Optimization of cellulase production by submerged fermentation of rice straw by Trichoderma harzianum Rut-C 8230

Author Information

GS Kocher, Ph.D.
Department of Microbiology, Punjab Agricultural University

KL Kalra, Ph.D.
Department of Microbiology, Punjab Agricultural University

G. Banta, Ph.D.
Department of Microbiology, Punjab Agricultural University

Abstract

The cellulase production by Trichoderma harzianum MTCC 8230 was studied using rice straw as substrate that supported better cellulase production than carboxymethyl cellulose (CMC). The optimum conditions for cellulase production were (NH4)2SO4, 0.5 g L-1 as nitrogen source, pH (5.0), temperature (28°C) and incoulum size (108 spores ml-1). Tween 80 (0.1%) improved the overall cellulase production as under these optimized conditions, C1, Cx and CB activities of 0.127, 0.15 and 1.65 U ml-1 respectively were produced. The enzyme was concentrated 2.65 folds with a yield of 73.8% using ammonium suplhate precipitation followed by dialysis. 

Introduction

The research on application of lignocellulosics for bioethanol production is catching up very fast to meet its increasing demand for the production. Paddy or rice straw is one such lignocellulosic material that is produced abundantly as a byproduct of rice crop with an annual worldwide production of 800 MT (Wati et al, 2007). So much so that rice straw is burnt in fields which leads to severe environmental constraints. As rice straw contains bound sugars in the form of cellulose and hemicellulose meshed with lignin, it needs to be promoted as a fermentation raw material for bioethanol production. The utilization of rice straw for the purpose passes through 3 major steps- physicochemical pretreatment, cellulase saccharification and glucose fermentation to ethanol with the first 2 steps constituting major inputs (Ward, 2002; Juhasz et al, 2004). 

Cellulase is an inducable enzyme complex involving synergistic action of endoglucanase (Cx), exoglucanase (C1) and Cellobiase (CB). It is produced by a number of bacteria and fungi though species of Trichoderma and Aspergillus are most reported (Zaldivar et al, 2001). However, the high cost of cellulase production (due to use of pure chemicals in production) coupled with low enzyme activities limits its industrial use. Therefore, efforts are needed to economize cellulase production by media optimization and use of supplements/ additives. In literature, many agricultural substrates like straw, bran, bagasse etc. have been reported (Griffin et al, 1974, Deumas et al, 1995, Pei-jun et al, 2004). In addition, research is being carried out on isolation of potential cellulase producing microorganisms from diverse habitats (Ray et al, 2007). 

The present study reports optimization of cellulase production by an isolate from soil, identified as Trichoderma harzianum MTCC 8230 from MTCC laboratory, Institute of Microbial Technology, Chandigarh, India, while using acid pretreated rice straw as substrate. 

Materials and methods

Inoculum preparation and Enzyme production: Spores of Trichoderma harzianum MTCC 8230 maintained on CMC agar slants were suspended in CMC broth containing g L -1 of {Carboxymethyl cellulose (CMC) -1.1, Yeast extract 0.1, (NH4)2SO4-0.5, KH2PO4-10.0, MgSO4.7H2O-0.1, NaCl-0.2, pH-5.0} and incubated on orbital shaker at 28±2°C for 3 days and used to inoculate enzyme production media for submerged fermentation. For enzyme production, erlenmeyer flasks containing 100 ml of basal synthetic medium containing g L -1 of {(NH4)2SO4, 0.5; KH2PO4, 10; K2HPO4, 5; MgSO4, 0.1; NaCl, 0.2; Yeast Extract, 0.1 with 1 g pretreated rice straw (Pretreatment carried out with 1.0% H2SO4 followed by authoclaving at 15 psi for 90 min) or 1 g CMC} were inoculated with 10 6 spores ml -1prepared inoculum were incubated at 28±2°C on orbital shaker (150 rpm) for 10 days. The mycelium free extract was used as crude cellulase preparation and used for estimating enzyme activities. 

Optimization of cellulase production: The cellulase production by T.harzianum was optimized for incubation time (up to 10 days), temperature (20-37°C with an interval of 5°C), pH (4.0-8.0 with an interval of 0.5), inoculum size (10 6 -10 8 spores ml -1 ), nitrogen sources {(NH4)2SO4, peptone, soybean meal, rice bran and NaNO3) and supplementation of Tween 80 (0.0.5 – 0.3%, v/v)}. For studying the effect of N sources, 0.5 g 100ml -1 of different nitrogen sources were sterilized separately and added aseptically before fermentation. Samples were drawn aspetically at different periods of time during fermentation and spun at 8000 rpm, 10 min for removing mycelium. The supernatant was used as crude enzyme filtrate for estimation of filter paper activity (C1) and carboxymethylcellulase activity (Cx) by the method of Mandel et al (1976), while cellobiase (CB) activity was assayed by the method of Srivastva et al (1987). One enzyme unit (IU) was defined as the amount of cellulase which is capable of producing one micromole (µM) of reducing sugars in one minute. Protein was estimated by the traditional Folin phenol reagent method.

