Pulping Characterictics of Blue Stain Fungi and Fungicide Treated Woods

Nam-Seok Cho1*·Yoo-Su SHIN2 and Soo-Jeong SHIN1

1 Wood and Paper Science, School of Forest Resources, Chungbuk National University, Cheongju Korea

2 National Institute of Crop Science, Rural Development Agency, Suwon, 441-857, Korea

INTRODUCTIONBlue stain fungi can cause extensive

economic losses due to wood discolorations that lower wood quality for lumber and paper production. Over past decades, research emphasis has focused on methods to eliminate blue stain fungi by managing pulpwood logs and chips, by chemical applications, or by biological control strategies.

Recent investigations have shown that despite the detrimental effects of blue stain fungi to wood, the fungi also have beneficial attributes that can be useful to the pulp and paper industry.

Blue stain fungi grow mainly in the ray parenchyma cells, resin canals, tracheids and fiber cells. They penetrate simple and bordered pits and form occasionally bore holes through wood cell walls. The fungi are not capable of degrading cellulose or lignin significantly, but metabolise resin extractives, starch, and simple sugars.

Blue stained woods

Pinus densiflora Pinus rigida

INTRODUCTION (Continued)A perspective and promising direction is development of the biocontrol, and resin degradative agents from the very blue stain fungi of Ophiostoma genus. The original fungal inoculum described for resin degradation, Cartapip 97, currently marketed by AgroSol, has been made by classical mating of isolated ascospores from various Ophiostoma piliferum isolates of the United States. This study was performed to evaluate the changes in wood extractives, mainly acetone extracts, in pine woods (Pinus densiflora and Pinus rigida) treated by three blue stain fungi (BSF) such as native BSF in Korea, Leptographium sp., screened Albino strain(BSFcs-1) and commercial Cartapip and fungicide, Wood guard. In addition their pulping and bleaching properties were investigated.

EXPERIMENTALSCHIP INOCULATIONPine chips (Pinus densiflora and Pinus rigida) were cutted at the Universty Forests of Chungbuk Nat’l Univ. and two-week after chipped. The chips were frozen in a –200 liter freezer to prevent background microbial growth. Samples of 1 kg (wet weight) were placed in plastic bags and inoculated with blue staining fungi including marketed CARTAPIP 58. Wood chips were not sterilized, and incubated at ambient temperature for two weeks.

Pinus densiflora Pinus rigida

EXPERIMENTALS (continued)CHEMICAL ANALYSIS

The chemical components, extractives of cold-water, hot-water, 1% NaOH and acetone, ash, lignin, pentosan, and holocellulose were analyzed with KS Standard Methods.

COMPOSITION OF ACETONE EXTRACTIVESComponents of acetone extractives, triglycerides, free fatt

y acids & sterols, resin acids, sterol esters, are dissolved in tetrahydrofurane and analyzed by HPLC(Hewlett packard HP 3396, Waters R401) with vanillin as an internal standard.Columns were used Ultrastyragel column (Milipore Co., 300x7.8mm, pore size 50-100 nm) and Shodex GPC KF-800P precolumn(Milipore Co.). Calibration curve was made based on standard samples, triolein, oleic acid, cholestrol, cholestryl palmitate, and abietic acid.

EXPERIMENTALS (continued)

PULP YIELD AND REJECTS Pulp yields and rejects were determined

by gravimetric method.

PULPING Chips were pulped by Soda and Kraft cooking method

s. Soda cooking : Active alkali – 18, 20, 22% Temperature - 170°C Wood to liquor ratio – 1 : 6Kraft cooking : Active alkali – 18, 20, 22% Sulfidity - 25% Temperature - 170°C Wood to liquor ratio – 1 : 6BLEACHING

Chemical – Na(OCl) 1.5% Pulp consistency – 10%, Temperature – 45 °C, Time - 3 hr, Initial pH – 9

Chemical compositions of sound woods

Chemical components

Contents, %

P. densiflora P. rigida

Extractives Cold Water Hot Water 1% NaOH Acetone Ash Lignin Pentosan Holocellulose

1.653.2813.84.510.3827.815.573.7

2.053.8514.85.440.4129.016.772.5

RESULTS & DISCUSSION

Total acetone extractives of blue-stained woods

0

1

2

3

4

5

6

Fresh Seasoned Stained BSFcs-1 Cartapip

Ace

ton

e ex

trac

tive

s, %

Red pinePitch pine

COMPOSITION OF ACETONE EXTRACTIVES

Contents in acetone extracts, %

Fatty acids

& Sterols

Triglycerides

Resin acids

Sterol ester

sOthers

Fresh woodAged 3 weeksBS fungi Albino,BSFcs-1 Cartapip

1.070.950.630.630.63

0.960.870.580.590.59

0.820.730.510.490.48

-----

1.711.761.881.851.77

Resin acids

0

10

20

30

40

50

Fresh Seasoned Stained BSFcs-1 Cartapip

Los

s, %

Triglycerides

0

10

20

30

40

50

Fresh Seasoned Stained BSFcs-1 Cartapip

Los

s, %

Fatty acids & Sterols

0

10

20

30

40

50

Fresh Seasoned Stained BSFcs-1 Cartapip

Los

s, %

LOSS OF ACETONE EXTRACTIVES IN RED PINE

Fatty acids & Sterols

Resin acids Triglycerides

Resin acids

0

10

20

30

40

50

Fresh Seasoned Stained BSFcs-1 Cartapip

Los

s, %

Triglycerides

0

10

20

30

40

50

Fresh Seasoned Stained BSFcs-1 Cartapip

Los

s, %

Fatty acids & Sterols

0

10

20

30

40

50

Fresh Seasoned Stained BSFcs-1 Cartapip

Los

s, %

LOSS OF ACETONE EXTRACTIVES IN PITCH PINE

Fatty acids & Sterols

Triglycerides Resin acids

The effect of active alkali on soda pulping of Red Pine

L/I

Active alkali, %

18 20 22

Pulp yields Pulp yields Pulp yields

Fresh chip

Seasoned (3 weeks)

