Comparison of the lignin-degrading white rot fungi Phanerochaete chrysosporium and Sporotrichum pulverulentum at the DNA level

Summary DNA-hybridisation studies showed a close relationship between Phanerochaete chrysosporium ME446, most used in lignin degradation studies, and Sporotrichum pulverulentum Novobranova, the other standard lignin degrading strain. Two other strains of P. chrysosporium were both less related. We show that P. chrysosporium ME446 and S. pulverulentum Novobranova both have a GC-content of 59% for chromosomal DNA with the rRNA genes present as an AT-rich satellite; the mitochondrial DNA has a GC-content of 33%. The genome size estimated for P. chrysosporium ME446 is about 4–5 × 10⁷ bp.     

The nature of extra-chromosomal maintenance of transforming plasmids in the filamentous basidiomycete Phanerochaete chrysosporium

Summary The nature of extra-chromosomal maintenance of the transforming plasmid p12-6 in Phanerochaete chrysosporium was studied. Our results indicate that the plasmid is maintained in the fungal transformants extra-chromosomally as part of a larger endogenous plasmid (designated pME) of P. chrysosporium. Using the total DNA of p12-6 fungal transformants, p12-6, as well as a larger plasmid, p511, were recovered in recA ^– E. coli strains while only p12-6 was recovered in recA ⁺ E. coli strains. The results also showed that the cytosine methylation system has no apparent effect on the strain-dependent recovery of p12-6 and p511 in E. coli from the total DNA of fungal transformants.     

Biodegradation of Gaseous Chlorobenzene by White-rot Fungus Phanerochaete chrysosporiurn

To evaluate the effect of white rot fungus Phanerochaete chrysosporium on removal of gaseous chlorobenzene.Methods Fungal mycelium mixed with a liquid medium was placed into airtight bottles.A certain amount of chlorobenzene was injected into the headspace of the bottles under different conditions.At a certain interval,the concentrations in the headspace were analyzed to evaluate the degradation of chlorohenzene by P.chtysosporium.Results The degradation effects of P chrysosporium on chlorobenzene under different conditions were investigated.The difference in the optimum temperature for the growth of the fungi and chlorobenzene degradation was observed.The data indicated that a lower temperature (28℃) would promote the degradation of chlorobenzene than the optimum temperature for the growth of the fungi (37℃).A low nitrogen source concentration (30 mg N/L) had a better effect on degrading chlorohenzene than a high nitrogen source concentration (higher than 100 mg N/L).A high initial concentration (over 1100 mg/m3) of chlorobenzene showed an inhibiting effect on degradation by P.chrysosporium.A maximum removal efficiency of 95% was achieved at the initial concentration of 550 mg/m3.Conclusion P.chrysosporium has a rather good ability to remove gaseous chlorobenzene.A low nitrogen source concentration and a low temperature promote the removal of chlorohenzene by P.chrysosporium.However,a high initial chlorobenzene concentration can inhibit chlorobenzene degradation.     

黄孢原毛平革菌合成锰过氧化物酶的工艺

研究了多种营养条件及培养条件对黄孢原毛平革菌 (Phanerochaetechrysosporium )WX2 13合成锰过氧化物酶的影响 .当培养基中葡萄糖质量浓度为 10 g/L ,酒石酸铵质量浓度为0 .2 g/L,吐温 80质量浓度为 1g/L ,MnSO4 ·H2 O为 0 .14g/L ,采用苯二甲酸缓冲液 ,最终pH 4 .5 ,2 5 0mL的三角瓶装液量 90mL ,接种量为 1.2× 10 6mL- 1时所获酶活较高 .经条件优化后锰过氧化物酶的活力达到 5 5 9U/L ,比未优化前提高了 36% .加入染料培养 ,发现该酶对所选用的偶氮染料、三苯甲烷类染料、杂环类染料均有较好的脱色效果     

Pentachlorophenol biodegradation and detoxification by the white‐rot fungus Phanerochaete chrysosporium

Pentachlorophenol (PCP) was widely used as a wood preservative and pesticide for several decades. Presently it is considered an ubiquitous contaminant, so it is important to find a good strategy to reduce PCP levels in the environment. One feasible option is using the ability of certain microorganisms to biodegrade pollutants and convert them into less toxic compounds. Phanerochaete chrysosporium, a white‐rot fungus, is recognized for its ability to metabolize a large diversity of compounds, including PCP, by the lignin degrading system. However, toxicity of PCP metabolic products generated by P. chrysosporium is not yet evaluated. The study's purpose is assessing toxicity resulting from PCP degradation by P. chrysosporium in soil and evaluating its potential usefulness in soil bioremediation. P. chrysosporium was cultured in a solid‐state system consisting of glass columns packed with crushed fibrous plant residue from sugar‐cane refining. Once the fungus grew, it was used to inoculate soil spiked with 100 ppm of PCP, at soil/plant residue ratio of 85/15. Under these conditions, PCP degradation kinetic study was performed for 11 days. Soil samples were collected during this period assessing PCP disappearance and soil toxicity changes using Microtox^®. A significant decrease (87%) in PCP levels in contaminated soil was observed 4 days after inoculation with P. chrysosporium. During this period, soil toxicity decreased rapidly, becoming almost negligible after 11 days. These results suggested P. chrysosporium application to PCP‐contaminated soil is a feasible bioremediation option, considering that this microorganism reduces PCP levels in a short period of time without generation of more toxic compounds. © 2000 John Wiley & Sons, Inc. Environ Toxicol 15: 107–113, 2000     

Would it be possible to use nonpathogenic fungi to improve the turnover of crop residues?

This study was aimed to assess the suitability of four fungal species for operating in the residues of three crops in Golestan province, Iran. For this, four experiments were conducted to analyze their ability to grow on five culture media (Experiment I) and on the residues (Experiment II) and their growth responses to different pHs (Experiment III) and temperature levels (Experiment IV). Then, the possibility of establishing these fungi in the cultivated lands of studied crops was examined. Fungal growth was high on soybean and cotton residues and low on those of rice, and all the fungi produced a significant reduction in the carbon to nitrogen ratios in relation to noninoculated residues. The amount of nitrogen in fungal-treated cotton residues increased about four times compared with the control and in other studied residues increased twice as much as the control. The lowest C:N values for cotton and rice residues were found for Pleurotus ostreatus while Aspergillus niger was the most efficient for those of soybean. The results also showed that these fungi will not show the best performance in respect to temperature and pH, but will not be ineffective. The results could be the basis for further studies on the use of these fungi to improve nutrient cycling, focusing on multicriteria zoning on climatic and soil-related components.     

黄孢原毛平革菌产蛋白酶对过氧化物酶的影响

在培养黄孢原毛平革菌产生木质素过氧化物酶(LiP)和锰过氧化物酶(MnP)过程中产生的胞外蛋白酶与LiP和MnP的快速失活有关.该蛋白酶在pH 7的条件下酶活很高,其主要作用是促进LiP和MnP的分解,而不是抑制它们的产生.HgCl2是蛋白酶的抑制剂,其抑制机理类似于HgCl2对蛋白酶K(PK)的抑制.添加HgCl2的发酵液能提高过氧化物酶的酶活和稳定性,最佳添加量为1 μmol/L,最佳添加时间在接种后第5天.