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Thermophilic anaerobic biodegradation of (/sup 14/C)lignin, (/sup 14/C)cellulose, and (/sup 14/C)lignocellulose preparations

Journal Article · · Appl. Environ. Microbiol.; (United States)
OSTI ID:5619670

Thermophilic (55/sup 0/C) anaerobic enrichment cultures were incubated with (/sup 14/C-lignin)lignocellulose, (/sup 14/C- polysaccharide)lignocellulose, and kraft (/sup 14/C)lignin prepared from slash pine, Pinus elliotti, and /sup 14/C-labeled preparations of synthetic lignin and purified cellulose. Significant but low percentages (2 to 4%) of synthetic and natural pine lignin were recovered as labeled methane and carbon dioxide during 60-day incubations, whereas much greater percentages (13 to 23%) of kraft lignin were recovered as gaseous end products. Percentages of label recovered from lignin-labeled substrates as dissolved degradation products were approximately equal to percentages recovered as gaseous end products. High-pressure liquid chromatographic analyses of CuO oxidation products of sound and degraded pine lignin indicated that no substantial chemical modifications of the remaining lignin polymer, such as demethoxylation and dearomatization, occurred during biodegradation. The polysaccharide components of pine lignocellulose and purified cellulose were relatively rapidly mineralized to methane and carbon dioxide; 31% to 37% of the pine polysaccharides and 56% to 63% of the purified cellulose were recovered as labeled gaseous end products. An additional 10% to 20% of the polysaccharide substrates was recovered as dissolved degradation products. Overall, these results indicate that elevated temperatures can greatly enhance rates of anaerobic degradation of lignin and lignified substrates to methane and low-molecular-weight aromatic compounds.

Research Organization:
Univ. of Georgia, Athens
OSTI ID:
5619670
Journal Information:
Appl. Environ. Microbiol.; (United States), Journal Name: Appl. Environ. Microbiol.; (United States) Vol. 50:4; ISSN AEMID
Country of Publication:
United States
Language:
English