Studies on biodegradation of nicotine by Arthrobacter sp. strain HF-2

A nicotine-degrading bacterium, strain HF-2, was isolated from tobacco waste-contaminated soil and identified as a member of Arthrobacter sp. based on morphology, physiological tests, 16S rDNA sequence and phylogenetic characteristics. At thermal denaturation test indicated that the G + C mol% of strain HF-1 was 63.5. The relationship between the growth of the isolate and the nicotine degradation suggested that strain HF-2 could utilize nicotine as sole sources of carbon, nitrogen and energy. Blue pigment was observed during the nicotine degradation by strain HF-2. The isolate grew well at 20 to 33 degrees C, initial pH 6.5 to 8.0 and 0.5 to 2.0 g L-1 of nicotine concentration in the nicotine inorganic salt media. The maximum growth and nicotine degradation occurred at 30 degrees C, initial pH 7.0 and 0.7 g.L-1 of nicotine concentration in media under natural incubation condition. Strain HF-2 could degrade 100% of nicotine under the optimized incubation conditions for 43 h. The concentrations of nicotine were monitored by high performance liquid chromatography. This study demonstrates Arthrobacter sp. strain HF-2 had a great ability to degrade nicotine, and it may be available for the application to the bioremediation of environments contaminated by tobacco waste.     

Mineralization of p-nitrophenol by a new isolate Arthrobacter sp. Y1

Arthrobacter sp. Y1, capable of metabolizing p-nitrophenol (PNP) as the sole carbon, nitrogen and energy source was isolated from activated sludge. The bacterium could tolerate concentrations of PNP up to 600 mg L(- 1), and degradation of PNP was achieved within 120 h of incubation. PNP and its metabolites were analyzed by high performance liquid chromatography (HPLC). The metabolite formed indicated that the organism followed the 4-nitrocathechol (4-NC) pathway for metabolism of this compound. The relevant degrading-enzyme was extracellular. Addition of other carbon source (glucose 0 approximately 30 g L(- 1)) led to accelerated degradation. If the glucose concentration exceeded 30 g L(- 1), however, degradation was repressed. Spectrophotometry assay of the nitrite and genotoxic study showed that strain Y1 could detoxify PNP. Therefore, the present study may provide a basis for the development of the bioremediation strategies to remedy the pollutants in the environment.     

Biodegradation of 4-aminobenzenesulfonate by Ralstonia sp. PBA and Hydrogenophaga sp. PBC isolated from textile wastewater treatment plant

A co-culture consisting of Hydrogenophaga sp. PBC and Ralstonia sp. PBA, isolated from textile wastewater treatment plant could tolerate up to 100 mM 4-aminobenzenesulfonate (4-ABS) and utilize it as sole carbon, nitrogen and sulfur source under aerobic condition. The biodegradation of 4-ABS resulted in the release of nitrogen and sulfur in the form of ammonium and sulfate respectively. Ninety-eight percent removal of chemical oxygen demand attributed to 20 mM of 4-ABS in cell-free supernatant could be achieved after 118 h. Effective biodegradation of 4-ABS occurred at pH ranging from 6 to 8. During batch culture with 4-ABS as sole carbon and nitrogen source, the ratio of strain PBA to PBC was dynamic and a critical concentration of strain PBA has to be reached in order to enable effective biodegradation of 4-ABS. Haldane inhibition model was used to fit the degradation rate at different initial concentrations and the parameters μ_max, K_s and K_i were determined to be 0.13 h⁻¹, 1.3 mM and 42 mM respectively. HPLC analyses revealed traced accumulation of 4-sulfocatechol and at least four unidentified metabolites during biodegradation. This is the first study to report on the characterization of 4-ABS-degrading bacterial consortium that was isolated from textile wastewater treatment plant.     

