Effects of exogenous calcium or oxalic acid on Pinus taeda treatment with the white-rot fungus Ceriporiopsis subvermispora

2012 ◽  
Vol 72 ◽  
pp. 88-93 ◽  
Author(s):  
André Aguiar ◽  
André Ferraz
2006 ◽  
Vol 123 (1) ◽  
pp. 71-77 ◽  
Author(s):  
Rudianto Amirta ◽  
Toshiaki Tanabe ◽  
Takahito Watanabe ◽  
Yoichi Honda ◽  
Masaaki Kuwahara ◽  
...  

Holzforschung ◽  
2008 ◽  
Vol 62 (4) ◽  
Author(s):  
Marcos Paulo Vicentim ◽  
André Ferraz

Abstract The effect of different culture conditions have been evaluated concerning the extracellular enzyme activities of the white-rot fungus Ceriporiopsis subvermispora growing on Eucalyptus grandis wood. The consequence of the varied fungal pretreatment on a subsequent chemithermomechanical pulping (CTMP) was addressed. In all cultures, manganese peroxidase (MnP) and xylanase were the predominant extracellular enzymes. The biopulping efficiency was evaluated based on the amount of fiber bundles obtained after the first fiberizing step and the fibrillation levels of refined pulps. It was found that the MnP levels in the cultures correlated positively with the biopulping benefits. On the other hand, xylanase and total oxalate levels did not vary significantly. Accordingly, it was not possible to determine whether MnP accomplishes the effect alone or depends on synergic action of other extracellular agents. Pulp strength and fiber size distribution were also evaluated. The average fiber length of CTMP pulps prepared from untreated wood chips was 623 μm. Analogous values were observed for most of the biopulps; however, significant amounts of shorter fibers were found in the biopulp prepared from wood chips biotreated in cultures supplemented with glucose plus corn-steep liquor. Despite evidence of reduced average fiber length, biopulps prepared from these wood chips presented the highest improvement in tensile indexes (+28% at 23° Schopper-Riegler).


Holzforschung ◽  
2008 ◽  
Vol 62 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Fernando Masarin ◽  
André Ferraz

Abstract In biopulping, efficient wood colonization by a selected white-rot fungus depends on previous wood chip decontamination to avoid the growth of primary molds. Although simple to perform in the laboratory, in large-scale biopulping trials, complete wood decontamination is difficult to achieve. Furthermore, the use of fungal growth promoters such as corn steep liquor enhances the risk of culture contamination. This paper evaluates the ability of the biopulping fungus Ceriporiopsis subvermispora to compete with indigenous fungi in cultures of fresh or poorly decontaminated Eucalyptus grandis wood chips. While cultures containing autoclaved wood chips were completely free of contaminants, primary molds grew rapidly when non-autoclaved wood chips were used, resulting in heavily contaminated cultures, regardless of the C. subvermispora inoculum/wood ratio evaluated (5, 50 and 3000 mg mycelium kg−1 wood). Studies on benomyl-amended medium suggested that the fungi involved competed by consumption of the easily available nutrient sources, with C. subvermispora less successful than the contaminant fungi. The use of acid-washed wood chips decreased the level of such contaminant fungi, but production of manganese peroxidase and xylanases was also decreased under these conditions. Nevertheless, chemithermomechanical pulping of acid-washed samples biotreated under non-aseptic conditions gave similar fibrillation improvements compared to samples subjected to the standard biodegradation process using autoclaved wood chips.


2020 ◽  
Vol 19 (2) ◽  
pp. 112-116
Author(s):  
Luana Maria dos Santos ◽  
Erick Martins Nieri ◽  
Flávia Alves Pereira ◽  
Sandra Mara Krefta ◽  
Jéssica Batista da Mata

The companies in the forestry sector seek highly durable wood, prioritizing the use of planted forests, and the thermal treatment is a viable alternative to provide quality to these woods. Thus, the objective of the study was to evaluate the resistance of the heat-treated Pinus taeda L wood by the attack of white rot fungus Trametes versicolor (L.) CG Lloyd. The P. taeda L. wood was deployed in joinery to obtain samples with dimensions of 30 x 15 x 2.5 cm (length x width x thickness), being treated at temperatures of 140, 160 and 180ºC. From these, 1.0 x 1.0 x 1.0 cm specimens were obtained and subjected to the fungus for six weeks. The accelerated rot test was carried out in accordance with the ASTM D2017 standard. The experiment was conducted in a completely randomized design with four treatments (T1 = 0; T2 = 140°C; T3 = 160°C and T4 = 180°C) and nine replications. The loss of mass caused by the fungus was less in heat treated wood. On the other hand, the increase in temperature did not provide greater resistance to the material. In conclusion, heat treatment has reduced the degradation caused by the white rot fungus Trametes versicolor. Heat treatment at 140°C is indicated to avoid loss of mass in P. taeda L. woods submitted to the fungus T. versicolor. All treated woods were classified as highly resistant.


