Arthrobacter sp. AG1菌株降解土壤中阿特拉津研究

在阿特拉津浓度为50mg/kg干土的黄棕壤、潮土和红壤接种1.5×106CFU/g干土的降解菌Arthrobacter sp. AG1,10天后土壤中的阿特拉津分别降解至1.5、6.6和10mg/kg干土。阿特拉津的降解速率受到土壤性质的影响,但AG1仍能在不满足其生长繁殖要求的pH值的土壤中有效降解酸性土壤中阿特拉津;土壤中水分含量对降解效果影响较大,>20%时降解效果较好;土壤低含水量和低pH值会导致AG1降解阿特拉津的活力下降。不同的接种量对降解效果有一定影响,但105～107CFU/g干土接种量的AG1都能有效发挥降解作用。AG1降解完土壤中的阿特拉津后,在土壤含水量分别为5%和15%的情况下能长期保持降解活性,对60天后第2次施入黄棕壤和潮土中的50mg/kg阿特拉津4天时降解效率在65%以上。     

Sphingobium属细菌土壤中降解异丙隆的特性

通过在不同环境条件的土壤中接入异丙隆降解菌悬液,研究了Sphingobium属的3株细菌—YBL1、YBL2和YBL3在土壤中降解异丙隆的特性,分析了土壤类型、温度、碳氮源、土壤含水量和菌株接种量等因素对3株细菌降解土壤中异丙隆的影响。结果表明,3株细菌在马肝土(pH 6.7)中能够高效降解异丙隆,在红壤(pH 4.5)中不能降解异丙隆,菌株YBL3在潮土(pH 8.2)中也有较好的降解效果;当接种量低于105CFU g-1土时,3株细菌均不能降解马肝土中的异丙隆,接种量高于106CFU g-1土时,菌株可以高效地降解土壤中的异丙隆;马肝土含水量低于40%时,3株细菌降解土壤中异丙隆的速率与土壤含水量呈正相关关系;在16~37℃范围内,菌株降解马肝土中异丙隆的速率与温度亦呈正相关关系。     

恶唑菌酮土壤降解影响因子研究

探讨了土壤环境中的主要因素:土壤微生物、温度、含水量、pH值以及施用有机肥对恶唑菌酮降解的影响。结果表明:土壤微生物对恶唑菌酮在土壤中的降解起着重要作用,相同条件下灭菌土壤的降解半衰期是非灭菌土壤的27.6倍。环境温度、土壤含水量等对恶唑菌酮降解也有影响,在15℃～40℃的试验条件下,随着温度升高,恶唑菌酮的降解速率加快,特别是15℃～25℃温度范围内降解速率上升较快;过高和过低的土壤含水量都不利于土壤中恶唑菌酮的降解,土壤含水量为50?～100?时适宜恶唑菌酮的降解;此外施用有机肥会加速恶唑菌酮的降解;而土壤pH值对降解的影响不显著。     

降解菌S113对甲磺隆污染土壤生物修复作用的研究

在室内条件下,研究了降解菌S113(Methylopila sp.)对甲磺隆污染土壤的修复作用。S113能够以甲磺隆为唯一碳源生长,72h对50mgL-1甲磺隆的降解率达98.38%。投加降解菌S113可显著提高土壤中甲磺隆的降解速率。当甲磺隆浓度为10mgkg-1干土,S113接种量为108个g-1土时,第30天土壤中甲磺隆降解率为76.9%,对照土壤中甲磺隆降解率仅为11.9%。S113降解甲磺隆的速率和接种量呈正相关,当接种量减少为105个g-1干土时,降解菌对甲磺隆的降解作用微弱。在土壤中甲磺隆浓度较低的条件下,S113的降解效果显著,而当土壤中甲磺隆浓度达到50mgkg-1时,甲磺隆降解率仅为39.6%。S113降解土壤中甲磺隆的最适温度为30℃,第30天的降解率可达75.9%。当温度为25℃、20℃时,第30天甲磺隆降解率仅为53.5%和23.9%。S113菌剂灌根,能不同程度地缓解土壤中浓度为40、80μgkg-1的甲磺隆对玉米生长的抑制作用,但当甲磺隆浓度增加到120μgkg-1时,接种S113对药害解除作用不显著。结果表明,人工接种降解菌S113,能有效去除土壤中甲磺隆残留。     

