- Email: [email protected]
Fungi and paper manufacture
f u n g a l b i o l o g y r e v i e w s 2 4 ( 2 0 1 0 ) 6 8 e7 2
journal homepage: www.elsevier.com/locate/fbr
Review
Fungi and paper manufacture Russell J. JERUSIK* Ashland Hercules Water Technology, Research Center, 500 Hercules Road, Wilmington, Delaware 19808-1599, United States
article info
abstract
Article history:
Fungi have a significant impact on the economics of paper making and the end use of paper
Received 14 September 2009
and products employing paper related components. Paper on a practical basis is a deriva-
Received in revised form
tive of wood, and fungi that possess cellulose-degrading enzymes can directly impact the
8 April 2010
value and utility of various types of products. Fungi further have a negative economic
Accepted 10 April 2010
impact on the pulp produced during paper manufacture. Contamination by fungi impacts on the quality and often the safety of the product to the end user. Packaging materials used
Keywords:
in warm humid climates can be infested with mold which impacts the value and safety of
Cellulase
the packaged product. Building materials whether gypsum wall board, the paper-facing on
Fungicides
insulation materials, or ceiling tiles can sustain fungi and cause numerous problems.
Paper
These fungi create an aesthetic, functional and ultimately, a safety issue to the occupants
Paper degrading fungi
in a mold infested dwelling. Fungal spores are linked to allergy, asthma, and various
Paper manufacture with fungal
pulmonary related disorders. In the U.S., 3e5 million tons of scrap wall board end up in
enzymes
landfills every year which can also create fungal environmental problems. This review article will describe these problems and strategies to minimize the adverse impact on paper by fungi. However, fungi are also utilized in a beneficial manner to enhance paper manufacture by removing detrimental components in paper and can aide in its production. ª 2010 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.
1.
Introduction
This review considers the role of fungi in paper manufacture. There is a beneficial role as well as the expected deleterious impact of fungi on paper. Fungi are utilized to remove free and esterified steroid ketones that prevents the formation of detrimental pitch in Eucalyptus wood (Martinez-Inogi et al., 2001). Pitch is low molecular weight oleophilic material which deposits during paper manufacture causing holes in the paper. The various approaches to the usage of fungi to remove undesirable components of wood to make paper will be described. Enzymes also attack hemicellulose favouring desired depolymerization (Suurnakki et al., 1997). Fungi also play a positive role in the actual process of making paper. Biobleaching
reduces the usage of conventional bleaching chemicals and improves pulp and eventual paper quality by improving brightness, breaking length, burst index, tear index, and manufacturing yield (Jimenez et al., 1997). This is accomplished with enzymes of fungal origin, such as xylanases (Sandal et al., 1997). Environmental benefits are derived from the reduction in chemical usage reducing effluent toxicity and pollution load. Filamentous fungi can be used as a raw material to make high gloss paper with acceptable writing and printing qualities (Yamanak et al., 1992; Van Horn and Shema, 1957). Fungi can also cause severe problems for the paper manufacturer and in the end product. Wet pulp is a source or raw material for the manufacture of paper and in 2007, 40.4 million
* Tel.: þ1 302 995 3177. E-mail address: [email protected] 1749-4613/$ e see front matter ª 2010 The British Mycological Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.fbr.2010.04.003
Fungi and paper manufacture
69
tons were shipped around the world. Pulp production involves adding large amounts of water to produce the pulp and significant energy is needed to remove the majority of the water content to minimize fungal infestation which can dramatically decrease the economic value of the pulp. Today there is a great emphasis on the use of re-cycled fibre for environmental reasons and these fibres are often heavily contaminated with organic matter increasing the tendency for mold growth.
2.
