Effect ofStreptomyces viridosporus T7A on kraft lignin (original) (raw)
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Effects of pH on lignin and cellulose degradation by Streptomyces viridosporus
Applied and Environmental Microbiology, 1986
Lignocellulose degradation by Streptomyces viridosporus results in the oxidative depolymerization of lignin and the production of a water-soluble lignin polymer, acid-precipitable polymeric lignin (APPL). The effects of the culture pH on lignin and cellulose metabolism and APPL production by S. viridosporus are reported. Dry, ground, hot-water-extracted corn (Zea mays) lignocellulose was autoclaved in 1-liter reagent bottles (5 g per bottle) and inoculated with 50-ml volumes of S. viridosporus cells suspended in buffers of specific pH (pH 6.0 to 9.2 at 0.4 pH unit intervals). Four replicates of inoculated cultures and of uninoculated controls at each pH were incubated as solid-state fermentations at 37°C. After 6 weeks of incubation the percent loss of lignocellulose, lignin, and carbohydrate and the amount of APPL produced were determined for each replicate.
Degradation of Kraft Indulin Lignin by Streptomyces viridosporus and Streptomyces badius
Applied and environmental microbiology, 1988
Crawford and collaborators have studied extensively the solubilization of lignocellulose by two Streptomyces species, S. badius and S. viridosporus. Using a condensed industrial lignin essentially devoid of carbohydrates, Indulin AT, as the sole source of carbon, similar results were obtained: (i) the growths of the bacteria were optimum at pH 7.5 to 8.5; (ii) yeast extract was a better source of nitrogen than NH(4)Cl; (iii) the products of the depolymerization of Indulin were soluble, acid-precipitable polymers. When d-glucose was added as a secondary carbon source, it was used preferentially and the production of acid-precipitable polymers began only after the complete depletion of the sugar. On the assumption that the degradation of Indulin was catalyzed by enzymes, proteins found in the culture media and soluble and insoluble intracellular proteins were incubated with Indulin at pH 7.0 at 37 degrees C. Proteins in all fractions from S. badius had ligninolytic activities which, w...
Microbial treatment of industrial lignin: Successes, problems and challenges
Renewable and Sustainable Energy Reviews, 2017
Lignin, one of the major components of plant/lignocellulosic biomass, is an irregular 3-D polymer comprised of potentially valuable phenolic monomers. Currently lignin and its colloidal solution in water, black liquor, obtained as by-products in many biomass treatment processes, e.g., pulping in paper industry, remain to be considered recalcitrant substrates of a limited commercial value. This study reviews the recent research on both fungal and bacterial lignin degradation, with a focus on the characterization of degradation products. The specific features and biological treatment of industrial lignin and black liquor are detailed along with the degradation conditions employed, complementing other review articles focusing on natural lignin degradation. An overview of ligninolytic enzymes frequently identified among microorganisms is presented, with the emphasis on factors responsible for their regulation and induction including the mediators involved and multienzyme systems employed by natural lignin degraders. Efficient regulation of ligninolytic enzymes can be achieved through the optimization of a cultivation medium composition with supplementation of strain specific stimulatory components such as salts, low molecular weight phenolic compounds and nutrition sources. Current research efforts in characterizing lignin degradation products are reviewed with the emphasis on both destructive and non-destructive gas chromatographic methods as they are essential for future detailed kinetic and mechanistic studies.
Lignin Decolorization and Degradation of Pulp and Paper Mill Effluent by Ligninolytic Bacteria
The aim of this research work is to isolate bacterial strains with high potential in the degradation and decolorization of lignocellulose compounds of paper mill effluent. Four bacterial strains were isolated from marine sediments and they were screened to their ability to degrade the lignin and decolorize the Century pulp and paper mill effluent. Among four bacterial strains, three bacterial strains Bacillus subtilis, Bacillus endo-phyticus, Bacillus sp. were capable of ligninolytic activity. Consortium made by these bacterial strains enhances the degradation of lignin as well as decolorization. Various nitrogen source, carbon source, pH, temperature and low molecular weight organic acids were used in the optimization process of decolorization and degradation of lignin in paper mill effluent. Maximum decolorization 68.29% was found at pH 7.92, temperature 33°C, in the presence of glucose (as carbon source) 0.99% and yeast extract (as nitrogen source) 0.36% when it was optimized through response surface methodology.
