Enhancement of Hydrocarbon Removal in a Clay and Drilling-Waste Polluted Soil

The application of biological processes in restoring oil polluted sites is growing due to their efficiency in removing different classes of pollutants. The aim of this study was to determine the ability of microorganisms present in a drilling-waste polluted soil (36,200 mg TPH kg^?1 soil) to remove weathered hydrocarbons under stimulated and non-stimulated soil conditions. The hypothesis under study was whether petroleum hydrocarbons removal could be enhanced by manipulating C/N ratio, water content and addition of three agroindustrial wastes. A Box-Behnken design was employed to evaluate the effect of each variable. Results demonstrated that, for orange peels and banana trunk treatments, the variable with the largest effect (p < 0.01) on hydrocarbon removal was the C/N ratio, indicating that higher ratio (100/3) improved removal (79.5–82%). The largest effect (p < 0.001) on hydrocarbon removal for pineapple wastes was observed with higher water content (60%) achieving the highest removal (89%). After 90 days of experimentation, the type of agricultural waste and the agricultural waste/soil ratio were not statistically significant in any treatment. However, their addition was important relative to non-stimulated soil, which showed a hydrocarbon removal of 17%. Data reported in this study showed the application of bioremediation in clay and drilling waste-polluted soils.     

Effects of soil amendment with different carbon sources and other factors on the bioremediation of an aged PAH-contaminated soil

Carbon supplementation, soil moisture and soil aeration are believed to enhance in situ bioremediation of PAH-contaminated soils by stimulating the growth of indigenous microorganisms. However, the effects of added carbon and nitrogen together with soil moisture and soil aeration on the dissipation of PAHs and on associated microbial counts have yet to be fully assessed. In this study the effects on bioremediation of carbon source, carbon-to-nitrogen ratio, soil moisture and aeration on an aged PAH-contaminated agricultural soil were studied in microcosms over a 90-day period. Additions of starch, glucose and sodium succinate increased soil bacterial and fungal counts and accelerated the dissipation of phenanthrene and benzo(a)pyrene in soil. Decreases in phenanthrene and benzo(a)pyrene concentrations were effective in soil supplemented with glucose and sodium succinate (both 0.2 g C kg⁻¹ dry soil) and starch (1.0 g C kg⁻¹ dry soil). The bioremediation effect at a C/N ratio of 10:1 was significantly higher (P < 0.05) than at a C/N of either 25:1 or 40:1. Soil microbial counts and PAH dissipation were lower in the submerged soil but soil aeration increased bacterial and fungal counts, enhanced indigenous microbial metabolic activities, and accelerated the natural degradation of phenanthrene and benzo(a)pyrene. The results suggest that optimizing carbon source, C/N ratio, soil moisture and aeration conditions may be a feasible remediation strategy in certain PAH contaminated soils with large active microbial populations.     

Mass Production of Conidia of Penicillium frequentans,a Biocontrol Agent Against Brown Rot of Stone Fruits

Conidial production of Penicillium frequentans , a biocontrol agent of the fungal pathogen Monilinia laxa , was tested in liquid and solid-state fermentation. Conidial production of P. frequentans in solid-state fermentation was higher than in liquid-state fermentation. Solidstate fermentation was made in specially designed plastic bags (VALMIC &#174; ) containing peat:vermiculite (1:1 w/w). Addition of nutrients to the peat:vermiculite increased conidial production of P. frequentans , especially when lentil meal was added. The number of conidia obtained in this solid-state fermentation was maintained in the range of 10 8 -10 9 conidia g -1 from 5 to 120 days after inoculation. Germinability of these conidia was > 90% until 90 days of incubation and declined at 120 days. Optimal initial moisture content in the substrate was 30-40% (v/w). At lower moisture contents, significant reductions in conidial production and germinability were observed, particularly at 10% (v/w). Conidial production was similar when the substrate was inoculated with 10 5 , 10 6 or 10 7 conidia g -1 dry substrate. Fresh conidia produced by solid-state fermentation reduced the incidence of brown rot on plums by 75%.     

