一种富集高温栅藻Desmodesmus sp. F51的新型生物絮凝剂

[背景]海科贝特氏菌(Cobetia marina)可产生大量具有絮凝活性的胞外产物,可视为一种新型的生物絮凝剂。高温栅藻(Desmodesmus sp.F51)是一种具有较高叶黄素含量的微藻,被认为是一种新兴的叶黄素来源,但利用该生物絮凝剂高效富集高温栅藻的相关研究迄今尚未见报道。[目的]以高温栅藻为对象,研究该新型生物絮凝剂的絮凝效率,并对絮凝机理进行初步探讨。[方法]探索在不同生长阶段微藻培养液添加生物絮凝剂、添加量、絮凝时间、pH对絮凝效率的影响,分析生物絮凝剂的功能基团,并测定在不同pH条件下添加生物絮凝剂前后高温栅藻的Zeta电位变化,以及在显微镜下分析藻细胞在添加生物絮凝剂前后的形态。[结果]在高温栅藻生长至稳定期(pH 8.0)添加2 mL生物絮凝剂,絮凝15 min絮凝效果最佳,达82.1%。傅里叶红外光谱(fourier transform infrared spectroscopy,FTIR)显示了多糖及酰胺结构的特征吸收峰,由此推测生物絮凝剂主要是多糖的混合物,含有少量蛋白质。根据Bradford法测定絮凝剂中蛋白含量约为0.4%(质量比),通过苯酚-硫酸法测定总糖质量分数约为34.5%(质量比),与FTIR分析结果基本相符。生物絮凝剂在pH 4.0-11.0保持60%以上的絮凝效率,说明无论是酸性或是碱性条件下絮凝效率都较高,结合Zeta电位的分析表明,推测生物絮凝剂对高温栅藻的絮凝机理中占主导地位的可能是吸附架桥作用。[结论]该研究对微藻生物絮凝具有重要的理论和实践意义。     

高效微生物絮凝剂D6对屠宰废水的应用研究

筛选出一株针对屠宰废水有高效絮凝活性的微生物絮凝剂产生菌,并对其所产微生物絮凝剂D6进行单因子絮凝条件优化和正交试验优化得到最佳絮凝条件。絮凝条件包括:微生物絮凝剂D6投加量、pH、金属离子种类、1%CaCl₂投加量。试验中发现碱性环境是微生物絮凝剂D6发挥絮凝活性的前提,表明微生物絮凝剂D6分子链的充分伸展对絮凝作用起决定因素,因此微生物絮凝剂D6的絮凝机理为吸附架桥作用。其最佳絮凝条件为微生物絮凝剂D6的投加量为25mL·L^-1,1%CaCl₂投加量55mL·L^-1,pH为8。在最佳絮凝条件下,絮凝率为96.6%,浊度去除率为97.8%,SS去除率为92.6%。     

沙漠生物结皮芽孢杆菌产胞外多糖的纯化及其絮凝性的研究

【目的】以新疆古尔班通古特沙漠的生物结皮为样品,通过培养、筛选、分离得到一株高产胞外多糖(EPS)的菌株XJ-27,对XJ-27菌株所产的胞外多糖进行分离纯化,并对其絮凝性进行研究。【方法】利用DEAE sepharose CL-6B阴离子层析和Sephadex G100凝胶层析的方法对胞外多糖进行纯化,通过紫外分析方法和高效凝胶渗透色谱进行纯度的测定,利用高效凝胶渗透色谱法(HP-GPC)测定其分子量,以高岭土为体系对其絮凝性进行研究。【结果】利用层析分离的方法共得到2个胞外多糖的组分,对其中一个组分进一步纯化,得到组分EPS-I。结果表明,EPS-I纯度较高,分子量为575 kD。同时对胞外多糖的絮凝性进行了研究,结果表明该胞外多糖对高岭土为体系的絮凝率为80.4%。【结论】菌株XJ-27产胞外多糖,其胞外多糖具有絮凝性,对该胞外多糖进行分离纯化后,得到分子量为575 kD的多糖组分EPS-I。     

