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미생물 펄프화시 trembling aspen의 화학적 성분 변화
안세희 대구대학교 생명과학연구소 2004 생명과학연구 Vol.3 No.1
Trembling aspen wood (Populus tremuloides) was treated with white rot fungi Ceriporiopsis subvermispora for 1, 2, 4 and 6 weeks. On a laboratory scale, steaming, cooling, and fungal inoculation were performed in a batchwise fashion. As fungal decay advanced on, lignin contents were decreased gradually up to 20 % after 6 weeks, whereas MeOH extracts were significantly increased. Alkali solubility of cell wall residues was improved until 4-weeks of fungal treatment, but additional treatment did not give any effects. Milled wood lignins (MWLs) were isolated from the each decayed wood by Bjoerkman procedure and subjected to thioacidolysis and analytical pyrolysis to investigate the modification of lignin structures during fungal incubation. Thioacidolysis revealed that the yields of trithioethylated C6C3 monomers, a parameter for frequency of β-O-4 linkages in lignin, were substantially reduced in purified lignins from each decayed wood as a function of periods of fungal treatment and the reduction of β-O-4 linkages reached 20 % after 6 weeks. 대구대학교 생명과학연구 제3권 제1호 (2004. 07) Furthermore, S/G ratios estimated by thioacidolysis demonstrated that syringyl-type lignin was much favorably degraded than guaiacyl-type lignin by C. subvermispora.
백색부후균인 Phanerochaete chrysosporium에 의한 리그닌 모델 화합물 분해
안세희,島田幹夫 대구대학교 과학기술연구소 1999 科學技術硏究 Vol.5 No.5
The degradation products were extracted with ethyl acetate and identified by NMR and GC-MS to elucidate degradation pathways of the lignin substructure model compounds. All degradation products were identified by GC-MS in comparison with mass spectra of synthetic authentic compounds. The results are classified to the cleavage of side chain and aromatic ring opening of the compounds. We found that lignin peroxidase of P. chrysosporium also catalyzes one electron oxidation of non-phenolic compounds in the initial degradation of lignin substructure model compounds. Lignin peroxidase catalyzes one electron oxidation of aromatic rings of non-phenolic aromatic compounds to give unstable cation radical which undergo spontaneous transformation. The Cα-Cβ 13 bond of the propyl side chain is homolytically cleaved via an aryl cation radical of the substrate to give benzyl cation, and guaiacoxyethyl radical which is attacked by dioxygen to form an unstable hemiketal. The O-Cβ bond of hemiketal is subsequently cleaved to give vanillin and benzaldehyde. The aromatic ring opening products were also identified as lignin peroxidase degradation products of β-O-4 model compound.