不同环境因子及施药量对土壤中唑菌酯残留的影响

在实验室条件下研究了土壤pH、温度、含水量及施药量对新型杀菌剂唑菌酯(E-2-(2-((3-(4-氯苯基)-1-甲基-1H-吡唑-5-基氧)甲基)苯基)-3-甲氧基丙烯酸甲酯)在土壤中残留量的影响。结果表明,在25d的培养时间内,随土壤含水量的增加,唑菌酯在土壤中的残留量减少;土壤含水量增加到60%田间最大持水量时,其残留达最低,为1.81μg/g,而在淹水环境中其残留量增加。随着土壤温度的升高,唑菌酯的残留呈现先降低后升高的趋势,4℃时的残留达最大(3.86μg/g)。土壤pH对其在土壤中的残留具有明显影响,在中性和弱碱性土壤中均具有相对较低的残留。在1～10μg/g施药量时,唑菌酯在土壤中的残留比例随其施药量的增加而少量降低,在药剂浓度为20μg/g时,土壤中唑菌酯的残留率为42.4%。     

多氯联苯复合污染土壤的土著微生物修复强化措施研究

通过室内模拟试验,以不同C源、C/N比、水分及通透性为调控因子,对多氯联苯(PCBs)长期复合污染土壤的土著微生物强化修复进行了初步研究。结果表明,PCBs长期复合污染土壤中,在土壤水分含量为田间持水量的60%时,加入淀粉、葡萄糖和琥珀酸钠均在一定程度上增加了细菌和真菌数量,从而促进土壤中PCBs的土著微生物降解。不同种类的C源对PCBs污染土壤的土著微生物降解效果存在明显差异,且其降解效果与C源的施用剂量密切相关。当淀粉加入量为C1.0g/kg土时,土壤中PCBs的降解效果较好,而葡萄糖和琥珀酸钠加入量为C0.2g/kg土时,PCBs的降解效果明显。土壤C/N比为10:1的处理效果优于C/N比为25:1和40:1。土壤人为翻动有利于PCBs污染土壤中细菌和真菌的生长,提高土著微生物的代谢活性,从而促进土壤中PCBs的自然降解。这为进一步探讨加速土壤中PCBs降解的最适条件和研发POPs污染土壤的生物修复技术提供了科学依据。     

降解多菌灵和啶虫脒残留的复合菌剂研发及初步应用

针对菜田土壤中多菌灵和啶虫脒的残留问题，以多菌灵降解菌株Rhodococcusqingshengiidjl-6和啶虫脒降解菌株Pigmentiphaga D-2作为材料，进行降解菌剂的复配，研究了使用复合降解菌剂对复合农药残留土壤的修复效果及微生态效应。研究结果表明：(1)复配降解菌株djl-6与D-2的最适体积比为5∶3，复合降解菌剂在3 d内对无机盐培养基中50μg/ml的多菌灵降解率为87.14%，对50μg/ml的啶虫脒降解率为96.10%。(2)初始接种量为7%时，复合降解菌剂可在6 d内将复合农药污染土壤中5 mg/kg多菌灵降解74.40%，将5 mg/kg啶虫脒降解95.87%。土壤含水率为25%时，复合降解菌剂对复合农药污染土壤中5 mg/kg多菌灵的降解率为80.80%，对5 mg/kg啶虫脒的降解率为97.87%。(3)复合农药污染土壤中10 mg/kg多菌灵和10 mg/kg啶虫脒即可对小青菜的生长产生明显的药害，小青菜生长24d时根长仅为空白对照的66.56%、茎叶长为58.35%、鲜重为45.13%。在7%的接种量条件下，复合降解菌剂可解除药害，使小青菜的生...     

