烟嘧磺隆降解菌SY-6的固定化、降解特性及其工程化应用

以海藻酸钠为载体,对烟嘧磺隆降解菌SY-6进行细胞固定化,通过单因素实验明确了菌株包埋SY-6的最优条件,并对其降解特性进行研究。结果表明,当海藻酸钠含量为4%,Ca Cl2含量为3%,固化时间为4 h,制得的固定化小球具有较强的机械强度和较好的传质性能及其对烟嘧磺隆的降解率较高。固定化细胞降解烟嘧磺隆的最佳条件为p H为7.0、温度为30℃、包菌量为5%。在不同p H或温度下,与游离细胞相比,固定化细胞有较宽泛的耐受性。将包埋的SY-6投加到序批式反应器(简称SBR)中处理烟嘧磺隆废水,结果表明,菌株SY-6在合适的使用周期内稳定性较高且对烟嘧磺隆废水降解效果较好,为烟嘧磺隆固定化细菌的工程化应用奠定了基础。     

淀粉/凹凸棒粘土复合吸附絮凝材料的研究

采用接枝聚合法在硅烷化凹凸棒粘土(OATP)表面接枝淀粉,制备淀粉/凹凸棒粘土(ATP)复合吸附絮凝材料.采用傅里叶变换红外光谱(FT-IR)、扫描电子显微镜(SEM)对淀粉/ATP进行了表征,并对其制备条件进行了优化.结果表明,当淀粉质量分数(相对OATP质量)为100%,聚合反应时间为3 h,引发剂质量分数为0.003%,反应温度为60℃时,制备的淀粉/ATP对镉离子的最大吸附容量可达到36.78 mg/g.与ATP、OATP相比,淀粉/ATP对镉离子的吸附容量增大了2倍以上.复合材料具有比OATP更强的捕获能力,所形成的絮凝体大而密实,比淀粉絮凝剂具有更好的沉降性能.     

一株羽毛角蛋白降解菌的分离鉴定及特性研究

采用富集培养的方法,从广西大学家禽养殖场废弃羽毛处土样中筛选获得一株高效降解羽毛角蛋白的菌株GZD-23。经形态学、生理生化特性和16S rDNA序列分析,鉴定该菌株为枯草芽孢杆菌(Bacillus subtilis)。环境因素影响和酶学特性实验结果表明,蔗糖与蛋白胨是菌株GZD-23降解羽毛的最佳外加碳氮源,pH 8.0、温度30℃、转速100 r/min和羽毛含量20 g/L为其降解羽毛的最适反应条件。菌株GZD-23合成的角蛋白酶最适反应温度为60℃,最适pH为7.5;金属离子Cu2+、Hg2+、Fe2+、Co2+、Zn2+、Mn2+以及SDS、EDTA和高浓度TritonX-100、异丙醇和β-巯基乙醇对其酶活有不同程度抑制作用;低浓度TritonX-100、异丙醇和β-巯基乙醇对其酶活具有一定促进作用。     

AJIC工艺处理木薯加工废水研究

采用AJIC工艺对木薯淀粉、变性淀粉、木薯酒精生产废水进行综合处理。结果表明:COD、BOD5和SS的去除率均高达99%,进水水质指标及水量处理后的废水水质可达到《农田灌溉水质标准》(GB 5084-2005)水作标准,符合国控重点污染源污染减排要求。此外,该工艺还同时实现对木薯废渣和污泥进行处理,可生产沼气595.2万立方米/年,有机肥400吨/年,实现直接经济效益422.9万元/年,具有较高的经济、环境和社会效益。     

聚乳酸/淀粉固体缓释碳源生物反硝化研究

以被硝酸盐氮污染的地下水为研究对象,利用共混/熔融聚合技术将聚乳酸和淀粉混合,制备成兼具碳源和生物载体的缓释碳.并考察不同质量比(聚乳酸∶淀粉为8∶2、7∶3、6∶4、5∶5)的缓释碳在反硝化间歇试验中硝氮、亚硝氮和COD的去除效果,结果表明,当聚乳酸/淀粉质量比为5∶5的缓释碳,其反硝化效果最佳,硝氮去除率达99%;以该比例的缓释碳进行反硝化填充柱连续动态试验时,反应器中反硝化效果显著,出水硝氮浓度在2 mg·L-1以下,为开发环境友好的可控性缓释碳源提供了科学依据.     

