Tween 80 enhanced TNT mineralization by Phanerochaete chrysosporium

The effect of a nonionic surfactant (Tween 80) on 2,4,6-trinitrotoluene (TNT) mineralization by the white-rot fungus Phanerochaete chrysosporium strain BKM-F-1767, was investigated in a liquid culture at 20, 50, and 100 mg TNT.L-1. The presence of 1% (w/v) Tween 80, at 20 mg.L-1 TNT, added to a 4-d-old culture, allowed the highest TNT mineralization level, that is 29.3% after 24 d, which is two times more than the control culture, without Tween 80 (13.9%). The mineralization of TNT resumed upon additional Tween 80 supplementation, consequently, 39.0% of the TNT was respired on day 68. Orbital agitation of the fungal culture was found detrimental to TNT mineralization, with or without Tween 80 in the culture medium. The surfactant also stimulated the growth of P. chrysosporium without any notable effect on either the glycerol consumption rate or the extracellular LiP and MnP activity levels. Respirometric assays highlighted some differences between the oxygen uptake rate of the fungal culture supplemented with or without Tween 80.     

Influence of the application of sugarcane bagasse on lindane (gamma-HCH) mobility through soil column: implication for biotreatment

In the present study we employed sugarcane bagasse for biotreatment of soil containing 50mgkg(-1) of lindane. Garden soil were treated with lindane and amended with varying concentrations of sugarcane bagasse (10%, 20%, 30%, 40% and 50%; w/w). Data on dissipation and degradation of lindane in soil columns (0-15, 15-30cm) were studied at six consecutive samplings (0, 3, 7, 45 and 60 days). Treatment with 50% sugarcane bagasse resulted in >53% degradation of lindane in upper soil column with minimal leaching to lower soil column (0.002%) while highest leaching of lindane from upper soil column to lower soil column was occurred in garden soil (35.8%). Similarly, a substantial microbial biomass input has detected in amended soil than garden soil. Our results provide evidence that sugarcane bagasse can accelerate lindane degradation by enhanced microbial activity and prevent pesticide mobility through soil column by adsorption. Sugarcane bagasse could be useful as cheaper, easy available alternative for the biotreatment of lindane impacted soil.     

Chemical-assisted phytoremediation of CD-PAHs contaminated soils using Solanum nigrum L

A well-characterized cadmium (Cd) hyperaccumulating plant Solanum nigrum was grown in Cd and polycyclic aromatic hydrocarbons (PAHs) co-contaminated soil that was repeatedly amended with chemicals, including EDTA, cysteine (CY), salicylic acid (Sa), and Tween 80 (TW80), to test individual and combined treatment effects on phytoremediation of Cd-PAHs contaminated soils. Plant growth was negatively affected by exogenous chemicals except for EDTA. S. nigrum could accumulate Cd in tissues without assistant chemicals, while there was no visible effect on the degradation of PAHs. Cysteine had significant effects on phytoextraction of Cd and the highest metal extraction ratio (1.27%) was observed in 0.9 mmol/kg CY treatment. Both salicylic acid and Tween 80 had stimulative effects on the degradation of PAHs and there was the maximal degradation rate (52.6%) of total PAHs while 0.9 mmol/kg Sa was applied. Furthermore, the combined treatment T(0.1EDTA+0.9CY+0.5TW80) and T(0.5EDTA+0.9CY+03Sa) could not only increase the accumulation of Cd in plant tissues, but also promote the degradation of PAHs. These results indicated that S. nigrum might be effective in phytoextracting Cd and enhancing the biodegradation of PAHs in the co-contaminated soils with assistant chemicals.     

Fate of [carbonyl-14C]methabenzthiazuron in an arid region soil — effect of organic amendment,soil disturbance and fumigation

