xylanases were induced by both oat and birch xylans, having a greater effect with oat spelt xylans. Electrophoretic analyses showed that the birchwood xylan induction exhibited different proteins profiles. No beta-xylosidase or beta-glucosidase was induced until d 5. The beta-xylanases were rapidly inactivated at 50 degrees C, however, birch xylanase appeared to be more stable than oat xylanase.48210711

Stability and chemical modification of xylanase from Aspergillus sp (2MI strain)

The 2M 1 strain of Aspergillus sp,, which showed high extracellular xylanolytic activities in a pre-screening, was studied, Oat-spelt, birch, eucalyptus and pine xylans were used as xylanolytic inductors, The following activities were found at 50 degrees C in the presence of 1% xylan: 120 units/ml (oat-spelt xylan), 132 units/ml (birch xylan), 107 units/ml (eucalyptus :xylan), 67 units/ml (pine xylan) and 137 units/ml (larch-wood xylan), Xylanase induced by pine xylan exhibited a higher stability than those induced by the other xylans, The stability was improved by addition of glycerol, In the crude extract, reagents which were found to affect xylanase activity were 1-ethyl-3-(3-dimethylaminopropyl)carbodi-imide for amidation of carboxylic groups and N-bromosuccinimide at a concentration of 0.5 mM for indole oxidation. Methylene Blue, butane-2,3-dione, N-acetylimidazole, chloramine-T and iodoacetate had little effect on the enzyme activity (more than 97% of the original activity remained).251192

NEW METHODOLOGY FOR FUNGAL SCREENING - XYLANOLYTIC ENZYMES

The technique for determining extracellular xylanolytic activity consists of growing selected fungi for four days on agar medium containing 1% xylan. A section of the agar is then homogenized in buffer and the filtered solution tested for xylanase activity and other related enzymes.71182182

AMAZONIAN LIGNOCELLULOSIC MATERIALS-V - SCREENING OF XYLANOLYTIC FUNGI

A plate-agar technique for fungal screening was applied to evaluate the xylanolytic activities of 18 Penicillium janthinellum and 10 Aspergillus sydowi species from the Amazon region. In order to compare these genera with those of other regions, one Aspergillus sp., one P. janthinellum, and 12 unknown genera from the southern region of Chile were studied. From these fungi strain, A. sydowi (56 strain) (25.2 IU/mL), P. janthinellum (671 strain) (47.3 IU/mL) from Amazonia, P. janthinellum (X4Z2 strain) (9.5 IU/mL), and an Aspergillus sp. (X2M1 strain) (33.3 IU/mL) from the southern region of Chile were identified.53215516