镁离子对氧化亚铁硫杆菌生物合成次生铁矿物的影响

通过摇瓶实验,在Mg2+分别为48,4.8mg/L,其他元素组成与9K液体培养基一致的体系中,采用氧化亚铁硫杆菌A.ferrooxidans催化合成次生铁矿物.考察了Mg2+含量对生物合成次生铁矿物体系pH值、氧化还原电位(ORP)、Fe2+氧化率、总Fe沉淀率、次生铁矿物矿相及矿物晶体尺寸的影响.结果表明,经过48h培养,Mg2+浓度为48,4.8mg/L生物成矿体系pH值分别从原来的2.50降低至2.30,2.19,ORP分别从初始259mV增加至269mV,276mV.两体系Fe2+氧化率培养至第48h均达到100%,然而两体系总Fe沉淀率及矿物形态及却不尽相同.Mg2+浓度为48mg/L生物成矿体系,总Fe沉淀率为23.7%,次生矿物紧密粘附于三角瓶底部.而Mg2+浓度为4.8mg/L生物成矿体系,总Fe沉淀率达到32.2%,次生矿物却均匀分散于溶液中.两体系合成次生铁矿物均为黄铁矾与施氏矿物共存的混合物,Mg2+含量4.8mg/L体系合成黄铁矾单个晶体长度(~1.60μm)约为Mg2+含量48mg/L体系的1.2倍.     

Isolation, identification and arsenic-resistance of Acidithiobacillus ferrooxidans HX3 producing schwertmannite

Schwertmannite, a ubiquitous mineral present in iron oxyhydroxides formed in iron- and sulfate-rich acid media, favors incorporation of some toxic anions in its structure. We reported an iron-oxidizing bacterial strain HX3 from a municipal sludge that facilitates the formation of pure schwertmannite in cultures. Ferrous iron oxidation by the isolated strain HX3 was optimum at an initial pH of 2.0-3.3 and temperature of 28-35°C. Pure schwertmannite was found through bacterial oxidation of ferrous iron at an initial pH 2.8and temperature 28°C. Following 16 S rDNA gene sequence analysis the bacterial strain HX3 was identified as Acidithiobacillus ferrooxidans. The arsenic-resistance A. ferrooxidans HX3 showed the potential of environmental application in arsenic removal from the As（Ⅲ）- and iron-rich acid sulfate waters directly by As（Ⅲ） adsorption or the formation of schwertmannite in the environment.     

Characterization of a salt-tolerant bacterium Bacillus sp. from a membrane bioreactor for saline wastewater treatment

High salt concentrations can cause plasmolysis and loss of activity of cells, but the salt-torlerant bacterium can endure the high salt concentrations in wastewater. In this research 7 salt-torlerant bacteria, which could survive in dry powder products and could degrade organic contaminants in saline wastewater, were isolated from a membrane bioreactor. The strain NY6 which showed the fastest growth rate, best property for organic matter degradation and could survive in dry powder more than 3 months was selected and characterized. It was classified as Bacillus aerius based on the analysis of the morphological and physiological properties as well as the 16 S rRNA sequence and Neigh borjoining tree. The strain NY6 could survive in the salinity up to 6% and the optimal growth salinity is2%; it belongs to a slightly halophilic bacterium. The capability of its dry powder products for COD removal was 800 mg COD/(g·day) in synthesized saline wastewater with salinity of 2%. According to salt-tolerant mechanism research, when the salinity was below 2%, the stain NY6 absorbed K+and Na+to maintain osmotic equilibrium, and when the salinity was above 2%, the NY6 kept its life by producing a large amount of spores.     

Evaluation of Bacillus sp. MZS10 for decolorizing Azure B dye and its decolorization mechanism

To evaluate decolorization and detoxification of Azure B dye by a newly isolated Bacillus sp. MZS10 strain, the cultivation medium and decolorization mechanism of the isolate were investigated. The decolorization was discovered to be dependent on cell density of the isolate and reached 93.55%(0.04 g/L) after 14 hr of cultivation in a 5 L stirred-tank fermenter at 2.0 g/L yeast extract and 6.0 g/L soluble starch and a small amount of mineral salts. The decolorization metabolites were identified with ultra performance liquid chromatography-tandem mass spectroscopy(UPLC-MS). A mechanism for decolorization of Azure B was proposed as follows: the C=N in Azure B was initially reduced to –NH by nicotinamide adenine dinucleotide phosphate(NADPH)-dependent quinone dehydrogenase, and then the –NH further combined with –OH derived from glucose to form a stable and colorless compound through a dehydration reaction. The phytotoxicity was evaluated for both Azure B and its related derivatives produced by Bacillus sp. MZS10 decolorization, indicating that the decolorization metabolites were less toxic than original dye. The decolorization efficiency and mechanism shown by Bacillus sp. MZS10 provided insight on its potential application for the bioremediation of the dye Azure B.     

污水处理的现状及发展方向分析

玉米淀粉是一种重要的工业原料,在食品、医药、工业中具有广泛的用途,在玉米淀粉生产过程中,会产生大量污水。本文对于玉米淀粉污水处理现状进行分析,同时结合玉米淀粉污水处理工艺,探讨玉米淀粉污水处理的发展方向。