Antibacterial potency of housefly larvae extract from sewage sludge through bioconversion

Use of the fly to convert sewage sludge into nutrient-rich soil conditioner and amendment is an attractive approach for sludge bioconversion. During this process, fecal coliforms, an indicating pathogen, in sludge were reduced to 5.3 × 102 most probable number /g dry solid from initial 3.32 × 106 MPN/g dry solid. It was also found that the extract of larvae grown in sludge during bioconversion have an observable inhibitory effect against bacteria compared to larvae grown in wheat bran as measured by minimum bacterial concentration tests. In vitro antimicrobial assay tests over time also showed that the extract had strong inhibitory efficiencies of ca. 99% against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Serratia marcescens, while the efficiency was 69% and 57% against Bacillus subtilis and Klebsiella pneumoniae, respectively. The observed pathogenic bacterial cell membrane damage was found to be responsible for the phenomenon mentioned above, with nuclear acids leaching out quickly and alkaline phosphatase increasing in the outer membrane, followed by an increase of β-galactosidase in the inner membrane. Clearly, housefly larvae extract from sewage sludge through bioconversion possesses antibacterial potency against pathogenic bacteria.     

Green synthesis, characterization and antimicrobial activity of silver nanoparticles using methanolic root extracts of Diospyros sylvatica

The current research study focuses to formulate the biosynthesized silver nanoparticles for the first time from silver acetate using methanolic root extracts of Diospyros sylvatica, a member of family Ebenaceae. TEM analysis revealed the average diameter of Ag NPs around 8 nm which is in good agreement with the average crystallite size (10 nm) calculated from X-ray Diffraction (XRD) analysis. Further the study has been extended to the antimicrobial activity against test pathogenic Gram (+) ve, Gram (−) ve bacterial and fungal strains. The bioinspired Ag-NP showed promising activity against all the tested bacterial strains and the activity was enhanced with increased dosage levels.     

酵母提取物对葡萄糖发酵生产生物破乳菌Alcaligenes sp. S-XJ-1的影响

以从石油污染的土壤中筛选出1株生物破乳菌Alcaligenes sp.S-XJ-1为对象,考察了以葡萄糖为碳源时添加酵母提取物对生物破乳菌菌体性质、破乳性能以及菌体元素组成的影响.结果表明,酵母提取物的投加能够有效提高生物破乳菌产量,在酵母提取物浓度为5 g.L-1时,生物破乳菌产量达到3.0 g.L-1,此时葡萄糖利用率亦达到最大的58%.随着酵母提取物的投加浓度的增大,培养得到的菌体破乳性能提高,在投加浓度为10 g.L-1时,破乳率达到76%;而培养得到的菌体C/N有所降低,对其菌体表面蛋白进行提取测定发现菌体总蛋白含量升高,这与FTIR分析破乳菌菌体表面蛋白质类物质提高的结论一致.推测该生物破乳菌菌体蛋白含量的提高增强了菌体的破乳性能,菌体蛋白类物质是影响其破乳性能的关键组分之一.     

'Pheromone-like' compounds in the cuticle of aquatic Chironomus larva

Chironomid midges are the most commonly found dipteran insects in all types of aquatic ecosystems. Cuticular extract was bio-assayed, and it exhibited enhanced attraction to the larvae. Therefore, it was subsequently analysed by gas chromatography-mass spectrometry. Two compounds were identified as farnesol and farnesene. Bioassay of farnesol indicated its attractive properties. The components present in the cuticular extract can, therefore, be considered as pheromone-like compounds.     

酵母菌-SBR法处理油脂碱炼废水研究

研究了8株酵母菌应用于序批式反应器(SBR)直接处理油脂碱炼废水的效果,并探讨了酵母菌的扩大培养方法和影响系统稳定运行的关键因素.结果表明,在不投加任何霉菌和细菌抑制剂的32 L开放体系中,6 d培养出MLSS 19 g/L、SVI 35 mL/g的酵母菌;30 d的连续运行结果表明,在COD 9000～23 000 mg/L、油4500～16000 mg/L的进水情况下,系统高效、稳定运行,COD、油去除率分别达到了86.8%～96.9%和99.5%;短期的pH冲击对系统造成的不利影响是可逆的;污泥龄对酵母菌的SVI有一定影响;长期氮缺乏会诱发某些酵母菌细胞由单细胞向菌丝形态转化,并影响到酵母菌的沉降性.     