梭柄松苞菇多糖组分的部分理化性质及对S-180瘤抑制活性研究

【目的】分离和纯化梭柄松苞菇子实体多糖, 并对其结构和抗肿瘤活性进行研究。【方法】采用热水浸提法提取梭柄松苞菇子实体多糖, 采用DE-52纤维素柱和Sephadex G-100进行多糖的分离纯化, HPGPC测定多糖分子量, HPLC测定单糖组成, 红外光谱进行结构分析, 甲基化实验测定连接方式, 核磁共振测定异头碳构型, 采用S-180荷瘤小鼠模型对梭柄松苞菇子实体多糖抗肿瘤活性进行研究, 并测定了荷瘤小鼠血清细胞因子TNF-α、IL-2和IL-6的含量。【结果】从梭柄松苞菇子实体中分离纯化得到多糖命名为CVP-A, 结果表明, CVP-A平均分子量为10 289, 单糖组成主要为葡萄糖, 还含有少量木糖, 含量比约为15:2, 甲基化实验, 核磁共振以及红外光谱分析结果表明CVP-A主链为(1→4)-α-D-葡聚糖, 侧链连接在主链葡萄糖残基2号碳位置, S-180荷瘤小鼠模型实验表明, CVP-A对实验性S-180实体瘤具有较好的抑制作用, 连续10 d腹腔注射25、50和75 mg/(kg·d) CVP-A的昆明小鼠的肿瘤抑制率分别为31.99%、42.68%和60.18%, 小鼠血清细胞因子测定表明, CVP-A能提高荷瘤小鼠血清TNF-α、IL-2和IL-6的含量。【结论】梭柄松苞菇多糖可能作为一个潜在的抗癌药物而开发利用。     

微生物絮凝剂水处理的影响因素及其工艺研究进展

本文对近年来微生物絮凝剂的发展进行了概述,在介绍微生物絮凝剂化学性质的基础上,讨论了与絮凝活性相关的絮凝剂投加量、投加顺序,待处理水体性质和水力条件等因素。重点论述了单一微生物絮凝剂水处理工艺、微生物絮凝剂和助凝剂复配水处理工艺、复合微生物絮凝剂水处理工艺和物理、化学方法和微生物絮凝剂联合水处理工艺。讨论发现结合现有研究成果,开发新的微生物絮凝剂水处理工艺具有重要的工业应用价值。     

乌勇布拉克盐湖嗜盐古菌絮凝效果筛选及活性检测

【目的】从嗜盐古菌中筛选可产生生物絮凝剂的菌株,对发酵液、上清液、菌悬液、胞外聚合物的絮凝作用进行检测,筛选能够适应高盐废水处理,且具有广谱盐度及pH作用范围的微生物絮凝剂。【方法】以新疆乌勇布拉克干盐湖沉积物为研究对象,利用纯培养方法对嗜盐古菌进行分离,对絮凝菌株进行初筛及16S rRNA基因测序,构建系统进化树,初步判断菌株分类地位;复筛检测不同生物材料的絮凝效果;选择絮凝效果较好的生物材料,检测其盐度、pH的絮凝效果稳定性。【结果】采用纯培养方法共分离到28株嗜盐古菌,絮凝初筛共筛选出16株嗜盐古菌,分布于碱线菌属(Natrinema)、盐缓长菌属(Halopiger)和盐土生菌属(Haloterrigena)。菌株发酵液、上清液、菌悬液、胞外聚合物具有不同程度的絮凝效果。菌株A279-1、A133、RP33、NGA0064、RM-152、A389的发酵液、上清液的絮凝效果较好,其中菌株A389的发酵液絮凝率为61.06%,上清液为67.92%。所有菌株菌悬液的絮凝率达到80%以上。菌株所产胞外聚合物表现出较好的絮凝效果,菌株RM-152所产胞外聚合物的絮凝率最高,达89.86%,其次是A389 (81.53%)。菌株A389所产胞外聚合物的产量最大,达12.53 g/L,具有广泛的盐度和pH适应性。【结论】乌勇布拉克干盐湖沉积物中蕴含丰富的可产生微生物絮凝剂的嗜盐古菌资源。嗜盐古菌菌株发酵液、上清液、菌悬液及胞外聚合物均具有良好的絮凝作用,尤其是胞外聚合物表现出较好的絮凝效果,具有广谱的盐度和pH耐受性。嗜盐古菌所产生物絮凝剂的发现对于后续高盐废水功能材料开发具有重要应用价值。     

产紫青霉EL-02的分离鉴定及其絮凝活性

摘要：【目的】分离鉴定有絮凝活性真菌,同时对其絮凝活性进行初步研究。【方法】采用梯度稀释、平板划线、18S rDNA检测等方法分离鉴定絮凝活性菌株。通过高速离心、超声破碎、乙醇沉淀、定性试验等方法确定絮凝活性物质性质。【结果】从渤海湾海岸土壤样品中分离筛选出一株有较高絮凝活性的真菌,经鉴定为产紫青霉（Penicillium purpurogenum）,命名为产紫青霉EL-02（P. purpurogenum EL-02）。超声破碎试验证实其絮凝活性主要存在于发酵上清液。根据絮凝活性曲线,确定4 d为积累絮     

一株产絮凝剂不动杆菌的筛选及其絮凝特性

从活性污泥中筛选出一株高效的微生物絮凝剂产生菌,鉴定为鲍曼不动杆菌.蚕豆根尖细胞微核试验未显示该菌株所产絮凝剂具有遗传毒性.该菌产絮凝剂的最佳碳源和氮源分别为葡萄糖和酵母浸出汁,培养时间为24 h.在絮凝体系中加入Ca2 能明显提高发酵液的絮凝率.在pH为8.0时对高岭土悬浊液和污水具有良好的絮凝效果.     

