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PubMed1980

Lignin degradation by Phanerochaete chrysosporium in hyperbaric oxygen.

Phanerochaete chrysosporium degraded aspen wood lignin as well in 2 atm O2 (1 atm = 101.325 kPa) as in 1 atm O2, but 3 atm O2 inhibited the fungus, and O2 pressures above 4 atm killed it. Lignin degradation in 5 atm of air was similar to that in 1 atm of O2, indicating that O2 concentration, not pressure, was the inhibitory factor. The selectivity with which P. chrysosporium metabolised lignin in preference to other wood components did not increase at O2 pressures above 1 atm.

Atmospheric Pressure↗

PubMed1995

Investigation of the lignin-degrading activity of Serratia marcescens: biochemical screening and ultrastructural evidence.

Forty-one morphologically distinct bacterial isolates were developed from six lignin-containing environments. Each isolate was initially screened for potential lignin-degrading activity using relative growth on a lignocellulosic substrate and relative decolorization of a polymeric dye. Screened isolates were then tested for the ability to oxidize various lignin-related monomers, and the dimers anisoin and veratrylglycerol-beta-guaiacyl ether. Although most of the isolates oxidized the monomers, only two successfully oxidized the dimers. The dimer-degrading isolates were tested for extracellular activity against the beta-O-4 dimer veratryl-glycerol-beta-guaiacyl ether. No activity was detected for the isolates. Phanerochaete chrysosporium Burds used as a positive control demonstrated a high degree of activity in each assay. Extensive ultrastructural studies of lignocellulose alteration by the dimer-degrading isolates were conducted via light and transmission electron microscopy. These studies indicate that one of the isolates, identified as Serratia marcescens, is capable of degrading highly lignified secondary cell wall components. This activity is localized, apparently requiring direct contact between cells and substrate, which could be facilitated by an associated glycocalix. The results of the dimer degradation assays concur with the characterization of the responsible enzyme system as being membrane associated.

Anthraquinones↗

PubMed2002

Lignin degrading system of white-rot fungi and its exploitation for dye decolorization.

With global attention and research now focused on looking for the abatement of pollution, white-rot fungi is one of the hopes of the future. The lignin-degrading ability of these fungi have been the focus of attention for many years and have been exploited for a wide array of human benefits. This review highlights the various enzymes produced by white-rot fungi for lignin degradation, namely laccases, peroxidases, aryl alcohol oxidase, glyoxal oxidase, and pyranose oxidase. Also discussed are the various radicals and low molecular weight compounds that are being produced by white-rot fungi and its role in lignin degradation. A brief summary on the developments in research of decolorization of dyes using white-rot fungi has been made.

Coloring Agents↗

PubMedDate not supplied

Mn2+ alters peroxidase profiles and lignin degradation by the white-rot fungus Pleurotus ostreatus under different nutritional and growth conditions.

The white-rot fungus Pleurotus ostreatus produces two types of extracellular peroxidases: manganese-dependent peroxidase (MnP) and versatile peroxidase (VP). The effect of Mn2+ on fungal growth, peroxidase activity profiles, and lignin degradation by P. ostreatus was studied in liquid culture and under solid-state fermentation conditions on perlite, the latter resembling the natural growth conditions of this fungus. The fungus was grown in either a defined asparagine-containing basidiomycete selective medium (BSM) or in a rich peptone medium (PM). Biomass production, as determined by respiration experiments in solid-state fermentation and liquid cultures and fungal growth on Petri dishes, was higher in the PM than in the BSM. Mn2+ affected biomass production only in the PM on Petri dishes. In the nonamended PM, high levels of MnP and VP activity were detected relative to the nonamended BSM. Nevertheless, a higher rate of 14C-lignin mineralization was measured in the Mn2+-amended BSM, as determined during the course of 47 d of fermentation. Mn2+ amendment of the PM increased mineralization rate to that obtained in the Mn2+-amended BSM. The enzyme activity profiles of MnP and VP were studied in the BSM using anion-exchange chromatography. In the nonamended BSM, only minute levels of MnP and VP were detected. On Mn2+ amendment, two MnP isoenzymes (B1 and B2) appeared. Isoenzyme B2 was purified and showed 100% identity with the MnP isoenzyme purified in our previous study from PM-solid-state fermentation (P6). P6 was found to be the dominant isoenzyme in terms of activity level and gene expression compared with the VP isoenzymes. Based on these results, we concluded that Mn2+ plays a key role in lignin degradation under different nutritional and growth conditions, since it is required for the production of MnP in P. ostreatus.