Fungi as part of the paper making process
While commercial products exist to remove pitch from wood, Martinez-Inogi et al. (2001) improved on the process by finding fungi that were able to remove both free and esterified sitosterol. A 1e2 week treatment with either Phlebia radiata or Poria subvermispora enabled a 70 % removal of sterols with only a moderate wood loss of 1e4 %. Biobleaching utilizes enzymes to prepare pulp for paper making. Improvements are documented in brightness, kappa index, yield, breaking length, burst index, and tear index with xylanases the most frequently used enzymes (Jimenez et al., 1997). A commercial recombinant xylanase enhances the brightness of the bleached pulp reducing the amount of chlorine typically used in conventional treatments (Sandal et al., 1997) providing an improved process from an environmental standpoint. The paper making process often leads to the production of toxic organochlorine compounds due to the use of chlorine based oxidizers during paper bleaching. Bajpai and Bajpai (1997) identified fungal enzymes capable of removing such chemicals from bleach plant effluents. Research has also shown that fungi can be used to biopulp wood. Wood is debarked, chipped and steamed, reducing the natural microbial flora. The material is then inoculated with the biopulping fungi and the piled chips ventilated with filtered and humidified air for 1e4 weeks. This process can provide an energy savings of at least 30 % and also increases mill output up to 30 % as well as increasing paper strength of the finished paper (Shukla et al., 2004). In addition, fungi can be a raw material to make paper. Fungal mycelium and conventional fibres are combined to strengthen the paper and this combination is particularly useful when re-cycled fibres are used. Yamanak et al. (1992) cultured Fusarium solani with broadleaf tree pulp at 28 C for 2 days after which the culture was filtered and washed to retain the fibre mycelium complex. A 1954 patent describes in detail the manufacture of highly flexible, high gloss paper with acceptable printing and writing qualities with fungal mycelium making up 10 % of the paper content. In addition, a transparent paper also possessing acceptable printing and writing properties contained 90 % fungal mycelia (Van Horn and Shema, 1957).
3.
Fungal destruction of paper
Fungi perform an important ecological role in the decay of paper and is historically problematic for the paper industry (Acree, 1915). A family of enzymes are known to participate in the breakdown of cellulose into glucose. The mechanism
Fig. 1 e Mechanism of cellulose degradation.
of cellulase activity as portrayed in Fig. 1 was elucidated by Matthew et al. (2008). Other researchers have shown variations in the cellulases produced depending on the fungal species (Bhat and Maheshwari, 1987) and at least eight different families of cellulases have been identified (Samejima and Kiyohiko, 2004). The most common fungi associated with paper degradation are shown in Table 1. This fungal destruction of cellulose can have a serious impact on the manufacture of paper. Re-cycled pulp is becoming a more common source for the manufacture of paper and packaging material for ecological and economic reasons. Re-cycled pulp is often stored in less than optimal conditions from the perspective of preventing mold infestation and is often contaminated with food materials. Paper manufactured with mold adulterated pulp can suffer a 50 % loss in strength and losses in brightness in the finished product (Meng, 1998) (see Figs 2 and 3). These data compare fresh material with pulp stored either covered or uncovered. The reduction of ring crush/basis weight indicates a lower strength to the finished packaging material (Fig. 3). The below photograph provides an example of a Penicillium species growing on pulp (Fig. 4). Paper/cardboard constructed products, either building material or packaging materials, can be compromised by fungal decay. This fungal decay can impact on the value, utility, and safety of the final product. Gypsum wall board in the United States is utilized in nearly 90 % of interior finished surfaces in buildings based on an EPA study. This same study estimated that 40 % of all homes in North America have fungal
Table 1 e Fungi that degrade papera Penicillium citrinium Aspergillus niger Sporotrichum thermophile Trichoderma reesei Penicillium pinophilium Chaetomium globosum Aureobasidium pullulans a Fungi noted in ASTM protocols for testing degradation to paper products.
70
R. J. Jerusik
Fig. 2 e Strength loss due to bio-deterioration of re-cycle pulp beverage box containers.
contamination problems (Figs 5 and 6). The rapid growth and dispersion of mold spores can induce allergy and asthma episodes for the occupants. These health effects can be even more serious with immunological, pulmonary and even oncogenic disorders. Manufacturers have responded to this problem by making mold resistant gypsum wall board. Two strategies are currently employed to overcome this problem. The first is the conventional incorporation of fungicides to the wall board and various commercial fungicides are available and are used commercially (Table 2). These fungicides are used in packaging materials, the paper-facing of home insulation, and on the coatings of paper-based ceiling tiles. The other strategy is to replace cellulose based materials susceptible to fungal growth with materials that are resistant. One manufacture of gypsum wall board replaces the paper with a glass mat resulting in a product with reduced susceptibility to fungal infestation. However, this material performs differently than conventional gypsum wall board for the end user, specifically in the effort required for cutting and has to be handled in a more labour intensive manner compared to conventional wall board and is a major technical drawback to this strategy. A patent from 2007 for manufacturing cellulose fibre with biocides, such as quaternary ammonium and bromide providing increased biostability to fungal attack (Jewell and Reimer, 2007). Murtoniemi et al. (2003) studied the influence
Fig. 4 e Pulp contaminated with mold.
of composition on the growth of Stachybotrys chartarum on gypsum wall board. Wall board was made without starch in the core and liner or if the gypsum core was desulfurized showed inhibited fungal growth. Incorporated biocides while functional however, led to the production of spores with even higher cytotoxicity to animal cells. Another study examined the influence of various fillers such as kaolin and titanium dioxide on fungal growth, staining and actual decay of the paper Nyuksha (1969). Natural products such as essential oils from clove and cinnamon and oregano are reported to retard fungal growth (Rodriguez et al., 2007). Serano et al. (2005) (Fig. 7) fungi can affect paper in more subtle ways than the overt destruction of the cellulose content. Art work and historical documents
Summer 2000 Summer 2001
0.350 0.300 Ring 0.250 Crush/ Basis 0.200 Weight 0.150 0.100 0.050 0.000 Fresh Market Bales
One Year Covered Storage
One Year on Slab
Fig. 3 e Impact of fungal deterioration on cardboard quality.