土霉素降解菌筛选及降解特性研究

【目的】 近年来,抗生素在畜禽及水产养殖中的使用量增加,导致固体废弃物和污水中存在大量的抗生素和耐药菌。土霉素作为用于养殖业主要的抗生素之一,在畜禽粪便和污水中的残留含量较高,因此,筛选并鉴定了能降解残留土霉素的微生物。 【方法】 采用富集驯化法,以菌肥、药渣和畜禽粪便为原料,采用摇床震荡的方法进行微生物培养,采用高效液相色谱法 (HPLC) 进行土霉素含量测定,筛选出能够高效降解土霉素的微生物。本研究还对降解菌在不同温度、pH、转速和接种量条件下的土霉素降解效果进行优化,并最终利用16S rDNA的方法鉴定菌种。 【结果】 筛选出一株能够高效降解土霉素的菌株T4菌,经16S rDNA测序鉴定该菌株为假单胞菌 (Pseudomonas sp.) ,该菌株在30℃时对土霉素的降解率最高,达到了26.75%;不同pH梯度下,T4菌在pH为7时对土霉素的降解率达到最高,为27.03%;转速为150 rpm和170 rpm时,T4菌对土霉素的降解率分别为26.18%和25.59%,考虑到摇床高转速耗能高的因素,因此选择150 rpm为优化的转速;接种量对T4菌降解土霉素的影响较小,而且二者之间呈负相关,接种量1%时降解率最高,为26.88%。优化条件下,T4菌对100 mg/L土霉素的降解率为26.29%;堆肥试验表明,添加了T4菌之后,土霉素去除率更高,为93.21%。 【结论】 本研究筛选出的菌株T4对土霉素有较好的降解能力。通过16S rDNA基因序列分析,T4菌属于假单胞菌 (Pseudomonas sp.),其降解土霉素的优化条件为温度30℃、pH 7.0、转速150 rpm、接种量1%。在堆肥中接种T4菌后,提高了对土霉素的去除作用,表明T4菌作为土霉素降解菌具有污染治理的潜力。      

不同改良剂对融雪剂盐害土壤的修复效果

[目的]探究不同改良剂对融雪剂盐害土壤的修复效果及其对矮牵牛生长的影响,为改良剂的大田推广提供理论依据。[方法]采用香菇菌糠、平菇菌糠和脱硫石膏3种改良剂,通过土柱室内模拟试验,对改良后土壤的pH值,土壤电导率(EC),K+,Na+,Cl-、容重和孔隙度进行测定。[结果]改良处理后,pH值均有不同程度的降低;香菇菌糠施用量为24g/kg时,降低土壤EC值效果最显著;平菇菌糠改良可以有效提高土壤中K+离子含量;对于降低土壤中Na+离子含量而言,表现为:平菇菌糠香菇菌糠脱硫石膏;香菇菌糠处理(24g/kg)对于降低土壤中Cl-离子含量、土壤容重和提高孔隙度等方面效果最显著,土壤容重比CK减少了57.3%,孔隙度增加了24.6%,使矮牵牛单株鲜重较CK增加了244.64%。[结论]当香菇菌糠施用量达到24g/kg时,改良融雪剂盐害土壤的效果最显著。     

多环芳烃污染土壤的植物-微生物联合修复初探

在温室盆栽条件下,通过种植紫花苜蓿单独或联合接种菌根真菌(Glomus caledonium L.)(AM)和多环芳烃专性降解菌(DB),研究了利用植物-微生物强化修复多环芳烃(PAHs)长期污染土壤的效果。试验结果表明,接种菌根真菌和PAHs专性降解菌能促进紫花苜蓿的生长和土壤中PAHs的降解。经过90天修复试验,种植紫花苜蓿接种AM、DB和DB+AM处理的PAHs的降解率分别为47.9%、49.6%、60.1%,均高于只种植紫花苜蓿的对照处理(CK)(21.7%)。另外,随着PAHs苯环数的增加,其平均降解率逐渐降低,但是接种PAHs专性降解菌能够提高4环和5环PAHs的降解率。同时也发现土壤中脱氢酶活性和PAHs降解菌数量越高的处理,土壤PAHs的降解率也越高,这也是种植紫花苜蓿接种微生物能够有效促进土壤PAHs降解的原因。     

Biodegradation of carbofuran by <Emphasis Type="Italic">Pichia anomala</Emphasis> strain HQ-C-01 and its application for bioremediation of contaminated soils

A novel yeast named HQ-C-01 was isolated from activated sludge and identified as Pichia anomala based on the morphology and 18S rDNA sequence analysis. The HQ-C-01 strain degraded 95.2% of carbofuran when the insecticide was used as the only C source and added at 50 mg/L in a mineral salts medium within 48 h. The optimal concentration, temperature, and pH of medium for degradation of carbofuran were 50 mg/L, 30°C, and pH 7.5, respectively. Strain HQ-C-01 could also effectively degrade other carbamate insecticides including carbaryl, indoxacarb, and fenobucarb, and the degradation rates were 99%, 85%, and 67%, respectively. Gas chromatography–mass spectrometry analysis showed that the strain metabolized carbofuran to produce benzofuranol as the intermediate metabolite, which was further degraded. Degradation of carbofuran added at 50 mg/kg of soil was higher in yeast-inoculated soil than in the control. These results indicated that strain HQ-C-01 may potentially be used in bioremediation of carbofuran-contaminated soil.     

