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PubMed1990

Selection and characterization of mutants of Phanerochaete chrysosporium exhibiting ligninolytic activity under nutrient-rich conditions.

Synthesis of the ligninolytic system of the wood-degrading fungus Phanerochaete chrysosporium is induced during secondary metabolism, brought about by nitrogen, carbon, or sulfur starvation. We describe here a strategy for selection of mutants which are ligninolytic (lignin----CO2) and overproduce lignin-degrading enzymes (ligninases) under nutrient-rich conditions (during primary metabolism). The strategy is based on using an adduct of lysine and a lignin model compound. Ligninase-dependent oxidation of this adduct releases free lysine, which complements the lysine requirements of a lysine auxotroph. Accordingly, a lysine auxotroph was mutagenized by UV irradiation and survivors were plated onto medium containing the adduct and high ammonia nitrogen. Four mutants which overproduce the ligninase isozymes were isolated by this procedure. Further characterization of one of the mutants, PSBL-1, indicated that the predominant isozymes produced are H1 (pI = 4.7) and H2 (pI = 4.4). The ligninase activity of PSBL-1, measured by veratryl alcohol oxidation, peaks on day 5 at over 1,000 U.liter-1. The mutant PSBL-1 was also able to degrade [14C]lignin to 14CO2, indicating that the complete ligninolytic system is deregulated.

Basidiomycota↗
PubMed1975

Basis for the resistance of several algae to microbial decomposition.

The basis for the resistance of certain algae to microbial decomposition in natural waters was investigated using Pediastrum duplex, Staurastrum sp., and Fischerella muscicola as test organisms. Enzyme preparations previously found to convert susceptible algae into spheroplasts had no such effect on the resistant species, although glucose and galacturonic acid was released from P. duplex walls. Little protein or lipid but considerable carbohydrate was found in the walls of the refractory organisms, but resistance was not correlated with the presence of a unique sugar monomer. A substance present in Staurastrum sp. walls was characterized as lignin or lignin-like on the basis of its extraction characteristics, infrared spectrum, pyrolysis pattern, and content of an aromatic building block. Sporopollenin was found in P. duplex, and cellulose in Staurastrum sp. Cell walls of the algae were fractionated, and the fractions least susceptible to microbial degradation were the sporopollenin of P. duplex, the polyaromatic component of Staurastrum sp., and two F. muscicola fractions containing several sugar monomers. The sporopollenin content of P. duplex, the content of lignin or a related constituent of Staurastrum sp., and the resistance of the algae to microbial attack increased with age. It is suggested that resistance results from the presence of sporopollenin in P. duplex, a lignin-like material in Staurastrum sp., and possibly heteropolysaccharides in F. muscicola.

Bacteria↗
PubMed2000

Thatch biodegradation and antifungal activities of two lignocellulolytic Streptomyces strains in laboratory cultures and in golf green turfgrass.

The use of lignocellulolytic Streptomyces spp. as biological agents, to enhance thatch degradation in turf and to slow its rate of accumulation while controlling fungal growth in the thatch layer, was studied. In flask scale studies, two lignocellulolytic Streptomyces violaceusniger (= hygroscopicus) strains (YCED9 and WYE53) decomposed thatch (> 30% dry weight) over a 12-week incubation period. Biodegradation was accompanied by production of extracellular cellulases, xylanases, and peroxidases. The accumulation of the polymeric, water-soluble lignin degradation intermediate acid, precipitable polymeric lignin (APPL), was also observed. Residual thatch from 12-week-old cultures had an increased lignin-to-carbohydrate ratio, an indication that although lignin was metabolized, carbohydrates were preferential carbon sources for these actinomycetes. A spore-containing soluble dry powder formulation was used as an inoculum in an in situ field experiment. This formulation was maintained in storage at 4 degrees C for over two years without viability loss. Results from the golf green experiment showed that although treated thatch layers in established greens were not appreciably reduced over the course of one summer, the Streptomyces were active and maintained their populations within the thatch, while fungal growth was suppressed as compared to controls. The results show that treatment of turfgrass with these Streptomyces may be useful for the long-term control of fungal populations within the thatch. Longer field studies are required to assess the long-term potential for also controlling thatch build-up and fungal pathogens.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2000

Fundamental factors affecting biomass enzymatic reactivity.