[Carbonyl-¹⁴C] methabenzthiazuron (MBT) was applied to an arid region soil at a rate of 5mg kg⁻¹ soil to give a¹⁴C content of 2400 KB kg⁻¹ soil. After 15 weeks of incubation at 22°C and 50% of the maximum water holding capacity of the soil, 7.2% of the applied¹⁴C was mineralized to¹⁴CO₂. Where the soil was amended with wheat straw, total mineralization increased to 17.3%. Soil disturbance caused a significant increase while chloroform fumigation caused a significant decrease in the rate of¹⁴CO₂ production, both from amended and unamended soils. These results suggest that MBT is degraded mainly through microbial co-metabolism. Wheat straw amendment resulted in increased transformation of MBT into soil humus. In unamended soil, a major portion of¹⁴C was recovered in fulvic acid and in fractions extracted with organic solvents. Recovery of¹⁴C in non-extractable bound residues (humins) increased as incubation progressed and seemed to be derived from the fulvic acid fraction, which showed a concomitant decrease. More than 99% of the residual¹⁴C in unamended soil consisted of unaltered MBT; the remainder occurred as 1-methyl-1 (benzthiazolyl) urea. In amended soil, a relatively higher percentage of the extractable¹⁴C was found in the metabolite. Small amounts of three unidentified¹⁴C-labelled compounds were also observed. In amended soil, disturbance caused a decrease in extractable-¹⁴C whereas fumigation caused a significant increase, as compared to the untreated control. The effects were more pronounced when the soils were reated at an early stage of incubation. In general, soil disturbance increased the availability of MBT for further transformations while chloroform fumigation decreased the process.     

Plasmid transfer between strains of Pseudomonas putida, and their survival, within a pilot scale percolating-filter sewage treatment system

Abstract: The effect of Pseudomonas aeruginosa UG2 biosurfactants or UG2 inocula on phenanthrene mineralization in uninoculated nonsterile soil slurries and slurries inoculated with the phenanthrene-mineralizing Pseudomonas sp. UG14r was investigated. In sandy loam and silt loam slurries amended with phenanthrene, inoculation with UG14r alone or in co-culture with UG2Lr reduced the lag period before onset of phenanthrene mineralization by 1 week. The total amount mineralized after 5 weeks was lower or not significantly different from the uninoculated control slurries. Inoculation with P. aeruginosa UG2Lr alone did not improve phenanthrene mineralization. In creosote-contaminated soil slurries, no lag period in phenanthrene mineralization was observed in any treatment. After 4 weeks, the greatest extent of mineralization was observed in creosote-contaminated soil slurries inoculated with the UG14r-UG2Lr co-culture and UG14r alone. In sandy loam and silt loam soil slurries inoculated with Pseudomonas sp. UG14r, addition of UG2 rhamnolipid biosurfactants (100 to 400 mg rhamnose equivalents (RE) · l⁻¹ slurry) inhibited phenanthrene mineralization by 10 to 15%. Mineralization was also inhibited in uninoculated sandy loam slurries. In creosote-contaminated soil slurries inoculated with Pseudomonas sp. UG14r, biosurfactants at 250 mg RE · l⁻¹ slurry enhanced mineralization whereas 400 mg RE · l⁻¹ had no effect, compared to unamended slurries. In uninoculated creosote-contaminated soil slurries, UG2 biosurfactants at 250 and 400 mg RE · l⁻¹ slurry enhanced mineralization, compared to unamended slurries.     

Effects of nonionic surfactants on the solubilization and mineralization of phenanthrene in soil-water systems

The solubilization and mineralization of (14)C-phenanthrene in soil-water systems was examined with several commercially available surface-active agents, viz., an alkyl ethoxylate C(12)E(4); two alkylphenol ethoxylate surfactants: C(8)PE(9.5) and C(9)PE(10.5); two sorbitan ethoxylate surfactants: the sorbitan monolaurate (Tween 20) and the sorbitan monooleate (Tween 80); two pairs of nonionic ethoxylate surfactant mixtures: C(12)E(4)/C(12)E(23) at a 1:1 ratio, and C(12-15)E(3)/C(12-15)E(9) at a 1:3 ratio; and two surfactants possessing relatively high critical micelle concentration (CMC) values and low aggregation numbers: CHAPS and octyglucoside. Surface tension experiments were performed to evaluate surfactant sorption onto soil and the surfactant doses required to attain the CMC in the soil-water systems. Surfactant solubilization of (14)C-phenanthrene commenced with the onset of micellization. The addition of surface-active agents was observed not to be beneficial to the microbial mineralization of phenanthrene in the soil-water systems and, for supra-CMC surfactant doses, phenanthrene mineralization was completely inhibited for all the surfactants tested. A comparison of solubilization, surface tension, and mineralization data confirms that the inhibitory effect on microbial degradation of phenanthrene is related to the CMC of the surfactant in the presence of soil. Additional tests demonstrated the recovery of mineralization upon dilution of surfactant concentration to sub-CMC levels, and a relatively high exit rate for phenanthrene from micelles. These tests suggest that the inhibitory effect is probably related to a reversible physiological surfactant micelle-bacteria interaction, possibly through partial complexing or release of membrane material with disrupting membrane lamellar structure. This study indicates that nonionic surfactant solubilization of sorbed hydrophobic organic compounds from soil may not be beneficial for the concomitant enhancement of soil bioremediation. Additional work is needed to address physicochemical processes for bioavailability enhancement, and effects of solubilizing agents on microorganisms for remediation and treatment of hydrophobic organic compounds and nonaqueous phase liquids. (c) 1992 John Wiley & Sons Inc.     

