• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.4
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• pp.18-27
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• 1998

Biopulping is defined as the treatment of wood chips with lignin-degrading fungi prior to pulping. Fungal pretreatment prior to mechanical pulping reduces electrical energy requirements during refining or increases mill throughput, improves paper strength, reduces the pitch content, and reduces the environmental impact of pulping. Our recent work involved scaling up the biopulping process towards the industrial level, investigating both the engineering and economic feasibility. We envision the process to be done in either a chip-pile or silo-based system for which several factors need to be considered: the degree of decontamination, a hospitable environment for the fungus, and the overall process economics. Currently, treatment of the chips with low-pressure steam is sufficient for decontamination and a simple, forced ventilation system maintains the proper temperature, humidity, and moisture conditions, thus promoting uniform growth of the fungus. The pilot-scale trial resulted in the successful treatment of 4 tons of wood chips (dry weight basis) with results comparable to those on a laboratory. Larger, 40-ton trials were also successful, with energy savings and paper properties comparable with the laboratory scale. The overall economics of the process also look very favorable and can result in significant annual savings to the mill. Although the current research has focused on biopulping for mechanical pulping, it is also beneficial for sulfite chemical pulping and some applications to recycled fiber have been investigated.

• Mycobiology
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• v.35 no.4
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• pp.205-209
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• 2007

Ergosterol involves in fungal cell growth as a major component in fungal cell membranes. It can be an indicator that shows the fungal activity, and its content depends on the fungal strains, culture, growth conditions and so on. In this study, fungal activities and growth patterns of three white-rot fungi strains isolated in Korea were evaluated by determination of ergosterol contents during the incubation. Wood decay test and chemical analyses of wood were also performed to verify the relationship between fungal activity and wood degrading capacity of white-rot fungi for 60 days. In the results of experiments, it is considered that the test strains selectively degrade large amount of lignin in wood at the early stage of decay. Especially, Phanerochaete chrysosporium showed the best capability on selective degradation of lignin among the test fungi. It is suggested that the determination of ergosterol content in the fungal culture during the incubation is the simple and effective screening method of white-rot fungi for the application to biopulping of wood.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2003.11a
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• pp.9-16
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• 2003

Interaction between wood-destroying basidiomycetes and blue stain fungi were studied during conjoint cultivation on 2% malt extract agar. The ability of basidial cultures to decolourise dark pigments of ophiostomatoid fungi was the main characteristics estimated during this investigation. Antrodiella hoehnelii(S28/91), Bjerkandera fumosa(137), Gleophyllum odoratum(124), Trametes versicolor (B18/91) cultures were found to be the most active in decreasing dark colour of blue stain fungi colonies. The cultures were recommended for further development as agents of biopulping and control of blue stain fungi in wood chips.

• The Korean Journal of Mycology
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• v.26 no.2 s.85
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• pp.144-152
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• 1998

To obtain white rot fungi which have selective delignification capacity and can be used in biopulping processes, 94 different wood rotting fungi were screened and the capabilities of selected species were evaluated on deciduous and coniferous wood blocks. White rot fungi, first of all, were selected by simple enzyme tests, i.e., cellulase activity test; phenol oxidase activity test; laccase and peroxidase activity test. Most organisms that gave a positive Bavendamm gave a strongly positive laccase test with syringaldazine whereas most of those that gave a negative Bavendamm test also negative test for laccase and peroxidase, even if some exceptions were noted. Wood decay experiement were carried out to select fungal species with selective lignin-degrading ability by inoculating selected fungi to both wood blocks of Populus tomentiglandulosa and Larix leptolepis. After 12 weeks of incubation, weight losses, lignin losses, and morphological characteristics of the decayed wood were investigated. Almost all fungi tested caused 2 or more times of weight losses in P. tomentiglandulosa than in L. leptolepis, while no weight losses were detected from the un-inoculated wood blocks. Ceriporiopsis subvermispora and Phanerochaete chrysosporium were the best delignifiers for both hardwood and softwood. P. chrysosporium, however, was less effective than C. subvermispora. Bjerkandera adusta and two unidentified spp. caused delignification for only P. tomentiglandulosa. B. adusta caused simultaneous rot of all cell wall components, resulted in thinning of the secondary cell wall layers. Other fungi caused selective delignification resulting in the removal of lignin from middle lamella and separation of cells from each other.