Journal of Biotechnology, 1990
The actinomycete Streptomyces viridosporus attacks wheat lignocellulose releasing soluble lignin-rich fragments (APPL). Chemical analyses indicated that these APPL contain 20% less guaiacyl and 70% less glucose residues than the original substrate. In order to determine the effect of non-filamentous bacteria on APPL, natural isolates were selected in synthetic media containing APPL as sole carbon source. From a total of eighty cultures, two strains (Pseudomonas spp. B23 and E21) and a consortium of two strains (Enterobacter sp. V 1 and Pseudomonas sp. V2) were selected for further studies. Strains Pseudomonas fluorescens biovar I and Pseudomonas acidovorans O3, previously isolated on fl-1 and r-o-4 lignin model compounds, respectively, were included for comparative purposes. Analysis of APPL recovered after bacterial growth indicated that Pseudomonas B23 attacked prefer-entiaUy both guaiacyl and syringyl hgnin units while barely affected their carbohydrate content. On the other hand, Pseudomonas E21 and the consortium metabolized sugar moieties without modifying the aromatic residues of APPL. P. fluorescens biovar I and P. acidovorans D 3, in spite of being able to cleave lignin linkages on dimeric model compounds, exhibited very limited growth on APPL. The
Effects of pH on Lignin and Cellulose Degradation by Streptomyces viridosporus
Applied and Environmental Microbiology, 1986
Lignocellulose degradation by Streptomyces viridosporus results in the oxidative depolymerization of lignin and the production of a water-soluble lignin polymer, acid-precipitable polymeric lignin (APPL). The effects of the culture pH on lignin and cellulose metabolism and APPL production by S. viridosporus are reported. Dry, ground, hot-water-extracted corn (Zea mays) lignocellulose was autoclaved in 1-liter reagent bottles (5 g per bottle) and inoculated with 50-ml volumes of S. viridosporus cells suspended in buffers of specific pH (pH 6.0 to 9.2 at 0.4 pH unit intervals). Four replicates of inoculated cultures and of uninoculated controls at each pH were incubated as solid-state fermentations at 37°C. After 6 weeks of incubation the percent loss of lignocellulose, lignin, and carbohydrate and the amount of APPL produced were determined for each replicate. Optimal lignocellulose degradation, as shown by substrate weight loss, was observed in the pH range of 8.4 to 8.8. Only minor differences were seen in the Klason lignin, carbohydrate, protein, and ash contents of the APPLS produced by cultures at each pH. The effects of pH on the degradation of a spruce (Picea pungens) [14C-lignin]lignocellulose and a Douglas fir (Pseudotsuga menziesii) [14C-glucan]-lignocellulose were also determined at pH values between 6.5 and 9.5 (0.5 pH unit intervals). The incubations were carried out for 3 weeks at 37°C with bubbler-tube cultures. The percentage of initial 14C recovered as 14Co2, 14C-labeled water-soluble products, and [14C]APPL was then determined. The mineralization of lignin and cellulose to CO2 was optimal at pHs 6.5 and 7.0, respectively. However, the optimum for lignin and cellulose solubilization was pH 8.5, which correlated with the pH 8.5 optimum for APPL production. Overall, the data show that, whereas lignin mineralization is optimal at neutral to slightly acidic pHs, lignocellulose degradation with lignin solubilization and APPL production is promoted by alkaline pHs. These findings indicate that ligninsolubilizing actinomycetes may play an important role in the metabolism of lignin in neutral to alkaline soils in which ligninolytic fungi are not highly competitive. In nature, the aromatic polymer lignin, which is covalently linked to cellulosic polysaccharides in lignocellulosic biomass, is resistant to degradation by most microorganisms. This recalcitrant phenylpropanoid polymer is degraded by a few fungi and filamentous bacteria (5, 7, 10-13,
World Journal of Microbiology and Biotechnology, 2005