Partial purification of cellulase: The crude cellulase (1150 ml) was partially purified by saturated ammonium sulphate precipitation (0-80%). The precipitates were dissolved in 50 ml of Tris buffer (pH 6.0) followed by its dialysis against the same buffer at 4°C.

Results and Discussion

The profile of cellulase production at different time intervals revealed that rice straw induced C1, Cx and CB activities of 0.09, 0.12 and 1.12 IU ml -1 respectively by T.harzianum 8230 at 8 days of incubation (Table 1). These activities were higher as compared to Trichoderma reesei QM 9414 taken as control as well as cellulase producing medium supplemented with CMC as carbon source. Therefore, further experiments were conducted to optimize the cellulase production by T.harzianum by using pretreated rice straw as sole carbon source in the cellulase production medium. Use of different inorganic and organic nitrogen sources revealed (NH4)2SO4 as the best nitrogen source (Table 2). Both the Cx and C1 activities were higher than other nitrogen sources, CB activity was lowest with (NH4)2SO4 among the five nitrogen sources tested. However, (NH4)2SO4 with higher C1 and Cx activities was chosen to further optimize the cellulase production for temperature, pH, inoculum size and the supplementation of Tween 80. Gashel (1992) also reported higher cellulase production with KNO3 than NH4Cl and urea. Pei-Jun et al (2004) on the other hand, reported combination of (NH4)2SO4 and wheat bran for optimum cellulase production by T.koningii.

Figure 1

Table 1: Effect of incubation period on cellulase production (IUml ) in MTCC 8230.

The incubation conditions were Inoculum Concentration- 10 6 spores ml -1 , pH - 6.5,Temperature-28±2 o C

Figure 2

Table 2: Effect of supplementation of different nitrogen sources on cellulase production by

Among the 4 pH levels tested, a pH of 5.0 was optimum after 8 days of incubation though activities at pH of 6.0 were comparable with those of pH 5.0 (Table 3). pH, temperature, aeration, growth period and additives have been reported to be important parameters in optimizing cellulase production (Immanuel et al, 2006). Among these, pH is of major interest (Juhasz et al, 2004) as they reported a high CB production in buffered medium while C1 and Cx activities were more in non buffered medium. Zaldivar et al (2001) observed that cellulase production by T.aureoviridae is best if pH doesn't fall below 3.5. Pei-Jun et al (2004) reported a pH of 6.5 for optimum cellulase production by T.koningii. Among the 4 temperature levels tested, 30°C was the optimum temperature with C1, Cx and CB activities of 0.096, 0.104 and 1.27 U ml -1 at 8, 8 and 6 days of incubation respectively (Table 3). The C1 activity was most affected by temperature as at temperatures of 20 and 37°C, it was drastically reduced while C1 and Cx activities didn't show much variation at the 5 temperatures tested. Zaldivar et al (2001) reported a temperature of 28°C by T.aureoviridae while Pei-Jun et al (2004) used two temperature zones of 32°C (first 30 h) and 27°C thereafter for cellulase production by T.koningii.

Three inoculum sizes were tested and it was found that a higher initial inoculum of 10 8spores ml -1 significantly increased cellulase activities as optimum C1, and Cx activities of 0.103 and 0.121 respectively after 8 days of incubation and CB activity of 1.687 U ml -1 after 6 days of incubation were reported (Table 3). While Zaldivar et al (2001) reported optimum cellulase production with 5 X 10 6 spores ml -1 of T.aureoviridae, a 2% (v/v) spore suspension of T.koningii was used by Pei-jun et al (2004). Ray et al (2007) optimized 3% (v/v) inoculum of Bacillus circulans TP3 for optimum cellulase production.

Detergents like Tween 80, SDS etc. have been reported to enhance cellulase activities by increasing availability of nutrients (El-Hawary and Mostafa ,2001). Among the 4 concentratiosn of Tween 80 used in this study, a concentration of 0.10% (v/v) was found to enhance the C1 and Cx activities to 0.127 and 0.15 respectively while CB activity (1.65 U ml -1 ) was not affected

Figure 3

Table 3: Effect of fermentation conditions on glucoamylase production by MTCC 8230.