Asparagine↗

PubMed2005

Effects of hemicellulose and lignin on enzymatic hydrolysis of cellulose from dairy manure.

This study focused on the effect of hemicellulose and lignin on enzymatic hydrolysis of dairy manure and hydrolysis process optimization to improve sugar yield. It was found that hemicellulose and lignin in dairy manure, similar to their role in other lignocellulosic material, were major resistive factors to enzymatic hydrolysis and that the removal of either of them, or for best performance, both of them, improved the enzymatic hydrolysis of manure cellulose. This result combined with scanning electron microscope (SEM) pictures further proved that the accessibility of cellulose to cellulase was the most important feature to the hydrolysis. Quantitatively, fed-batch enzymatic hydrolysis of fiber without lignin and hemicellulose had a high glucose yield of 52% with respect to the glucose concentration of 17 g/L at a total enzyme loading of 1300 FPU/L and reaction time of 160 h, which was better than corresponding batch enzymatic hydrolysis.

Carbohydrates↗

PubMed1999

Effect of lignin on growth and tyrosinase activity of fungi from the genus Aspergillus.

The effect of lignin hydrolyzate (a waste product of the pulp and paper industry) on the growth and tyrosinase activity of several strains of fungi of the genus Aspergillus was studied. During fungal growth lignin was degraded with the formation of soluble aromatic products. Accumulation of these products in the growth medium leads to a 60-100-fold increase in tyrosinase synthesis. The intensity of tyrosinase synthesis depends on the composition of the growth medium. The ratio between lignin and glucose concentrations seems to be the main factor; the activity was maximal at the ratio 2:1.

Aspergillus↗

PubMedDate not supplied

[Transformation of lignins from grape solids during alcoholic fermentation].

Conversion of lignins contained in solid parts of Rkatsiteli grapes (crests, seeds, and skin) during alcoholic fermentation by wine yeast in Reader's medium was studied. Various species of wine yeast were used: Saccharomyces oviformis, S. vini Kakhuri 42, S. chodati Teliani 79, and S. uvarum Tsinandali 77. We found that lignins from solid parts of grapes are partially decomposed during alcoholic fermentation, which releases low-molecular-weight aromatic compounds into the medium. A peculiar feature of lignin decomposition during alcoholic fermentation is the formation of reduction products.

Alcohols↗

PubMedDate not supplied

[Change in composition of hydrolyzed lignin during composting].

Microbial assemblages were composed for composting hydrolysed lignin. Data on bioconversion of aromatic compounds with various types of substitution in the ring were used for this purpose. Composting of hydrolysed lignin reduced the contents of lignin, low-hydrolyzable polysaccharides, resins, and low-molecular-weight phenols and resulted in accumulation of humic acids. The resulting compost showed no phytotoxicity.

Hydrolysis↗

PubMed2001

[Optimization of synthetic culture condition on lignin biodegradation ability of alkaliphilic ligninolytic bacteria using orthogonal experimental design].

The effects of seven single culture factors on lignin biodegradation ability of alkaliphilic ligninolytic bacteria strain 6 in alkaline liquid medium (pH approximately 10.5) with compounded carbons were optimized using orthogonal experiments. The result showed the seven single culture factors promote the activities of Laccase and MnP and the degradation rate of wheat straw lignin in varying degrees. The synthetic result was analysised. The optimal synthetic condition was static culture (10 days culture period), 37 degrees C, the initial pH10.6, 1 g/L sugar (the starting carbons), wheat straw lignin (the second carbons, wheat straw powder 20 g/L, added into on the fourth day after inoculation), 1.2 g/L NH4NO3 (nitrogen), 0.3% detergent T-80, 70 ml medium/250 ml flask.

Bacteria↗

PubMedDate not supplied

[Ecological and hygienic evaluation of the lignin by-products utilization].

Main trends in utilization of lignin wastes formed in complex wood processing are discussed. Toxicological and hygienic characteristics of lignins and products of their biotransformation and chlorination are presented. Ecology and hygiene of fertilizers, preserving agents, and construction materials based on lignins are evaluated.

Environmental Pollutants↗

PubMed2002

[Mechanisms of separating lignin from black liquid by inorganic microfiltration].