Translocation and degradation of injected uniconazole in apple during a 4-month growing period

One-year-old Golden Delicious apple trees grafted onto MM 106 rootstocks were injected in the rootstock stem (shank) with¹⁴C-uniconazole to determine the extent to which uniconazole is translocated and degraded over the length of an average growing season. In 4 months, 16% of recovered¹⁴C-activity was translocated to the new shoots. Most of the¹⁴C-activity remained in the rootstock. Chromatographic evaluation of shoot extracts demonstrated that the¹⁴C-activity associated with uniconazole decreased 49% in 4 months. However, shoot growth was still inhibited which suggests that the amount of uniconazole that was degraded did not interfere with the inhibition of gibberellin biosynthesis, probably due to the continuous translocation of uniconazole that occurred.     

Effect of salt on aerobic biodegradation of petroleum hydrocarbons in contaminated groundwater

Hydrocarbon-contaminated soil and groundwater at oil and gas production sites may be additionally impacted by salts due to release of produced waters. However, little is known about the effect of salt on the in-situ biodegradation of hydrocarbons by terrestrial microbes, especially at low temperatures. To study this effect, we prepared a groundwater-soil slurry from two sites in Canada: a former flare pit site contaminated with flare pit residue (Site A), and a natural gas processing facility contaminated with natural gas condensate (Site B). The slurry with its indigenous microbes was amended with radiolabeled hydrocarbons dissolved in free product plus nutrients and/or NaCl, and incubated in aerobic biometer flasks with gyrotory shaking at either 25 or 10°C for up to 5 weeks. Cumulative production of ¹⁴CO₂ was measured and the lag time, rate and extent of mineralization were calculated. For Site A, concentrations of NaCl ≥1% (w/v) delayed the onset of mineralization of both ¹⁴C-hexadecane and ¹⁴C-phenanthrene under nutrient-amended conditions, but once biodegradation began the degradation rates were similar over the range of salt concentrations tested (0–5% NaCl). For Site B, increasing concentrations of NaCl ≥1% (w/v) increased the lag time and decreased the rate and extent of mineralization of aliphatic and aromatic substrates. Of particular interest is the observation that low concentrations of salt (≤1% NaCl) slightly stimulated mineralization in some cases.     

Coupling of manganese peroxidase-mediated lipid peroxidation with destruction of nonphenolic lignin model compounds and 14C-labeled lignins.

Linoleic acid, the predominant unsaturated fatty acid (UFA) in the lipids of wood-rotting fungi, was oxidized by manganese peroxidase (MnP) from the white-rot fungus Phlebia radiata through a peroxidation mechanism. The peroxidation was markedly stimulated by hydrogen peroxide. UFAs that are substrates for lipid peroxidation and surfactants that emulsify water-insoluble components were essential for the MnP-catalyzed destruction of a nonphenolic beta-O-4-linked lignin model compound (LMC). Moreover, both components stimulated the MnP-catalyzed mineralization of 14C-labeled synthetic lignin and 14C-labeled wheat straw. A high level of destruction was obtained in reaction systems with Tween 80 acting both as surfactant and source of UFAs. The presence of the linoleic acid in reaction systems with MnP and Tween 80 additionally enhanced rate and level of LMC destruction and lignin mineralization. The results indicate that lipid peroxidation may play an important role in lignin biodegradation by wood-rotting basidiomycetes and support the hypothesis of coupling between the processes.     