(Table 3). While Goshel (1992) and El- Hawary and Mostafa (2001) reported increase in cellulase activities with Tween 80, Pei-jun et al (2004) reported negative effect of Tween 80 on cellulase activities. The optimized cellulase activities if converted to per g of paddy straw, came out to be 12.7, 15.0 and 165 IU of C1, Cx and CB activities, respectively.) In literature, a number of agricultural materials have been used for cellulase production. Gashel (1992) reported wheat straw, Liming and Xueling (2004) used corn cobs and Pei-jun et al (2004) used rice straw for cellulase production by Trichoderma sp. A001, T. reeseiand T.koningii respectively. The CB activity of this strain was unusually high while Cx activity was comparatively low. Earlier, Khan et al (2007) reported C1 and Cx activities of 1.43 and 2.4 U ml -1 using rice straw by Phanerochaete chrysosporum under SSF. Wen et al (2005) reported C1, Cx and CB activities of 1.74, 12.22 and 0.0978 IU ml -1 by Trichoderma reesei using dairy manure as substrate.

The cellulase complex of T.harzianum 8230 was concentrated by SAS precipitation followed by dialysis from 1150 ml to 50 ml with a C1 activity of 3.89 U ml -1 (Table 4). Elsewhere, commercial enzymes with a C1 activity of around 30 U ml -1 have been reported to be used at a concentration of 0.5 to 2%, v/v (Wati et al, 2007).The specific activity was 1.88 U mg -1 of protein and total purification was 2.65 folds with a yield of 73.8% of activity. Though the C1 activity of our cellulase is around 10 times less than commercial cellulase, it can be used in its crude form (salt precipitated) at higher ratios. This cellulase has the potential and can thus be used to saccharify pretreated rice straw for bioethanol production. The work in this regard is in progress in our laboratory. 

Figure 4

Table 4: Partial purification of the cellulase of

Acknowledgements

Authors are grateful to Indian Council of Agricultural Research for the financial assistance provided during the project. 

References

r-0. Das, M., R. Banerjee and S. Bal (2008) Multivariate parameter optimization for the endoglucanase production by Trichoderma reesei RUT C30 from Ocimum gratissium seed. Braz. Arch. Biol. Technol. 51: 35-41.
r-1. Deumas, R., R.P. Tengerdy and M. Qutierrez-Correa (1995) Cellulase production by mixed fungi in solid substrate fermentation of bagasse. World J. Microbiol. Biotechnol. 11: 333-337.
r-2. El-Hawary, F.I and Y.S. Mostaka (2001) Factors affecting cellulase production by Trichoderma koningii. Acta Alimentaria 30: 3-13.
r-3. Gashel, B.A (1992) Cellulase production and activity by Trichoderma sp. A-001. J. Appl. Microbiol. 73: 79-82.
r-4. Griffin, H.L., J.H. Sloneker and G.E. Inglett (1974) Cellulase production by Trichoderma viridae on Feedlot waste. Appl. Microbiol. 27: 1061-1066.
r-5. Immanuel, G., R. Dhanusha, P. Prema, A. Palavesam (2006) Effect of different growth parameters on endoglucanase enzyme activity by bacteria isolated from coir retting effluents of estuarine environment. International J. Environ. Sci. Technol. 3: 25-34.
r-6. Juhasz, T., Z. Szengyel, N. Szijarto and K. Reczey (2004) Effect of pH on cellulase production of Trichoderma reesei RUT C30. Biotechnolgy 113: 201-212.
r-7. Khan, M.H., S. Ali, A. Fakhru'l-Razi and Z. Alam (2007) Use of fungi for the bioconversion of rice straw into cellulase complex. J. Environ. Sci. Health 42: 381-388.
r-8. Liming, X. and S. Xueliang (2004) High yield cellulase production by Trichoderma reesei ZU-02 on corn cob residue. Bioresource Tech. 91: 259-262.
r-9. Mandel, M., R. Andreotti and C. Roche (1976) Measurement of saccharifying cellulase. Biotechnol. Bioeng. Symp. 6: 21-23.
r-10. Pei-Jun, L.I., J. De-bing, Z. Qi-xing and Z. Chun-gui (2004) Optimization of solid fermentation of cellulase from Trichoderma koningii. J. Envion. Sci. 6: 816-820.
r-11. Ray, A.K., A. Bairagi, K.S. Ghosh and S.K. Sen (2007) Optimization of fermentation conditions for cellulase production by Bacillus subtilis CY5 and Bacillus circulans TP3 isolated from fish gut. Acat. Icht. et Pist. 37: 47-53.
r-12. Srivastva, S.K., S.K. Gopalakrishnana and K.B. Ramachandran (1987) The production of β-glucosidase in shake flask by Aspergillus wentii. J. Ferment. Technol. 65: 95-99.
r-13. Wen, Z., W. Liao and S. Chen (2005) Production of cellulase by Trichoderma reesei from dairy manure. Bioresource Technol. 96: 491-499.
r-14. Wati, L., S. Kumari and B.S. Kundu (2007) Paddy straw as substrate for ethanol production. Ind. J. Microbiol. 46: 26-29.
r-15. Ward, O.P. (2002) Bioethanol technology development and perspective. Adv. Appl. Microbiol. 51: 53-80.
r-16. Zaldivar, M., J.C. Velasquez, I. Contreras and L.M. Perez (2001). Trichoderma aureoviridae 7-121, a mutant with enhanced production of lytic enzymes: its potential use in waste cellulose degradation and/or biocontrol. EJB Electronic J. Biotechnology ISSN:0717-3458, 4, 10 pages.