Changes of chromium behavior in soil during phenanthrene removal by <Emphasis Type="Italic">Penicillium frequentans</Emphasis>

Soil contamination due to polycyclic aromatic hydrocarbons is often associated with the presence of high levels of potentially toxic metals. Bioremediation is an important option for the clean up of this type of contamination. Changes of chromium fluxes and concentrations during the phenanthrene removal by Penicillium frequentans in soil were investigated. During the bioremediation process, changes in chromium behavior were monitored by Diffusive Gradients in Thin-films (DGT) and by filtration in both sterilized and non-sterilized soils. DGT provided absolute data on fluxes from the solid phase and relative trends of concentrations of the most labile metal species. Filtration provided data on the concentrations of Cr in the solution phase. Together the data provided information about the physical and chemical metal behavior. Results showed that the highest phenanthrene removal was observed in non-sterilized soil (which included the autochthonous microorganisms and P. frequentans inoculum), with a phenanthrene removal of 73 ± 3.2%. However, in all cases microbial activity increased chromium fluxes and chromium soil solution concentration. The bioremediation of soil by P. frequentans increased the lability and mobility of chromium in soil, with potential consequences for plant uptake and for increased movement of metals into the human food chain. Published online December 2004     

Purification and partial characterization of exopolygalacturonase I from Penicillium frequentans

A polygalacturonase with a molecular mass of 74 kDa, an isoelectric point around pH 4.2 and pH--and temperature optima of 3.9 and 50 degrees C, respectively, was purified from a culture fluid of Penicillium frequentans. The enzyme was characterized as an exo-alpha-1,4-polygalacturonase (exo-PG I). Km and Vmax for sodium polypectate hydrolysis were 0.68 g/l and 596.8 U x mg(-1), respectively. The enzyme, a glycoprotein with a carbohydrate content of 81%, is probably the main pectinase of Penicillium frequentans responsible for cleaving monomer units from the non-reducing end of pectin.     

Bioavailable cadmium during the bioremediation of phenanthrene-contaminated soils using the diffusive gradients in thin-film technique

AIMS: To study the impact of fungal bioremediation of phenanthrene on trace cadmium solid-solution fluxes and solution phase concentration. METHODS AND RESULTS: The bioremediation of phenanthrene in soils was performed using the fungus Penicillium frequentans. Metal behaviour was evaluated by the techniques of diffusive gradient in thin-films (DGT) and filtration. Fluxes of cadmium (Cd) show a significant (P < 0.002) increase after the start of bioremediation, indicating that the bioremediation process itself releases significant amount of Cd into solution from the soil solid-phase. Unlike DGT devices, the solution concentration from filtration shows a clear bimodal distribution. We postulate that the initial action of the fungi is most likely to breakdown the surface of the solid phase to smaller, 'solution-phase' material (<0.45 microm) leading to a peak in Cd concentration in solution. CONCLUSIONS: Phenanthrene removal from soils by bioremediation ironically results in the mobilization of another toxic pollutant (Cd). SIGNIFICANCE AND IMPACT OF THE STUDY: Bioremediation of organic pollutants in contaminated soil will likely lead to large increases in the mobilization of toxic metals, increasing metal bio-uptake and incorporation into the wider food chain. Bioremediation strategies need to account for this behaviour and further research is required both to understand the generality of this behaviour and the operative mechanisms.     

Microbiological Synthesis of Fat: THE INFLUENCE OF PHOSPHATE CONCENTRATION ON THE METABOLISM OF PENICILLIUM LILACINUM THOM IN SURFACE CULTURE ON A SUCROSE MEDIUM

The influence of phosphate concentration in the medium on therelative amounts of fat, protein, and carbohydrate synthesizedby Penicillium lilacinum Thom has been studied. In a sucrose salts medium in which the C:N ratio was high (65:1)and conducive to fat synthesis, the carbohydrate content ofthe felt was decreased and the fat content increased when theconcentration of sodium dihydrogen phosphate in the medium wasraised from 0.73 to 1.46 per cent. w/v. In a similar mediumin which the C:N ratio was low (65:2) this effect was not observed.In the medium of high C:N ratio with phosphate at the higherlevel, fat accumulated over a longer period than in any othercase. Felts grown with the high C:N ratio and with phosphate at thehigher concentration were richer in protein and in total nitrogenthan were felts developed with the high C:N ratio and less phosphate.This effect was still more pronounced in the medium of low C:Nratio. Change in the initial concentration of nitrate in themedium exercised more marked effects on the metabolism of themould than did change in the initial phosphate level.     

