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11.
The decomposition of the amidinohydrazone-type insecticide Hydramethylnon (HMN) by soil fungi has been investigated. A simple spectrophotometric method was developed for the estimation of HMN in soil and fungal culture media. HMN was found to be degraded in soil with a half life of 14 to 25 days.Degradation of HMN by the lignolytic fungus,Phanerochaete chrysosporium yielded two major breakdown products;p-(trifluoromethyl)-cinnamic acid (TFCA) andp-(trifluoromethyl)-benzoic acid (TFBA). TFCA was converted to TFBA which was subsequently metabolised via themeta-fission pathway. Fluoride release from HMN could not be detected.Abbreviations BzDAc
benzene, dioxane, acetic acid (60: 36: 4)
- DCM
dichloroethane
- DNPH
2,4-dinitro-phenylhydrazine
- HMN
Hydramethylnon
- TDAc
toluene, dioxane, acetic acid (90: 30: 1)
- TFCA
p-(trifluoromethyl)-cinnamic acid
- TFBA
p-(trifluoromethyl)-benzoic acid
- TFP
1,5-bis(trifluoro-p-tolyl)-1,4-pentadien-3-one
- VA
veratryl alcohol 相似文献
12.
Shinichi Yoshida Saori Yonehara Shigemi Minami Hyo-cheol Ha Kenji Iwahara Takashi Watanabe Yoichi Honda Masaaki Kuwahara 《Mycoscience》1996,37(4):417-425
Manganese peroxidase (MnP) and lignin peroxidase (LiP) were produced by growing a white-rot fungusBjerkandera adusta statically, on a wood meal/wheat bran culture in flasks. MnP and LiP reached their maximum activity after 6 and 19 days of
inoculation, respectively. Both MnP and LiP are thought to be important enzymes in lignin biodegradation byB. adusta. Ion exchange chromatography showed thatB. adusta produced a single LiP and a single MnP enzyme in wood meal/wheat bran culture. These enzymes were separated and characterized.
The molecular weight of MnP was 46,500 with a pl of 3.9. The molecular weight of LiP was estimated to be 47,000 with a pl of 3.5. Spectral analysis demonstrated that both enzymes are heme proteins. Production of these enzymes was also achieved
using a rotarysolid culture fermenter. MnP, LiP and veratryl alcohol oxidase were produced byB. adusta in the fermenter. 相似文献
13.
Manipulation of quality and mineralization of tropical legume tree prunings by varying nitrogen supply 总被引:5,自引:1,他引:4
The effect of N supply on the quality of Calliandra calothyrsus and Gliricidia sepium prunings was studied in a glasshouse over a 7-month growing period. Increasing the concentration of N supplied from 0.625 to 10.0 mM NO3-N resulted in increased N concentration but decreased polyphenol concentration, protein-binding capacity and C:N ratio of prunings from both species. Lignin concentration was not consistently altered by the N treatment. Mineralization of N from the prunings was measured over a 14-week period under controlled leaching and non-leaching conditions. The results indicated a strong interaction between legume species and concentration of N supply in their influence on N mineralization of the prunings applied to the soil. Differences in the %N mineralized were dictated by the quality of the prunings. The (lignin + polyphenol):N ratio was the pruning quality factor which could be used most consistently and accurately to predict N mineralization of the legume prunings incubated under leaching conditions, and the relationship was best described by a linear regression. Under non-leaching conditions, however, the protein-binding capacity appeared to be the most important parameter in determining the patterns of N release from the prunings studied. The relationship between the N mineralization rate constant and the protein-binding capacity was best described by a negative exponential function, y=0.078 exp(–0.0083x). The present study also indicated that the release of N from legume prunings containing a relatively high amount of polyphenol could be enhanced by governing the N availability conditions under which the plant is grown, for example whether or not it is actively fixing nitrogen. Estimates of pruning N mineralization after 14 weeks with the difference method averaged 6% (leaching conditions) and 22% (nonleaching conditions) more than with the 15N method for all legume prunings studied. The recovery of pruning by maize (4–38%) was well correlated with the % pruning N mineralized suggesting that incubation data closely reflect the pruning N value for a given catch crop under non-leaching conditions. 相似文献
14.
Evaluation of cellulase recycling strategies for the hydrolysis of lignocellulosic substrates 总被引:8,自引:0,他引:8
Recycling of cellulases should lower the overall cost of lignocellulosiic bioconversion processes. In this study, three recycling strategies were evaluated to determine their efficiencies over five successive rounds of hydrolysis. The effect of lignin on recycling was examined by comparing water-washed, steam-exploded birch (WB; 32% lignin) and WB which had been further extracted with alkali and peroxide (PB; 4% lignin). When the cellulases were recovered from the residual substrates after partial hydrolysis of both substrates, the recovered cellulase activity toward the mixture of fresh and residual substrates decreased after each recycling step. When the cellulases in the supernatants were also recycled, up to 20% more activity could be recovered. In both of these cases, the recovered activities did not correspond to the activities expected from the amount of cellulase protein recovered during recycling. The best recovery was obtained when the cellulases were recovered from both the residue and the supernatant after complete hydrolysis of the PB substrate. In this case, all of the originally added cellulase activity could be recovered for four consecutive hydrolysis rounds. However, when the same recycling strategy was carried out using the WB substrate, the recovered cellulase activity declined quickly with each recycling round. In all three of the recycling strategies, lower cellulase activities were recovered from the substrates with higher lignin contents. (c) 1995 John Wiley & Sons, Inc. 相似文献
15.
