Characterization of efficient aerobic denitrifiers isolated from two different sequencing batch reactors by 16S-rRNA analysis

By adopting two sequencing batch reactors (SBRs) A and B, nitrate as the substrate, and the intermittent aeration mode, activated sludge was domesticated to enrich aerobic denitrifiers. The pHs of reactor A were approximately 6.3 at DOs 2.2-6.1 mg/l for a carbon source of 720 mg/l COD; the pHs of reactor B were 6.8-7.8 at DOs 2.2-3.0 mg/l for a carbon source of 1500 mg/l COD. Both reactors maintained an influent nitrate concentration of 80 mg/l NO3- -N. When the total inorganic nitrogen (TIN) removal efficiency of both reactors reached 60%, aerobic denitrifier accumulation was regarded completed. By bromthymol blue (BTB) medium, 20 bacteria were isolated from the two SBRs and DNA samples of 8 of these 20 strains were amplified by PCR and processed for 16SrRNA sequencing. The obtained results were analysed by a Blast similarity search of the GenBank database, and constructing a phylogenetic tree for identification by comparison. The 8 bacteria were found to belong to the genera Pseudomonas, Delftia, Herbaspirillum and Comamonas. At present, no Delftia has been reported to be an aerobic denitrifier.     

苦瓜颗粒冲剂的工艺研究

研究了苦瓜颗粒冲剂固体饮料的加工工艺。结果表明,以鲜苦瓜为原料,用100mg/kg葡萄糖酸锌作为护色剂、1%β-环状糊精作为苦味包埋剂,可制得质量良好的苦瓜汁;采用浓缩苦瓜汁、麦芽糊精、蔗糖、柠檬酸等原料的复配重量比5∶45∶50∶0.3以及恰当的工艺条件,可得到品质风味优良的苦瓜颗粒冲剂。     

The acceleration of sludge granulation using the chlamydospores of Phanerochaete sp. HSD

In the present paper, a novel method to accelerate sludge granulation is presented. Inoculation with chlamydospores of Phanerochaete sp. HSD accelerated sludge granulation during the treatment process of phenol wastewater, and the sludge granulation rate reached 66 ± 2% on day 7, 32 days earlier than that of the control inoculated with activated sludge only. Aerobic granule in R1 (AG_R1) showed an annual ring-like multilayer structure and a primary core also existed in the nuclear area of the granule. The mechanism of rapid granulation revealed that the chlamydospore could survive in phenol wastewater and form the primary matrix on which aerobic granule was developed layer by layer. In addition, AG_R1 developed in a phenol uptake system to counteract the adverse effects of phenol inhibition. Higher tolerance toward wastewater with high phenol strength was exhibited, and the maximum specific phenol degradation rate reached 1.54 g phenol g⁻¹ VSS day⁻¹.     

小麦淀粉颗粒大小和糊化特性的相关性研究

本文探讨了小麦淀粉颗粒A型和B型直径的大小及颗粒形态对其糊化特性的影响.结果表明品种间A型淀粉颗粒直径越大,B型淀粉颗粒直径则越小;A型淀粉颗粒直径越大,淀粉则越难糊化;B型淀粉颗粒直径越大,淀粉则越易糊化;热力学参数顶点温度与热焓值间存在较大的正相关性.     

工厂中环境和海产品加工前后的微生物学检验

检测了2个海产品加工厂的环境及加工前后海产品样品的菌落总数(个/cm2,个/g或个/mL)、李斯特氏菌和单核细胞增生李氏菌数(每100cm2,100g或100mL样品的MPN数),其结果如下:2个工厂对应样品的菌落总数及其分布规律相接近,但李斯特氏菌和单核细胞增生李氏菌的出现率和数量却相差很大;单核细胞增生李氏菌数都低于或远低于李斯特氏菌,且单核细胞增生李氏菌与李斯特氏菌的数量和分布呈正相关;加工后海产品中的李斯特氏菌和单核细胞增生李氏菌可能来自原料和加工过程;环境中李斯特氏菌和单核细胞增生李氏菌主要来自原料.     