Mineralization of p-nitrophenol by a new isolate Arthrobacter sp. Y1

Arthrobacter sp. Y1, capable of metabolizing p-nitrophenol (PNP) as the sole carbon, nitrogen and energy source was isolated from activated sludge. The bacterium could tolerate concentrations of PNP up to 600 mg L^{? 1}, and degradation of PNP was achieved within 120 h of incubation. PNP and its metabolites were analyzed by high performance liquid chromatography (HPLC). The metabolite formed indicated that the organism followed the 4-nitrocathechol (4-NC) pathway for metabolism of this compound. The relevant degrading-enzyme was extracellular. Addition of other carbon source (glucose 0～ 30 g L^{? 1}) led to accelerated degradation. If the glucose concentration exceeded 30 g L^{? 1}, however, degradation was repressed. Spectrophotometry assay of the nitrite and genotoxic study showed that strain Y1 could detoxify PNP. Therefore, the present study may provide a basis for the development of the bioremediation strategies to remedy the pollutants in the environment.     

Acclimation of anaerobic sludge degrading chlorophenols and the biodegradation kinetics during acclimation period

The acclimation of sludge from Hangzhou citrate factory and Hangzhou municipal wastewater treatment plant for degradation dechlorination of chlorophenols (CPs) compounds, and its biodegradation kinetics were studied in batch process with or without addition of sucrose. Three monochlorophenols (2-CP; 3-CP; 4-CP) and pentachlorophenol (PCP) were concurrently fed to different bioreactors. The parameters that were monitored included biogas production, biogas composition and chemical oxygen demand (COD). The results showed that acclimation with chlorophenol can increase the degradation activity of anaerobic sludge and degradation rate of chlorophenolic compounds, and reduce the lag time. Degradation dechlorination activity of the acclimated sludge strongly depended on sludge source, microorganism population and chlorophenol congener. 2-CP was more easily acclimated than 3-CP and 4-CP. Among the four tested compounds, 4-CP was the most difficult to be acclimated. The observed degradation rate with presence of sucrose was higher than that with absence of sucrose, suggesting that addition of the external carbon source can stimulate the formation of acclimated sludge which could effectively degrade chlorophenols. Kinetic equations of biodegradation of chlorophenols were also presented in this paper.     

Implications of urine-to-feces ratio in the thermophilic anaerobic digestion of swine waste.

Thermophilic anaerobic digestion of swine manure represents a potential waste treatment technology to address environmental concerns, such as odor emissions and removal of pathogenic microorganisms. However, there are concerns relative to the stability of this process when swine manure is the sole substrate. In this study, the potential of biogas production from swine manure as the sole substrate under thermophilic (50 degrees C) conditions was investigated in the laboratory, to determine whether separation of urine and feces as part of the waste collection process would benefit anaerobic digestion. Effluent from a continuously stirred tank reactor was used as the inoculum for batch tests, in which the substrate contained three different concentrations of urine (urine-free, as-excreted urine-to-feces ratio and double the as-excreted urine-to-feces ratio). Inocula were acclimated to these same urine-to-feces ratios to determine methane production. Results show that both urine-free and as-excreted substrates were not inhibitory to anaerobic inocula. Anaerobic microorganisms can be readily acclimated to substrate with double the as-excreted urine concentration, which contained nitrogen concentrations up to 7.20 g/L. Cumulative methane production reached similar levels in the batch tests, regardless of the substrate urine concentration.     

稠油高效降解菌的降解特性及其应用

以稠油为唯一碳源,对细菌B0501、B0505和B0510的降解特性进行了分析,结果表明3株菌对稠油的不同组分具有不同程度的降解能力,其中B0505对烷烃、B0510对芳香烃以及B0501对胶质和沥青质的去除率较高,分别为42.26%、35.30%和40.76%;混合菌协同作用强化了稠油组分的降解,3株菌株组合对烷烃、芳香烃以及胶质沥青质的降解率分别达到44.23%、38.56%和62.12%;微生物对稠油降解过程符合一级动力学方程,其中3株菌株组合对稠油降解的速率最快,半衰期(t_1/2)为5.36 d。将微生物应用于稠油废水处理实践,结果表明外源微生物的投加强化了废水中COD的去除率;GC-MS图谱及降解前后有机成分分析进一步佐证了微生物对稠油废水中有机成分的降解能力。     

苯酚的厌氧生物处理

采用不断增加苯酚浓度而降低葡萄糖浓度的方法可驯化厌氧污泥中的微生物,使厌氧污泥最终以苯酚为唯一碳源生长,可显著提高厌氧污泥降解苯酚的能力;对苯酚间歇厌氧降解过程进行了分析。苯酚浓度在0～1.680 mg/L范围内,其厌氧降解过程符合一级动力学。Aiba模型、Haldane模型和Teisser 模型均可很好地描述处于对数期时厌氧污泥的比生长速率与初始底物浓度之间的关系,其中以Teisser 模型模拟的效果最好。将驯化污泥接种于UASB中可实现对含酚废水处理的连续运行,最大的有机负荷达2 g COD/（L·d）,稳定运行时苯酚的去除率可维持在96%以上。     