Fig. 5 e Wet Lap contaminated with mold.
Fungi and paper manufacture
Fig. 6 e Mold growing on gypsum wall board during an antifungal evaluation.
can be adversely impacted by fungi due to the production of coloured pigments that stain and permeate the paper. Szczepanowska and Lovett (1992) investigated several factors that influence stain production by several fungi growing on paper. Temperature, pH, and light were varied with four fungal strains (Chaetomium globosum, a very active degrader of paper, Fusarium oxysporum, Alternaria solani, and Penicillium notatum) and the outcomes were scored based on the degree of visible staining of the paper. The affect of pH was examined between 5 and 8 with acidic conditions favouring fungal growth at pH 5.0 were the stain production was most pronounced. A notable exception was C. globosum which produced staining equally at all pH’s tested. Stain production for the other three test fungi followed a direct correlation with pH with no stain produced at pH 8.0. Growth did occur to varying degrees at the elevated pH’s for the three fungi. A. solani did not grow at pH 8.0 while P. notatum and F. oxysporum grew to equal degrees independent of the pH being acidic or basic. Temperature and its impact on fungal growth was studied extensively by Wolf and Wolf (1947). This work showed that temperatures at 30 and 50 C fungi grew poorly and also at the elevated temperatures of 30 and 37 C. Optimal growth was evident between 22 and 29 C. In comparison, the study by Szczepanowska and Lovett (1992), none of the four strains grew at 40 C. C. globosum was unique in growing the best at 37 C. The other 3 test fungi were
Table 2 e Examples of commercially available fungicides TCMTB Sulfone MBTC TBZ Zinc or Sodium Omadine Quats Ziram IPBC Carbendazim Iso
2-(Thiocyanomethylthio)benzothiazole (Diiodo-methyl p tolylsulfone) (Methylene bisthiocyanate) (Thiabendazole) (Pyrithione) (Quaternary amine surfactants) (Zinc dimethyldithiocarbamate) (3-iodo 2 propynyl butylcarbamte) (Methyl 1H-benzimiazol-2-carbamate) 4,5 dichloro-2-n-octyl-4-isothiazolin-3-one
71
Fig. 7 e Control of mold with eugenol after 16 d of storage at 2 C.
adversely affected by the elevated temperature, P. notatum was unable to grow and while growth was inhibited for F. oxysporum and A. solani. The last physical parameter examined was the influence of light on fungal growth on paper. Wolf and Wolf (1947) also looked at light and found both stimulatory and inhibitory influences were evident with different fungi. In the study by Szczepanowska and Lovett (1992), light was a positive influence on both growth and stain production. Stain production by F. oxysporum was enhanced with light exposure compared to growth in the dark. Szczepanowska and Lovett (1992) also examined the use of solvents to remove stains on paper as a possible remedial treatment for fungal stained paper. The principal pigments responsible for the staining by the four test fungi were characterized. Citronen and xanthocillin are yellow coloured antibiotics produced by P. notatum (Rothe, 1950; Wolf and Wolf, 1947). Chaetomidin is a pigment extracted from Chaetomium species and was found to be identical to oosprein from Oospora colorans (Itabashi et al., 1955). Intracellular anthraquinine-like black pigments from Alternaria have been isolated and identified as altersolanols (Stoessl, 1969; Zaprometova et al., 1971). General characterization of fungal stains by Stoessl (1969) suggest a resemblance to humic acids and melanins. While numerous solvents were utilized to assess stain removal, very limited success was observed. The exceptions were 1,4dioxane which was able to completely remove the stains of F. oxysorum and removed most of the staining caused by C. globosum and P. notatum. N,N dimethylformamide significantly removed the stains caused by C. globosum and P. notatum. Papers after drying were tested for any adverse impact on paper quality and no detectable changes in wet tensile strength or sizing was measured. These solvents have both flammability and toxicity issues relevant their usage.
4.