Poplar wood was treated with peracetic acid, KOH, and ball milling to produce 147 model lignocelluloses with a broad spectrum of lignin contents, acetyl contents, and crystallinity indices (CrIs), respectively. An empirical model was identified that describes the roles of these three properties in enzymatic hydrolysis. Lignin content and CrI have the greatest impact on biomass digestibility, whereas acetyl content has a minor impact. The digestibility of several lime-treated biomass samples agreed with the empirical model. Lime treatment removes all acetyl groups and a moderate amount of lignin and increases CrI slightly; lignin removal is the dominant benefit from lime treatment.

Acetylation↗
PubMed2000

On the interaction of UV screens with the lignocellulosic matrix.

In this report, we describe our attempt to understand the photochemical interactions that occur between dihydroxybenzophenone (DHB)-based UV screens and lignin when high-yield pulps are treated with such materials. Milled wood lignin (MWL) and filter paper were used as models, and various irradiation protocols were carried out in the presence and absence of UV screens. After irradiation, the lignin and the UV screen were extracted and the products analyzed. These experiments showed that upon irradiation, fragments of MWL-containing chromophores were linked to cellulose via an acid-labile linkage. In the presence of UV screens, these reactions were minimized. Molecular weight measurements of the extracted lignin showed that the MWL is degraded upon solid-state irradiation. The samples that contained UV screens showed a reduced tendency to degrade. Using quantitative 31P NMR, it was possible to probe further the detailed structural changes that occurred in MWL during irradiation. In general, DHB-based UV screens and derivatives were found to interact actively with MWL when irradiated.

Benzophenones↗
PubMed2005

Evaluation of simplifying assumptions on pesticide degradation in soil.

There is evidence that degradation of pesticides in simple laboratory systems may differ from that in the field, but it is not clear which of the simplifications inherent in laboratory studies present serious shortcomings. Laboratory experiments evaluated several simplifying assumptions for a clay loam soil and contrasting pesticides. Degradation of cyanazine [2-(4-chloro-6-ethylamino-1,3,5-triazin-2-ylamino)-2-methylpropiononitrile] and bentazone [3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] at fluctuating temperature and moisture was predicted reasonably well based on parameters derived from degradation under constant conditions. There was a tendency for slower degradation of cyanazine and bentazone in soil aggregates of 3 to 5 mm in diameter (DT50 at 15 degrees C and 40% maximum water holding capacity of 25.1 and 58.2 d, where DT50 is the time for 50% decline of the initial pesticide concentration) than in soil sieved to <3 mm (DT50 of 19.1 and 37.6 d), but the differences were not significant for most datasets. Degradation of cyanazine, isoproturon [3-(4-isopropylphenyl)-1,1-dimethylurea], and chlorotoluron [3-(3-chloro-p-tolyl)-1,1-dimethylurea] was measured in soil amended with different amounts of lignin. The effect of lignin on degradation was small despite considerable differences in sorption. The DT50 values of cyanazine, isoproturon, and chlorotoluron were 16.2, 18.6, and 33.0 d, respectively, in soil without lignin and 19.0, 23.4, and 34.6 d, respectively, in soil amended with 2% lignin. Degradation of bentazone and cyanazine in repacked soil columns was similar under static and flow conditions with 50.1 and 47.2% of applied bentazone and 74.7 and 73.6% of applied cyanazine, respectively, degraded within 20 d of application. Thus, the assumptions underpinning laboratory to field extrapolation tested here were considered to hold for our experimental system. Additional work is required before general conclusions can be drawn.

Aluminum Silicates↗
PubMed1987

Properties of ligninase from Phanerochaete chrysosporium and their possible applications.

The wood-degrading fungus Phanerochaete chrysosporium Burds produces a family of enzymes which degrade lignin and lignin-like substrates. These ligninases exhibit a high degree of homology in being hemeprotein peroxidases, in Mr, in cross reactivity to polyclonal antibodies, in being glycosylated, and in catalytic properties. The predominant ligninase is able to generate cation radicals in its aromatic substrates. These radicals can undergo a variety of reactions thus explaining the nonspecific nature of the enzyme. A similar mechanism is suggested for the other isoenzymes. There are numerous potential applications for ligninases. These include: biopulping, waste treatment of byproduct lignins, detoxification of environmental pollutants, and modification of lignins to produce small molecular weight organics.

