Papers by Anthony Pometto
Iowa State University animal industry report, 1999
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Applied Microbiology and Biotechnology, Dec 1, 2001
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ACS Food Science & Technology
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Journal of Food Science and Nutrition, Mar 1, 1998
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Applied and Environmental Microbiology, Mar 1, 1985
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Applied and Environmental Microbiology, Feb 1, 1981
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Elsevier eBooks, 1988
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Applied and Environmental Microbiology, Jul 1, 1997
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Journal of Industrial Microbiology & Biotechnology, Oct 1, 1997
ABSTRACT
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Applied and Environmental Microbiology, Mar 1, 1983
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Biotechnology Advances, 1984
Lignin degrading strains of Streptomyces were grown on lignocelluloses from a variety of plant so... more Lignin degrading strains of Streptomyces were grown on lignocelluloses from a variety of plant sources. These actinomycetes readily degraded the lignin present in the residues and released a major portion of the lignin into the growth medium as a water soluble, modified polymer. The polymer, an acid precipitable polyphenolic lignin (APPL), was recovered from spent culture media by acid precipitation or dialysis/lyophilization. APPL's were shown to be mostly free of nonlignin components. As compared to native lignin they were more oxidized, were especially enriched in phenolic hydroxyl groups, and were significantly reduced in methoxyl groups. The yield of APPL from different lignocelluloses correlated with their biodegradability. Grasses such as corn stover were the optimal lignocellulose type for APPL production by Streptomyces. In contrast white-rot fungi produced only small amounts of APPL as they decomposed lignin. A solid state bioconversion process was developed using Streptomyces viridosporus T7A to produce APPL from corn stover lignocellulose in yields >or= 30% of the initial lignin present in the substrate. APPL produced by S. viridosporus was examined for its properties and possible use as an antioxidant. The APPL was shown to have good antioxidant properties after mild chemical treatment to reduce the alpha-carbonyl groups present in the APPL. Oxidation of the APPL with hydroxyl radical (OH(*)) further improved its antioxidant properties probably as the result of aromatic ring hydroxylation reactions. As compared with currently used commercial antioxidants, the modified APPL was thought to be competitive when economics of production was considered. Native lignin on the other hand was shown to exhibit no antioxidant properties, even after reduction and/or oxidation.
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Enzyme and microbial technology, 1981
An enzymatic method using phenylalanine ammonia-lyase (l-phenylalanine ammonia-lyase, EC 4.3.1.5)... more An enzymatic method using phenylalanine ammonia-lyase (l-phenylalanine ammonia-lyase, EC 4.3.1.5) for the rapid conversion of l-[U-14C]phenylalanine to the deaminated lignin precursor trans-[U-14C]cinnamic acid is described. The method produces an experimentally useful 14C-labelled deaminated lignin precursor unavailable from radiochemical supply companies.
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Applied and Environmental Microbiology, May 1, 1983
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Journal of Food Protection, Nov 1, 1994
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Canadian Journal of Microbiology, Apr 1, 1977
The comparative rates of microbial degradation 14C-lignin-labeled lignocelluloses and 14C-Kraft l... more The comparative rates of microbial degradation 14C-lignin-labeled lignocelluloses and 14C-Kraft lignins were investigated using selected soil and water samples as sources of microorganisms. Natural lignocelluloses containing 14C primarily in their lignin components were prepared by feeding plants uniformly labeled L-[14C]phenylalanine through their cut stems. 14C-Kraft lignins were prepared by pulping lignin-labeled lignocelluloses. Rates of lignin biodegradation were determined by monitoring 14CO2 evolution from incubation mixtures over incubation periods of up to 1000 h. Observed rates of lignin degradation were slow in all cases. Kraft lignins appeared more resistant to microbial attack than natural lignins, even though they were decomposed more rapidly during the first 100–200 h of incubation. Similar degradation patterns were observed in both soil and water. Individual samples, however, varied greatly in their overall rates of degradation of either lignin type. A Kraft-lignin preparation was separated into a variety of molecular weight fractions by column chromatography on LH-20 Sephadex and the biodegradability of the different molecular weight fractions determined. The lower molecular weight fractions of the Kraft lignin were decomposed at a significantly faster rate by the microflora of soil than were the fractions of higher molecular weight.
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Canadian journal of botany, Apr 1, 1983
Eighteen strains of fungi in the genus Fusarium, including varieties of F. episphaeria, F. lateri... more Eighteen strains of fungi in the genus Fusarium, including varieties of F. episphaeria, F. lateritium, F. moniliforme, F. nivale, F. oxysporum, F. rigidiusculum, F. roseum, F. solani, and F. tricinctum, slowly degraded lignocelluloses from blue spruce (Picea pungens) and wheat (Triticum aestivum). When grown with [lignin-14C]lignocellulose from blue spruce, 15 of the Fusarium strains converted 2.2 to 4.3% of the [14C]lignin in 60 days to 14CO2 and 3.9 to 8.4% to labeled water-soluble products. When grown with unlabeled lignocellulose from wheat straw, the strains caused total weight losses in 60 days of 7 to 25%, acid-insoluble (Klason) lignin losses of 2 to 17%, and carbohydrate losses of 3 to 33%. Crude protein contents of degraded wheat-straw lignocellulose samples were 3.2 to 5.1%. Among the aromatic degradation products from wheat-straw lignocellulose degraded by different strains, as shown by gas chromatography, were p-coumaric acid, vanillic acid, vanillin, syringaldehyde, and p-hydroxybenzaldehyde.
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Canadian Journal of Microbiology, Nov 1, 1979
Forty-two actinomycete strains were isolated by enrichment techniques from soils and other lignoc... more Forty-two actinomycete strains were isolated by enrichment techniques from soils and other lignocellulose-containing natural habitats. Isolates were screened for their lignocellulose-decomposing abilities using a substrate weight loss – 14C-labeled lignocellulose degradation assay which determined the relative abilities of each isolate to attack lignin versus glucan components of lignocellulose. Six Streptomyces strains were selected for further study, based upon their abilities to decompose significantly both lignin and glucan components of lignocellulose. The selected strains were examined under defined cultural conditions for their abilities to decompose 14C-labeled lignocelluloses prepared from Douglas fir. The 14C-labeled lignocellulose substrates included specifically lignin-labeled or glucan-labeled lignocelluloses, and two [14C]lignin lignocelluloses labeled specifically in only the lignin side chain or ring components. Results showed that the Streptomyces strains decomposed substantial amounts of both lignin and glucan components to 14CO2, and 14C-labeled water-soluble products. As compared with previously described lignocellulose-degrading streptomycetes, these strains were generally more efficient decomposers of the lignin component of lignocellulose, but were similar in their abilities to decompose the glucan component. Characterization of growth on specifically labeled lignins showed that aromatic ring structures within the lignin were cleaved and a substantial percentage of the ring carbons were released as CO2. In contrast, side-chain components were attacked to only a limited degree. These streptomycetes were similar to other recently characterized lignin-decomposing bacteria in their overall abilities to degrade lignin, but their specificity of attack on the structural components of lignin appears to be different.
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Archives of Microbiology, Mar 1, 1982
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Papers by Anthony Pometto