Conclusions
This review highlights the positive and negative impact that fungi can impose on paper. The destructive aspects of fungi are daily real consequences that impose severe financial
72
impact to paper manufacturers and subsequently cause health issues for people when these materials become colonised due to the release of fungal spores into contained indoor environments. While incorporation of fungicides are aimed at reducing the negative impacts of fungal growth, continuing effort will need to continue to elucidate new approaches to curb the negative impact of fungi on paper both during the manufacturing process and post production.
Acknowledgements Thanks Linda Chaney, Christopher Davis, Kurt Bottjer and other Ashland Hercules Water Technology personnel for their assistance in providing information for this review.
references
Acree, S.F., 1915. Destruction of wood and pulp by fungi and bacteria. Pulp and Paper Magazine 17, 569e571. Bajpai, P., Bajpai, P.K., 1997. Reduction of organochlorine compounds in bleach plant effluents. Advances in Biochemical Engineering Biotechnology 57, 213e259. Bhat, K.M., Maheshwari, R., 1987. Sporotrichum thermophile growth, cellulose degradation and cellulase activity. Applied and Environmental Microbiology 53, 2175e2182. Itabashi, M., Murakami, Y., Nishikawa, H., 1955. Biochemistry of the filamentous fungi. Tohoku Journal of Agricultural Research 5, 281e283. Jewell, R.A., Reimer, J.A., 2007. Method for producing cellulose fibre having improved biostability and the resulting products. U.S Patent 7,244,338. Jimenez, L., Martinez, C., Perez, I., Lopez, F., 1997. Biobleaching procedures for pulp from agricultural residues using Phanerochaete chrysosporium and enzymes. Process Biochemistry 32, 297e304. Martinez-Inogi, M.J., Gutierrez, A., del Rio, J.C., Martinez, M.J., Martinez, A.T., 2001. Time course of fungal removal of lipophilic extractives from Eucalyptus globulus wood. Journal of Biotechnology 84, 119e126. Matthew, G.M., Sukumaran, R.K., Singhania, R.R., Pandy, A., 2008. Progress in research on fungal cellulases for lignocellulose
R. J. Jerusik
degradation. Journal of Scientific and Industrial Research 67, 898e907. Meng, M., 1998. Fibre Storage in Beverage Cartons a Study of Fibre Deterioration During Storage. Proceedings, 1998 Tappi Recycling Conference. Tappi. Press, Atlanta, Ga, pp. 97e115. Murtoniemi, T., Nevalainen, A., Hirvonen, M.R., 2003. Effect of plasterboard composition on Stachybotrys chartarum growth and biological activity of spores. Applied and Environmental Microbiology 69, 3751e3757. Nyuksha, Y.P., 1969. Effect of fungi on paper. Mikologiyai Fitopaptologiya 3, 463e470. Rodriguez, A., Battle, R., Nerin, C., 2007. The use of natural essential oils as antimicrobial solutions in paper packaging. Progress in Organic Coatings 60, 33e38. Rothe, W., 1950. New antibiotic. Pharmazie 5, 190. Samejima, M., Kiyohiko, I., 2004. Recent advances of research on fungal system of cellulose degradation and related enzymes. Journal of the Japan Wood Research Society 50, 359e367. Sandal, T., Kofod, L.V., Kauppinen, M.S., Andersen, L.N., 1997. An enzyme with xylanase activity. Patent WO/1997/027293. Serano, M., Martinez-Romero, D., Guillen, F., Castillo, J.M., Valero, D., 2005. Active packaging development to improve ‘starking’ sweet cherry postharvest quality. Acta Horticulturae 682, 1675e1682. Shukla, O.P., Rai, U.N., Subramanyam, S.V., 2004. Biopulping and biobleaching: an energy and environmental saving technology for Indian pulp and paper industry. Vol. 10 No. 2 (Reproduced from the archives if Enviro News ISEB of India). Stoessl, A., 1969. Metabolites of Alternaria solani. Canadian Journal of Chemistry 47, 767e776. Suurnakki, A., Tenkanen, M., Buchert, J., Viikari, L., 1997. Hemicellulases in the bleaching of chemical pulps. Advances in Biochemical Engineering Biotechnology 57, 261e287. Szczepanowska, H., Lovett, C.M., 1992. A study of the removal and prevention of fungal stains on paper. Journal of the American Institute for Conservation 31, 147e160. Van Horn, W., Shema, B.F., 1957. Sheets comprising filaments of fungi. U.S. Patent 2,811,442. Wolf, F.A., Wolf, F.T., 1947. The Fungi, vol. 2. John Wiley and Sons. 83e86, 96e164. Yamanak, S., Kikuchi, R., Ajinomoto, K.K., 1992. Manufacture of reinforced fibres with fungi. Japanese patent 04112794. Zaprometova, K.M., Mirchink, G., Orolov, D.S., Yukhnin, 1971. Characteristics of black pigments of the dark-coloured soil fungi. Pochvovedenie 7, 22e30.
