芽胞杆菌属(Bacillus sp.)10株细菌混合制剂对4种作物出苗及苗期生长的影响

以10株具有促生及抑制病害的芽胞杆菌属菌株(Bacillus sp．)的培养物，按不同比例配制成5个混合剂型细菌制剂．A、B、C、D剂型播种时接种不结球小白菜30d后，株高、叶片数、根长和干重分别增加7．8％、6．2％、9．4％和13．8％，除C处理的株高与对照差异不显著外，其余均达显著水平．接种A和B剂型显著提高豌豆出苗率，出苗9d时两菌剂处理的地上和地下部干重分别平均提高92．3％和183．3％，并发现5株供试菌株对引起豌豆病害病原菌有明显的抑菌作用．以A、B、E三个剂型菌悬液培养水稻种子4d时，各处理的平均芽长提高33．3％，根长提高16．0％，培养25d时株高、根数和地上部干重平均分别提高16．0％、9．5％和22．7％，均达显著水平．B剂型的培养物培养小麦27d时发现对株高、叶片数和植株干重的影响都不显著，但对根数和根重有显著的促进作用．综合分析认为，A菌剂最有利于供试作物出苗和苗期生长，其次为B剂型．表5参17     

原生质体融合构建高产碱性蛋白酶工程菌

用原生质体融合的方法，将碱性蛋白酶生产菌2709与含有碱性蛋白酶基因克隆载体pDW2的工程菌枯草杆菌BD105进行细胞融合，得到1株高产碱性蛋白酶的工程菌A16，菌落的原位杂交表明，该菌株携有双亲的遗传物质，A16的表型与生长特征与2709相似，但同样条件下发酵酶活比2709高50%-100%，摇瓶发酵的产酶水平最高可达30000u/mL,A16发酵所产酶的最适pH与耐温性及发酵条件等特征均与2709相同。适用于工业生产。     

溶胞菌的筛选、特性及其污泥减量效果

采用抑菌圈法从活性污泥中筛选溶胞菌,研究溶胞菌用于污泥减量的效果。在5种溶胞菌中RJM-2对金黄色葡萄球菌的溶胞能力最好。根据形态、生理生化及16SrRNA测序,鉴定RJM-2为短小芽孢杆菌属。为了分析RJM-2的活性物质成分,分别对发酵上清液进行121℃高压蒸汽处理及蛋白酶K处理。结果表明,10 min内RJM-2发酵上清液与对照组相比能使金黄色葡萄球菌(S.aureus)的OD580(580 nm条件下检测溶液的吸光度)下降0.12,而经过处理的发酵上清液OD580在2 h内无下降,这表明溶胞能力主要来自蛋白酶的作用。RJM-2对受试的5株革兰氏阴性菌及多株革兰氏阳性菌具有溶胞能力。RJM-2接种到污泥中24 h后能够使污泥SCOD(溶解性化学需氧量)达到111.96 mg/L,与不接种RJM-2的对照组相比SCOD增加了90.50 mg/L;在36 h内TSS(悬浮物固体)去除率达到56.68%,使污泥比阻下降了47.73%,污泥滤饼的含水率从83.6%下降到78.0%。研究表明,RJM-2能有效减少污泥TSS含量,降低污泥的比阻,改善污泥脱水性能。     

Identification and comprehensive evaluation of a novel biocontrol agent Bacillus atrophaeus JZB120050

Abstract

Bacillus spp. have long been used as biocontrol agents because of their efficient broad-spectrum antimicrobial activity. We identified a novel strain of Bacillus atrophaeus, named JZB120050, from soil. B. atrophaeus JZB120050 had a strong inhibitory effect against Botrytis cinerea and many other phytopathogens. Gas chromatography-mass spectrometry showed that B. atrophaeus JZB120050 produced many secondary metabolites, such as alkanes, alkenes and acids; some of which were related to pathogen inhibition. Enzyme activity analysis showed that B. atrophaeus JZB120050 secreted cell-wall-degrading enzymes, including chitinase, glucanase and protease, which degraded fungal cell walls. Both the novel glucanase gene bglu and chitinase gene chit1 were cloned and heterologously expressed in Escherichia coli and the products showed strong enzyme activity. In addition, B. atrophaeus JZB120050 secreted siderophores and formed a significant biofilm. Future studies should focus on these antimicrobial factors to facilitate widespread application in the field of agricultural biocontrol.     

Bacillus thuringiensis field applications: Effect of nozzle type,drop size,and application timing on efficacy against gypsy moth

Abstract

In a series of recent studies, we evaluated the influence of delivery systems, drop size and application timing on the efficacy of aerially applied Bacillus thuringiensis against gypsy moth infestations. Use of different nozzle systems including Micronair, Flat Fan or Twin Jet, did not appear to result in significant differences in Bt coverage efficiency, foliage protection or population reduction. Nor was there any significant difference in population reduction when Bt was applied at two different drop sizes with volume median diameters of 110 and 163 μm. The efficacy of different formulations on larval populations were similar when used against the younger 1st and 2nd instar but differed when treatment was delayed until the population matured to the 3rd and 4th instar stages.     