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Production of extra cellular lipase from Bacillus sp LBN 4 by solid state fermentation

Author Information

Limpon Bora
Centre for Studies in Biotechnology, Dibrugarh University

MC. Kalita
Department of Biotechnology, Gauhati University

Abstract

Bacillus sp LBN4 produced lipase during solid substrate fermentation. Maximum lipase production was 14.0IUg-1 with rice bran as sold substrate. 50% more lipase production was achieved when rice bran was supplemented with soyabean mixture. Supplementation of the medium with wheat bran led to 70% increase in lipase production. Optimum temperature and pH were 500C and 7.0 respectively. Na+ induced more lipase than K+ and Mg++ 

Introduction

Lipases are hydrolytic enzymes that catalyses the cleavage of ester bonds in triglycerides and producing glycerol and free fatty acids. These are biotechnologically relevant enzymes and find potential applications in detergent, food, pharmaceutical, leather, paper and pulp industries1. However for commercial applications development of low cost processes and production of lipases using simple and inexpensive substrates such as agro industrial residues are more favorable. Solid state fermentation is an low cost alternative and involves the growth and metabolism of microorganisms on moist solids without free flowing water. Solid state fermentation (SSF) has many advantages over submerged fermentation (SmF) including simplification of the fermentation media, low capital investment, absence of complex machinery, reduced energy requirement and improved product recovery (Losane et al 1983; Satyanarayana 1994). Major group of microorganisms used in Solid state fermentation are bacteria, actinomycetes, fungi and yeast. The vast majority of literature on Solid state fermentation refers to the fungi and yeast using different solid substrates ( Pandey et al 1999; Rao et al 1993; Falony et al 2006; Kamini et al 1997) The exploitation of new microorganisms capable to produce lipase in Solid state fermentation conditions would be useful for industrial applications in the near future. A strain of Bacillus Sp LBN 4 was taken from stock repository which was originally isolated from the alkaline soil of hot spring of Arunachal Pradesh was investigated for production of extra cellular lipase by solid state fermentation using rice bran as a solid substrate.

Solid state fermentation was carried out in 250ml conical flasks. 10 g of rice bran was mixed with mineral salt medium and final moisture ratio of 1:2 w/v was achieved. The pH of the mixture was adjusted to 7.0 in sodium phosphate buffer. The above mixture was autoclaved at 1210C for 20min, cooled to room temperature and inoculated with 10% of 12h grown seed culture of Bacillus sp and incubated at 400C for different time intervals (12, 24, 36,48h). Enzyme extraction was carried out by adding 10 ml of 0.2M phosphate buffer having pH 7.0 to each flask and agitating in the orbital shaker at 200rpm for 1h. The particulate matter was filtered through a muslin cloth and centrifuged at 10,000rpm for 30 minutes. The clear supernatant was used for lipase assay.

In another experiment, effects of various cheap substrates like soyabean oil, soybean meal, Wheat bran and coconut oil was studied by adding each of the substrate in the rice bran mixture and the lipase activity was determined accordingly.

Lipase activity was determined by (Watnabe et al method 1977). The reaction mixture containing 5ml of olive oil emulsion composed of 25 ml olive oil and 75 ml 2% polyvinyl alcohol solution, 4ml of 0.2M tris buffer, 1ml of 110mM CaCl2 and 1ml enzyme solution. The control containing boiled inactivated enzyme (at 1000C for 5 minutes) was treated similarly. After the incubation, the enzyme activity was blocked by 20 ml of acetone ethanol (1: 1) mixture and liberated free fatty acid was titrated against 0.02 M NaoH using phenolphthalein as indicator. One unit of lipase was defined as the amount of enzyme, which liberates 1 m mol of fatty acid/ min under standard assay conditions. The enzyme activity was expressed as Ug-1 dry substrate.