journal homepage: www.elsevier.com/locate/fbr
Review
Fungi and paper manufacture Russell J. JERUSIK* Ashland Hercules Water Technology, Research Center, 500 Hercules Road, Wilmington, Delaware 19808-1599, United States
article info
abstract
Article history:
Fungi have a significant impact on the economics of paper making and the end use of paper
Received 14 September 2009
and products employing paper related components. Paper on a practical basis is a deriva-
Received in revised form
tive of wood, and fungi that possess cellulose-degrading enzymes can directly impact the
8 April 2010
value and utility of various types of products. Fungi further have a negative economic
Accepted 10 April 2010
impact on the pulp produced during paper manufacture. Contamination by fungi impacts on the quality and often the safety of the product to the end user. Packaging materials used
Keywords:
in warm humid climates can be infested with mold which impacts the value and safety of
Cellulase
the packaged product. Building materials whether gypsum wall board, the paper-facing on
Fungicides
insulation materials, or ceiling tiles can sustain fungi and cause numerous problems.
Paper
These fungi create an aesthetic, functional and ultimately, a safety issue to the occupants
Paper degrading fungi
in a mold infested dwelling. Fungal spores are linked to allergy, asthma, and various
Paper manufacture with fungal
pulmonary related disorders. In the U.S., 3e5 million tons of scrap wall board end up in
enzymes
landfills every year which can also create fungal environmental problems. This review article will describe these problems and strategies to minimize the adverse impact on paper by fungi. However, fungi are also utilized in a beneficial manner to enhance paper manufacture by removing detrimental components in paper and can aide in its production. ª 2010 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.
1.
Introduction
This review considers the role of fungi in paper manufacture. There is a beneficial role as well as the expected deleterious impact of fungi on paper. Fungi are utilized to remove free and esterified steroid ketones that prevents the formation of detrimental pitch in Eucalyptus wood (Martinez-Inogi et al., 2001). Pitch is low molecular weight oleophilic material which deposits during paper manufacture causing holes in the paper. The various approaches to the usage of fungi to remove undesirable components of wood to make paper will be described. Enzymes also attack hemicellulose favouring desired depolymerization (Suurnakki et al., 1997). Fungi also play a positive role in the actual process of making paper. Biobleaching
reduces the usage of conventional bleaching chemicals and improves pulp and eventual paper quality by improving brightness, breaking length, burst index, tear index, and manufacturing yield (Jimenez et al., 1997). This is accomplished with enzymes of fungal origin, such as xylanases (Sandal et al., 1997). Environmental benefits are derived from the reduction in chemical usage reducing effluent toxicity and pollution load. Filamentous fungi can be used as a raw material to make high gloss paper with acceptable writing and printing qualities (Yamanak et al., 1992; Van Horn and Shema, 1957). Fungi can also cause severe problems for the paper manufacturer and in the end product. Wet pulp is a source or raw material for the manufacture of paper and in 2007, 40.4 million
* Tel.: þ1 302 995 3177. E-mail address: [email protected] 1749-4613/$ e see front matter ª 2010 The British Mycological Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.fbr.2010.04.003
Fungi and paper manufacture
69
tons were shipped around the world. Pulp production involves adding large amounts of water to produce the pulp and significant energy is needed to remove the majority of the water content to minimize fungal infestation which can dramatically decrease the economic value of the pulp. Today there is a great emphasis on the use of re-cycled fibre for environmental reasons and these fibres are often heavily contaminated with organic matter increasing the tendency for mold growth.
2.
Fungi as part of the paper making process
While commercial products exist to remove pitch from wood, Martinez-Inogi et al. (2001) improved on the process by finding fungi that were able to remove both free and esterified sitosterol. A 1e2 week treatment with either Phlebia radiata or Poria subvermispora enabled a 70 % removal of sterols with only a moderate wood loss of 1e4 %. Biobleaching utilizes enzymes to prepare pulp for paper making. Improvements are documented in brightness, kappa index, yield, breaking length, burst index, and tear index with xylanases the most frequently used enzymes (Jimenez et al., 1997). A commercial recombinant xylanase enhances the brightness of the bleached pulp reducing the amount of chlorine typically used in conventional treatments (Sandal et al., 1997) providing an improved process from an environmental standpoint. The paper making process often leads to the production of toxic organochlorine compounds due to the use of chlorine based oxidizers during paper bleaching. Bajpai and Bajpai (1997) identified fungal enzymes capable of removing such chemicals from bleach plant effluents. Research has also shown that fungi can be used to biopulp wood. Wood is debarked, chipped and steamed, reducing the natural microbial flora. The material is then inoculated with the biopulping fungi and the piled chips ventilated with filtered and humidified air for 1e4 weeks. This process can provide an energy savings of at least 30 % and also increases mill output up to 30 % as well as increasing paper strength of the finished paper (Shukla et al., 2004). In addition, fungi can be a raw material to make paper. Fungal mycelium and conventional fibres are combined to strengthen the paper and this combination is particularly useful when re-cycled fibres are used. Yamanak et al. (1992) cultured Fusarium solani with broadleaf tree pulp at 28 C for 2 days after which the culture was filtered and washed to retain the fibre mycelium complex. A 1954 patent describes in detail the manufacture of highly flexible, high gloss paper with acceptable printing and writing qualities with fungal mycelium making up 10 % of the paper content. In addition, a transparent paper also possessing acceptable printing and writing properties contained 90 % fungal mycelia (Van Horn and Shema, 1957).