小麦籽粒硬度与胚乳显微结构关系研究

本文选用了8个籽粒角质率不同的小麦品种(系)进行籽粒硬度和胚乳横断面显微结构关系的研究。结果表明籽粒硬度不同的小麦品种其胚乳结构存在差异：硬度值较大的硬质品种胚乳蛋白质较多。淀粉粒与蛋白质结合紧密；而硬度值较小的软质小麦品种胚乳蛋白质较少。淀粉粒与蛋白质结合松散。     

湿热处理对玉米淀粉颗粒结构及热焓特性的影响

湿热处理前后玉米淀粉的颗粒形貌基本未发生变化。随着热处理温度的提高 ,淀粉的结晶结构发生一定程度的变化 ,表现为特征峰的部分融合、峰强度的下降以及结晶度的降低。但处理前后的X射线图谱表明 ,处理后的玉米淀粉基本保持了原有的A型结晶结构。与原淀粉相比 ,湿热处理后玉米淀粉的结晶结构变化幅度不大。淀粉的DSC图谱表明 ,湿热处理后淀粉的相变初始和峰值温度提高 ,相变焓先增加后减小。     

芋头淀粉的研究

本文研究了芋头淀粉的性质,实验采用电子显微镜拍摄了芋头淀粉颗粒的形态;运用X射线衍射仪测定了X-光衍射图样及结晶结构;通过重结晶法制得纯度较高的芋头直链淀粉和支链淀粉,利用高效液相色谱仪测定了芋头淀粉及其直、支链淀粉淀粉的重均聚合度、数均聚合度、分子量分布及分散度等,并与大米淀粉进行了比较.研究了芋头淀粉糊在不同质量分数、pH值以及不同蔗糖添加量的条件下,Micro Visco-Amylo-Graph黏度曲线的变化情况.本研究为进一步了解芋头淀粉的特性及应用开发提供了一定的理论依据.     

鸡蛋壳表面细菌数量及种群多样性分析

采用GB 4789.2-2010菌落总数计数及Miseq测序分析物种多样性及群落结构的方法,对蛋鸡场鸡蛋壳表面细菌数量及种群结构进行研究。结果检测8组样品的菌落总数为3.79±0.67~5.06±0.75 Log CFU/eggshell±SD;获得的163214条优化序列分属于变形菌门(Proteobacteria)、厚壁菌门(Firmicutes)、放线菌门(Actinobacteria)、拟杆菌门(Bacteroidetes)、梭杆菌门(Fusobacteria)及蓝菌门(Cyanobacteria)。8组样品普遍存在假单胞菌属(Pseudomonas)、埃希氏-志贺氏菌属(Escherichia-Shigella)、泛菌属(Pantoea)、芽孢杆菌属(Bacillus)、肠球菌属(Enterococcus)细菌;而各样品分别以假单胞菌属(Pseudomonas)、埃希氏-志贺氏菌属(Escherichia-Shigella)、不动杆菌属(Acinetobacter)、芽孢杆菌属(Bacillus)、寡养单胞菌属(Stenotrophomonas)以及肠球菌属(Enterococcus)的相对丰度最大,依次为67.89%、36.15%、68.08%、40.12%、21.59%和26.98%。试验结果表明鸡蛋壳表面细菌数量大、种群多,不同样品间存在相似性差异。鸡蛋腐败变质可能与鸡蛋壳表面细菌种群有关,有待进一步研究。     

生物厌氧-好氧处理在印染废水治理中的应用

根据印染厂废水治理改造工程的要求，在分析原有设施存在的问题后，确定了对碱减量、退浆废水局部厌氧预处理工艺；论证并实施了生物厌氧-好氧处理为主的工艺路线；优选了工艺参数，采取多项措施提高好氧生化处理的运行水平。实际运行表明，改造后排放水的CODcr，平均值小于75mg／L，CODcr去除率小于93％，达标率为100％。