The effect of pH on lipase production was studied in a pH range of 5- 10.0 using different buffers ( citrate buffer 3-6, sodium phosphate, 6-7, Tris HCL pH8.0 and glycine NaOH 9-10.0) at 50mM concentration. Temperature effect on lipase production was determined by carrying out the incubation at different temperatures in the range of 30-800C at pH 7.0. The effects of metal ions were also studied.

The maximum lipase yield from Bacillus sp LBN 4 with rice bran as a substrate was found to be (14.0IUg-1 wet weight) obtained after 36 hours of incubation. The enzyme activity was found to be decreasing on further incubation. The addition of soybean oil results in the marginal increase in the lipase yield (10%) whereas soybean mixture enhanced maximum (50%) of the lipase activity when used as a substrate. The increase in lipase production may be due to the presence of additional factors like nitrogen and oil compounds which acts as stimulating factors in the medium. The addition of wheat bran increased the yield upto 70% whereas marginal increase was obtained with coconut oil (20%). Sekhon et al 10 reported 42% of increase in the lipase yield from Bacillus megaterium AKG 1 using wheat bran as a soild substrate. 17% increase in the lipase yield has been reported in Candida rugosa grown on rice bran as soild substrate ( Rao et al 1993). Increased lipase production from alkalophilic yeast was observed when Rice bran and wheat bran were used as substrate (Bhushan et al 1994) 4.8 IU/ml of lipase activity was found in Aspergillus niger when wheat bran was used as substrate ( Faloni et al 2006) . Babassu oil cake was used for lipase production by Penicillium restrictum (Gombart et al 1999) whereas wheat rawa supplemented with corn steep liquor and olive oil was studied by (Adinarayana et al 2004).

Figure 1

Table 1: Effect of different substrates on lipase production by Bacillus sp in solid state fermentation

In most of the earlier reports the lipase production was reported after prolonged fermentation period (72-192h) whereas in our study the maximum lipase yield was observed after 36h, (Sekhon et al 2004) reported maximum lipase production after 48h..

Lipase from Bacillus sp showed optimal activity at 500 C. The optimum temperature for lipase production corresponds with the given temperature of the respective microorganism. The best temperature for growth of lipase production in case of Bacillus sp RSJ1 was found to be 500C 

(Sharma et al 2002) . Similar results were also observed in Bacillus sp (Khayami H 1996).

Figure 2

Fig 1: Effect of incubation temperature on lipase production

The optimum lipase activity was observed at pH 7.0. The activity was found to be decreasing on increasing the pH values. The initial pH of the growth medium was important for lipase production. The pH in and around 7.0 was found to be preferable for bacteria for better growth and lipase production. Similar results have been reported for other Bacillus lipases (Sugihara et al 1991). 

Figure 3

Fig 2Effect of pH on lipase production.

Divalent cation plays an important role in enzyme production. Earlier reports suggested that K+ and Mg++ are essential for lipase production. To study the effect of metal ions KCl, NaCl and MgCl2 at a concentration of 0.5, 1 and 1.5% (w/v) were added to the medium and incubated. Optimum concentration was found to be 1% in all three cases. The best lipase production was achieved with Na+ followed by K+ and Mg++. Similar results of lipase stimulation have been has been reported ( Van ort et al 1989) .

