Microbial degradation of lignin-derived compounds under anaerobic conditions

Thesis/Dissertation · Sat Jan 01 00:00:00 EST 1983

OSTI ID:5552964

Colberg, P J

Lignin is the second most abundant form of organic carbon in the biosphere. Recent laboratory studies indicate that a large fraction of polymeric lignin is incompletely degraded by aerobic lignolytic microorganisms and is subsequently released as lignin fragments of reduced molecular size. If such lignin-derived compounds become available in the anaerobic environment, they may serve as potential sources of organic carbon for organisms which release methane precursors. The methanogenic bacteria, in turn, serve as terminal members of the anaerobic food chain, and thus, limit the accumulation of organic carbon in anaerobic sinks. This thesis presents evidence to suggest that lignin-derived compounds which have molecular sizes greater than those of single-ring aromatic compounds (MW > 200) are anaerobically biodegradable to methane. This research involved development of selective enrichment cultures capable of utilizing oligolignols as sole carbon sources. Radiolabeled water-soluble catabolites, released during aerobic lignin degradation by the white rot fungus Phanerochaete chrysosporium, were subjected to anaerobic degradation. The second phase of work involved capillary gas chromatographic analyses of enrichment cultures fed a /sup 14/C-labeled, lignin-derived substrate of average molecular weight 600. 2-Bromoethanesulfonic acid was used to inhibit methane formation and enhance buildup of metabolic intermediates, resulting in the accumulation of volatile fatty acids, phenylacetate, benzoate, catechol, 3-phenyl-propionate, vanillin, syringic acid, vanillic acid, ferulic acid, and caffeic acid. A conceptual model for the anaerobic degradation of two- and three-ring lignin fragments is proposed which overlaps both the ferulate and benzoate degradation pathways at the level of single-ring aromatic compounds.

• OSTI ID: 5552964
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
09 BIOMASS FUELS
LIGNIN
BIODEGRADATION
CATABOLISM
METHANE
BIOSYNTHESIS
PHANEROCHAETE
CULTURE MEDIA
ANAEROBIC CONDITIONS
BIOLOGICAL PATHWAYS
REACTION INTERMEDIATES
ALKANES
CARBOHYDRATES
CHEMICAL REACTIONS
DECOMPOSITION
FUNGI
HYDROCARBONS
METABOLISM
ORGANIC COMPOUNDS
PLANTS
POLYSACCHARIDES
SACCHARIDES
SYNTHESIS
550700* - Microbiology
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