Degradation of atrazine in mineral salts medium and soil using enrichment culture

Atrazine degrading enrichment culture was prepared by its repeated addition to an alluvial soil and its ability to degrade atrazine in mineral salts medium and soil was studied. Enrichment culture utilized atrazine as a sole source of carbon and nitrogen in mineral salts medium and degradation slowed down when sucrose and/or ammonium hydrogen phosphate were supplemented as additional source of carbon and nitrogen, respectively. Biuret was detected as the only metabolite of atrazine while deethylatrazine, deisopropyatrazine, hydroxyatrazine and cyanuric acid were never detected at any stage of degradation. Enrichment culture degraded atrazine in an alkaline alluvial soil while no degradation was observed in the acidic laterite soil. Enrichment culture was able to withstand high concentrations of atrazine (110 μg/g) in the alluvial soil as atrazine was completely degraded. Developed mixed culture has the ability to degrade atrazine and has potential application in decontamination of contaminated water and soil.     

氐温喹啉降解菌的筛选及降解性能

从吉林石化污水处理厂的活性污泥中驯化、筛选获得一株降解效率高且生长速率快高效耐冷菌,命名为WS-5。该菌能以喹啉作为惟一的碳源、氮源及能源。结合菌体的形态观察、生理生化特性实验及16SrDNA序列同源性对比分析,鉴定菌株WS-5为恶臭假单胞菌（Pseudomonasputida）。不同降解条件下的实验结果表明,菌株WS-5的最佳降解条件是投菌量为15％,pH值范围在8～10,摇床转速为100r／min。最佳降解环境下对200mg／L的喹啉在132h降解率达到了85．3％。菌株WS-5对初始喹啉浓度为50、100、200和300mg／L的初始喹啉浓度分别在36、72、192和262h内完全降解。这将为今后在低温条件下处理含喹啉废水提供技术指导。     

低温喹啉降解菌的筛选及降解性能

从吉林石化污水处理厂的活性污泥中驯化、筛选获得一株降解效率高且生长速率快高效耐冷菌,命名为WS-5.该菌能以喹啉作为惟一的碳源、氮源及能源.结合菌体的形态观察、生理生化特性实验及16S rDNA序列同源性对比分析,鉴定菌株WS-5为恶臭假单胞菌(Pseudomonas putida).不同降解条件下的实验结果表明,菌株WS-5的最佳降解条件是投菌量为15％,pH值范围在8～10,摇床转速为100 r/min.最佳降解环境下对200 mg/L的喹啉在132 h降解率达到了85.3％.菌株WS-5对初始喹啉浓度为50、100、200和300 mg/L的初始喹啉浓度分别在36、72、192和262 h内完全降解.这将为今后在低温条件下处理含喹啉废水提供技术指导.     

Characteristics of biotic and abiotic removals of dissolved organic carbon in wastewater effluents using soil batch reactors.

Biodegradable dissolved organic carbon (BDOC) analyses and abiotic adsorption of dissolved organic carbon (DOC) from different wastewater effluent were conducted to evaluate biotic and abiotic removal mechanisms as a function of the initial DOC concentration and source of DOC using soil batch reactors. To obtain high DOC concentrations, a laboratory-scale reverse osmosis unit was used. It was found that BDOC fraction was independent of the initial DOC concentration and was dependent on the source of wastewater and/or the types of wastewater treatment. The BDOC fractions varied from 9 to 73%. Trickling filter effluent (Tucson, Arizona) showed the highest BDOC, ranging from 65 to 73% biodegradable, while wastewater treated by the soil aquifer treatment (SAT) (NW-4) was found to be most refractory, with DOC removals of 9 to 14%. For nitrified/denitrified tertiary effluent (Mesa, Arizona) and secondary effluent (Scottsdale, Arizona), 36 to 42% removal of DOC was observed during the BDOC test. The amount of BDOC in the wastewater depended not on the concentration of DOC, but on the effectiveness of pretreatment. Abiotic adsorption capacity of wastewater effluent varied from 6 to 18%. Molecular weight distribution analyses showed that more than 50% of DOC in the Scottsdale concentrate had a molecular weight of less than 1000 Da, and no significant change in distribution profiles occurred after approximately 12% abiotic adsorption with both soils with acclimated microorganisms (SAT soil) and soils without acclimated microorganisms (non-SAT soils). Hence, preferential adsorption was not observed and the presence of acclimated microbes did not influence adsorption.     