不同因素交互作用对棕壤硝态氮累积及pH值的影响

本文采用室内恒温好气培养法,研究了温度（10℃和30℃）、水分（田间持水量的70%和100%）及尿素态氮用量（N 0、450、600、750）mg/kg 的交互作用对硝态氮累积和土壤酸化的影响。结果表明, 10℃下硝化作用进行缓慢,最大硝化率(K max)与施氮量呈极显著负相关（r=-0935**）,达到最大硝化率的时间(t0)与尿素态氮用量呈极显著正相关（r=0876**）。30 ℃下的硝化率随尿素态氮用量的增加而增加。低温环境延长了t0。10 ℃（70%和100%含水量）下,N 750 mg/kg 处理的t0分别相当于30 ℃下该处理的1.9 和 2.5 倍。所有处理土壤的硝态氮累积量均随培养热量的增加呈指数增长趋势, 且70%含水量下的累积量高于100% 含水量下的累积量, N 600 和 750 mg/kg 处理的累积量显著高于其他处理。培养结束后,30 ℃所有处理的pH值均显著低于初始土壤,其中N 600 和 750 mg/kg 处理的pH5.1, 酸化明显。通径分析结果表明, 尿素施用量和培养天数是影响硝化率进而影响pH值的重要因素,其次是培养温度和含水量。     

Dicyandiamidabbau im Boden in Abhängigkeit von der Temperatur

Effect of temperature on the breakdown of dicyandiamide in the soil The breakdown of dicyandiamide in a soil (sandy silty loam, pH 6.2, 0.13 % N) was investigated in relation to temperature. 1. The rate of conversion of dicyandiamide (DCD) (20 mg DCD-N/100 g soil) to guanylurea increased with rising temperature (10°–90°C). After 20 days, 14–100 % of the added DCD was metabolized. Small amounts of DCD (0.67 resp. 1.34 mg DCD-N/100 g soil) were broken down completely within 20–80 days at 8°–20°C. 2. Guanylurea was transformed to guanidine and then to ammonium. Increasing temperature in the region of 10° and 30°C accelerated the transformation. At higher temperatures (up to 70°C) an accumulation of guanidine occurred.     

Umsetzung von Cyanamid,Harnstoff und Ammonsulfat in Abhängigkeit von Temperatur und Bodenfeuchtigkeit

Transformation of cyanamide, urea and ammonium sulfate as influenced by temperature and moisture of soil The conversion of cyanamide, urea and ammonium sulfate solutions to nitrate was investigated in a sandy silt loam (pH 6.2) in relation to temperature and soil moisture conditions. 1. Cyanamide was transformed to urea within 1–5 days. Increasing temperature (2°–100°C) accelerated the breakdown, whereas high moisture conditions (120 % of total water capacity) decreased transformation. 2. The hydrolysis of urea to ammonia took place within 5–10 days even at 2°C regardless of whether cyanamide or urea was added. Low soil moisture (40 % of total water capacity) and high temperature (up to 50°) accelerated the breakdown. 3. Following urea application (20 mg N) there was a transient formation of up to five times more nitrite (0.5 mg NO₂-N) as compared with cyanamide or ammonium sulfate treatments. 4. Clear differences were observed in the rates of nitrification. The rate was greater for urea than for cyanamide and ammonium sulfate. The formation of nitrate began at 2°C, with an optimum between 20° and 30°C. Under flooded conditions (120 % of total water capacity) and low temperature the rate of nitrification was slow. At higher temperatures rapid denitrification took place.     

