Simultaneous biodegradation of pyridine and quinoline by two mixed bacterial strains

Experiments were conducted to provide data on the effectiveness of bioaugmentation in the removal of pyridine and quinoline from different wastewaters. A pyridine-degrading bacterial strain (Paracoccus sp. BW001) and a quinoline-degrading strain (Pseudomonas sp. BW003) were isolated from the activated sludge of a coking wastewater treatment plant. In this study, a consortium of these two bacterial strains was used as inoculum to simultaneously degrade pyridine and quinoline in three types of wastewaters: sterile synthetic, domestic, and industrial. In addition, variation of the bacterial community structures during degradation was monitored by denaturing gradient gel electrophoresis and amplicon length heterogeneity polymerase chain reaction techniques. The results of our experiments indicate that pyridine and quinoline can be removed efficiently using this inoculum but that the degradation process results in the production of ammonium as a by-product. Also, in the two actual wastewaters investigated, we observed that several autochthonous strains of bacteria in both the domestic and industrial wastewater were tolerant of pyridine and quinoline and grew rapidly.     

Degradation of predigested distillery effluent by isolated bacterial strains

Batch studies were conducted on degradation of anaerobically digested distillery wastewater by three bacterial strains, viz. Xanthomonas fragariae, Bacillus megaterium and Bacillus cereus in free and immobilized form, isolated from the activated sludge of a distillery wastewater treatment plant. The removal of COD and colour with all the three strains increased with time up to 48 hr and only marginal increase in COD and colour removal efficiency was observed beyond this period up to 72 hr. After this period removal efficiency remained fairly constant up to 120 hr. The maximum COD and colour removal efficiency varied from 66 to 81% and 65 to 75%, respectively for both free and immobilized cells of all the three strains. The strain Bacillus cereus showed the maximum efficiency of COD (81%) and colour (75%) removal out of the three strains. An interrelationship between the percent COD and colour removal was carried out by correlation and regression analysis and was justified by high values of coefficient of correlation (r = 0.99) for all the cases. The first order removal rate kinetics was also applied and rate constants were evaluated for COD and colour removal efficiencies.     

一株红球菌属细菌LV4在高盐条件下的吡啶降解特性

由微生物介导的吡啶降解技术是解决高盐吡啶环境污染的经济有效方法之一,开发具有吡啶降解性能且能够耐受高盐分的微生物是该类研究的重要前提。本研究从山西太原钢铁公司焦化废水处理厂活性污泥中分离培养了一株耐盐吡啶降解菌,通过菌落形态和16S rDNA基因系统发育分析,鉴定其为红球菌属(Rhodococcus sp.)的细菌。耐盐性实验结果表明,菌株LV4能够在0%–6%盐度范围内生长,并完全降解初始浓度为500 mg/L的吡啶;但当盐度高于4%时,菌株LV4因其生长变缓而导致吡啶完全降解时间明显延长。扫描电镜结果显示,高盐环境会使菌株LV4的菌体细胞分裂变慢,诱导细胞表面分泌更多的颗粒状胞外聚合物(extracellular polymeric substance, EPS)。当盐度不高于4%时菌株LV4主要依靠EPS中蛋白含量的增加来响应高盐环境的冲击。单因素实验优化发现,菌株LV4在盐度为4%的高盐环境中降解吡啶的最佳条件为温度30℃、pH 7.0、转速为120 r/min (DO 10.30 mg/L)。最优条件下菌株LV4对于初始浓度为500 mg/L的吡啶,在经过12 h的适应期后,...     

Bioaugmentation accelerates the shift of bacterial community structure against shock load: a case study of coking wastewater treatment by zeolite-sequencing batch reactor

