温度对嗜酸性硫杆菌活性和生物成因次生铁矿物形成的影响

通过实验室摇瓶试验研究了温度对嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidan)氧化亚铁的活性及对生物成因次生铁矿物形成的影响.结果表明,在FeSO4-H2O-A.ferrooxidans休止细胞体系中,低温明显抑制了A.ferrooxidans菌的氧化活性.培养5 d后,10℃和28℃体系中Fe2+氧化率分别为11.81%和100%.当温度从10℃(培养7 d)调至28℃后,Fe2+氧化率在1 d内就迅速上升到95.10%.Fe2+最高氧化速率依次为:10℃(培养7 d)+28℃(2.25 h-1)>28℃(1.42 h-1)>10℃(0.81 h-1).次生铁矿物XRD图谱表明,在9K培养基中,10℃条件下较低的Fe3+供应速率更有利于无定型施威特曼石的形成.而在28℃条件下,施威特曼石优先于黄铁矾生成,且随着时间延长黄铁矾结晶度愈来愈高.通过XRD图谱和SEM微形貌特征判断,28℃下生物合成次生铁矿物主要为施威特曼石和黄钾铁矾的混合物.     

二氯甲烷降解菌Methylobacterium rhodesianum H13的分离鉴定及降解特性研究

对分离筛选到1株能以二氯甲烷(DCM)为唯一碳源和能源生长的菌株Methylobacterium rhodesianum H13进行降解特性研究.在初始菌体浓度0.82 mg.L-1、pH 7.0和温度30℃的条件下,M.rhodesianum H13能够于23 h内将5 mmol.L-1DCM完全降解,细胞得率(细胞/DCM)为0.136 g.g-1.随着DCM的降解,溶液中的Cl-浓度逐渐升高(释放的Cl-浓度约为DCM的2倍),溶液pH值降至6.75,呈弱酸性.通过摇瓶实验考察了温度、pH、DCM浓度、Cl-等因素对菌株H13降解DCM性能的影响,获得其较适宜的生长和降解条件为:温度30℃、pH值7.0.研究还发现M.rhodesianum H13降解DCM的最适浓度为5 mmol.L-1,高浓度的DCM会抑制其降解.研究成果对高效处理环境中的DCM污染具有重要的应用价值.     

1株嗜酸硫杆菌的分离鉴定及其对污染底泥中重金属的去除效果

采用常规细菌分离方法,从河流底泥中筛选到1株细菌FD97,通过序批式摇瓶培养考察了不同温度下(22~40℃)该菌株对污染底泥中Zn、Cu和Cr的去除效果.结果表明,形态学和16S rDNA序列同源性分析鉴定菌株FD97为嗜酸硫杆菌属(Acidithiobacillussp.).在22~40℃条件下,以Acidithiobacillussp.FD97为主要菌株的生物沥浸作用可有效去除污染底泥中Zn、Cu和Cr.沥浸处理16 d,Zn、Cu和Cr的去除率可分别达70%、90%和25%.从底泥pH值变化、SO42-产生以及重金属去除率角度衡量不同温度的底泥沥浸处理效果依次为:34℃28℃≈40℃22℃.控温28℃较适宜今后的实际应用.底泥重金属生物沥浸去除率的大小与底泥pH值变化密切相关,与温度无直接关系.当底泥pH值降至5.0、3.5和2.5时,底泥中Zn、Cu和Cr分别开始溶出,pH值降为2.0,重金属去除率达最大.     

Isolation of marine benzo[a]pyrene-degrading Ochrobactrum sp. BAP5 and proteins characterization

A bacterial strain BAP5 with a relatively high degradation ability of benzo[a]pyrene (BaP) was isolated from marine sediments of Xiamen Western Sea, China and identified as Ochrobactrum sp. according to 16S rRNA gene sequence as well as Biolog microbial identification system. Strain BAP5 could grow in mineral salt medium with 50 mg/L of BaP and degrade about 20% BaP after 30 d of incubation. Ochrobactrum sp. BAP5 was able to utilize other polycyclic aromatic hydrocarbons (PAHs) (such as phenanthrene, pyrene and fluoranthene) as the sole carbon source and energy source, suggesting its potential application in PAHs bioremediation. The profile of total soluble protein from Ochrobactrum sp. BAP5 was also investigated. Some over- and special-expressed proteins of strain BAP5 when incubated with the presence of BaP were detected by two-dimensional polyacrylamide gel electrophoresis, and found to be related with PAHs metabolism, DNA translation, and energy production based on peptide fingerprint analysis through matrix-assisted laser desorption/ionization-time of flight mass spectrometry.     