M. Pal A. M. Calvo M. C. Terrón A. E. González 《World journal of microbiology & biotechnology》1995,11(5):541-545
The mushroom Flammulina velutipes and the white-rot fungus Trametes versicolor were cultivated separately on sugarcane bagasse for 40 days. Trametes versicolor produced laccase and manganese-peroxidase activities, showing a simultaneous degradation of lignin and holocellulose. However, only phenoloxidase activity was found with Flammulina velutipes. A preferential degradation of lignin was detected in F. velutipes, which exhibited a greater reduction in the ratio of weight loss to lignin loss than T. versicolor. A decrease in the syringyl/guaiacyl ratio observed with both fungi indicated the preferential degradation of non-condensed (syringyl-type) lignin units. An increase in the relative abundance of aromatic carboxylic acids suggested that the oxidative transformation of lignin unit side-chains was occurring. This was more noticeable with Flammulina velutipes than with T. versicolor. 相似文献
16.
Wheat straw was pretreated with saturated lithium chloride in 4 m hydrochloric acid at 50°C for 1 h, then hydrolysed at 100°C for 1 min, to give 84% conversion to monosaccharides. Particle sizes, 150–355 mesh, were easily hydrolysed. Samples pretreated with saturated lithium chloride in 1 m hydrochloric acid at 27°C for 24 h were hydrolysed by Trichoderma viride cellulase (MVA 1284) [1,4-(1,3;1,4)-β-d-glucan 4-glucanohydrolase, EC 3.2.1.4] to give 20–23% monosaccharides for particle sizes of 150–250 mesh, and 82–95.4% for particle sizes of 250–355 mesh. 相似文献
17.
Abstract A lignin substructure model, 1-(4-ethoxy-3,5-dimethoxyphenyl)-2-(4-ethoxy-3-methoxyphenyl)-propane-1,3-diol(I), was actively metabolized by a white-rot fungus Coriolus versicolor in low nitrogen stationary cultures favouring the ligninolytic activity in the fungus. Cleavage of the dimer I between Cα and Cβ of the propanoid side chain was the major degradative reaction by the fungus. 相似文献
18.
Effects of chemical composition on nitrogen mineralization from green manures of seven tropical leguminous trees 总被引:8,自引:1,他引:7
Green manures from seven tropical leguminous trees were incubated with soil to determine the rates and controls of net nitrogen release. Fresh green manure (leaves and succulent twigs) was mixed with moist soil and incubated in polyethylene bags. Net N mineralization from green manures was estimated by the accumulation of extractable ammonium and nitrate minus the accumulation in soil alone. Patterns of N mineralization were complex, differed among species, and at 12 weeks ranged from 10 to 65 percent of original green-manure N. Cumulative net N mineralization was negatively correlated with initial soluble polyphenol content in the early phases of decomposition (1 through 8 weeks) and with initial lignin content in later phases (4 through 12 weeks). Neither initial percent N nor lignin: N ratio were strongly correlated with N mineralization. The best chemical index of N release was the initial polyphenol: N ratio. This study confirms previous findings that N mineralization from tropical legumes is controlled more by soluble polyphenols than by lignin or N content. 相似文献
19.
Pablo Collazo Lluís Montoliu Pere Puigdomènech Joan Rigau 《Plant molecular biology》1992,20(5):857-867
The isolation and characterization of cDNA and homologous genomic clones encoding the lignin O-methyltransferase (OMT) from maize is reported. The cDNA clone has been isolated by differential screening of maize root cDNA library. Southern analysis indicates that a single gene codes for this protein. The genomic sequence contains a single 916 bp intron. The deduced protein sequence from DNA shares significant homology with the recently reported lignin-bispecific caffeic acid/5-hydroxyferulic OMTs from alfalfa and aspen. It also shares homology with OMTs from bovine pineal glands and a purple non-sulfur photosynthetic bacterium. The mRNA of this gene is present at different levels in distinct organs of the plant with the highest accumulation detected in the elongation zone of roots. Bacterial extracts from clones containing the maize OMT cDNA show an activity in methylation of caffeic acid to ferulic acid comparable to that existing in the plant extracts. These results indicate that the described gene encodes the caffeic acid 3-O-methyltransferase (COMT) involved in the lignin biosynthesis of maize. 相似文献
20.
The biodegradation of anthracene-9, 10-diethanol by the ligninolytic fungus Phanerochaete chrysosporium, previously though to involve singlet oxygen, is shown to be catalyzed by lignin peroxidases. Veratryl alcohol stimulated the enzymatic degradation of anthracenediethanol, and anthracenediethanol inhibited enzymatic oxidation of veratryl alcohol. Competition for oxidation by lignin peroxidase is suggested as the mechanism of the inhibition of lignin biodegradation by anthracenediethanol and related anthracene derivatives.Abbreviations ADE
anthracene-9,10-diethanol
- AES
anthracene-9,10-bisethanesulfonic acid
- DHP
dehydrogenative polymerizate
- DMF
N,N-dimethylformamide
- EPX
9,10-endoperoxide of ADE
- PMR
proton magnetic resonance 相似文献