Bioaugmentation with degrading bacteria is an effective method to improve the treatment of refractory industrial wastewater; nevertheless there were controversial opinions about the fate of inoculated bacteria and microbial community dynamics. In this study, two lab-scale sequencing batch reactors filled with modified zeolite were used to treat a coking wastewater with pyridine and quinoline shock load, and a bacterial consortium containing three degrading strains was added in one reactor for bioaugmentation. During 120-day operation, the bioaugmented reactor removed over 99 % pyridine, 99 % quinoline, 85 % TOC, 65 % COD, and 95 % NO₃ ^?-N with higher resistance to the shock load than the non-bioaugmented reactor. Based on the terminal restriction fragment length polymorphism of 16S rDNA, bacterial community diversity increased in the bioaugmented reactor. Principal component analysis revealed that, to cope with the shock load, the indigenous bacterial community recovered to the initial structure by acclimatizing itself constantly to the inhospitable environment; but bioaugmentation accelerated the shift of whole bacterial community, resulting in a far different structure from the initial one. Canonical correspondence analysis indicated that the environmental parameters of pyridine, quinoline, TOC, and NO₃ ^?-N had close negative correlations with bioaugmentation; and NH₃-N and COD were the main parameters to impact on the bacterial community changes and treatment efficiency.     

玉米芯、竹炭及油枯吸附-海藻酸钠包埋施氏假单胞菌PFS-4对二氯喹啉酸的降解

采用玉米芯、竹炭及油枯吸附-海藻酸钠包埋对分离到的施氏假单胞菌PFS-4进行复合固定.采用正交试验对固定化条件进行优化,研究了固定化菌剂及游离菌体对二氯喹啉酸的降解效果.结果表明: 固定化菌剂制备的最佳条件为:海藻酸钠质量分数为4%、吸附载体比例(玉米芯∶竹炭∶油枯)为1∶2∶1、CaCl₂质量分数为3%、交联时间4 h.固定化菌剂在温度为30 ℃、初始pH=7的条件下,经6 d培养后,对浓度为800 mg·L^-1的二氯喹啉酸降解率为91.4%,而游离菌体的降解率为72.8%.将游离菌体和固定化菌剂用于实际污水及土壤处理时,固定化菌剂对水中及土壤中二氯喹啉酸去除率仍能分别达到84.2%和74.3%.研究结果表明,载体及其联结方式对土壤中二氯喹啉酸去除产生显著影响,翻动频率与土壤中二氯喹啉酸的去除率呈显著正相关.因此,玉米芯、竹炭及油枯吸附-海藻酸钠复合固定施氏假单胞菌PFS-4对不良环境具有较好的缓冲性能,对二氯喹啉酸污染水体及土壤原位生态修复具有潜力.     

固体发酵法固定工业废水处理优势菌的研究

为实现优势菌种的工程应用,由焦化废水处理站污泥筛选优势好氧菌A和兼性厌氧菌F,使用谷壳g、豆皮d为载体,采用固体发酵法进行固定化产品制备。初步研究表明固体发酵法固定菌种具有可行性,主要调控因素有温度、初始含水率、工业废水比例、pH、通风量和发酵时间。以pH8．0、温度好氧菌30℃（兼性厌氧菌35℃）、接种量1mL茴液儋田定化载体,初始含水量80％,固体发酵时间5d,低于60℃鼓风干燥,制备固定化产品。保存三个月,谷壳固定化产品好氧菌八的硝化能力和兼性厌氧菌R的反硝化能力不随保存时间的延长而改变;豆皮固定化产品氏、Fd降解能力随保存时问延长下降12％左右。以实验室岔／O工艺系统验证固定化产品处理焦化废水效果,缺氧池中无NO3-N积累,反硝化作用明显。氐和气对氰化物的去除率均达99％以上;对苯酚的去除效果气（98．84％）优于氏（79．6％）;但对NH4＋-N的去除率氏（75．46％）优于Ag（62．55％）。     

Degradation and decolorization of monosodium glutamate wastewater with <Emphasis Type="Italic">Coriolus versicolor</Emphasis>

Degradation and decolorization of monosodium glutamate wastewater (MSGW) with Coriolus versicolor were firstly carried out. The effects of various operation parameters namely wastewater concentrations, pH, culture time and incidence of sterilization on maximum percentage of degradation and decolorization of wastewater were investigated. Studies of mycelium and enzyme for C. versicolor degradation and decolorization were estimated in this study. Ten percentage of wastewater concentration and pH = 5.0 were found to be the most suitable ones among the other experiments. The highest degradation and decolorization efficiency of wastewater was obtained at the fifth day of cultivation, which was displayed with more than 70% chemical oxygen demand removal, 83% total sugar removal and 55% color removal, respectively. Sterile operation had no remarkable effect on the degradation and decolorization efficiency for C. versicolor. Mycelium and the extra cellular fungal enzyme were both necessary for the degradation and decolorization of MSGW. C. versicolor possesses great potential and economic advantages in MSGW treatment.     

