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.     

物理诱变处理氧化亚铁硫杆菌的育种研究

以氧化亚铁硫杆菌作为出发菌,采用物理诱变进行处理。研究结果表明,经过微波和超声波诱变均能加快氧化亚铁硫杆菌氧化Fe2+和转化SO32-的速度。尤其是经过90 s微波处理的氧化亚铁硫杆菌进入对数期的时间比未经诱变前缩短12 h,48 h时Fe2+的氧化率达到99%,4小时后SO32-基本全部转化为SO42-。     

Biodegradation of Crystal Violet by Agrobacterium radiobacter

Agrobacterium radiobacter MTCC 8161 completely decolorized the Crystal Violet with 8 hr (10 mg/L) at static anoxic conditions. The decreased decolorization capability by A. radiobacter was observed, when the Crystal Violet concentration was increased from 10 to 100 mg/L. Semi-synthetic medium containing 1% yeast extract and 0.1% NH4Cl has shown 100% decolorization of Crystal Violet within 5 hr. A complete degradation of Crystal Violet by A. radiobacter was observed up to 7 cycles of repeated addition (10 mg/L). When the effect of increasing inoculum concentration on decolorization of Crystal Violet (100 mg/L) was studied, maximum decolorization was observed with 15% inoculum concentration. A significant increase in the activities of laccase (184%) and aminopyrine N-demethylase (300%) in cells obtained after decolorization indicated the involvement of these enzymes in decolorization process. The intermediates formed during the degradation of Crystal Violet were analyzed by gas chromatography and mass spectroscopy (GC/MS). It was detected the presence of N,N,N′,N′′-tetramethylpararosaniline, [N; N-dimethylaminophenyl] [N-methylaminophenyl] benzophenone, N; N-dimethylaminobenzaldehyde, 4-methyl amino phenol and phenol. We proposed the hypothetical metabolic pathway of Crystal Violet biodegradation by A. radiobacter. Phytotoxicity and microbial toxicity study showed that Crystal Violet biodegradation metabolites were less toxic to bacteria (A. radiobacter, P. aurugenosa and A. vinelandii) contributing to soil fertility and for four kinds of plants (Sorghum bicolor, Vigna radiata, Lens culinaris and Triticum aestivum) which are most sensitive, fast growing and commonly used in Indian agriculture.     

Application of waste frying oils in the biosynthesis of biodemulsifier by a demulsifying strain Alcaligenes sp. S-XJ-1

Exploration of biodemulsifiers has become a new research aspect. Using waste frying oils (WFOs) as carbon source to synthesize biodemulsifiers has a potential prospect to decrease production cost and to improve the application of biodemulsifiers in the oilfield. In this study, a demulsifying strain, Alcaligenes sp. S-XJ-1, was investigated to synthesize a biodemulsifier using waste frying oils as carbon source. It was found that the increase of initial pH of culture medium could increase the biodemulsifier yield but decrease the demulsification ratio compared to that using paraffin as carbon source. In addition, a biodemulsifier produced by waste frying oils and paraffin as mixed carbon source had a lower demulsification capability compared with that produced by paraffin or waste frying oil as sole carbon source. Fed-batch fermentation of biodemulsifier using waste frying oils as supplementary carbon source was found to be a suitable method. Mechanism of waste frying oils utilization was studied by using tripalmitin, olein and tristearin as sole carbon sources to synthesize biodemulsifier. The results showed saturated long-chain fatty acid was difficult for S-XJ-1 to utilize but could effectively enhance the demulsification ability of the produced biodemulsifier. Moreover, FT-IR result showed that the demulsification capability of biodemulsifiers was associated with the content of C=O group and nitrogen element.     

苏云金芽孢杆菌BtZ01对小鼠胚胎和胚后发育的影响

为了探讨苏云金芽孢杆菌(Bacillus thuringiensis,Bt)Bt Z01对小鼠胚胎发育和胚后生长发育的影响,将48只孕鼠随机分组,试验组饲喂浓度分别为106CFU·m L-1、108CFU·m L-1、5×109CFU·m L-1的Bt Z01菌液,并设灭菌水为对照组。采用行为致畸学方法检查Bt Z01对小鼠胚胎和胚后发育的影响并制作脏器切片,测量脏器指数等指标。结果表明,与对照组相比,各试验组小鼠在胚胎和胚后发育各阶段体重和体长无显著差异(P0.05),胚胎畸形发生率无增加,骨骼染色观察发现高剂量组小鼠后囟门显著大于其他3组(P0.05)。18 d与48 d小鼠部分脏器指数存在显著差异,但病理切片观察发现仅高剂量组肾脏有病变发生。试验结果表明,苏云金芽孢杆菌Bt Z01在浓度为108CFU·m L-1及以下时对小鼠胚胎发育及胚后生长发育无不良影响。