Figure 4

Fig 3: Effect of Metal ions on lipase production

References

1. Adinarayana, K., Raju, BKVVSN., Zargar, ML., Devi, RB., Lakshmi, PJ., and Elliah P (2004)
Optimization of process parameters for production of lipase in solid state fermentation by
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2. Bhushan, B., Dosanjh, NS., Kumar, K., and Hoondal, GS (1994) Lipase production from an
alkalophilic yeast by solid state fermentation. Biotechnol Lett., 16, 841-842
3. Falony, G., Armas, CJ., Mendoza, DCJ., and Hernandez, M.L.J. (2006) Production of 
Extracelllular lipase From Aspergillus niger by solid state fermentation. Food Technol 
Biotechnol., 44(2), 235- 240.
4. Ghosh, PK., Saxena, RK., Gupta, R., Yadav, RP., and Davidson, W. ( 1996) Microbial lipases: productions and applications Sci Prog 79, 119-157.
5. Gombert, AK., Pinto, AL., Castillo, LR., and Friere, D.M.G. (1999) Lipase production by
Penicillium restrictum in solid state fermentation using babassu oil cake as substrate
Process Biochem., 35, 85-89.
6. Kamini, NR., Mala, JGS., and Pravana, K.R. (1997) Production and characterization of 
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7. Khyami horani, H. ( 1996) Thermotolerant strain of Bacillus licheniformis producing lipase.
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aspects of solid state fermentation, Enzyme Microbial Technol., 7, 258-265.
9. Pandey, A., Benjamin, S., Soccol, CR., Nigam, P, Krieger, N., and Soccol VT ( 1999) The realm of microbial lipases in Biotechnology. Biotechnol Appl Biochem., 29, 119-131.
10. Pandey, A., Selvakumar, P., Soccol, CR., and Nigam P (1999) Solid state fermentation for production of Industrial enzymes. Curr Sci .,49, 51-61.
11. Sekhon, A., Dahia, N., Tewari, RP., and Hoondal, G.S. (2004) Production of lipase from
Bacillus megaterium AKG-1 using wheat bran in soild substrate fermentation Indian J 
Microbiol., 44 3, 219-220.
12. Sharma, R., Soni, SK., Vohra, RM., Jooly, RS., Gupta, JK., and Gupta L.K. (2002b). Production of
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thermostable lipase from Bacillus sp. J. Biochem., 109, 211-216.
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15. T, Satnayarayana. ( 1994) Production of extracellular enzymes by solid state fermentation. 
In : solid state fermentation, A pandey (Ed)., wiley Eastern limited., New delhi., India pp 
122- 129.
16. Van, Oort., MG., Deever ,AMJJ., Dijkman, R., Tjeenk, ML., Veerhej, HM., DeeHass ,GH.,
Wenzing, E., and Gotz ,F ( 1989) purification of substrate specificity of staphylococcus hycius
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alkaline lipase producing micororganisms, cultural conditions and some properties of crude
enzymes. Agric. Biol. Chem., 41(8), 1353-1358.

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Thermo-hydro and thermo-hydro-mechanical wood processing: An opportunity for future environmentally friendly wood products

DOI:

10.1080/17480272.2012.751935

Dick Sandberg^a*, Peer Haller^b & Parviz Navi^c

pages 64-88

Publishing models and article dates explained

• Received: 30 May 2012
• Accepted: 15 Nov 2012
• Published online: 18 Dec 2012

Abstract

This state-of-the-art report presents the basic concepts of some of the thermo-hydro (TH) and thermo-hydro-mechanical (THM) wood processes that are in use today, i.e. heat treatment, compression of wood in the longitudinal or transverse direction and wood welding. The reasons for the growing interest in TH and THM techniques are discussed, and the development of the different concepts, from first ideas to current status, is briefly presented. The physical and chemical changes that occur in wood during TH and THM processing according to the latest research are also presented. Finally, developments that are close to or already have an industrial application are presented, and the challenges for further development of the heat treatment, compression and wood welding processes are discussed. The TH processing of wood is based entirely on water and heat, and a THM process incorporates an additional mechanical force. The purpose of wood transformation by a TH or a THM process is to improve the intrinsic wood properties, to acquire a form and functionality desired by engineers without changing its eco-friendly characteristics or hindering its further use in the total material life cycle. Only a few of the recently developed techniques, e.g. heat treatment, wood welding and various densification applications, have been industrialized to some extent. There are many reasons for this relatively low transfer of the research results to a full up-scaled industrial production. Some of them are related to unsolved problems at the laboratory level on small-sized samples and others are related to the scaling-up processes in industry. Furthermore, the ageing of heated wood leads to deterioration with time, in some cases there is an unpleasant odour, the strength of the wood decreases substantially and the wood becomes more brittle. These are new challenges which need to be resolved by the collaboration of researchers from the different scientific domains of academia, research institutes and industry.

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Challenges in wood modification technology on the way to practical applications

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DOI:

10.1080/17480270903275578

Holger Militz^a* & Stig Lande^b

pages 23-29

Publishing models and article dates explained

• Received: 21 Aug 2009
• Published online: 29 Oct 2009

Abstract

During the past decade, researchers worldwide have developed and investigated new treatment techniques to improve intrinsic wood properties. Because of environmental concerns, the pressure on the wood industry is higher than ever before to find alternatives to tropical hardwoods and preservative-treated wood. This is the reason why some new modification technologies, e.g. furfurylation, heat treatments, acetylation and resin treatments, have been introduced to the market. Researchers from universities and research institutes, the wood modification industry, wood producers and consumers face a lot of new challenges. The combination of several research areas, such as chemistry, biology and material technology, unknown and partly new material properties, new production technology, non-existent or inappropriate testing and analytical methods, changed aesthetic properties, etc., are just some of the many bottlenecks to overcome to introduce successfully a new technology to the market.