Isolation and lipid degradation profile of Raoultella planticola strain 232-2 capable of efficiently catabolizing edible oils under acidic conditions

The lipids (fats and oils) degradation capabilities of soil microorganisms were investigated for possible application in treatment of lipids-contaminated wastewater. We isolated a strain of the bacterium Raoultella planticola strain 232-2 that is capable of efficiently catabolizing lipids under acidic conditions such as in grease traps in restaurants and food processing plants. The strain 232-2 efficiently catabolized a mixture (mixed lipids) of commercial vegetable oil, lard, and beef tallow (1:1:1, w/w/w) at 20–35 °C, pH 3–9, and 1,000–5,000 ppm lipid content. Highly effective degradation rate was observed at 35 °C and pH 4.0, and the 24-h degradation rate was 62.5?±?10.5 % for 3,000 ppm mixed lipids. The 24-h degradation rate for 3,000 ppm commercial vegetable oil, lard, beef tallow, mixed lipids, and oleic acid was 71.8 %, 58.7 %, 56.1 %, 55.3?±?8.5 %, and 91.9 % at pH 4 and 30 °C, respectively. R. planticola NBRC14939 (type strain) was also able to efficiently catabolize the lipids after repeated subculturing. The composition of the culture medium strongly influenced the degradation efficiency, with yeast extract supporting more complete dissimilation than BactoPeptone or beef extract. The acid tolerance of strain 232-2 is proposed to result from neutralization of the culture medium by urease-mediated decomposition of urea to NH₃. The rate of lipids degradation increased with the rates of neutralization and cell growth. Efficient lipids degradation using strain 232-2 has been achieved in the batch treatment of a restaurant wastewater.     

Study of phenol biodegradation using Bacillus amyloliquefaciens strain WJDB-1 immobilized in alginate–chitosan–alginate (ACA) microcapsules by electrochemical method

An aerobic microorganism with an ability to utilize phenol as sole carbon and energy source was isolated from phenol-contaminated wastewater samples. The isolate was identified as Bacillus amyloliquefaciens strain WJDB-1 based on morphological, physiological, and biochemical characteristics, and 16S rDNA sequence analysis. Strain WJDB-1 immobilized in alginate–chitosan–alginate (ACA) microcapsules could degrade 200 mg/l phenol completely within 36 h. The concentration of phenol was determined using differential pulse voltammetry (DPV) at glassy carbon electrode (GCE) with a linear relationship between peak current and phenol concentration ranging from 2.0 to 20.0 mg/l. Cells immobilized in ACA microcapsules were found to be superior to the free suspended ones in terms of improving the tolerance to the environmental loadings. The optimal conditions to prepare microcapsules for achieving higher phenol degradation rate were investigated by changing the concentrations of sodium alginate, calcium chloride, and chitosan. Furthermore, the efficiency of phenol degradation was optimized by adjusting various processing parameters, such as the number of microcapsules, pH value, temperature, and the initial concentration of phenol. This microorganism has the potential for the efficient treatment of organic pollutants in wastewater.     

Analysis of the characteristics of short-cut nitrifying granular sludge and pollutant removal processes in a sequencing batch reactor

Aerobic granular sludge is a new type of microbe auto-immobilization technology; in this paper, short-cut nitrification and denitrification were effectively combined with the granular sludge technology. Simultaneous nitrification and denitrification granules were developed in a sequencing batch reactor (SBR) using synthetic wastewater with a high concentration of ammonia nitrogen at 25 °C with a dissolved oxygen concentration above 2.0 mg/L and a 15 days sludge retention time. The characteristics of the sludge and the removal efficiency were studied, and the removal mechanisms of the pollutants and the process of short-cut nitrification were analyzed. The average granule diameter of the granular sludge was 704.0 μm. The removal rates of pollutants and the accumulation rate of nitrite in the SBR were studied. During treatment of wastewater with a high concentration of ammonia nitrogen, simultaneous nitrification, and denitrification and the stripping process could contribute to the removal of total nitrogen. The high pH value, the high concentration of free ammonia, and the delamination of granular sludge were the main factors contributing to the short-cut nitrification property of granular sludge in the reaction process.     