Removal of phenanthrene from soil by co-cultures of bacteria and fungi pregrown on sugarcane bagasse pith

Sixteen co-cultures composed of four bacteria and four fungi grown on sugarcane bagasse pith were tested for phenanthrene degradation in soil. The four bacteria were identified as Pseudomonas aeruginose, Ralstonia pickettii, Pseudomonas sp. and Pseudomonas cepacea. The four fungi were identified as: Penicillium sp., Trichoderma viride, Alternaria tenuis and Aspergillus terrus that were previously isolated from different hydrocarbon-contaminated soils. Fungi had a statistically significant positive (0.0001相似文献   

Removal of nitrate and phosphorus from hydroponic wastewater using a hybrid denitrification filter (HDF)

A laboratory-scale hybrid-denitrification filter (HDF) was designed by combining a plant material digester and a denitrification filter into a single unit for the removal of nitrate and phosphorus from glasshouse hydroponic wastewater. The carbon to nitrate (C:N) ratio for efficient operation of the HDF was calculated to be 1.93:1 and the COD/BOD₅ ratio was 1.2:1. When the HDF was continuously operated with the plant material replaced every 2 days and 100% internal recirculation of the effluent, a high level of nitrate removal (320–5 mg N/L, >95% removal) combined with a low effluent sBOD₅ concentration (<5 mg/L) was consistently achieved. Moreover, phosphate concentrations in the effluent were maintained below 7.5 mg P/L (>81% reduction). This study demonstrates the potential to combine a digester and a denitrification filter in a single unit to efficiently remove nitrate and phosphate from hydroponic wastewater in a single unit.     

MYCOLOGICAL SYNTHESIS OF FAT FROM WHEY. II. COMPARATIVE STUDIES WITH SHAKEN AND STATIONARY CULTURES USING SELECTED MOULDS

SUMMARY: In detailed studies of the growth of Aspergillus ustus, Penicillium oxalicum, P. frequentans and P. notatum in whey with fat production in view, the first two showed the highest lactose utilization and felt weights in shaken cultures while the last two gave as good or better felt yields in stationary cultures.
When A. ustus was grown in shaken culture in whey with and without the addition of 1·14 g/1. of ammonium nitrate, the extra nitrogen led to the production of larger amounts of fat, but P. frequentans did not form additional fat in these circumstances. A. ustus was the best mould; in whey plus ammonium nitrate it utilized up to 96% of the lactose and formed, per litre of whey, about 17 g of mycelial felt containing 13% of protein and 28% of fat.     

Immunological differentiation of Penicillium species

Antisera were obtained from a rabbit immunized with Penicillium verrucosum var. verrucosum. These antisera were characterized by immunofluorescence and by indirect enzyme-linked immunosorbent assay for their reactivity with 44 strains of moulds. Antigenically, P. verrucosum var. verrucosum (subgenus Penicillium) appears to be similar to strains belonging to subgenus Furcatum, but strongly different from Penicillium frequentans (subgenus Aspergilloides). Specific absorption of antibodies to antigens confirmed the existence of similar biochemical structures on Penicillium frequentans, Aspergillus versicolor, and Aspergillus fumigatus. Immunological procedures may thus significantly contribute to refine the taxonomic classification of moulds.     

Selective partitioning of conidia of some Penicillium and Aspergillus species in aqueous two-phase systems.

Conidia of Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, Penicillium brevi-compactum, Penicillium frequentans, Penicillium spinulosum, and Penicillium verrucosum var. cyclopium were subjected to partition at varying pH values in an aqueous two-phase system containing charged polyethylene glycol. In the system, the partition behavior of the conidia of the Penicillium species varied when the pH was raised, while the conidia of the Aspergillus species seemed unaffected. P. brevi-compactum was separated from P. verrucosum var. cyclopium after only 10 transfers when subjected to stepwise partitioning. In the same way, 10 transfers were needed to separate P. verrucosum var. cyclopium from a mixture of conidia of three Aspergillus species. The partition behavior was influenced by the culture media used.     

Optimization of soil physical and chemical conditions for the bioremediation of creosote-contaminated soil