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Development of Modified Wood Products Based on Furan Chemistry

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DOI:

10.1080/15421400801901456

S. Lande^a*, M. Westin^b & M. Schneider^c

pages 1/[367]-12/[378]

Publishing models and article dates explained

• Published online: 22 Sep 2010
• 
  

Abstract

The first processes for “furfurylation” of wood (wood modification with furfuryl alcohol) were developed several decades ago. Furfuryl alcohol is a renewable chemical since it is derived from furfural, produced from hydrolysed biomass waste. Over the last decade modernised processes for furfurylation of wood have been developed. These new processes are based on completely new catalytic systems and process additives. The properties of furfurylated wood depend on the retention of grafted/polymerised furfuryl alcohol (PFA) in the wood. At high modification levels (high retention of PFA) the enhancement of a wide variety of properties are achieved: an exceptional hardness increase, exceptional resistance to microbial decay and insect attack, high resistance to chemical degradation, increase in MOR and MOE, and high dimensional stability. At lower modification levels many property enhancements also occur, however to slightly lower extent. Notable are resistance to microbial decay and insect attack, increase in MOR and MOE, and relatively high dimensional stability. Two main processes for production of furfurylated wood have been developed for Kebony ASA (Former Wood Polymer Technology ASA) by the authors. Kebony ^TM for hardwood modification and VisorWood ^TMfor soft wood modification, where the name reflects the colour of the material produced by the process. Commercial production according to the Kebony process has been running since October 2003, mainly for flooring. A small Kebony production plant is now in operation in Lithuania. A Kebony/VisorWood production plant was started during of 2003 in Porsgrunn, Norway. There are now planed for an expansion of this plant, and plans for a large Visorwood plant is ongoing. Further commercialisation of the technology will be done through licences issued by Kebony ASA.

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Properties of furfurylated wood

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DOI:

10.1080/0282758041001915

Stig Lande^ab, Mats Westin^c & Marc Schneider^d

pages 22-30

Publishing models and article dates explained

• Published online: 06 Oct 2011

Abstract

The first processes of wood modification with furfuryl alcohol (FA) (furfurylation) were developed several decades ago. FA is a renewable chemical, produced from hydrolysed biomass waste. Over the past decade modernized processes for furfurylation of wood have been developed. This study presents decay properties of furfurylated wood. Laboratory methods and field tests were performed on fungi, termite and marine borer attack. Tests on physical and mechanical properties are also presented. The properties of furfurylated wood depend on the retention of grafted/polymerized poly-FA in the wood. At high modification levels (high retention of poly-FA) the enhancement of a wide variety of properties is achieved: an exceptional increase in hardness, exceptional resistance to microbial decay and insect attack, increase in modulus of rupture (MOR) and modulus of elasticity, and high dimensional stability. At lower modification levels property enhancements also occur. Notable are resistance to microbial decay and insect attack, and relatively high dimensional stability.

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http://www.tandfonline.com/doi/abs/10.1080/0282758041001915?src=recsys

Chemistry and ecotoxicology of furfurylated wood

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DOI:

10.1080/02827580410017816

Stig Lande^ab, Morten Eikenes^b & Mats Westin^c

pages 14-21

Publishing models and article dates explained

• Published online: 06 Oct 2011

Abstract

Over the past decade modernized processes for furfurylation of wood have been developed. These new processes are based on completely new catalytic systems and process additives. These new systems do not add metals or halogens to the product, which is important for an environmentally acceptable product. However, little is known about the ecotoxicity of furfurylated wood or other environmental impacts that may result from the modification method. The study shows that concentrations of non-reacted furfuryl alcohol in the final products are low and do not contribute to any fungicidal effect. Environmental tests show no significant level of increased ecotoxicity, and degradation through combustion does not release any volatile organic compounds or polyaromatic hydrocarbons above normal levels for wood combustion. Hence, furfurylation of wood to enhance wood properties is not believed to be harmful to the environment.

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Caffeine & Neck Pain

A young woman sits at her desk with a cup of coffee, rubbing her neck. Photo Credit Wavebreakmedia Ltd/Lightwavemedia/Getty Images

Caffeine is one of the most popular psychoactive drugs in the word. The stimulant occurs naturally in coffee and tea and is added to energy drinks in generous amounts. Caffeine is also found in some over-the-counter pain medications. Caffeine is a mild analgesic, according to the Cleveland Clinic, and can improve drug absorption. While consuming caffeine has some unwanted side effects, it also has some beneficial properties, especially for pain relief.