壳聚糖固定化气单胞菌处理餐厨高油脂废水

为有效解决餐厨废水中的高油脂对下游处理工艺的严重影响,本研究以筛选获得的一株高效的油脂降解菌株嗜糖气单胞菌Aeromonas allosaccarophila CY-01为研究对象,以壳聚糖为载体材料,对其进行固定化包埋制备壳聚糖-气单胞菌小球(CH-CY01);探究CH-CY01小球的油脂降解效率以及性能影响评估。研究结果表明,经壳聚糖固定后的菌株CY-01其细胞的生长活性几乎不受影响,对大豆油脂的最大降解率为89.7%;相比于未固定的细胞,CH-CY01在0.5%NaCl的盐度条件下对油脂的降解效率显著提高了20%;在浓度为1 mg/L的表面活性剂(十二烷基苯磺酸钠)存在条件下,CH-CY01对油脂的降解效率显著提高了40%。以餐饮高油脂污水为处理对象,结果显示经添加1%(V/V)的CH-CY01小球处理7 d后,超过80%以上的固态油脂被降解,明显高于未固定的CY-01。综上所述,经壳聚糖固定包埋的CH-CY01小球显著提高了菌株的生存能力和油脂降解效率,对于高油脂餐饮污水的高效处理具有较大的应用潜力。     

Analysis of denitrifier community in a bioaugmented sequencing batch reactor for the treatment of coking wastewater containing pyridine and quinoline

The denitrifier community and associated nitrate and nitrite reduction in the bioaugmented and general sequencing batch reactors (SBRs) during the treatment of coking wastewater containing pyridine and quinoline were investigated. The efficiency and stability of nitrate and nitrite reduction in SBR was considerably improved after inoculation with four pyridine- or quinoline-degrading bacterial strains (including three denitrifying strains). Terminal restriction fragment length polymorphism (T-RFLP) based on the nosZ gene revealed that the structures of the denitrifier communities in bioaugmented and non-bioaugmented reactors were distinct and varied during the course of the experiment. Bioaugmentation protected indigenous denitrifiers from disruptions caused by pyridine and quinoline. Clone library analysis showed that one of the added denitrifiers comprised approximately 6% of the denitrifier population in the bioaugmented sludge.     

混合白腐真菌的固定化及其在治理铅污染废水中的应用

【目的】为缓解重金属废水污染对全球食品安全和人类健康的威胁,降低铅(plumbum, Pb)在土壤及动植物体内的积累,借助固定化技术提高菌株的重金属去除效率。【方法】以白腐真菌(white rot fungi)为实验材料,通过混菌兼容性及铅离子(Pb²⁺)去除能力筛选出吸附效果好且兼容性优的复合菌种,探究最优混菌类型及其比例,优化菌球最佳固定化助剂配方,在此基础上深入探究菌球在实际应用中的最优吸附条件。【结果】黄孢原毛平革菌(Phanerochaete chrysosporium)、云芝(Coriolus versicolor)、凤尾菇(Lentinus sajor-caju)和平菇(Pleurotus ostreatus) 4种菌株兼容效果佳,可进行后续实验;其中云芝和凤尾菇以体积1:1混合后对Pb²⁺去除效果显著优于各单菌作用;固定化条件优化实验中,20.0 g/L海藻酸钠、15.0 g/L生物炭和2.0×10⁶个/mL白腐真菌组成混菌体系,辅以二氧化硅及沸石制得的固定化菌球在96 h Pb²⁺...     

