Transverse sections of white birch (Betula platyphylla) were treated with anhydrous ammonia at 60–140°C (ammonia treatment, AT). As a result, the crystal structure of cellulose in the AT samples changed to cellulose IIII, and acetamide was produced. The surface area of the AT samples, the amount of sugar released upon acid hydrolysis and the lignin content were not changed. However, a small amount of lignin became acid soluble. Mäule color reaction, indicative of the presence of syringyl lignin, showed decreasing color intensities with increasing temperature of AT. The results can be easily interpreted that AT affects ester linkages and side chains of hemicelluloses and syringyl lignin. In addition, AT was carried out on 1-μm thick transverse sections and block specimens. Xylanase treatment and immunolabeling revealed that AT enhances xylan degradation, but ray cells are resistant to xylanase even after AT. On the block sample, a deposited xylan layer appeared on the inner surface of fiber cell walls. Apparently, xylan moved to the surface in contact with the fluid ammonia during AT. The vessel cell wall did not show a similar migration effect, indicating a cell wall-specific interaction with ammonia.
This research was supported by a Grant-in-Aid for JSPS Fellows to D.Y. (26-11122) and by a Grant-in-Aid for Scientific Research to M.S. (23248025) from JSPS.
Chundawat, S.P.S., Vismeh, R., Sharma, L.N., Humpul, J.F., da Costa Sousa, L., Chambliss, C.K., Jones, A.D., Balan, V., Dale, B.E. (2010) Multifaceted characterization of cell wall decomposition products formed during ammonia fiber expansion (AFEX) and dilute acid based pretreatments. Bioresour. Technol. 101:8429–8438.10.1016/j.biortech.2010.06.027Search in Google Scholar
Grous, W.R., Converse, A.O., Grethlein, H.E. (1985) Effect of steam explosion pretreatment on pore size and enzymatic hydrolysis of poplar. Enzyme Microb. Technol. 8:274–280.10.1016/0141-0229(86)90021-9Search in Google Scholar
Holtzapple, M.T., Jun, J.H., Ashok, G., Patibandla, S.L., Dale, B.E. (1991) The ammonia freeze explosion (AFEX) process. A practical lignocellulose pretreatment. Appl. Biochem. Biotechnol. 28–29:59–74.10.1007/BF02922589Search in Google Scholar
Igarashi, K., Wada, M., Samejima, M. (2007) Activation of crystalline cellulose to cellulose IIII results in efficient hydrolysis by cellobiohydrolase. FEBS J. 274:1785–1792.10.1111/j.1742-4658.2007.05727.xSearch in Google Scholar PubMed
Iiyama, K., Pant, R. (1988) The mechanism of Mäule colour reaction Introduction of methylated syringyl nuclei into softwood lignin. Wood Sci. Technol. 22:167–175.10.1007/BF00355852Search in Google Scholar
Knappert, D., Grethlein, H., Converse, H. (1980) Partial acid hydrolysis of cellulosic materials as a pretreatment for enzymatic hydrolysis. Biotechnol. Bioeng. 22:1449–1463.10.1002/bit.260220711Search in Google Scholar
Nishiyama, Y., Langan, P., Chanzy, H. (2002) Crystal structure and hydrogen bonding system in cellulose Iβ from synchrotron X-ray and neutron fiber diffraction. J. Am. Chem. Soc. 124:9074–9082.10.1021/ja0257319Search in Google Scholar PubMed
Nishiyama, Y., Sugiyama, J., Chanzy, H., Langan, P. (2003) Crystal structure and hydrogen bonding system in cellulose Iα from synchrotron X-ray and neutron fiber diffraction. J. Am. Chem. Soc. 125:14300–14306.10.1021/ja037055wSearch in Google Scholar PubMed
Oka, D., Kobayashi, K., Isobe, N., Ogawa, Y., Yokoyama, T., Kimura, S., Kim, U., Tokuyasu, K., Wada, M. (2013) Enzymatic hydrolysis of wood with alkaline treatment. J. Wood Sci. 59:484–488.10.1007/s10086-013-1359-xSearch in Google Scholar
Puri, V.P., Mamers, H. (1983) Explosive pretreatment of lignocellulosic residues with high-pressure carbon dioxide for the production of fermentation substrates. Biotechnol. Bioeng. 25:3149–3163.10.1002/bit.260251226Search in Google Scholar PubMed
Yamashita, D., Kimura, S., Wada, M., Takabe, K. (2016) Improved Mäule color reaction provides more detailed information on syringyl lignin distribution in hardwood. J. Wood Sci. 62:131–137.10.1007/s10086-016-1536-9Search in Google Scholar
©2018 Walter de Gruyter GmbH, Berlin/Boston