3.
Fungal destruction of paper
Fungi perform an important ecological role in the decay of paper and is historically problematic for the paper industry (Acree, 1915). A family of enzymes are known to participate in the breakdown of cellulose into glucose. The mechanism
Fig. 1 e Mechanism of cellulose degradation.
of cellulase activity as portrayed in Fig. 1 was elucidated by Matthew et al. (2008). Other researchers have shown variations in the cellulases produced depending on the fungal species (Bhat and Maheshwari, 1987) and at least eight different families of cellulases have been identified (Samejima and Kiyohiko, 2004). The most common fungi associated with paper degradation are shown in Table 1. This fungal destruction of cellulose can have a serious impact on the manufacture of paper. Re-cycled pulp is becoming a more common source for the manufacture of paper and packaging material for ecological and economic reasons. Re-cycled pulp is often stored in less than optimal conditions from the perspective of preventing mold infestation and is often contaminated with food materials. Paper manufactured with mold adulterated pulp can suffer a 50 % loss in strength and losses in brightness in the finished product (Meng, 1998) (see Figs 2 and 3). These data compare fresh material with pulp stored either covered or uncovered. The reduction of ring crush/basis weight indicates a lower strength to the finished packaging material (Fig. 3). The below photograph provides an example of a Penicillium species growing on pulp (Fig. 4). Paper/cardboard constructed products, either building material or packaging materials, can be compromised by fungal decay. This fungal decay can impact on the value, utility, and safety of the final product. Gypsum wall board in the United States is utilized in nearly 90 % of interior finished surfaces in buildings based on an EPA study. This same study estimated that 40 % of all homes in North America have fungal
Table 1 e Fungi that degrade papera Penicillium citrinium Aspergillus niger Sporotrichum thermophile Trichoderma reesei Penicillium pinophilium Chaetomium globosum Aureobasidium pullulans a Fungi noted in ASTM protocols for testing degradation to paper products.
70
R. J. Jerusik
Fig. 2 e Strength loss due to bio-deterioration of re-cycle pulp beverage box containers.
contamination problems (Figs 5 and 6). The rapid growth and dispersion of mold spores can induce allergy and asthma episodes for the occupants. These health effects can be even more serious with immunological, pulmonary and even oncogenic disorders. Manufacturers have responded to this problem by making mold resistant gypsum wall board. Two strategies are currently employed to overcome this problem. The first is the conventional incorporation of fungicides to the wall board and various commercial fungicides are available and are used commercially (Table 2). These fungicides are used in packaging materials, the paper-facing of home insulation, and on the coatings of paper-based ceiling tiles. The other strategy is to replace cellulose based materials susceptible to fungal growth with materials that are resistant. One manufacture of gypsum wall board replaces the paper with a glass mat resulting in a product with reduced susceptibility to fungal infestation. However, this material performs differently than conventional gypsum wall board for the end user, specifically in the effort required for cutting and has to be handled in a more labour intensive manner compared to conventional wall board and is a major technical drawback to this strategy. A patent from 2007 for manufacturing cellulose fibre with biocides, such as quaternary ammonium and bromide providing increased biostability to fungal attack (Jewell and Reimer, 2007). Murtoniemi et al. (2003) studied the influence
Fig. 4 e Pulp contaminated with mold.
of composition on the growth of Stachybotrys chartarum on gypsum wall board. Wall board was made without starch in the core and liner or if the gypsum core was desulfurized showed inhibited fungal growth. Incorporated biocides while functional however, led to the production of spores with even higher cytotoxicity to animal cells. Another study examined the influence of various fillers such as kaolin and titanium dioxide on fungal growth, staining and actual decay of the paper Nyuksha (1969). Natural products such as essential oils from clove and cinnamon and oregano are reported to retard fungal growth (Rodriguez et al., 2007). Serano et al. (2005) (Fig. 7) fungi can affect paper in more subtle ways than the overt destruction of the cellulose content. Art work and historical documents
Summer 2000 Summer 2001
0.350 0.300 Ring 0.250 Crush/ Basis 0.200 Weight 0.150 0.100 0.050 0.000 Fresh Market Bales
One Year Covered Storage
One Year on Slab
Fig. 3 e Impact of fungal deterioration on cardboard quality.