一株产絮凝剂不动杆菌的筛选及其絮凝特性

从活性污泥中筛选出一株高效的微生物絮凝剂产生菌, 鉴定为鲍曼不动杆菌。蚕豆根尖细胞微核试验未显示该菌株所产絮凝剂具有遗传毒性。该菌产絮凝剂的最佳碳源和氮源分别为葡萄糖和酵母浸出汁, 培养时间为24 h。在絮凝体系中加入Ca2+能明显提高发酵液的絮凝率。在pH为8.0时对高岭土悬浊液和污水具有良好的絮凝效果。     

高效微生物絮凝剂产生菌TJ-3的絮凝特性分析

从活性污泥中分离筛选出一株高效絮凝剂产生菌TJ-3, 经生理生化试验检测其属于革兰氏阴性菌, 短杆状, 16S rDNA测序鉴定为铜绿假单胞菌。生长曲线表明, TJ-3的生长稳定期较长, 所产微生物絮凝剂(MBF)的稳定性良好。TJ-3产MBF对高岭土悬液具有良好的絮凝效果, 最佳条件下的絮凝率为98.2%。絮凝活性分布实验结果表明, TJ-3所产MBF的活性物质大部分存在于离心后的沉淀物中。处理100 mL高岭土悬液, pH值8.5、1%(质量分数)CaCl2溶液投加量3.5 mL、菌液投加量1.5 mL时, 絮凝效果最佳。     

R1767, an example of the evolution of resistance plasmids

The Salmonella R-factor system R1767 undergoes frequent rearrangement of its plasmid components. The flux of genetic material within this plasmid system depends on a combination of illegitimate and homologous recombination. The presence of several copies of IS160 and two multiresistance transposons, Tn2410 and Tn2411, are substantial reasons for the observed variations.     

Demonstration of Laccase in the White Rot Basidiomycete Phanerochaete chrysosporium BKM-F1767

It has been widely reported that the white rot basidiomycete Phanerochaete chrysosporium, unlike most other white rot fungi, does not produce laccase, an enzyme implicated in lignin biodegradation. Our results showed that P. chrysosporium BKM-F1767 produces extracellular laccase in a defined culture medium containing cellulose (10 g/liter) and either 2.4 or 24 mM ammonium tartrate. Laccase activity was demonstrated in the concentrated extracellular culture fluids of this organism as determined by a laccase plate assay as well as a spectrophotometric assay with ABTS [2,2(prm1)-azinobis(3-ethylbenzathiazoline-6-sulfonic acid)] as the substrate. Laccase activity was observed even after addition of excess catalase to the extracellular culture fluid to destroy the endogenously produced hydrogen peroxide, indicating that the observed activity is not due to a peroxidase. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by activity staining with ABTS revealed the presence of a laccase band with an estimated M(infr) of 46,500.     

Lernaeocera branchialis (L., 1767) on cod in Baltic waters

Field surveys have shown a limited distribution ofL. branchialis in Baltic waters due to heterogenic salinity. The parasite is not suited as “natural” tagging of the cod population in these waters.     

Diuron degradation by Phanerochaete chrysosporium BKM- F-1767 in synthetic and natural media

When incubated in synthetic (N-limited) medium and on ashwood chips, Phanerochaete chrysosporium BKM-F-1767 degraded 14 and 10 mg/l diuron, respectively. The wood chips were used as support and sole nutrient source for the fungus. A higher degradation efficiency was found in ashwood culture as compared to the liquid culture, probably as a result of the synergetic effect of attached fungal growth, presence of limiting-substrate conditions and the microenvironment provided by ashwood, all favorable for production of high extracellular enzyme titres. Diuron degradation occured during the idiophasic growth, in the presence of manganese peroxidase, detected as dominant enzyme in both cultures.     