Degradation of chlorophenols catalyzed by laccase

The degradations of 2,4-dichlorophenol (2,4-DCP), 4-chlorophenol (4-CP) and 2-chlorophenol (2-CP) catalyzed by laccase were carried out. The optimal condition regarding degradation efficiency was also discussed, which included reaction time, pH value, temperature, concentration series of chlorophenols and laccase. Results showed that the capability of laccase was the best, while to oxidize 2,4-DCP among the above-mentioned chlorophenols. Within 10 h, the removal efficiency of 2,4-DCP, 2-CP and 4-CP could reach 94%, 75% and 69%, respectively. The optimal pH for laccase to degrade chlorophenols was around 5.5. The increase of laccase concentration or temperature might result in the degradation promotion. The trends of degradation percentage were various among these three chlorophenols with the concentration increase of chlorophenols. Degradation of 2,4-DCP is a first-order reaction and the reaction activation energy is about 44.8 kJ mol⁻¹. When laccase was immobilized on chitosan, crosslinked with glutaraldehyde, the activity of immobilized laccase was lower than that of free laccase, but the stability improved significantly. The removal efficiency of immobilized laccase to 2,4-DCP still remained over 65% after six cycles of operation.     

高效净水异养硝化细菌的筛选鉴定及固定化应用研究

本研究从海参养殖水体、泥土中筛选出4株具有硝化能力的异养硝化细菌。分别将其游离菌体细胞投入海参养殖水体,测定亚硝态氮、氨氮去除率,筛选出HS．NOB2为高效净化菌株,对HS-NOB2进行16SrDNA扩增及序列测定,初步鉴定为节杆菌（Arthrobactersp．）。利用海藻酸钠包埋法对高效净化菌体细胞进行固定化,将该固定化菌投入养殖水体及人工合成污水,研究其对水体中亚硝态氮、氨氮的处理效果,并与游离菌体细胞进行比较。结果表明,固定化后亚硝态氮去除率达到49．85％,氨氮去除率达到56．58％,均明显高于游离菌体细胞。上述研究为探寻水体净化提供了新思路,为水质改良剂的实际生产提供可选菌株。     

Effect of herbicide adjuvants on the biodegradation rate of the methylthiotriazine herbicide prometryn

A microbial community, selected by its ability to degrade triazinic herbicides was acclimatized by successive transfers in batch cultures. Initially, its ability to degrade prometryn, was evaluated using free cells or cells attached to fragments of a porous support. As carbon, nitrogen and sulfur sources, prometryn, (98.8 % purity), or Gesagard, a herbicide formulation containing 44.5 % prometryn and 65.5 % of adjuvants, were used. In batch cultures, a considerable delay in the degradation of prometryn, presumptively caused by the elevated concentration of inhibitory adjuvants, occurred. When pure prometryn was used, volumetric removal rates remarkably higher than those obtained with the herbicide formulation were estimated by fitting the raw experimental data to sigmoidal decay models, and differentiating them. When the microbial consortium was immobilized in a continuously operated biofilm reactor, the negative effect of adjuvants on the rate and removal efficiency of prometryn could not be detected. Using the herbicide formulation, the consortium showed volumetric removal rates greater than 20 g m^?3 h^?1, with prometryn removal efficiencies of 100 %. The predominant bacterial strains isolated from the microbial consortium were Microbacterium sp., Enterobacter sp., Acinetobacter sp., and Flavobacterium sp. Finally, by comparison of the prometryn removal rates with others reported in the literature, it can be concluded that the use of microbial consortia immobilized in a biofilm reactor operated in continuous regime offer better results than batch cultures of pure microbial strains.     

Efficacy of Acinetobacter sp. B9 for simultaneous removal of phenol and hexavalent chromium from co-contaminated system

The present study shows the feasibility of a newly isolated strain Acinetobacter sp. B9 for concurrent removal of phenol and Cr (VI) from wastewater. The experiments were conducted in a batch reactor under aerobic conditions. Initially, when mineral salt solution was used as the culture medium, the strain was found to utilize phenol as sole carbon and energy source while no Cr (VI) removal was observed. However, the addition of glucose as co-carbon source resulted in the removal of both toxicants. This co-removal efficiency of the strain was further improved with nutrient-rich media (NB). Optimum co-removal was determined at 188 mg L^?1 of phenol and 3.5 mg L^?1 of Cr (VI) concentrations at pH 7.0. Strain B9 followed the orthometabolic pathway for phenol degradation. Transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR) studies showed sorption of chromium as one of the major mechanisms for Cr (VI) removal by B9 cells. Acinetobacter sp. B9 was later on checked for bioremediation of real tannery wastewater. After 96 h of batch treatment of tannery effluent containing an initial 47 mg L^?1 phenol and 16 mg L^?1 Cr (VI), complete removal of phenol and 87 % reduction of Cr (VI) were attained, showing high efficiency of the bacterial strain for potential application in industrial pollution control.     