Stained

Albino, BSFcs-1

Cartapip

42.8 %

41.5

41.7

41.0

41.8

44.9 %

44.5

43.6

43.2

43.3

42.2 %

41.9

40.9

41.1

41.5

Effect of active alkali on screened rejects of red pine soda pulp

The effect of active alkali on soda pulping of Pitch Pine

L/I

Active alkali, %

18 20 22

Pulp yields Pulp yields Pulp yields

Fresh chip

Seasoned (3 weeks)

Stained

Albino, BSFcs-1

Cartapip

42.9%

42.5

42.6

41.7

41.8

43.7%

44.0

42.9

42.7

43.0

42.0%

42.1

41.9

41.7

41.6

Effect of active alkali on screened rejects of pitch pine soda pulp

The effect of active alkali on kraft pulping of Red Pine

L/I

Active alkali, %

18 20 22

Pulp yields Pulp yields Pulp yields

Fresh chip

Seasoned (3 weeks)

Stained

Albino, BSFcs-1

Cartapip

43.0%

42.8

43.7

44.0

44.9

47.8%

46.6

45.5

44.8

45.1

43.6%

43.7

43.5

43.9

44.0

Effect of active alkali on screened rejects of red pine kraft pulp

The effect of active alkali on kraft pulping of Pitch Pine

L/I

Active alkali, %

18 20 22

Pulp yields Pulp yields Pulp yields

Fresh chip

Seasoned (3 weeks)

Stained

Albino, BSFcs-1

Cartapip

42.0%

41.5

40.7

41.2

41.8

46.9%

45.7

43.5

43.9

43.8

45.6%

43.1

42.8

42.2

43.5

Effect of active alkali on screened rejects of pitch pine kraft pulp

CONCLUSIONSThe woods employed, red pine and

pitch pine, showed rather different resin contents in the untreated woods. The red pine wood contained 4.51% resin, whereas the pitch pine contained 5.44%. In both cases, about 20% of resin was removed during 3 week natural aging. By incubation with blue staining fungi, 25.1-30.4% of resin in red pine and 22.9-28.1% of resin in pitch pine were removed.

Concentrations for fatty acids and sterols were lower by the aging treatment and blue-stained wood chips, 10.6-11.2% removal by 3 week aging and 36 -41.1% removal by blue-staining fungi. Triglycerides were decreased by 5.68-9.4% with aging and by 38.5-40.0% with blue-staining. Resin acids also were removed by 6.1-11.3% with aging and by 36-41.5% with blue-staining.

CONCLUSIONS (continued) BSF treatment has significantly reduced acetone extracts, 25.1-30.4% decreasing in red pine and 22.9-28.1% in pitch pine. Three week aging treatment showed about 20% decreasing in red pine and 19.3% in pitch pine. There were not so significant differences in acetone extracts among native BSF and Albino-type strains (Albino strain, BSFcs-1, and commercial Cartapip). But fungicide, Wood guard, treated wood showed relatively lower decreasing rates of extractives, 14% in red pine and 10.1% in pitch pine.  Therefore it is understandable that the fungicide could protect the wood from blue stain fungi attack, but has no effect on its extractive reduction.

CONCLUSIONS (continued)

  Concerned to pulping properties of BSF and fungicide treated woods, red pine and pitch pine,

optimum pulping conditions were 20% active alkali, wood to liquor ratio 1 to 6, 170 , and 2.5 hr.  In t℃he case of BSF-treated woods, 43.5-45% of pulp yields and 1.3-1.45% of rejects.

Concerned to the pulping of blue-stained woods, both wood species were shown 2 - 3% higher pulp yields in kraft pulping than that of the alkali pulping method.Screened pulp yield of fungicide treated wood was lower than those of BSF-treated woods.  Rejects in pulps were higher in fungicide-treated woods than BSF treated woods. 

Bleached pulp yields were ranged of 92 to 93.5%.  BSF, Cartapip and fungicide treated woods resulted in lower brightness of 55-58%, but Albino-type strain(BSFcs-1) 61.3-62.3%, very similar to untreated one. Therefore bleaching chemicals could be saved in the processing of chemical pulping. 

CONCLUSIONS

Screened Albino type staining fungus is very much promising in terms of active growth, lowering extractives in chips and comparable pulp yields.

Conclusions

These cultures could be applied as promising agents for decolourization of stained wood chips as well as biobleaching application in pulping and papermaking industry.

In addition, successful basidial fungi application for stain protection of wood and pulp industry depends on progress of our knowledge on the biology and ecology of wood-inhabiting fungi.

Thanks for your kind attention

ACKNOWLEDGEMENTSThis work was carried out with the support

of KOSEF Grant (R01-2001-000519).