Fig. 5 e Wet Lap contaminated with mold.
Fungi and paper manufacture
Fig. 6 e Mold growing on gypsum wall board during an antifungal evaluation.
can be adversely impacted by fungi due to the production of coloured pigments that stain and permeate the paper. Szczepanowska and Lovett (1992) investigated several factors that influence stain production by several fungi growing on paper. Temperature, pH, and light were varied with four fungal strains (Chaetomium globosum, a very active degrader of paper, Fusarium oxysporum, Alternaria solani, and Penicillium notatum) and the outcomes were scored based on the degree of visible staining of the paper. The affect of pH was examined between 5 and 8 with acidic conditions favouring fungal growth at pH 5.0 were the stain production was most pronounced. A notable exception was C. globosum which produced staining equally at all pH’s tested. Stain production for the other three test fungi followed a direct correlation with pH with no stain produced at pH 8.0. Growth did occur to varying degrees at the elevated pH’s for the three fungi. A. solani did not grow at pH 8.0 while P. notatum and F. oxysporum grew to equal degrees independent of the pH being acidic or basic. Temperature and its impact on fungal growth was studied extensively by Wolf and Wolf (1947). This work showed that temperatures at 30 and 50 C fungi grew poorly and also at the elevated temperatures of 30 and 37 C. Optimal growth was evident between 22 and 29 C. In comparison, the study by Szczepanowska and Lovett (1992), none of the four strains grew at 40 C. C. globosum was unique in growing the best at 37 C. The other 3 test fungi were
Table 2 e Examples of commercially available fungicides TCMTB Sulfone MBTC TBZ Zinc or Sodium Omadine Quats Ziram IPBC Carbendazim Iso
2-(Thiocyanomethylthio)benzothiazole (Diiodo-methyl p tolylsulfone) (Methylene bisthiocyanate) (Thiabendazole) (Pyrithione) (Quaternary amine surfactants) (Zinc dimethyldithiocarbamate) (3-iodo 2 propynyl butylcarbamte) (Methyl 1H-benzimiazol-2-carbamate) 4,5 dichloro-2-n-octyl-4-isothiazolin-3-one
71
Fig. 7 e Control of mold with eugenol after 16 d of storage at 2 C.
adversely affected by the elevated temperature, P. notatum was unable to grow and while growth was inhibited for F. oxysporum and A. solani. The last physical parameter examined was the influence of light on fungal growth on paper. Wolf and Wolf (1947) also looked at light and found both stimulatory and inhibitory influences were evident with different fungi. In the study by Szczepanowska and Lovett (1992), light was a positive influence on both growth and stain production. Stain production by F. oxysporum was enhanced with light exposure compared to growth in the dark. Szczepanowska and Lovett (1992) also examined the use of solvents to remove stains on paper as a possible remedial treatment for fungal stained paper. The principal pigments responsible for the staining by the four test fungi were characterized. Citronen and xanthocillin are yellow coloured antibiotics produced by P. notatum (Rothe, 1950; Wolf and Wolf, 1947). Chaetomidin is a pigment extracted from Chaetomium species and was found to be identical to oosprein from Oospora colorans (Itabashi et al., 1955). Intracellular anthraquinine-like black pigments from Alternaria have been isolated and identified as altersolanols (Stoessl, 1969; Zaprometova et al., 1971). General characterization of fungal stains by Stoessl (1969) suggest a resemblance to humic acids and melanins. While numerous solvents were utilized to assess stain removal, very limited success was observed. The exceptions were 1,4dioxane which was able to completely remove the stains of F. oxysorum and removed most of the staining caused by C. globosum and P. notatum. N,N dimethylformamide significantly removed the stains caused by C. globosum and P. notatum. Papers after drying were tested for any adverse impact on paper quality and no detectable changes in wet tensile strength or sizing was measured. These solvents have both flammability and toxicity issues relevant their usage.
4.
Conclusions
This review highlights the positive and negative impact that fungi can impose on paper. The destructive aspects of fungi are daily real consequences that impose severe financial
72
impact to paper manufacturers and subsequently cause health issues for people when these materials become colonised due to the release of fungal spores into contained indoor environments. While incorporation of fungicides are aimed at reducing the negative impacts of fungal growth, continuing effort will need to continue to elucidate new approaches to curb the negative impact of fungi on paper both during the manufacturing process and post production.