Basidiomycota↗
PubMed2001

Association of lignifying enzymes in shell synthesis of oil palm fruit (Elaeis guineensis--dura variety).

Scanning electron microscopic (SEM) observation demonstrates the differentiation of mesocarp and endocarp tissues and their lignified nature in dura fruits at 8 weeks after pollination (WAP). During shell formation, the endocarp cells become lignified to a hard shell while the mesocarp tissue remains cellular and fibrous. A transition zone made up of fibrous units was also visible beneath the shell. The soluble phenols of mesocarp and endocarp tissues at their developmental stage was analyzed using Reverse phase high performance liquid chromatography (RP-HPLC). The appearance of ferulic acid at 4 WAP and its absence at 8 WAP indicates the role of ferulic acid in lignin synthesis. The HPLC data was supported by the lignin concentration. To ascertain the biochemical relationship of lignin pathway enzymes, phenylalanine ammonia lyase (PAL), cinnamyl alcohol-NADPH-dehydrogenase (CAD) and peroxidase (POD) with shell synthesis, the activities of these enzymes and lignin content were assessed during development of the shell between 4 and 8 WAP. The three enzymes, PAL, CAD and POD expressed high level of activity in the mesocarp and endocarp at 4 WAP. At 8 WAP a sharp decline in activity was observed in the endocarp whereas the mesocarp showed a moderate reduction. This variation is an indication of the role of these enzymes in shell formation.

Chromatography, High Pressure Liquid↗
PubMed2001

Fractal analysis of STM images of photochemical polymer of coniferyl alcohol.

Fractal analysis was applied to images of photochemical lignin polymer obtained using scanning tunneling microscope. We studied the polymer obtained in vitro by ionic mechanism through UV radiation--induced polymerization. The analysis showed the regularity of the lignin-like polymer at different levels of organization. At the 95% confidence level, there was no significant difference in the fractal dimension between images representing different organizational levels of photochemical lignin. That means that lignin produced in in vitro conditions by photochemical mechanism of synthesis, has a fractal structural organization. The obtained values of the fractal dimension are in good agreement with the theoretically predicted value for the polyaddition and polycondensation mechanism of polymerization, known as the bulk model.

Fractals↗
PubMed2003

[Degradation of poplar wood by Fomes sclerodermeus: production of ligninolytic enzymes in sawdust of poplar and cedar].

Fomes sclerodermeus is a white-rot fungus. Its production of laccase, manganese peroxidase and lignin peroxidase on sawdust-based media was evaluated. No lignin peroxidase activity was measured in any media tested. The higher production of laccase and manganese peroxidase were found on media containing poplar sawdust. F. sclerodermeus was grown on wood blocks of poplar during six months. Dry weight losses of the blocks reached a mean value of 51%. The quantification of cellulose and lignin in the 6-months incubated blocks showed losses of up to 58 and 56% for cellulose and lignin, respectively. The decay examined under microscope revealed mycelium colonizing the lumen of vessel elements, cell wall thinning and entire degradation of the radial parenchyma.

Biodegradation, Environmental↗
PubMedDate not supplied

Induction of cytotoxic factor in mice by lignified materials combined with OK-432 (Picibanil).

Intravenous administration of pine cone lignin-related substance (Fr. VI) significantly stimulated OK-432-elicited cytotoxic factor (CF) production in ICR mouse serum. The level of CF elicited after OK-432 administration peaked after 2 h and declined to basal level within 6 h. The CF productibility depended greatly on both dose and the interval between the administration of the Fr. VI and OK-432. Most natural and synthetic lignins, their degradation products, and polysaccharides, including pine cone hemicellulose fractions, had much weaker CF-inducing (priming) activity. When Fr. VI was treated with NaCl02 to decompose the lignin portion, the priming activity was significantly reduced. The data suggest that the potent priming activity of Fr. VI might de a result of some conjugation between the lignin portion and other components including polysaccharides.

Animals↗
PubMed1985

Dietary fiber constituents of selected fruits and vegetables.