The effects of rejection to lignin from black liquid were carried out by inorganic membranes which had pore size 50 nm, 0.2 micron and 0.8 micron, respectively. The results show that MF membranes can effectively separate lignin from black liquid. The flux of 0.2 micron alpha-Al2O3 and ZrO2 membranes were larger than the flux of 50 nm and 0.8 micron membranes. The flux of each membrane drops deeply as the SS concentration increased under the conditions of low SS in black liquid. However, the flux dropping had the linear relationship with SS concentration when it was high. 2 g/L polyethylene glycol 4000 solution can not affect the fluxes of 0.2 micron and 50 nm membranes, effectively, instead of decreasing the flux of 0.8 micron membrane about 60%. 2 g/L polyethylene glycol 20,000 solution can sharply decrease the flux of each membrane. Reason that provoke flux decreasing and change the rejective ability was the cake formation on the surface membrane and the lignin aggregation.

Filtration↗

PubMedDate not supplied

Effect of lignins and their precursors on nitric oxide, citrulline and asparagine production by mouse macrophage-like Raw 264.7 cells.

Lignins, tannins and flavonoids are commonly found polyphenols. Among these polyphenols, lignins, polymers of phenylpropenoids complexed with polysaccharides, were the least cytotoxic and most potently stimulated the production of nitric oxide (NO), citrulline and asparagine by mouse macrophage-like Raw 264.7 cells. The maximum production of these substances reached the level attained by lipopolysaccharide (LPS). However, epigallocatechin gallate, phenylpropenoid monomers (ferulic acid, caffeic acid) and gallic acid (component unit of tannin) were inactive. These data suggest that the macrophage-stimulation activity of polyphenols depends, at least in part, on their molecular weight or structural configuration. There was a positive relationship between the extent of asparagine production and that of NO or citrulline. Western blot analysis demonstrated that both lignins and LPS elevated the cellular level of asparagine synthetase. The present study suggests the possible link between the stimulated asparagine production and macrophage activation.

Animals↗

PubMed2001

14C-[lignin]-lignocellulose biodegradation by bacteria isolated from polluted soil.

Four bacterial species [Branhamella catarrhalis (gram -ve), Brochothrix species (gram -ve), Micrococcus luteus (gram +ve) and Bacillus firmus (gram +ve)], isolated from the soil polluted with cane sugar factory effluents, were found capable of growing on solid media supplemented with indulin AT (a polymeric industrial lignin) as sole C source. All the four species could metabolize cinnamic acid (a non-hydroxylated phenylpropanoid) as sole carbon source with significant suppression on addition of readily metabolizable carbon source (glucose). However, Br. catarrhalis and Brochothrix sp. were capable of metabolizing ferulic acid, but could not do so on addition of glucose. Of the four species, Br. catarrhalis could evolve significant amount of 14CO2 from U-14C (lignin)-lignocellulose prepared from rice stalks (ca. 10% of the added radioactivity in 3 weeks), in addition to solubilization of another 11.7% radioactivity in culture filtrate. The other three species could not significantly evolve 14CO2, though a significant fraction of added 14C-lignin (6.1 to 11.2%) could be solubilized into culture filtrate, suggesting lack of ring-cleavage or other CO2 evolving mechanisms in these species.

Bacteria↗

PubMedDate not supplied

[Degradation of lignin-carbohydrate substrate by soil fungi--producers of laccase and cellobiose dehydrogenase].

The growth of nonsporulating mycelial fungi INBI 2-26(+), producer of laccase; INBI 2-26(-), producer of cellobiose dehydrogenase; and their mixed culture on lignin-carbohydrate substrates under conditions of submerged fermentation were studied. The degrees of degradation of lignin, cellulose, and hemicellulose of cut straw over 23 days amounted to 29.8, 51.4, and 72% for the laccase producer; 15.8, 33.9, and 59.1% for the cellobiose dehydrogenase producer; and 15.8, 39.4, and 64.5% for the mixed culture, respectively. The laccase activity in the medium when strain 2-26(+) was cultivated individually reached its maximum on day 28; the activity of cellobiose dehydrogenase of strain 2-26(-), on days 14 to 28. A method for determining cellobiose dehydrogenase activity in the presence of laccase was developed. In the mixed culture, both enzymes were formed; however, the level of laccase synthesis was 1.5-fold lower compared to that of strain 2-26(+), while synthesis of cellobiose dehydrogenase was similar to that of the corresponding producer. Cellobiose dehydrogenase failed to boost the action of laccase while degrading the lignin of straw.

Carbohydrate Dehydrogenases↗

PubMed1992

[Lignin and ligninase].