Age, growth and feeding in the ballan wrasse Labrus bergylta Ascanius 1767

A study of the age, growth and feeding of the protogynous wrasse Labrus bergylta (Teleostei: Labridae) was made on 25 male and 316 female specimens taken from the southern coasts of the Isle of Man from October 1972 to October 1974. Age determination and back-calculations for length were made from the opercular bones. The oldest male and female specimens were 29 and 25 years old respectively. The growth curves showed only a slight increase in growth rate after sexual inversion, and a pattern of slow irregular increase, with no pronounced levelling off in old fish. The time of sexual inversion varied widely: intersexual specimens of 5 and 14 years were found. The youngest functional male was 6 years old. The weight/length relationships of males and females were very similar and the following equation, derived from all individuals, was used to calculate weights for age utilizing the back-calculated lengths:
The mouth, pharyngeal teeth and gut length to fish length ratio (0.622) suggested an omnivorous diet. Analysis of gut contents confirmed this, with decapod Crustacea, isopods and molluscs the dominant food items. There were seasonal changes in feeding intensity and composition of the diet, related to temperature changes, onshore-offshore migration patterns, availability of food items, and changes in habitat associated with maturation.     

Manganese peroxidase production by immobilized Phanerochaete chrysosporium BKM-F-1767 in a cell bioreactor

Manganese-dependent peroxidase (MnP) production was performed in an immobilized cell bioreactor in which Phanerochaete chrysosporium BKM-F-1767 was immobilized on polystyrene foam. The immobilized cell culture yielded significantly greater MnP activity than the conventional stationary liquid culture. Cultivation was carried out in batch mode; the effect of glucose concentration was investigated and growth kinetics parameters were found as, micromax=0.59 day(-1), Ks=0.33 g/L and Kss=14.5. Batch operation led to maximum MnP (770.82 U/L) in the culture medium containing 0.05% Tween 80, 10 g/L glucose, and 174 microM Mn2+ at 37 degrees C and pH 4.5. Enzyme productivity was obtained as 110.12 U/day/L.     

Halocynthia papillosa (Linnaeus, 1767) as an indicator of SCUBA diving impact

The solitary ascidian Halocynthia papillosa (Linnaeus, 1767) is proposed as a good indicator of the deleterious effect of SCUBA diving on the Mediterranean coralligenous communities. A comparative survey of H. papillosa populations at frequented and unfrequented localities was carried out over a two-year period (during 2006 and 2007), before and after a peak diving season in the Sierra Helada Marine Park (SW Western Mediterranean Sea). We observed bigger and more abundant individuals of H. papillosa at undived sites than at frequented dived sites during the period of study. Furthermore, individuals of H. papillosa in the most frequented localities occupied more cryptic positions than in the undived localities. H. papillosa was shown to be very sensitive to the adverse effects of SCUBA diving. This species could represent a reliable bioindicator of diving activity and as such constitute a useful tool for the quick and easy monitoring of impact on coralligenous communities before this damage becomes unmitigatable.     

Overproduction of lignin peroxidase by Phanerochaete chrysosporium (BKM-F-1767) under nonlimiting nutrient conditions.

The ligninolytic enzymes synthesized by Phanerochaete chrysosporium BKM-F-1767 immobilized on polyurethane foam were characterized under limiting, sufficient, and excess nutrient conditions. The fungus was grown in a nonimmersed liquid culture system under conditions close to those occurring in nature, with nitrogen concentrations ranging from 2.4 to 60 mM. This nonimmersed liquid culture system consisted of fungal mycelium immobilized on porous pieces of polyurethane foam saturated with liquid medium and highly exposed to gaseous oxygen. Lignin peroxidase (LIP) activity decreased to almost undetectable levels as the initial NH4+ levels were increased over the range from 2.4 to 14 mM and then increased with additional increases in initial NH4+ concentration. At 45 mM NH4+, LIP was overproduced, reaching levels of 800 U/liter. In addition, almost simultaneous secretion of LIP and secretion of manganese-dependent lignin peroxidase were observed on the third day of incubation. Manganese-dependent lignin peroxidase activity was maximal under nitrogen limitation conditions (2.4 mM NH4+) and then decreased to 40 to 50% of the maximal level in the presence of sufficient or excess initial NH4+ concentrations. Overproduction of LIP in the presence of a sufficient nitrogen level (24 mM NH4+) and excess nitrogen levels (45 to 60 mM NH4+) seemed to occur as a response to carbon starvation after rapid glucose depletion. The NH4+ in the extracellular fluid reappeared as soon as glucose was depleted, and an almost complete loss of CO2 was observed, suggesting that an alternative energy source was generated by self-proteolysis of cell proteins.(ABSTRACT TRUNCATED AT 250 WORDS)