Biodegradation of triazine herbicide metribuzin by the strain Bacillus sp. N1

By enrichment culturing of soil contaminated with metribuzin, a highly efficient metribuzin degrading bacterium, Bacillus sp. N1, was isolated. This strain grows using metribuzin at 5.0% (v/v) as the sole nitrogen source in a liquid medium. Optimal metribuzin degradation occurred at a temperature of 30ºC and at pH 7.0. With an initial concentration of 20 mg L^?1, the degradation rate was 73.5% in 120 h. If the initial concentrations were higher than 50 mg L^?1, the biodegradation rates decreased as the metribuzin concentrations increased. When the concentration was 100 mg L^?1, the degradation rate was only 45%. Degradation followed the pesticide degradation kinetic equation at initial concentrations between 5 mg L^?1 and 50 mg L^?1. When the metribuzin contaminated soil was mixed with strain N1 (with the concentration of metribuzin being 20 mg L^?1 and the inoculation rate of 10¹¹ g^?1 dry soil), the degradation rate of the metribuzin was 66.4% in 30 days, while the degradation rate of metribuzin was only 19.4% in the control soil without the strain N1. These results indicate that the strain N1 can significantly increase the degradation rate of metribuzin in contaminated soil.     

枯草芽孢杆菌对土臭素和2-甲基异冰片的降解动力学特性

土臭素(geosmin,GSM)和2-甲基异冰片(2-methylisoborneol,2-MIB)是2种普遍存在于养殖水体中的土腥异味化合物,微生物降解是去除这两种物质的有效途径.本文研究了枯草芽孢杆菌(Bacillus subtilis)降解GSM和2-MIB的动力学特性.结果表明,枯草芽孢杆菌对GSM(1 000~2 000 ng·L-1)和2-MIB(1 000~2 000 ng·L-1)具有较好的降解性能,降解率均达90%以上;枯草芽孢杆菌对这些异味化合物的降解符合伪一级反应动力学,其生物降解速率常数(K)范围为0.14~0.41,降解速率不随GSM和MIB初始浓度的变化而变化;枯草芽孢杆菌对GSM降解的最大比生长速率umax为0.311,Monod常数KS为1.73,而在降解MIB过程中枯草芽孢杆菌的生长不符合Monod方程(R2=0.781).     

碳化稻壳-铁锰氧化菌耦合净化严寒村镇高铁锰地下水效能与机制

针对严寒地区特有地理气候条件及制约当前村镇建设与发展的典型问题,以建设绿色低碳、节能环保村镇为目标,研发碳化稻壳-优势铁锰氧化菌耦合工艺净化严寒村镇高铁锰地下水,探究生物滤柱低温快速启动方式;基于接触氧化与生物法,对比分析不同滤速条件下滤柱沿程除铁效能与反应速率,研究生物滤层除铁机制;基于扫描电子显微镜(scanning electron microscope,SEM)、傅立叶红外线光谱(Fourier transform infrared spectroscopy,FTIR)、X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)、拉曼光谱(Raman spectra)、电子顺磁共振(electron paramagnetic resonance,EPR)对运行不同阶段的滤料与反冲洗水泥样表征剖析生物滤层除锰机制.结果表明,优势菌液低滤速-全循环的运行方式使稻壳生物滤层成熟且稳定仅需15 d;稳定运行阶段出水铁、锰、细菌浓度分别低于0.3 mg·L~(-1)、0.1 mg·L~(-1)、100 CFU·m L~(-1),均满足国家生活饮用水卫生标准(GB 5749-2006);除铁机制主要依靠物化作用、辅以生物作用;在滤料成熟阶段与稳定运行初期除锰主要依靠生物作用,稳定运行后期物理化学作用占优势;该研究为严寒村镇Fe~(2+)、Mn~(2+)地下水集中处理应用提供了技术支撑.     

高效甲醛降解菌处理突发污染事故研究

通过选择培养,选育到1株能快速降解高浓度甲醛的菌株BZ-001H,经鉴定为Bacillus cereus,其最适降解条件是30℃和pH 7.0,最适浓度为8 000 mg L-1,最佳接种量为0.3‰,甲醛浓度越高时对pH的变化越敏感.用BZ-001H作为功能菌株对活性污泥系统强化后应急处理含2 035.67 mg L-1、4 155.63 mg L-1、8 099.27 mg L-1浓度甲醛的模拟废液,2.5h、6 h、14 h后去除率都能达到99%以上.模拟甲醛突发污染事故场景与应用条件,用BZ-001H强化常规SBR工艺应急处理4 073.65 mg L-1甲醛废液,经过8 h降解,可使出水甲醛达到《污水综合排放标准》(GB 8978-1996)一级标准.同时,考察了应急处理过程对应急系统和常规系统的影响,结果表明,应急处理结束后,应急SBR系统运行2周期后COD达标排放,6周期后氨氮达标排放;而对照系统受冲击明显,运行10周期后氨氮仍未达标,去处率仅为18.81%.     

蓝藻发酵生产微生物农药的影响因素研究

采用摇瓶发酵试验探讨了蓝藻为原料制备苏云金杆菌生物杀虫剂的可行性,并考察了不同培养条件（蓝藻含固率、种龄、接种量、初始pH、摇床转速、发酵温度）对苏云金杆菌生长增殖、产孢与产毒效果的影响。研究结果表明,无需任何预处理工序,Btk 130菌株能在蓝藻为唯一原料的培养基中正常生长发育,并且产孢产毒。发酵48 h后,芽孢产率达到86.7%,远高于常规培养基;生物毒效为282 IU.mL-1,与常规培养基相当。培养条件优化结果表明,在蓝藻含固率为2%、初始pH为7.0、接种物种龄为9 h、接种量为2%、培养温度为30℃、摇瓶转速为200 r.min-1的条件下培养48 h,Btk 130可达到较好的发酵效果,活菌数及抗热芽孢数可达7.32 CFU.mL-1和6.38 CFU.mL-1,生物毒效为528 IU.mL-1。该研究不仅为蓝藻提供了高附加值的处置新途径,而且可显著降低生物杀虫剂的生产成本,具有广阔的应用前景。