Ligninases (lignin peroxidases) are heme-containing peroxidases excreted by some white-rot fungi as components of their lignolytic multienzyme complexes. These peroxidases functioning at rather acidic media catalyze oxidative cleavage of both synthetic non-phenolic lignin models and many other oxidation-proof compounds (chloroorganic pesticides, carcinogenic hydrocarbons, etc.). Data on the ligninase structure and functions not only shed light of the lignin biodegradation but also open new perspectives in peroxidation chemistry and biotechnology. Many aspects of ligninase catalytic mechanism can be understood in comparative studies of congruent chemical reactions, e.g., peroxidisulfate-supported oxidation, as well as of ligninase-like activity of some plant and animal peroxidases which is also manifested at low pH. Ligninases are not only more powerful oxidative agents than other peroxidases, but also, in contrast to latters, appear to be able to control the contributions of C-C and C-O bond splitting in primary radical-cations of substrates. The contribution of the oxidative-hydrolytic dealkylation of radical cations can be considered as one of classification criteria for lignolytic enzymes.

Amino Acid Sequence↗

PubMedDate not supplied

Inhibitory effect of lignin-related pine cone extract on cell proliferating enzyme activity of spontaneous mammary tumours in mice.

A lignin-related cone extract of pine (Pinus parviflora Sieb et Zucc) (FrVI) or a synthetic lignin (DHP-FA) (175 micrograms/0.1 ml 0.9% NaCl solution) was injected intravenously to SHN mice bearing spontaneous mammary tumours three cycles each with consecutive 3 days of treatment and 4 days of interruption. Activities of both thymidylate synthetase (TS) and thymidine kinase (TK), i.e., DNA synthesizing enzymes in de novo and salvage pathways of pyrimidine metabolism, respectively, were apparently decreased in mammary tumours of FrVI-treated mice compared to those of the control mice bearing tumours without treatment. While the percent change of mammary tumour size during the experiment differed little among groups, both FrVI and DHP-FA prevented tumours from ulceration. Furthermore, the development and growth of preneoplastic mammary hyperplastic alveolar nodules were decreased by the treatments of both agents. They showed no toxicity. All results suggest that these lignin-related compounds, especially FrVI, may be useful as chemopreventive agents, with some improvement of administration method, and/or for employment in combination with any other agents.

Animals↗

PubMed2006

Reduction of DNA-damaging effects of anti-HIV drug 3'-azido-3'-dideoxythymidine on human cells by ursolic acid and lignin biopolymer.

In this study we verified our assumption that the genotoxicity of the effective anti-HIV drug 3'-azido-3'-dideoxythymidine (AZT) on human cells could be reduced by non-toxic concentrations of two antioxidants that occur frequently in nature (ursolic acid and lignin biopolymer). Cytotoxicity of these natural compounds, well-known by their antimutagenic effects, was evaluated by the trypan blue exclusion technique. Genotoxic activity of AZT was measured on the basis of AZT-induced single and double strand breaks to DNA in two histopathologically different types of human cells, hepatoma cells HepG2 and colonic cells Caco-2. Induction of DNA strand breaks was measured by the comet assay processed in parallel at pH > or = 13.0 (standard alkaline technique which enables to recognize single strand DNA breaks of different origin) and at pH = 9.0 (neutral technique which enables to recognize double strand DNA breaks). As the level of AZT-induced double strand DNA breaks was rather low, protective effects of the antioxidants tested were evaluated only against AZT-induced single strand DNA breaks by the standard alkaline comet assay. Our findings showed that 1 h pre-incubation of cells with ursolic acid or lignin preceding to 3 h treatment of cells with AZT (3 mg/ml) significantly decreased in both cell types the level of AZT-induced single strand DNA breaks. Pre-incubation of HepG2 or Caco-2 cells with a mixture of both natural antioxidants did not increase the effects of individual treatments. This study confirms that AZT is genotoxic toward both used cell types of human origin and that ursolic acid and biopolymer lignin can protect the cells studied against genotoxic effect of AZT.

Anti-HIV Agents↗

PubMedDate not supplied

Stimulation of mouse peritoneal macrophages by lignin-related substances.

Various lignified materials, including pine cone extract and a commercial lignin, stimulated the morphological change (spreading) of mouse peritoneal macrophages, and their functional maturation as judged by increase in NBT-reducing activity. When these materials were treated with NaClO2 to decompose the phenolic structure, their activity was completely eliminated, whereas the activity was rather enhanced when they were treated with H2SO4 to decompose their sugar moiety. Some monomeric phenolic compounds structurally related to lignin components and several antitumor glucan derivatives had little or no macrophage stimulating activity. The results strongly suggest the importance of lignin-structure in macrophage activation.

Animals↗