Integrated Approach for Polycyclic Aromatic Hydrocarbon Solubilization from the Soil Matrix to Enhance Bioremediation

Polycyclic aromatic hydrocarbons (PAHs) are known to be toxic to living organisms and have been identified as carcinogenic. In this study, a pathway of surfactant flushing, chemical oxidation, and biological treatment is proposed to remediate the soils polluted with the hydrophobic PAHs. Different surfactants such as Tween 80, Brij 35, sodium dodecyl sulfate (SDS), and polyethylene glycol (PEG) 6000 were tested in order to increase the PAH solubilization from the soil matrix. The maximum desorption efficiency of naphthalene and anthracene were found to be 56.5% and 59%, respectively, when Brij and SDS were used. The soluble PAH in the aqueous phase was amended with sodium thiosulfate (3%) to oxidize the PAH into a more bioavailable form. The chemical oxidation with subsequent biodegradation by Pseudomonas aeruginosa exhibited the relatively high PAH degradation rate (1.24 times higher) when compared with chemical oxidation alone. These results display the efficiency of chemical pretreatment of PAH-contaminated soil for improved bioremediation.     

Importance of chemical structure on the development of hydrocarbon catabolism in soil

A soil was amended with (14)C-analogues of naphthalene, phenanthrene, pyrene, B[a]P or hexadecane at 50 mg kg(-1) and the development of catabolic activity was assessed by determining the rate and extent of (14)CO(2) evolution at time points over 180 days. The catabolic potential of the soil was hexadecane>naphthalene>phenanthrene>pyrene>B[a]P, determined by the decrease in lag time (as defined by the time taken for 5%(14)CO(2) to be evolved from the minerialization of the (14)C-labeled hydrocarbons). The results clearly showed the difference between constitutive and inducible biodegradation systems. The 0 day time point showed that hexadecane minerialization was rapid and immediate, with a 45.4 +/- 0.6% mineralization extent, compared with pyrene minerialization at 1.0 +/- 0.1%. However, catabolism for pyrene developed over time and after a 95 days soil-pyrene contact time, mineralization extent was found to be 63.1 +/- 7.8%. Strong regression was found (r(2)>0.99) between the maximum rates of mineralization and the partioning coefficient between the mineralized hydrocarbons, which may indicate linearity in the system.     

Effects of Soil Water Content on Biodegradation of Phenanthrene in a Mixture of Organic Contaminants

Phenanthrene biodegradation was investigated at different soil water contents [0.11, 0.22, 0.33, 0.44 g H₂O (g soil)^?1] to determine the effects of water availability on biodegradation rate. A subsurface horizon of Kennebec silty loam soil was used in this study. [9-¹⁴C] phenanthrene was dissolved in a mixture of organic contaminants that consisted of 76% decane, 6% ρ-xylene, 6% phenanthrene, 6% pristane, and 6% naphthalene, and then added to the soil. The highest rate of mineralization, in which 0.23% of the [9-¹⁴C] phenanthrene degraded to ¹⁴CO₂ after 66 days of incubation, was observed at the soil water content of 0.44 g H₂O/g dry soil. Most of the ¹⁴C remained in the soil as the parent compound or as nonextractable compounds by acetonitrile at the highest water content. Concentrations of nonextractable compounds increased with water content, but residual extractable phenanthrene decreased significantly with increasing water content, which presumably indicates that bio-transformation occurred. The mineralization analysis of radiolabeled 9th carbon in phenanthrene underestimated phenanthrene biodegradation. The strong adsorption and low solubility of phenanthrene contributed to the low mineralization of phenanthrene 9th carbon. The other components were subject to higher biological and abiotic dissipation processes with increasing soil water content.     

Nutrient-enhanced survival of and phenanthrene mineralization by alginate-encapsulated and freePseudomonas sp. UG14Lr cells in creosote-contaminated soil slurries

The effects of nutrient amendment and alginate encapsulation on survival of and phenanthrene mineralization by the bioluminescentPseudomonas sp. UG14Lr in creosote-contaminated soil slurries were examined. UG14Lr was inoculated into creosote-contaminated soil slurries either as a free cell suspension or encapsulated in alginate beads prepared with montmorillonite clay and skim milk. Additional treatments were free-cell-inoculated slurries amended with sterile alginate beads, free-cell-inoculated and uninoculated slurries amended with skim milk only, and uninoculated, unamended slurries. Mineralization was determined by measuring¹⁴CO₂ released from radiolabelled phenanthrene. Survival was measured by selective plating and bioluminescence. Inclusion of skim milk was found to enhance both survival of and phenanthrene mineralization by free and encapsulated UG14Lr cells.     