硝态氮为惟一氮源时异养微生物增长特性

采用SBR研究了缺氧条件下硝态氮为惟一氮源时异养微生物的增长特性。结果表明,异养微生物能利用硝态氮作为氮源进行增殖。当进水COD浓度为1 400 mg/L,硝态氮浓度为280 mg/L时,COD和硝态氮的去除率分别达到97%和99%;污泥中微生物的含氮量为8.8%,低于常规利用氨氮作为氮源的微生物;在实验条件下活性污泥的产率系数为0.30 g VSS/g COD。反硝化菌可利用硝态氮作为氮源进行细胞合成对含硝氮的废水处理具有重要意义。一方面由于无需投加氨氮降低了废水处理成本,另一方面由于污泥产率低,降低了污泥处理成本。     

Application of Klebsiella oxytoca immobilized cells on the treatment of cyanide wastewater

Klebsiella oxytoca, isolated from cyanide-containing industrial wastewater, has been shown to be able to biodegrade cyanide to non-toxic end products. The technology of immobilized cells can be applied in biological treatment to enhance the efficiency and effectiveness of biodegradation. In this study, potassium cyanide was used as the target compound and both alginate and cellulose triacetate techniques were applied for the preparation of immobilized cells. Results from this study show that KCN can be utilized as the sole nitrogen source by K. oxytoca. The free suspension systems reveal that the cell viability was highly affected by initial KCN concentration and pH. Results show that immobilized cell systems could tolerate a higher level of KCN concentration and wider ranges of pH. In the batch experiments, the maximum KCN removal efficiencies using alginate and cellulose triacetate immobilized beads were 0.108 and 0.101mM h(-1) at pH 7, respectively. Results also indicate that immobilized system can support a higher biomass concentration. Complete KCN degradation was observed after the operation of four consecutive degradation experiments with the same batch of immobilized cells. This suggests that the activity of immobilized cells can be maintained and KCN can be used as the nitrogen source throughout KCN degradation experiments. The maximum KCN removal rates using alginate and cellulose triacetate immobilized beads in continuous-column system were 0.224 and 0.192mMh(-1) with initial KCN concentration of 3mM, respectively. Results indicate that the immobilized cells of K. oxytoca would be applicable to the treatment of cyanide-containing wastewaters.     

Microbial and kinetic characterization of pure and mixed cultures aerobically degrading 4-nitrophenol

The molecular and kinetic characterization of a microorganism able to aerobically degrade 4-nitrophenol (4NP) is presented. The microorganism was isolated from a mixed culture operating in a laboratory-scale sequencing batch reactor with an aerobic anoxic cycle. It was identified as a member of Ralstonia genus within Betaproteobacteria. It is a gram negative coccobacillum (cell length of 2-3 microm) able to aerobically store lipid inclusions when grown aerobically on nitrophenol as the sole carbon source in the range of tested concentrations (80-320 mg l(-1)). Batch kinetic tests were performed with the pure culture, while the kinetics of the mixed biomass was directly investigated in the reactor. For pure cultures exponential growth was observed, with growth rate values in the range of 2-6 d(-1); in experiments with the mixed cultures 4NP concentrations were correlated with growth using the Haldane equation (k(max) = 0.30 mg 4NP mg(-1) VSSh(-1); K(s) = 55 mg 4NPl(-1) and K(I) = 15 mg 4NPl(-1)). Observed pure culture growth rates were higher than those of mixed cultures. This result can be explained by considering that in mixed culture the biomass is evaluated as volatile suspended solids, including both specialized biomass for 4NP removal and denitrifying bacteria.     