Nitrogen and phosphate removal by free and immobilised cells of Scenedesmus bijugatus (Kützing) from the Pinang River estuary,Penang, Malaysia

This research studied the effects of inorganic nutrient removal by free and immobilized Scenedesmus bijugatus cells, measured by algal growth (i.e., the chlorophyll a concentration) and the efficiency of the uptake of inorganic nutrients by the cells (uptake rate (b) and removal percentage) in water samples from the organically polluted Pinang River estuary (PRE). Water samples from the PRE were collected during low and high tide. S. bijugatus cells had a higher growth rate when incubated in low tide PRE water samples compared to high tide PRE water samples, with a growth rate of 0.29 µgml^?1d^?1 and 0.06 µgml^?1d^?1 for free and immobilized cells, respectively. S. bijugatus was able to more efficiently remove nitrogen, especially ammonium (81–94%), compared to phosphate (62–88%) from both low and high tide water samples. S. bijugatus cells in low tide PRE water samples recorded highest phosphate (0.36 mgL^?1d^?1 and 0.25 mgL^?1d^?1 for free and immobilized cells, respectively) and ammonium uptake rates (0.44 mgL^?1d^?1 and 0.29 mgL^?1d^?1 for free and immobilized cells respectively). Both inorganic nutrient removal and microalgal cell growth were not significantly different between free and immobilized S. bijugatus (p > 0.05). The data obtained indicated that the removal of nutrients by microalgae was affected by salinity and the immobilization technique applied may have good potential for bioremediation.     

Stability of immobilized laccase on Luffa Cylindrica fibers and assessment of synthetic hormone degradation

In this work were studied the pH, thermal, and storage stability of free and immobilized laccases. Enzymes were produced by Pleurotus ostreatus on potato dextrose (PD) broth and potato dextrose modified (PDM) broth, and immobilized using Luffa cylindrica fibers as support. Both free and immobilized enzymes were assessed on their respective enzymatic activities and for 17α-ethinylestradiol (EE2) degradation. The optimum pH conditions concerning laccase activity ranged from 3.6 to 4.6, while temperature ranged between 30?°C and 50?°C for both free and immobilized enzyme. Laccase produced using PD broth presented greater storage stability and thermal stability than that of PDM. Best EE2 removals were of 79.22% and 75.00% for the free and immobilized enzymes, respectively. Removal rates were assessed during 8?h at pH 5. The removal of 17α-ethinylestradiol was stabilized in the fourth cycle of use. Results imply that immobilization promoted stability towards pH and temperature variations, although media played a decisive role in the enzymatic activity. Both free and immobilized laccases of P. ostreatus were able to degrade EE2, whereas immobilized laccase in PDM medium presented possible reuse applicability, albeit removal was not optimal when compared to other reports.     

Simultaneous wastewater treatment,electricity generation and biomass production by an immobilized photosynthetic algal microbial fuel cell

A photosynthetic algal microbial fuel cell (PAMFC) was constructed by the introduction of immobilized microalgae (Chlorella vulgaris) into the cathode chamber of microbial fuel cells to fulfill electricity generation, biomass production and wastewater treatment. The immobilization conditions, including the concentration of immobilized matrix, initial inoculation concentration and cross-linking time, were investigated both for the growth of C. vulgaris and power generation. It performed the best at 5 % sodium alginate and 2 % calcium chloride as immobilization matrix, initial inoculation concentration of 10⁶ cell/mL and cross-linking time of 4 h. Our findings indicated that C. vulgaris immobilization was an effective and promising approach to improve the performance of PAMFC, and after optimization the power density and Coulombic efficiency improved by 258 and 88.4 %, respectively. Important parameters such as temperature and light intensity were optimized on the performance. PAMFC could achieve a COD removal efficiency of 92.1 %, and simultaneously the maximum power density reached 2,572.8 mW/m³ and the Coulombic efficiency was 14.1 %, under the light intensity of 5,000 lux and temperature at 25 °C.