• Journal of the Korean Wood Science and Technology
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• v.33 no.2 s.130
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• pp.65-71
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• 2005

This study was performed to understand the interaction between Ophiostomataceae and basidiomycetes fungi during cultures, and whether the basidiomycetes fungi inhibit the growth and decolorize dark pigments of blue staining fungi. The conjoint cultivation was studied on 2% malt extract agar. The ability of basidial cultures to decolorize dark pigments of ophiostomatoid fungi was the main characteristics estimated during this study. More than half of basidial cultures were characterized by deadlock interaction with blue staining fungi. In the dual cultures, where basidial partners were presented by Agaricus bisporus(64), Laetiporus sulphureus(L01/89), Trametes versicolor(09) and unknown fungus(02), antagonism was found at the phase of primary contact of colonies. Replacement interaction resulted usually in decreasing dark colour of substrate was observed for 11 basidial cultures that were belonging mainly to white-rot fungi. Among them Abortiporus biennis(123), Antrodiella hoehnelii(S28/91), Bjerkandera fumosa (137), and Gleophyllum odoratum(124) were characterized by the absence of deadlock-phase: they began to grow over dark colonies of their partners just after primary contact. Basidiomycetes did not affect strongly the pigments of Ceratocystis spp. and Leptographium sibirica isolates, but completely decolorized colonies of Ophiostoma ips and to a smaller degree Ophiostoma minus. Antrodiella hoehnelii(S28/91), Bjerkandera fumosa(137), Gleophyllum odoratum(124) and Trametes versicolor(B18/91) cultures were found to be the most active in decreasing dark color of blue staining fungi colonies. The cultures were recommended for further development as agents of biopulping of wood chips and bio-control of blue stain in woods.

• Bulletin of the Korean Chemical Society
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• v.23 no.7
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• pp.985-989
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• 2002

For efficient biopulping process, very active and stable lignase is essential. Laccase is one of the best enzyme in terms of environmentally benign processes, since the enzyme uses oxygen as an oxidant to degrade lignin and produces no hamful prod ucts. We could purify a laccase homogeneously from Cerrena unicolor in a very active state. It shows characteristic absorption feature with blue band at λmax = 604 ㎚. Molecular weight of the enzyme is 57,608 which could be accurately determined by MALDI/TOF MS. The enzyme has 2.8 copper ions per enzyme implying apoenzymes might exist together. The enzyme is active in lignin degradation and the activity increases 4 times in the presence of ABTS as a mediator.

• Journal of Microbiology and Biotechnology
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• v.17 no.3
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• pp.468-473
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• 2007

White rot fungi, Phanerochaete chrysosporium and Phanerochaete sordida, have been mostly studied in a variety of industrial processes like biopulping and pulp bleaching as well as in bioremediation. Whereas P. sordida is widely distributed in the North Temperate Zone, P. chrysosporium is reported in the restricted area and hundreds of reports have been described from a few strains of P. chrysosporium, which are deposited at various fungal collections in the world. The isolates of two species are not easily discriminated because of their morphological and molecular similarity. Through the ITS sequence analyses, a region containing substantial genetic variation between the two species was identified. PCR amplification using two specific primers was successfully used to differentiate P. chrysosporium from P. sordida. These results were supported by cultural studies. The growth rates at $37^{\circ}C$ on PDA, MEA, and Cza and the microscopic features of conidia on PDA and YMA were also very useful to differentiate those two species.

• Journal of the Korean Wood Science and Technology
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• v.29 no.4
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• pp.103-110
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• 2001

Bio-kraft pulping of Populus alba${\times}$glandulosa pretreated with white-rot fungus, Phanerochaete chrysosporium KCCM 34740, was investigated The biopulping efficiency was evalued based on fungal pretreatment time and properties of bio-kraft pulp (pulp yield, freeness, WRY, kappa number and brightness) in comparison to the controls. Pretreatment of poplar wood chips with Phanerochaete chrysosporium KCCM 34740 for 10days resulted in a some increase in screened yield (by 2%). According to increase of fungal incubation time, decrease in freeness (CSF) and increase in WRY were observed And bio-kraft pulping also led to improvement of physical properties of handsheet. As a result of bio-beating effect, we expect the saving of chemicals in kraft cooking process and energy consumption in beating process.