This study compared the dietary fiber (DF), neutral detergent fiber (NDF), cellulose, hemicellulose, lignin, and pectin content of selected fruits and vegetables. Apples and peaches (fresh and canned), oranges (fresh), strawberries (fresh, canned, and frozen), carrots, green beans, and potatoes (fresh, fresh cooked, canned, and frozen), and tomatoes (fresh, fresh cooked, and canned) were studied. When possible, two varieties, two stores, and name and store brands were chosen. Samples were analyzed for NDF, acid detergent fiber, 72% sulfuric acid, lignin, and pectin. From those values, DF, cellulose, and hemicellulose were calculated. Fresh fruits in gm/100gm wet weight had decreasing DF, NDF, and hemicellulose values as follows: apples, peaches, strawberries, and oranges. Apples were highest in cellulose; strawberries, highest in lignin; and oranges, highest in pectin. Fresh-cooked vegetables in gm/100gm wet weight have decreasing DF and NDF values as follows: green beans, carrots, potatoes, and tomatoes. Green beans were highest in cellulose and hemicellulose; potatoes highest in lignin; and carrots highest in pectin. On a wet-weight basis, fresh apples and peaches, fresh-cooked green beans, canned carrots, and canned and frozen potatoes were higher in DF and NDF than other forms of the fruit or vegetable. There were few differences according to stores, brands, or varieties of fruits and vegetables. On a dry-weight basis, fresh apples, peaches, strawberries, green beans, and tomatoes appear to have higher DF and NDF contents than their processed counterparts. Fresh-cooked carrots and fresh potatoes appear to have less DF and NDF than their canned and frozen counterparts.

Cellulose↗
PubMedDate not supplied

[Biotransformation of lignocellulse by the fungi Pleurotus floridae (Fries) Kummer and Phellinus igniarius (Linnearus:Fries) Quelet--the pathogens of white rot in trees].

The peculiarities of lignocellulose biotransformation by white-rot fungi Pleurotus floridae and Phellinus igniarius during their solid-state fermentation of wastes of oil-bearing crops processing has been studied. The dynamics of oil-bearing crops processing wastes bioconversion has been studied. It has been marked that P. floridae utilized 20% cellulose and lignin during 9 weeks and 40% lignin and 30% cellulose during all period of fermentation (19 weeks). The fungus P. igniarius utilized mainly cellulose (40% cellulose and 24% lignin in 19 weeks). Lignin-degradative capacity of P. floridae (KL = 0.57) and P. igniarius (KL = 0.34) has been quantitatively estimated. The degradation of plant biopolimers corresponded to the production of ligninolytic (laccase, Mn(2+)-dependent peroxidase,) and cellulolytic (CMC-cellulase) enzymes. The component and isoenzyme content of ligninolytic enzyme complex of fungi Pleurotus floridae and Phellinus igniarius has been determined.

Basidiomycota↗
PubMed1999

Addition of veratryl alcohol oxidase activity to manganese peroxidase by site-directed mutagenesis.

Manganese peroxidase and lignin peroxidase are ligninolytic heme-containing enzymes secreted by the white-rot fungus Phanerochaete chrysosporium. Despite structural similarity, these peroxidases oxidize different substrates. Veratryl alcohol is a typical substrate for lignin peroxidase, while manganese peroxidase oxidizes chelated Mn2+. By a single mutation, S168W, we have added veratryl alcohol oxidase activity to recombinant manganese peroxidase expressed in Escherichia coli. The kcat for veratryl alcohol oxidation was 11 s-1, Km for veratryl alcohol approximately 0.49 mM, and Km for hydrogen peroxide approximately 25 microM at pH 2.3. The Km for veratryl alcohol was higher and Km for hydrogen peroxide was lower for this manganese peroxidase mutant compared to two recombinant lignin peroxidase isoenzymes. The mutant retained full manganese peroxidase activity and the kcat was approximately 2.6 x 10(2) s-1 at pH 4.3. Consistent with relative activities with respect to these substrates, Mn2+ strongly inhibited veratryl alcohol oxidation. The single productive mutation in manganese peroxidase suggested that this surface tryptophan residue (W171) in lignin peroxidase is involved in catalysis.

Alcohol Oxidoreductases↗
PubMed1990

Characteristics and N-terminal amino acid sequence of a manganese peroxidase purified from Lentinula edodes cultures grown on a commercial wood substrate.