两种N源对石油烃降解菌群降解柴油能力的影响

分别以酵母膏作为有机N源,(NH4)2SO4作为无机N源,在含N量相同(70 mmol/L)的条件下,按接种量2%,柴油1%,25℃,150 r/min摇床恒温培养,对海洋石油烃降解菌群进行了为期30 d 的液体摇瓶降解实验,通过GC-MS测定和分析,对柴油中正烷烃的降解情况进行了对比研究.结果表明,对柴油含量为1%的培养液,应用这两种不同N源,降解菌群对正烷烃的最终降解效果相同,均能完全降解,但有机N源只需3 d 时间就能完全降解正烷烃,比无机N源的降解时间短10倍多.因此,酵母膏对柴油的微生物降解具有极大的促进作用.     

硫酸铵-锌试剂-Tween-80萃取分离废镍镉电池金属

以废旧镍镉电池为原料,探索盐酸溶解废镍镉电池的溶解条件,并用ICP仪检测镍镉电池溶液中金属离子含量。研究了硫酸铵-锌试剂-Tween-80体系萃取分离金属离子Ni（Ⅱ）,Cd（Ⅱ）,Co（Ⅱ）的行为。实验表明：Ni（Ⅱ）,Co（Ⅱ）在pH6-9范围内,与锌试剂形成的螯合物可被Tween-80相完全萃取,而Cd（Ⅱ）基本不被萃取。进而实现了镍镉电池溶液中的Ni（Ⅱ）,Co（Ⅱ）离子与Cd（Ⅱ）离子的分离。     

松花江及哈尔滨市饮用水雌激素活性的调查与分析

利用固相萃取/酵母双杂交法调查了哈尔滨市饮用水及周边松花江水的雌激素活性.结果表明,松花江哈尔滨段江水在夏秋两季的雌激素活性［以雌二醇当量（EEQs）计］为528～965 pg·L^-1,其中上游水源地水雌激素活性水平较高.自来水厂对雌激素活性的去除率为34.6%～50.5%,整个水处理工艺并不能有效去除源水中的雌激素类物质,致使出厂水仍具有298～718 pg·L^-1的雌激素活性;自来水厂所采用的3种净水工艺中以混凝沉淀工艺对雌激素活性的去除最为稳定,去除率为11.4%～26.1%,占总去除的32.9%～69.0%,而砂滤与氯消毒工艺出水不稳定,雌激素活性有时较进水有升高现象发生.此外,由于管网配送过程中产生了二次污染,致使管网水雌激素活性较出厂水最高可升高44.9%.7次取样测得哈尔滨市管网水的雌激素活性为347～1 362 pg·L^-1,均值为738 pg·L^-1.     

高硫抗生素废水微好氧连续处理系统的进水负荷效应研究

在14~18℃条件下探讨了不同进水负荷对高硫抗生素废水微好氧连续处理系统的处理效果和污泥中细菌、酵母菌含量的影响.结果表明,在低负荷[COD=2 kg.(m3.d)-1]条件下,污泥以细菌为优势菌群(细菌含量为96%),污泥浓度和污泥脱氢酶活性(TF/MLSS.t)分别为300 mg.L-1、4300 mg/(g.h),污泥SVI=35 mL.g-1,COD去除率仅为13%;当升高负荷至初始负荷的5倍和10倍时,污泥中以酵母菌为优势菌(酵母菌含量分别为67%和71%),污泥浓度分别为2300、1500 mg.L-1,污泥DHA活性(TF/MLSS.t)分别为9600、10800 mg/(g.h),污泥SVI值分别为160、110 mL.g-1,COD去除率升高到40%~50%,进水负荷对污泥微生态构成和系统处理效果均具有显著影响.     

含钛矿渣的生产及综合利用新进展

高炉法冶炼钒钛磁铁矿过程中生产了大量含TiO225%左右的高钛渣,总结了高钛高炉渣提钛技术和制备新材料方面取得的新进展,指出了高钛高炉渣综合利用的难点,比较有发展前景的工艺及应该遵循的原则。针对转底炉预还原-电炉熔分方法处理钒钛磁铁矿生产出的TiO2品位在40%左右的钛渣,提出了两步调渣法新工艺,并进行了理论分析,为钛资源的综合利用提供一条新途径。