Mispah type soil (FAO : Lithosol) contaminated with >250 000 mg kg^-1 creosote was collected from the yard of a creosote treatment plant. The soils carbon, nitrogen and phosphorus contents were determined. Due to creosote contamination, thecarbon content of the soil was found to be 130,000 mg C kg^-1. This concentration was found to greatly affect the nitrogen content (0.08%). The phosphorus content was less affected (4.5%). It was estimated that a nutrient amendment to bring the soil to a C : N 10 : 1 would be adequate to stimulate microbial growth and creosote degradation. The soil was amended with a range of C : N ratios below and above the estimated ratio. In one of the treatments, the phosphorus content was amended. Sterile and natural controls were also set up. The soil was incubated at 30 °C on a rotaryshaker at 150 rpm in the dark for six weeks. Water content was maintained at 70% field capacity. The lowest nitrogen supplementation (C : N = 25 : 1) was more effective in enhancing microbial growth (3.12E + 05) and creosote removal (68.7%) from the soil. Additional phosphorus was not very effective in enhancing the growth of microorganisms and removal of creosote. The highest nitrogen supplementation(C : N = 5 : 1) did not enhance microbial growth and creosote removal.A relationship between mass loss and creosote removal was also observed. Phenolics and lower molecular mass polycyclic aromatic hydrocarbons (PAHs) were observed to be more susceptible to microbial degradation than higher molecular mass compounds. Nutrient concentration, moisture content and pH were thus observed to play very significant roles in the utilization of creosote in soil. These results are being used for the development of a bioremediation technology for the remediation of creosote contaminated soils in a treatment plant in South Africa.     

Effect of C/N/P ratio and nonionic surfactants on polychlorinated biphenyl biodegradation

This work investigated whether polychlorinated biphenyl (PCB) removal from a highly contaminated soil (7000-p.p.m.) could be enhanced by manipulating the carbon to nitrogen to phosphorus (C/N/P) ratio, and by nonionic surfactant addition. A Box–Behnken statistical experimental design was used to evaluate the combined effect of surfactant type, surfactant concentration, and C/N/P ratio in a relatively short treatment period (35 days). The variable with the greatest effect on PCB degradation was the type of surfactant used. Higher PCB removal efficiencies (39–60%) were obtained with Tween 80 (compared to Tergitol NP 10 and Triton X-100). This was attributed to its lower critical micelle concentration. Higher C/N/P ratios (increased by biphenyl addition) significantly stimulated the soil heterotrophic activity without enhancing PCB removal. This suggests that nonionic surfactants have a greater potential to enhance bioremediation of PCB-contaminated soil than efforts to enhance the soil heterotrophic activity through nutrient and analogue substrate addition.     

Relative contribution of environmental and nutritional variables to net primary production of Cynodon dactylon (Linn.) Pers in the riparian zone of a Three Gorges tributary

Our knowledge of fundamental drivers of terrestrial net primary production (NPP) is crucial for improving the predictability of ecosystem stability under global climate change. However, the patterns and determinants of NPP are not fully understood, especially in the riparian zone ecosystem disturbed by periodic drought–rewetting (DRW) cycles. The environmental (flooding time, pH, moisture, and clay content) and nutritional properties (soil organic carbon, total nitrogen, total phosphorus, ammonium (NH₄⁺‐N), nitrate (NO₃^‐‐N), and C:N:P stoichiometry) were investigated in the riparian zone of Pengxi River‐a typical tributary of Three Gorges Reservoir (TGR). Structure equation modeling was performed to evaluate the relative importance of environmental and nutritional properties on NPP of Cynodon dactylon (Linn.) Pers (C. dactylon)‐a dominating plant in the riparian zone of TGR. Our results indicated that NPP was much lower under much severe flooding stress. All of these variables could predict 46% of the NPP variance. Nutrient use efficiency (NUE) was one of the most critical predictor shaping the change of NPP. Specifically, flooding stress as a major driver had a direct positive effect on soil moisture and soil clay content. The soil clay content positively affects the soil C: N ratio, which further had an indirect negative impact on NPP by mediating NUE. Overall, our study provided a comprehensive analysis of the effects of the combined effect of environmental and nutrient factors on NPP and showed that continuous DRW cycles induced by hydrological regime stimulate the decrease of NPP of C. dactylon by changing NUE strategies. Further research is needed to explore the responses of NPP and NUE under different land use to DRW cycles and to investigate the DRW effects on the combined effect of environmental and nutrient factors by in situ experiments and long‐term studies.     