十三碳二元酸发酵有机废水处理研究

运用物化预处理和ＳＢＲ生化工艺对十三碳二元酸发酵废水中高浓度有机物的降解特征及高２硫酸钠对微生物的有害抑制作用进行处理试验,研究结果表明。采用物化预处理与ＳＢＲ生化法相结合的工艺可有效地处理该类废水。经驯化的耐盐微菌胶力和裂口虫为主,废水的ＣＯＤｃｒ去除率可达９２％以上,ＢＯＤ５去除率可达９５％以上。     

Microbial degradation of guanidinium ion

Guanidinium ion was degraded by microorganisms in a variety of surface water samples. Degradation of the cation was characterized by long and variable periods prior to enhanced microbial activity and was considerably slower than the degradation of the amino acid arginine. A carbon source could potentiate the degradation of guanidinium ion, in which case its carbon was mineralized and its nitrogen could be used for growth; but at nutrient levels in surface water, only slight mineralization of the cation's carbon was demonstrated and was considerably slower than that of urea carbon. Degradation of guanidinium ion by microorganisms capable of growing on it as a sole carbon source was estimated to be slow relative to two xenobiotic compounds. The development of such populations in surface water samples was dependent on the concentration of guanidinium ion.     

Studies on Biodegradation of Nicotine by Arthrobacter sp. Strain HF-2

A nicotine-degrading bacterium, strain HF-2, was isolated from tobacco waste-contaminated soil and identified as a member of Arthrobacter sp. based on morphology, physiological tests, 16S rDNA sequence and phylogenetic characteristics. At thermal denaturation test indicated that the G + C mol% of strain HF-1 was 63.5. The relationship between the growth of the isolate and the nicotine degradation suggested that strain HF-2 could utilize nicotine as sole sources of carbon, nitrogen and energy. Blue pigment was observed during the nicotine degradation by strain HF-2. The isolate grew well at 20 to 33°C, initial pH 6.5 to 8.0 and 0.5 to 2.0 g L^?1 of nicotine concentration in the nicotine inorganic salt media. The maximum growth and nicotine degradation occurred at 30°C, initial pH 7.0 and 0.7 g·L^?1 of nicotine concentration in media under natural incubation condition. Strain HF-2 could degrade 100% of nicotine under the optimized incubation conditions for 43 h. The concentrations of nicotine were monitored by high performance liquid chromatography. This study demonstrates Arthrobacter sp. strain HF-2 had a great ability to degrade nicotine, and it may be available for the application to the bioremediation of environments contaminated by tobacco waste.     

Isolation and characterization of a potential paraffin-wax degrading thermophilic bacterial strain Geobacillus kaustophilus TERI NSM for application in oil wells with paraffin deposition problems

Paraffin deposition problems, that have plagued the oil industry, are currently remediated by mechanical and chemical means. However, since these methods are problematic, a microbiological approach has been considered. The bacteria, required for the mitigation of paraffin deposition problems, should be able to survive the high temperatures of oil wells and degrade the paraffins under low oxygen and nutrient conditions while sparing the low carbon chain paraffins. In this study, a thermophilic paraffinic wax degrading bacterial strain was isolated from a soil sample contaminated with paraffinic crude oil. The selected strain, Geobacillus TERI NSM, could degrade 600mg of paraffinic wax as the sole carbon source in 1000ml minimal salts medium in 7d at 55 degrees C. This strain was identified as Geobacillus kaustophilus by fatty acid methyl esters analysis and 16S rRNA full gene sequencing. G. kaustophilus TERI NSM showed 97% degradation of eicosane, 85% degradation of pentacosane and 77% degradation of triacontane in 10d when used as the carbon source. The strain TERI NSM could also degrade the paraffins of crude oil collected from oil wells that had a history of paraffin deposition problems.     

氮源对气相生物滴滤床净化效果的影响

氮源对于气相生物滴滤床的净化效果有显著的影响。由于喷淋液体在生物滴滤床中分布不均匀 ,导致床层中局部氮源不充足 ,从而使滤床的去除效果降低。提高喷淋液中氮源的浓度 ,可以较大幅度提高净化效率。采用NH-4 N会导致滤床中硝化细菌的生长和累积 ,使得异养菌和硝化细菌在溶解氧、氮源和填料空间上形成竞争 ,并致使氮源分布不均匀 ,而采用NO3 N作为氮源可以改善这种状况