14C-labelled maleic hydrazide degradation in soil: Influence of temperature,moisture, clay and organic material

¹⁴C-labelled maleic hydrazide (MH) was added to each of three soils at a concentration of 4 mg kg^?1, and its degradation measured by the release of ¹⁴CO₂ after 2 days. Between 1 and 30°C, at a constant moisture content (full field capacity), the mean degradation rate increased by a factor of 3 for each temperature increment of 10°C (Q₁₀ = 3). The mean activation energy was 78 kJ mol^?1. Above 35°C, the degradation rate decreased.At soil moisture contents between wilting point and 80–90% of field capacity, the degradation rate doubled with an increase in moisture content of 50% of field capacity (constant temperature, 25°C). Above field capacity, the degradation rate was either unchanged or decreased. Below wilting point the degradation was very slow, even after 2 months.The rate of decomposition of MH at all temperatures and moisture contents was lowest in the soil with the highest content of organic matter and the lowest clay content. This soil had the highest Freundlich K value, and presumably adsorbed MH the most strongly, although the lower clay content may also play a role in the lower decomposing capacity of this soil.     

一株耐盐解磷菌的解磷能力及对玉米敏感期生长的影响

从黄河三角洲盐碱化土壤中筛选了一株高效解磷真菌QL1501,经鉴定为草酸青霉菌,菌株QL1501对无机磷的解磷能力远大于对有机磷的解磷,解无机磷最大浓度达85.21 mg/L。菌株QL1501的最适生长pH值为8时菌体生长极好。当NaCl浓度为1%～5%时,菌株解磷能力变化不大,溶液中有效磷浓度为76.08～65.37 mg/L。当溶液中NaCl浓度高于7%时,菌体生长受到较大影响。接种解磷真菌QL1501处理的玉米株高、根干重和植株干重均显著高于未接种的对照处理,说明该解磷菌作为解磷生物肥料具有良好的效果。     

Effects of Extrusion Variables and Chemicals on the Properties of Starch-Based Binders and Processing Conditions

The effects of extrusion variables (moisture, screw speed, and temperature) and chemicals (urea and sodium bicarbonate) on the properties of starch-based binders (water absorption, bulk density, binder yield, expansion ratio, solubility, pH) and processing conditions (die temperature and pressure, feed rate, and specific mechanical energy) were studied using a central composite design. All quadratic regression models, except the models for bulk density and pH, were significant at the P ≤ 0.06 level. These models can predict the binder properties and processing conditions when extrusion variables and the chemical concentrations are known. Optimum combinations of the chemical concentrations (g/100 g of starch) and extrusion variables to achieve high water absorption in the binders were 15–20 g of urea /100 g of starch, 0–4 g of sodium bicarbonate/100 g of starch, 35–40 g of moisture/100 g of starch, 100–120 rpm screw speed, and 185–215°C barrel temperature. The molecular degradation of the starch occurred during extrusion, especially when the moisture content of starch was <30 g/100 g of starch.     

Some factors affecting survival of sclerotia of Macrophomina phaseolina in soil

At least 75% of the sclerotia of Macrophomina phaseolina survived for 1 yr in most natural soils kept at 26°C and at 50–55% of the soil moisture holding capacity (m.h.c.). Although survivability was reduced in a very acid soil (pH 4.5) collected under a pine stand, 33% of the sclerotia survived for 1 yr. Soil pH had very little or no effect on sclerotial survivability. Of three organic amendments tested (alfalfa hay, chitin, pine needles) only ground alfalfa hay at 0.8% (w/w) reduced survivability of sclerotia in soil by about 75% in a year. Alfalfa hay at 0.4% reduced survivability by 36%. Various N sources added at 200 μg Ng^?1 soil had no effect on survival. Of 13 fungicides tested, only benomyl and captan at 20 μg a.i. g^?1 soil appreciably reduced populations of sclerotia in soil.Soil temperature and moisture content were the two most important factors affecting survivability of sclerotia. At ?5 or 5°C the biggest drop in sclerotial survivability occurred when the soil was incubated moist (at 50% m.h.c. or more). At 26°C the biggest drop occurred in air-dried soil (2–3% m.h.c.) and survivability was decreased to some extent at 15 and 30% m.h.c. Survivability also dropped rapidly in moist soil (50–55% m.h.c.) exposed to four cycles each having 3-week freezing (?5°C) and 1 week thawing (26°C). Sclerotia in air-dried soil (2–3% m.h.c.) continuously kept at ?5°C maintained nearly complete survivability after 16 weeks. Sclerotia survived almost 80–90% in moist soil (50–55% m.h.c.) kept for 16 weeks at 26°C or in moist soil exposed to four cycles each having 3-week thawing (26°C) and 1-week freezing (?5°C).