Acknowledgements Thanks Linda Chaney, Christopher Davis, Kurt Bottjer and other Ashland Hercules Water Technology personnel for their assistance in providing information for this review.
references
Acree, S.F., 1915. Destruction of wood and pulp by fungi and bacteria. Pulp and Paper Magazine 17, 569e571. Bajpai, P., Bajpai, P.K., 1997. Reduction of organochlorine compounds in bleach plant effluents. Advances in Biochemical Engineering Biotechnology 57, 213e259. Bhat, K.M., Maheshwari, R., 1987. Sporotrichum thermophile growth, cellulose degradation and cellulase activity. Applied and Environmental Microbiology 53, 2175e2182. Itabashi, M., Murakami, Y., Nishikawa, H., 1955. Biochemistry of the filamentous fungi. Tohoku Journal of Agricultural Research 5, 281e283. Jewell, R.A., Reimer, J.A., 2007. Method for producing cellulose fibre having improved biostability and the resulting products. U.S Patent 7,244,338. Jimenez, L., Martinez, C., Perez, I., Lopez, F., 1997. Biobleaching procedures for pulp from agricultural residues using Phanerochaete chrysosporium and enzymes. Process Biochemistry 32, 297e304. Martinez-Inogi, M.J., Gutierrez, A., del Rio, J.C., Martinez, M.J., Martinez, A.T., 2001. Time course of fungal removal of lipophilic extractives from Eucalyptus globulus wood. Journal of Biotechnology 84, 119e126. Matthew, G.M., Sukumaran, R.K., Singhania, R.R., Pandy, A., 2008. Progress in research on fungal cellulases for lignocellulose
R. J. Jerusik
degradation. Journal of Scientific and Industrial Research 67, 898e907. Meng, M., 1998. Fibre Storage in Beverage Cartons a Study of Fibre Deterioration During Storage. Proceedings, 1998 Tappi Recycling Conference. Tappi. Press, Atlanta, Ga, pp. 97e115. Murtoniemi, T., Nevalainen, A., Hirvonen, M.R., 2003. Effect of plasterboard composition on Stachybotrys chartarum growth and biological activity of spores. Applied and Environmental Microbiology 69, 3751e3757. Nyuksha, Y.P., 1969. Effect of fungi on paper. Mikologiyai Fitopaptologiya 3, 463e470. Rodriguez, A., Battle, R., Nerin, C., 2007. The use of natural essential oils as antimicrobial solutions in paper packaging. Progress in Organic Coatings 60, 33e38. Rothe, W., 1950. New antibiotic. Pharmazie 5, 190. Samejima, M., Kiyohiko, I., 2004. Recent advances of research on fungal system of cellulose degradation and related enzymes. Journal of the Japan Wood Research Society 50, 359e367. Sandal, T., Kofod, L.V., Kauppinen, M.S., Andersen, L.N., 1997. An enzyme with xylanase activity. Patent WO/1997/027293. Serano, M., Martinez-Romero, D., Guillen, F., Castillo, J.M., Valero, D., 2005. Active packaging development to improve ‘starking’ sweet cherry postharvest quality. Acta Horticulturae 682, 1675e1682. Shukla, O.P., Rai, U.N., Subramanyam, S.V., 2004. Biopulping and biobleaching: an energy and environmental saving technology for Indian pulp and paper industry. Vol. 10 No. 2 (Reproduced from the archives if Enviro News ISEB of India). Stoessl, A., 1969. Metabolites of Alternaria solani. Canadian Journal of Chemistry 47, 767e776. Suurnakki, A., Tenkanen, M., Buchert, J., Viikari, L., 1997. Hemicellulases in the bleaching of chemical pulps. Advances in Biochemical Engineering Biotechnology 57, 261e287. Szczepanowska, H., Lovett, C.M., 1992. A study of the removal and prevention of fungal stains on paper. Journal of the American Institute for Conservation 31, 147e160. Van Horn, W., Shema, B.F., 1957. Sheets comprising filaments of fungi. U.S. Patent 2,811,442. Wolf, F.A., Wolf, F.T., 1947. The Fungi, vol. 2. John Wiley and Sons. 83e86, 96e164. Yamanak, S., Kikuchi, R., Ajinomoto, K.K., 1992. Manufacture of reinforced fibres with fungi. Japanese patent 04112794. Zaprometova, K.M., Mirchink, G., Orolov, D.S., Yukhnin, 1971. Characteristics of black pigments of the dark-coloured soil fungi. Pochvovedenie 7, 22e30.