The actinomycete strain Streptomyces griseus B 1 , isolated from soil, when grown on cellulose powder as submerged culture produced high levels of all the three components i.e. filter paper lyase (FPase), CMCellulase and bglucosidase of the cellulolytic enzyme system. FP activity and CMCellulase were present only extracellularly, while b-glucosidase was both intra-and extra-cellular. It produced highest FPase activity when grown on hardwood powder under submerged culture. It was unable to use lignin monomers (ferulic acid, vanillic acid and syringic acid) as carbon source. While growing on hardwood and softwood powders under solid-state conditions, it depleted them of cellulose (36.3% in the case of softwood and 14.4% in the case of hardwood). It also caused partial loss of lignin content in both the substrates by solubilizing them. These solubilized lignins could be recovered as acid precipitable polymeric lignins (APPL) from extracts of wood powders upon acidification. Extracts of inoculated wood powders yielded higher amounts of APPL than uninoculated controls. Also, the APPLs from Streptomyces-treated wood powders differed from control APPLs in their molecular weight distribution, as observed from their elution pattern using Sephadex G-100.
Chemistry of softwood lignin degradation byStreptomyces viridosporus
Archives of Microbiology, 1982
Polymeric lignin isolated from ground spruce phloem/bark tissue following decay by the actinomycete Streptomyces viridosporus (T7A) was characterized chemically and compared to undegraded lignin from the same source. The chemical transformations resulting from degradation were compared to those that result from fungal degradation of softwood lignins by brown-and white-rot fungi. Degradative chemical analyses showed that S.
Applied and Environmental Microbiology
Degradation of ground and hot-water-extracted corn stover (Zea mays) lignocellulose by Streptomyces viridosporus T7A generates a water-soluble lignin degradation intermediate termed acid-precipitable polymeric lignin (APPL). The further catabolism of T7A-APPL by S. viridosporus T7A, S. badius 252, and S. setonii 75Vi2 was followed for 3 weeks in aerated shake flask cultures at 37C in a yeast extract-glucose medium containing 0.05% (wt/vol) T7A-APPL. APPL catabolism by Phanerochaete chrysosporium was followed in stationary cultures in a low-nitrogen medium containing 1% (wt/vol) glucose and 0.05% (wt/vol) T7A-APPL. Metabolism of the APPL was followed by turbidometric assay (600 nm) and by direct measurement of APPL recoverable from the medium. Accumulation and disappearance of soluble low-molecular-weight products of APPL catabolism were followed by gas-liquid chromatography and by high-pressure liquid chromatography, utilizing a diode array detector. Identified and quantified compounds present in culture media included p-coumaric acid, ferulic acid, p-hydroxybenzoic acid, p-hydroxybenzaldehyde, protocatechuic acid, vanillic acid, and vanillin. The further catabolism of these APPL-derived aromatic compounds varied with the culture examined, and only S. setonui and P. chrysosporium completely degraded all of them. Some new intermediates of APPL metabolism also appeared in culture media, but the patterns were culture specific. Additional evidence from high-pressure liquid chromatography analyses indicated that one strain, S. badus, converted a water-soluble fraction evident by high-pressure liquid chromatography (7 to 10 min retention time range) into new products appearing at shorter retention times. Mineralization of a [14C-lignin]APPL was also followed. The percent 14C recovered as 04C02, '4C-APPL, 14C-labeled water-soluble products, and cell mass-associated radioactivity, were determined for each microorganism after 1 and 3 weeks of incubation in bubbler tube cultures at 37°C. P. chrysosporium evolved the most 14CO2 (10%), and S. viridosporus gave the greatest decrease in recoverable 14C-APPL (23%). The results show that S. badius was not able to significantly degrade the APPL, while the other microorganisms demonstrated various APPL-degrading abilities. The significance of these findings relative to the fate of APPLs in nature was discussed.