Extracellular culture filtrates from ligninolytic cultures of the lignin-degrading basidiomycete Lentinula (syn. Lentinus) edodes (Berk.) Pegler contained one major peroxidase when grown on a commercial oak-wood substrate. The peroxidase was purified by polyethylenimine clarification, anion-exchange chromatography, and hydrophobic-interaction HPLC. The enzyme (MnP1) was a heme-iron protein with an apparent molecular weight of 44,600 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels and an isoelectric point of pH 3.2. The native enzyme had an absorption maximum at 407 nm, which shifted to 420 nm upon H2O2 addition. The pyridine-hemochrome-absorption spectrum indicated that one heme group was present per enzyme as protoporphyrin IX. N-Terminal amino acid sequencing showed that MnP1 had higher sequence homology with manganese peroxidases than with lignin peroxidases reported from Phanerochaete chrysosporium. L. edodes MnP1 was capable of oxidizing lignin and lignin-model compounds in the presence of manganese and H2O2.

Amino Acid Sequence↗
PubMed1991

Immunologic relatedness of extracellular ligninases from the actinomycetes Streptomyces viridosporus T7A and Streptomyces badius 252.

Four isoforms of the extracellular lignin peroxidase of the ligninolytic actinomycete Streptomyces viridosporus T7A (ALip-P1, P2, P3, and P4) were individually purified by ultrafiltration and ammonium sulfate precipitation, followed by electro-elution using polyacrylamide gel electrophoresis. Three of the purified peroxidases were compared for their immunologic relatedness by Western blot analysis using a polyclonal antibody preparation produced in rabbits against pure isoform P3. The anti-P3 antibody was also tested for its reactivity towards a lignin peroxidase from the white-rot fungus Phanerochaete chrysosporium and another ligninolytic actinomycete Streptomyces badius 252. Results showed that peroxidases ALip-P1 through ALip-P3 are immunologically related to one another. The peroxidases of S. badius, but not the peroxidase of P. chrysosporium, also reacted with the antibody, thus indicating that the lignin peroxidases of S. viridosporus and S. badius are immunologically related. Based upon its specific affinity, lignin peroxidase isoform ALip-P3 of S. viridosporus was readily purified using an anti-P3 antibody affinity column.

Blotting, Western↗
PubMed2002

Degradation of chlorophenols by Phanerochaete chrysosporium: effect of 3,4-dichlorophenol on extracellular peroxidase activities.

Extracellular peroxidases play an important role in the degradation of chlorophenols by Phanerochaete chrysosporium. Depending on the moment of 3,4-dichlorophenol addition, the production of lignin peroxidase and manganese peroxidase in C-limited agitated cultures was affected in opposite ways. In cultures that received 3,4-dichlorophenol at the time of inoculation, fungal growth was reduced and peroxidases were not produced, whereas peroxidase activities were stabilized after 3,4-dichlorophenol addition to pregrown cultures. Further investigation revealed that mRNA encoding lignin peroxidase was not produced in cultures started with 3,4-dichlorophenol, suggesting that the onset of secondary metabolism was affected. In addition, the stabilization of lignin peroxidase activity was not the result of an activation of lignin peroxidase gene transcription, as shown by Northern blot experiments, but likely due to the inhibition of peroxidase degradation by extracellular proteases.

Biodegradation, Environmental↗
PubMed1991

Degradation of azo compounds by ligninase from Phanerochaete chrysosporium: involvement of veratryl alcohol.

Phanerochaete chrysosporium decolorized several polyaromatic azo dyes in ligninolytic culture. The oxidation rates of individual dyes depended on their structures. Veratryl alcohol stimulated azo dye oxidation by pure lignin peroxidase (ligninase, LiP) in vitro. Accumulation of compound II of lignin peroxidase, an oxidized form of the enzyme, was observed after short incubations with these azo substrates. When veratryl alcohol was also present, only the native form of lignin peroxidase was observed. Azo dyes acted as inhibitors of veratryl alcohol oxidation. After an azo dye had been degraded, the oxidation rates of veratryl alcohol recovered, confirming that these two compounds competed for ligninase during the catalytic cycle. Veratryl alcohol acts as a third substrate (with H2O2 and the azo dye) in the lignin peroxidase cycle during oxidations of azo dyes.

Agaricales↗