Alcaligenes sp. XJ-T-1利用废弃油脂生产破乳剂研究

生物破乳剂是一种应用于油水乳状液分离的新型破乳剂.本研究对筛选得到的1株高效破乳剂产生菌XJ-T-1（鉴定结果为Alcaligenes sp.）代谢产生的生物破乳剂进行了理化性质、破乳能力和废弃油脂利用能力分析.采用废弃油脂Ⅱ为碳源,可提高生物破乳剂产量4.6倍,XJ-T-1在以液体石蜡和废弃油脂培养8　d后该菌能使水的表面张力从72 mN/m下降到32 mN/m, CMC-1分别为10、 20;以液体石蜡为碳源培养得到的生物破乳剂在油包水型、水包油型模型乳状液的破乳率分别达到了96%、 50%;而以废弃油脂Ⅱ为碳源培养得到的生物破乳剂的破乳率分别为97.8%、 65％;采用煤油脱出率、乳状液脱除率和水脱出率3种评价方式对破乳效果评价发现生物破乳剂最先作用于乳状液的连续相;采用TLC和IR对废弃油脂生产破乳剂得到的破乳剂有效成分进行鉴定,结果为脂肽与石蜡培养产物相同.     

适应菲胁迫的高效聚磷菌筛选及聚磷特性研究

采用平板法分离菌株、蓝斑筛选和聚磷培养液除磷能力验证3种方法相结合,从太湖底泥样品中分离到2株能够利用菲的高效聚磷菌Y11和Y4-2,经形态观察、生理生化和16S rDNA鉴定为不动杆菌属（Acinetobacter sp.）.通过固体平板和液体培养的方法对2株不动杆菌的环境适应能力和聚磷、除磷能力进行了测定,结果显示,2菌株的生长温度范围均为10～35℃,菌株Y11的pH范围为6～9,菌株Y4-2的pH范围为6～8;高磷浓度对菌株Y11的生长没有抑制作用,但对菌株Y4-2的生长产生一定的抑制作用;Y11和Y4-2能在以菲为唯一碳源（50 mg/L）的无机盐平板上良好生长,对菲有一定的适应性.菌株Y11和Y4-2在30℃,170　r/min,1%接种量（体积分数,菌悬液D₆₀₀ =0.4）的条件下,2 mg/L磷浓度的聚磷培养液中最大聚磷率分别为96.13%和94.65%,培养液的磷浓度由2 mg/L分别降至0.08 mg/L和0.11 mg/L;5 mg/L磷浓度的聚磷培养液中最大聚磷率分别为95.94%和71.19%,培养液的磷浓度由5 mg/L分别降至0.20 mg/L和1.44 mg/L;8 mg/L磷浓度的聚磷培养液中最大聚磷率分别为71.24%和47.81%,培养液的磷浓度由8 mg/L分别降至2.30 mg/L和4.18 mg/L.使用2菌株处理云南滇池污水（磷含量为1.01 mg/L）,30℃,170　r/min,4%接种量（菌悬液D₆₀₀ =0.4）条件下,菌株Y11处理6　h后磷浓度由1.01 mg/L降至0.06 mg/L,菌株Y4-2处理48　h后磷浓度由1.01 mg/L降至0.06 mg/L.研究结果表明,菌株Y11和Y4-2对环境的适应性较强,均能高效、快速地降低聚磷培养液和云南滇池水体的磷浓度,不动杆菌Y11的除磷能力和环境适应性都大于菌株Y4-2,菌株Y11适用于南方和北方含磷较高的、菲污染的各种富营养化水体修复,菌株Y4-2更适用于pH8.0以下、低磷和菲污染的富营养化水体修复.     