表面活性剂对出芽短梗霉多糖生产影响的研究

研究了表面活性剂对出芽短梗霉细胞培养过程中多糖释放的影响。在摇瓶中,比较添加0.05%(w/v)的Tween 80、Tween 60、Tween 40,结果显示几种表面活性剂均能促进细胞释放多糖,其中以Tween 80的效果最佳。在5L发酵罐中,以100g/L玉米粉水解液做碳源的出芽短梗霉细胞培养液中分别添加了表面活性剂Tween 80 0.01%、0.05%、0.1%,其中以添加Tween 800.05%时的效果最好,与不添加表面活性剂相比多糖产量提高25%左右,发酵周期缩短了将近2d。     

Permeabilization of elicited suspension culture of madder (Rubia akane Nakai) cells for release of anthraquinones

To enhance the productivity of anthraquinone colorants during madder (Rubia akane Nakai) cell cultures, the effects of permeabilizing agents on the production of anthraquinone colorants were investigated. Tween 80 was the best among the permeabilizing agents tested. Addition of 1% Tween 80 increased the total and released concentrations of anthraquinones about 1.6 times (159 mg l–1) and 14 times (71 mg l–1), respectively. In addition, anthraquinone production was increased to 220 mg l–1, 2.2 times as the level of control culture by simultaneous use of 1% Tween 80, 5 mg chitosan/l and 2% (w/v) XAD-7. Also, 47% (105 mg l–1) of total anthraquinones was released to medium or adsorbed on XAD-7.     

Development of models for predicting carbon mineralization and associated phytotoxicity in compost-amended soil

Phytotoxicity of compost-amended soil is related to carbon mineralization associated with compost decomposition. The objective of this research was to determine if compost carbon mineralization potential, estimated using compost respiration rate measurements, could be combined with carbon mineralization kinetic models to predict phytotoxicity of compost-amended soil. First-order, second-order, and Monod kinetic models that include compost carbon mineralization potential, compost amendment rate, incubation time, and temperature were developed and compared for their ability to predict carbon mineralization kinetics. Experiments utilized two soil types amended with 0%, 5%, and 50% (v/v) food waste and green waste composts, incubated at 20 degrees C, 25 degrees C, 30 degrees C, 35 degrees C, and 45 degrees C for model development and under a diurnal temperature cycle from 20 degrees C to 30 degrees C for model validation. For most cases, a first-order model had an equivalent or better fit to the data than the other models. Mineralizable carbon estimated using the first-order model was significantly correlated to the probability of phytotoxicity in compost-amended soil.     

Uptake, transport and metabolism of 14C-2,4-dichlorophenoxyacetic acid (14C-2,4-D) in cucumber (Cucumis sativus L.) explants

The uptake, distribution and metabolism of 2,4-D using 14C-labelled 2,4-dichlorophenoxyacetic acid (14C-2,4-D) was studied in isolated hypocotyl and cotyledon explants of cucumber (Cucumis sativus L.) in vitro. Cotyledons had a higher uptake capacity than hypocotyls; the uptake in cotyledons increased linearly up to 20 h, while in hypocotyls only up to 8 h. The distribution of 14C-activity in both organs was basipetal, but more pronounced in cotyledons. The 2,4-D taken up by cotyledons was metabolized very rapidly: only 7% of 14C-activity was associated with free 2,4-D after 20 h exposure. Hypocotyls metabolized 2,4-D more slowly: after 20 h 50% of the 14C-activity was still associated with free 2,4-D. After short incubation periods (2–5 h) 2,4-D-aspartate was a predominant metabolite, after longer incubation (8–20 h) 2,4-D-glucosyl ester prevailed. Roots or callus were formed on the base of cotyledons depending on the length of exposure to 2,4-D.     