Production and Some Properties of a New Type of Acid Carboxypeptidase of Penicillium Molds

Among some 38 strains of the genus Penicillium we investigated seven wild-type strains (P. daleae IFO-6087, P. frequentans AHU-8328, P. funiculosum IAM-7013, P. janthinellum IFO-8070, IAM-7026, P. lividum IAM-7200, and P. oxalicum AHU-8336) that were found to be excellent strains for a new type of acid carboxypeptidase production in a surface koji culture at 25 C. The production of acid carboxypeptidase was determined in various culture conditions in a koji culture. The maximum yields of acid carboxypeptidase were obtained by P. janthinellum IFO-8070. Partial purification and isolation of the acid carboxypeptidase from strains of Penicillium were performed with gel filtration on Bio-Gel P-100. Characterization studies indicate that the acid carboxypeptidases from P. daleae IFO-6087, P. funiculosum IAM-7013, P. janthinellum IFO-8070, and P. oxalicum AHU-8336 have some properties similar to those of the enzyme of Aspergillus saitoi with regard to the hydrolysis of several peptides at acidic pH range but have other slightly different properties with regard to stability, pH optima, inhibitors, and molecular weights.     

Influence of cultivating conditions on the alpha-galactosidase biosynthesis from a novel strain of Penicillium sp. in solid-state fermentation

AIMS: The work is intended to achieve optimum culture conditions of alpha-galactosidase production by a mutant strain Penicillium sp. in solid-state fermentation (SSF). METHODS AND RESULTS: Certain fermentation parameters involving incubation temperature, moisture content, initial pH value, inoculum and load size of medium, and incubation time were investigated separately. The optimal temperature and moisture level for alpha-galactosidase biosynthesis was found to be 30 degrees C and 50%, respectively. The range of pH 5.5-6.5 was favourable. About 40-50 g of medium in 250-ml flask and inoculum over 1.0 x 10(6) spores were suitable for enzyme production. Seventy-five hours of incubation was enough for maximum alpha-galactosidase production. Substrate as wheat bran supplemented with soyabean meal and beet pulp markedly improved the enzyme yield in trays. CONCLUSIONS: Under optimum culture conditions, the alpha-galactosidase activity from Penicillium sp. MAFIC-6 indicated 185.2 U g(-1) in tray of SSF. SIGNIFICANT AND IMPACT OF THE STUDY: The process on alpha-galactosidase production in laboratory scale may have a potentiality of scaling-up.     

Nutritional requirements of antagonists to peach twig blight,Monilinia laxa,in relation to biocontrol

Different carbon and nitrogen sources and accessory substances were tested to determine their effect on the growth and sporulation of the peach twig blight pathogen,Monilinia laxa, and of three of its antagonists (Penicillium frequentans, Penicillium purpurogenum andEpicoccum nigrum), since the success in twig blight biological control by treatments with the fungal antagonists depends on the type of nutrients added to the antagonist formulation. Combinations of sucrose-ammonium tartrate, glucose-(NH₄)₃PO₄-folic acid and lactose-KNO₃ were selected from these laboratory experiments because they enhanced the growth and sporulation ofP. frequentans, P. purpurogenum andE. nigrum, respectively, but notM. laxa. In glasshouse experiments, twig blight was reduced following the application of mixtures of antagonists with the corresponding enhancing nutrients.     

Effect of C/N ratio and moisture content on the composting of poplar wood

Summary Milled poplar wood (1.7 mm mesh size) was composted in lab-scale reactors. Initial C/N ratios were adjusted to 10:1, 30:1, and 50:1 using urea as the nitrogen source. At each C/N ratio, three moisture levels (30, 50, and 70%) were tested. C/N ratios of 50:1 or 30:1 and moisture content of 70% favored more effective composting as indicated by higher levels of mineralization of the poplar wood to CO₂.     

How to account for the lipid effect on carbon stable-isotope ratio (δ13C): sample treatment effects and model bias

This study investigated the impact of lipid extraction, CaCO₃ removal and of both treatments combined on fish tissue δ¹³C, δ¹⁵N and C:N ratio. Furthermore, the suitability of empirical δ¹³C lipid normalization and correction models was examined. δ¹⁵N was affected by lipid extraction (increase of up to 1·65‰) and by the combination of both treatments, while acidification alone showed no effect. The observed shift in δ¹⁵N represents a significant bias in trophic level estimates, i.e. lipid-extracted samples are not suitable for δ¹⁵N analysis. C:N and δ¹³C were significantly affected by lipid extraction, proportional to initial tissue lipid content. For both variables, rates of change with lipid content (ΔC:N and Δδ¹³C) were species specific. All tested lipid normalization and correction models produced biased estimates of fish tissue δ¹³C, probably due to a non-representative database and incorrect assumptions and generalizations the models were based on. Improved models need a priori more extensive and detailed studies of the relationships between lipid content, C:N and δ¹³C, as well as of the underlying biochemical processes.