Biodegradation of 2-naphthol and its metabolites by coupling Aspergillus niger with Bacillus subtilis

To explore biodegradation of 2-naphthol and its metabolites accumulated in wastewater treatment, a series of bio-degradation experiments were conducted. Two main metabolites of 2-naphthol, 1,2-naphthalene-diol and 1,2-naphthoquinone, were identified by high-performance liquid chromatography with standards. Combining fungus Aspergillus niger with bacterium Bacillus subtilis in the treatment enhanced 2-naphthol degradation e ciency, lowered the accumulation of the two toxic metabolites. There were two main phases during the degradation process by the kinetic analysis: 2-naphthol was first partly degraded by the fungus, producing labile and easily accumulated metabolites, and then the metabolites were mainly degraded by the bacterium, attested by the degradation processes of 1,2-naphthalene-diol and 1,2-naphthoquinone as sole source of carbon and energy. Sodium succinate, as a co-metabolic substrate, was the most suitable compound for the continuous degradation. The optimum concentration of 2-naphthol was 50 mg/L. The overall 2-naphthol degradation rate was 92%, and the CODCr removal rate was 80% on day 10. These results indicated that high degradation rate of 2-naphthol should not be considered as the sole desirable criterion for the bioremediation of 2-naphtholcontaminated soils/wastewater.     

Anaerobic benzene biodegradation by a pure bacterial culture of Bacillus cereus under nitrate reducing conditions

A pure culture using benzene as sole carbon and energy sources was isolated by screening procedure from gasoline contaminated soil. The analysis of the 16S rDNA gene sequence, morphological and physiological characteristics showed that the isolated strain was a member of genus Bacillus cereus. The biodegradation performance of benzene by B. cereus was evaluated, and the results showed that benzene could be e ciently biodegraded when the initial benzene concentration was below 150 mg/L. The metabolites of anaerobic nitrate-dependent benzene oxidation by strain B. cereus were identified as phenol and benzoate. The results of substrate interaction between binary combinations for benzene, phenol and benzoate showed that the simultaneous presence of benzene stimulated the degradation of benzoate, whereas the addition of benzene inhibited the degradation of phenol. Benzene degradation by B. cereus was enhanced by the addition of phenol and benzoate, the enhanced e ects were more pronounced at higher concentration. To our knowledge, this is the first report that the isolated bacterial culture of B. cereus can e ciently degraded benzene under nitrate reducing conditions.     

芽孢杆菌K1降解亚硝酸盐的特性研究

研究了芽孢杆菌K1对NO2-N的降解作用.对影响降解的主要因素如NO2-N初始浓度、培养时间、接种量、装液量、静置与摇床培养等进行实验,结果表明:K1在NaNO2初始浓度为500 ㎎/L的营养肉汤培养48 h后,NO2-N盐降解率最高,达到了98.92%.随着培养时间的延长,NO2-N降解率升高,在K1菌生长对数期,NO2-N降解速度最快.24和48 h时,接种量为0.5%的NO2-N降解率低于接种量大于1%的降解率,说明了培养液初始菌量的大小对NO2-N的降解有影响.NO2-N降解率随着装液量的减少而降低.K1静置培养的菌量和NO2-N降解率都低于摇床培养的菌量和NO2-N降解率.     

苏云金芽胞杆菌无晶体突变株对小鼠和雏鸡的安全性

以苏云金芽胞杆菌无晶体突变株BMB304为受试菌株,对小鼠和雏鸡进行安全性测试,考察BMB304在鸡肠道中的存留情况,以探索利用苏云金芽胞杆菌S-层表面展示系统研制热稳定性禽用口服活菌疫苗的安全性和可行性.小鼠腹腔一次性注射1010 CFUBMB304菌液1.0 mL,观察14 d,未发现有急性毒性反应.小鼠饮用含BMB304 108 CFU/mL、107 CFU/mL和106 CFU/mL的饮用水28 d,各组小鼠精神和饮食正常,剖检未见异常变化,各剂量组小鼠体重变化、脏器系数、血常规指标及血液生化指标与对照组无显著性差异.雏鸡24 h内灌服1010 CFU BMB304芽胞液1.0mL,14 d内未出现急性毒性反应.饲喂雏鸡含BMB304芽胞108 CFU/g、107 CFU/g和106 CFU/g饲料28 d,雏鸡精神和饮食正常,剖检未见异常变化,各剂量组的日增重与对照组差异不显著.饲喂雏鸡含BMB304芽胞106 CFU/g饲料3 d后,经测定,芽胞能在肠道中萌发并至少存留5 d但不超过7 d.研究表明,苏云金芽胞杆菌无晶体突变株BMB304对小鼠和雏鸡安全无毒,且能在鸡肠道内暂时定植,能被用于研制在细胞表面展示外源抗原并能常温长期保存的新型禽用口服疫苗.