Sorption and Desorption of Napropamide in Sandy Soil Amended with Chicken Dung and Palm Oil Mill Effluent

Beach Ridges Interspersed with Swales (BRIS) is a sandy soil and in Malaysia it is found exclusively in the east coast of Peninsular Malaysia. It is a marginal soil because of its low nutrient and water-holding capacity. However, with proper management and organic matter amendments some areas with BRIS soil are cultivated. Napropamide is a selective herbicide widely used to control weeds in BRIS soil. No previous studies have been reported on the effects of organic matter amendments on napropamide sorption in BRIS soil. This study was conducted to determine sorption and desorption of napropamide in BRIS soil amended with chicken dung (CD) and palm oil mill effluent (POME) at 0, 20, 40, and 80 Mg ha^?1. Potential interaction of dissolved organic carbon (DOC) with napropamide and their competition for sorption sites were also determined. Sorption isotherm data were fitted to the log-transformed Freundlich's equation. Sorption of napropamide was higher in soils amended with CD and POME as compared to non-amended soil. At the same rates of application, sorption was higher in soil amended with CD than POME. The Freundlich's coefficient (K_f) values were 0.22, 3.96, and 41.6 for nonamended soil, soil amended with 80 Mg ha^?1 POME, and soil amended with 80 Mg ha^?1 CD, respectively. Desorption of napropamide showed positive hysteresis and the hysteresis were greater with higher rates of CD and POME. There was no association between napropamide and DOC extracted from BRIS soil amended with either CD or POME and also there were no competitions between napropamide and DOC extracted from either CD or POME for sorption sites of the soil samples.     

Mineralization of hexachlorocyclohexane in soil during solid-phase bioremediation

Soil containing hexachlorocyclohexane (HCH) was spiked with ¹⁴C--HCH and then subjected to bioremediation in bench-scale microcosms to determine the rate and extent of mineralization of the ¹⁴C-labeled HCH to ¹⁴CO₂. The soil was treated using two different DARAMEND amendments, D6386 and D6390. The amendments were previously found to enhance natural HCH bioremediation as determined by measuring the disappearance of parent compounds under either strictly oxic conditions (D6386), or cycled anoxic/oxic conditions (D6390). Within 80 days of the initiation of treatment, mineralization was observed in all of the strictly oxic microcosms. However, mineralization was negligible in the cycled anoxic/oxic microcosms throughout the 275-day study, even after cycling was ceased at 84 days and although significant removal (up to 51%) of indigenous -HCH (146 mg/kg) was detected by GC with electron capture detector. Of the amended, strictly oxic treatments, only one, in which 47% of the spiked ¹⁴C-HCH was recovered as ¹⁴CO₂, enhanced mineralization compared with an unamended treatment (in which 34% recovery was measured). Other oxic treatments involving higher amendment application rates or auxiliary carbon sources were inhibitory to mineralization. Thus, although HCH degradation occurs during the application of either oxic or cycled anoxic/oxic DARAMEND treatments, mineralization of -HCH may be inhibited depending on the amendment and treatment protocol.     

Evaluation of chemical pretreatment of contaminated soil for improved PAH bioremediation

The efficiency of several chemical treatments as potential enhancers of the biodegradation of polycyclic aromatic hydrocarbons (PAHs) in contaminated soil was evaluated by analyzing the mineralization of ¹⁴C-labeled phenanthrene, pyrene, and benzo(a)pyrene. The effect of nonionic surfactants with Fenton oxidation and combinations of surfactants with the Fenton oxidation was evaluated in a microtiter plate assay. The surfactants selected for the study were Tween 80, Brij 35, Tergitol NP-10, and Triton X-100. The addition of Fentons reagent significantly enhanced the mineralization of pyrene at the two concentrations studied: 2.8 M H₂O₂ with 0.1 M FeSO₄ and 0.7 M H₂O₂ with 0.025 M FeSO₄. Phenanthrene mineralization was also positively induced by the Fenton treatments. However, none of the treatments had a significant effect on benzo(a)pyrene mineralization. Surfactant additions at concentrations of 20% and 80% of the aqueous critical micelle concentration did not significantly affect the mineralization rates. When surfactant addition was combined with the Fenton oxidation, reduced mineralization rates were obtained when compared with mineralization after Fentons treatment alone. The results indicate that the addition of Fentons reagent may enhance the mineralization of PAHs in contaminated soil, whereas the addition of surfactants has no significant beneficial effect. The efficiency of the Fenton oxidation may decrease when surfactants are added simultaneously with Fentons reagent to contaminated soil.