Caffeine and Pain

Caffeine can help reduce muscle pain. In 2009, researchers from the department of kinesiology and community health at the University of Illinois found that consuming caffeine prior to a workout could lower pain levels and can help exercisers train harder and longer. This affect occurs because caffeine affects neurotransmitters in the brain and spinal cord heavily involved with pain processing. This study is similar to research originally published in 2006 by the Journal of Pain, indicating that caffeine could produce a large reduction in pain of delayed-onset muscle injury, which is pain that occurs several hours after a traumatic event.

Dosing Amount

In these studies, volunteers were provided with 5 milligrams of caffeine per kilogram of body weight, which amounts to about two or three cups of coffee. According to MedlinePlus, 200 to 300 milligrams of caffeine, equivalent to the amount used in the study, is considered a moderate amount of the stimulant and won’t put you at risk for dependence. The researchers also found that caffeine has the same analgesic effect in people who use caffeine regularly. So even if you do have three to four cups of coffee per day, using the psychoactive substance for muscle and body pain relief at this dose is still beneficial.

Withdraw

Reports of caffeine withdrawal syndrome date back nearly two centuries, according to Laura M. Juliano, Ph.D., a psychology professor at American University. In 2005, Johns Hopkins Medicine announced the inclusion of the disorder into the “Diagnostic and Statistical Manual of Mental Disorders,” the official mental disorder compendium in the United States. In addition to mood disturbances, withdrawing from caffeine can cause body aches, muscle pain and stiffness 12 to 24 hours after taking your last cup of coffee, energy drink or caffeine pill.

About Caffeine

While much of the research on caffeine has be centered on relieving tension headaches and general, exercise-induced muscle pain, the consensus on the stimulant is that it helps the body rapidly absorb pain-killing medications, according to My Family Doctor magazine, which provides pain relief sooner. Caffeine added to pain relievers make the drugs 40 percent more effective, says the Cleveland Clinic. Additionally, because of this increased effect, less pain-numbing drug is necessary, which reduces the risk for liver toxicity, especially in acetaminophen. If your doctor suggests getting plenty of rest and immobilizing your neck, forego caffeinated beverages and medications since you’re at risk for feeling energetic, jittery and anxious.

www.livestrong.com

Three Reasons Why Smoking Should Be Banned

Not smoking saves lives, money and the environment. Photo Credit no smoking image by Alex White from <a href='http://www.fotolia.com'>Fotolia.com</a>

Tobacco use is the major cause of preventable and premature death and disease worldwide, according to the Centers of Disease Control and Prevention. The CDC reports that 46 million Americans age 18 years and older smoke cigarettes, 443,000 smoking-related deaths occur annually in the U.S. Smoking affects the population, causes premature deaths and is a substantial financial burden to society.

Population

Smoking affects the population in many ways. It affects smokers' health and controls their smoking habits and use of time, and the spiraling cost of tobacco makes it an expensive pastime. Secondhand smoke affects others and pollutes the environment. According to the Environmental Protection Agency, children are susceptible to the effects of secondhand smoke because they are growing and developing. Children exposed to secondhand smoke have increased risks of sudden infant death syndrome, middle ear infection, asthma, pneumonia and bronchitis.

Preventable Deaths

Annually, one of every five deaths in the U.S. is related to smoking, due to conditions such as pneumonia, bronchitis, lung cancer and emphysema, according to the CDC website. Smoking may affect sexual performance and increase the risks of heart disease and infections. Deaths attributed to smoking varied from state to state during the years 2000 to 2004, with Alaska reporting 492 deaths and California reporting 36,687 deaths, notes the CDC. The good news is, according to a report from the CDC, some states show signs of improved health of their citizens and a decrease in smoking rates, deaths and health care costs due to increased awareness, education and resources available to help people fight the smoking habit.

Cost

Smoking puts a financial burden on society. According to the CDC, this burden continues to rise, with approximately $193 billion spent annually in the United States---$97 billion from lost productivity and $96 billion due to smoking-related health care costs, respectively. The Society of Actuaries reported in 2006, which is the latest data available, that secondhand smoke costs the U.S. around $10 billion a year: about $5 billion in medical costs associated with secondhand smoke and $4.6 billion in lost wages---youth exposure was not included in these costs.

www.livestrong.com

20,000 Pages of Woodworking Ultimate Collection

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