2013 ◽  
Vol 12 (2) ◽  
pp. 120-128 ◽  
Author(s):  
Daniela Chmelová ◽  
Miroslav Ondrejovič

Abstract The aim of this study was to set parameters of repeated-batch cultivation of Ceriporiopsis subvermispora for laccase production and evaluate the efficiency of this type of cultivation for production of selected enzyme. The suitable conditions for repeated-batch cultivation were designed on the base of study of batch cultivation of white-rot fungus C. subvermispora. C. subvermispora was cultivated in media with different concentration of casein hydrolysate as nitrogen source and glucose as carbon source. A suitable concentration of casein hydrolysate to stimulate the laccase production was 1.5 and 2.5 g/L. Laccase production was started at certain critical concentration of glucose (5 g/L). In order to improve laccase production by repeated-batch cultivation of C. subvermispora, glucose was tested in concentration 10 g/L and casein hydrolysate in concentration 1.5 g/L. During a repeated-batch cultivation was measured increase laccase activities from 177.8 to 266 U/L. It was also observed, the cultivation time needed to reach maximum laccase production was shortened to 10 days.


2020 ◽  
Author(s):  
Alex R Gonzalez ◽  
Gino R Corsini ◽  
Sergio Lobos ◽  
Daniela Seelenfreund ◽  
Mario Tello

Abstract Background: Ceriporiopsis subvermispora is a white-rot fungus that displays a high specificity towards lignin mineralization when colonizing dead wood or lignocellulosic compounds. The lignocellulose degrading system from C. subvermispora is formed by genes that encode cellulose hydrolytic enzymes, manganese peroxidases, and laccases that catalyze the efficient depolymerization and mineralization of lignin in the presence of Mn3+ through the formation of lipoperoxides from unsaturated lipid acids. This highly specific lignin-degrading system is unique among white-rot fungi. Methods: In order to determine if this metabolic specialization has modified codon usage of the ligninolytic system, leading to an increased adaptation to the fungal translational machine, we analyzed the adaptation to host codon usage (CAI), tRNA pool (tAI, and AAtAI), codon pair bias (CPB) and the number of effective codons (Nc). These indexes were correlated with gene expression of C. subvermispora, as evaluated by microarray in the presence of two carbon sources, glucose and Aspen wood.Results: General gene expression of C. subvermispora was not correlated with the CAI, tAI, AAtAI, CBP or Nc indexes used to evaluate adaptation to codon bias or the tRNA pool, neither in the presence of glucose or Aspen wood. However, in media containing Aspen wood, the induction of expression of lignin-degrading genes showed a strong correlation with all the former indexes. Lignin-degrading genes, defined as genes whose expression increases at least two-fold in Aspen wood, showed significantly (p<0.001) higher values of CAI, AAtAI, CPB, tAI and lower values of Nc with respect to non-induced genes. Among ligninolytic genes, cellulose-binding proteins and manganese peroxidases presented the highest adaptation values. We also identified an expansion of genes encoding glycine and glutamic acid tRNAs.Conclusions: Our results suggest that the metabolic specialization to use wood as the sole carbon source has introduced a bias in the codon usage of genes involved in lignocellulose degradation. This bias reduces codon diversity and increases codon usage adaptation to the tRNA pool available in C. subvermispora. To our knowledge, this is the first study showing that codon usage is modified to improve the translation efficiency of a group of genes involved in a particular metabolic pathway.


2018 ◽  
Vol 280 ◽  
pp. S88-S89
Author(s):  
Gordana Selo ◽  
Mirela Planinic ◽  
Marina Tisma ◽  
Darijo Sibalic ◽  
Ana Bucic Kojic

Holzforschung ◽  
2001 ◽  
Vol 55 (1) ◽  
pp. 42-46
Author(s):  
G. Idárraga ◽  
J. Ramos ◽  
R.A. Young ◽  
F. Denes ◽  
V. Zuñiga

Summary The effect of biological pretreatment of sisal with several white rot fungi on the energy consumption in refining and on the mechanical properties of the pulps was evaluated in this investigation. Improvements were realized in all the mechanical properties (22–66 %) and a reduction in the energy consumption of > 39% was realized for the treated pulps with the different fungi. The best strength improvement and energy reduction results overall were obtained with the white-rot fungus, Ceriporiopsis subvermispora. The incubation time was optimized for this fungus with the optimum mechanical properties obtained with a two week treatment time.


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