一株解淀粉芽胞杆菌的分离鉴定及水质净化效果的研究

采用富集培养及摇瓶实验,从污染河沟底质活性污泥中分离筛选到1株对亚硝态有较强转化能力的菌株HN.经形态特征、生理生化特性、16S rDNA基因序列分析、细胞脂肪酸组成及Biolog全自动微生物鉴定系统分析,鉴定菌株HN为解淀粉芽胞杆菌(Bacillus amyloliquefaciens),并在3种模拟水体环境中对菌株HN的水质净化效果进行了初步研究.结果表明,该菌株在试验第4d能将高浓度模拟污水(水样Ⅰ)、鲫鱼养殖废水(水样Ⅱ)、鲤鱼和对虾养殖废水(水样Ⅲ)中初始浓度分别为6.47、1.20和4.50mg·L-1的亚硝态氮去除100%、46%和100%,而对照的转化率分别为-10.4%、-800%和16.0%,同时对硝态氮也表现较强的去除能力且基本不累积氨氮.环境耐受性试验表明,该菌株在20～45℃、pH5.0～10.0、海盐浓度0.5%～3.0%的范围内都能正常生长.研究认为,解淀粉芽胞杆菌HN能显著降低水体中亚硝态氮和硝态氮的含量,且环境耐受力强,有望将其开发成高效的水产养殖水体净化微生态制剂.     

微波无极紫外方法对二沉池出水的消毒研究

采用自制微波无极紫外连续式消毒反应器,对二沉池出水进行消毒.紫外光源为自制圆柱形无极灯,灯内充汞10mg、氩气压强666.61Pa紫外光强5.07mW/cm²,进水流量0.072L/s,出水细菌总数2CFU/mL,大肠菌群数0.微波无极紫外作用过程中,微波破坏细胞壁细胞膜结构使蛋白质、K⁺等胞内物质产生渗漏,这种不可逆的破坏过程有效抑制紫外光复活现象.     

Protoplast preparation and regeneration conditions of Bacillus subtilis ZGL14 producing alkaline pectinase北大核心CSCD

The protoplast fusion technique is one of the important microbial breeding methods. The main factors that affect protoplast preparation and regeneration were investigated using Bacillus subtilis ZGL14 as the starter strain. The optimal conditions for protoplast preparation and regeneration were determined in this study by optimizing the cell age, lysozyme concentration, enzymolysis time, enzymolysis temperature, pH values of the osmotic pressure stabilizer, regeneration medium types, and culture type. The results indicated that the optimal condition for protoplast preparation of B. subtilis ZGL14 was as follows: 9 h of cell age, 0.2 mg/mL of lysozyme concentration, 10 min of enzymolysis time, 32 °C of enzymolysis temperature, and 7.0 of osmotic pressure stabilizer pH value. Under this condition, the protoplast formation and regeneration rates were > 98% and > 30%, respectively. A good protoplast regeneration effect can be achieved using the regeneration medium with sodium succinate as osmotic pressure stabilizer in combination with Ca2+. The single-layer culture was better than double-layer for regeneration. The optimal condition for protoplast preparation and regeneration of B. subtilis ZGL14 was determined in this study, which provides technical support for protoplast fusion breeding of B. subtilis. © 2018 Science Press. All rights reserved.     

Isolation,identification, and the degradation characteristics of a thiobencarb-degrading bacterium Bacillus sp. T2北大核心CSCD

Thiobencarb, a thiocarbamate herbicide, is widely used to control weeds in rice paddies. Screening for highly efficient thiobencarb-degrading bacteria is important for the bioremediation of thiobencarb-contaminated environments. The aim of this study was to isolate and identify highly efficient thiobencarb-degrading bacteria and to identify the degradation pathway and the degrading properties. The thiobencarb-degrading strain was isolated using methods of microbiological acclimation and enrichment and was then identified using a 16S rRNA phylogenetic analysis. The degrading properties of the isolated bacterium were determined by single-factor experiments, and the degradation products were identified using gas chromatography-mass spectrometry (GC-MS). A thiobencarb-degrading strain T2, which can utilize thiobencarb as the sole source of carbon for energy and growth, was isolated from paddy soil. Strain T2 degraded more than 98.3% of 0.4 mmol/L of thiobencarb within 36 h. It was preliminarily identified as Bacillus sp. T2 according to the 16S rRNA gene analysis and from its morphological, physiological, and biochemical characteristics. The metabolic products of the thiobencarb degradation for strain T2 were identified as 4-chlorobenzyl mercaptan, 4-chlorobenzaldehyde, and 4-chlorobenzoic acid by the GC-MS. Based on metabolite identification, it was speculated that thiobencarb degradation in strain T2 was initiated by the hydrolysis of the thioester bond to produce 4-chlorobenzyl mercaptan, which was further oxidized to 4-chlorobenzaldehyde and 4-chlorobenzoic acid. The thiobencarb degradation that was initiated by the hydrolysis of the thioester bond by strain T2 is a new metabolic pathway, which provides valuable research material and reliable experimental data for revealing the metabolic process and mechanism of thiobencarb microbial degradation in soil. The strain Bacillus sp. T2 has a very high degradation efficiency, suggesting it is a good prospect for microbial remediation in thiobencarb-polluted environments. © 2018 Science Press. All rights reserved.     

一株溶藻细菌对铜绿微囊藻生长的影响及其鉴定

从山东黄岛边某富营养化池塘中分离得到1株具有溶藻作用的菌株(J1),研究了其对铜绿微囊藻(Microcystis aeruginosa)的抑制效果、作用方式以及细菌培养基、菌株与铜绿微囊藻不同生长阶段等因素对溶藻效果的影响,并对该菌株进行了生理生化鉴定.结果表明,将牛肉膏蛋白胨培养基加入藻液,培养基与藻液的投放体积比为6%时,9d内对藻的生长无影响.将初始浓度为6×107 cfu/mL的菌液加入藻液,共培养第9d,铜绿微囊藻的去除率达87%以上.对数期的J1细菌具有较好的溶藻效果,作用于稳定期铜绿微囊藻的实验组,藻的去除率较低.J1通过分泌溶藻物质的间接作用方式抑制铜绿微囊藻的生长,且溶藻活性物质具有一定的热稳定性.根据生理生化及16S rDNA序列分析鉴定,菌株J1属于芽胞杆菌属(Bacillus).     

红树林沉积物Bt菌株的分离与cry基因型的鉴定（Isolation of Bacillus thuringiensis Strains from Mangrove Sediment Samples and Identification for cry Genes）

从收集自泉州洛江红树林保护区的400个沉积物土壤样品中,分离到18株苏云金芽孢杆菌(Bacillus thuringiensis,Bt).利用PCR-RFLP体系对Bt菌株杀虫晶体蛋白的基因型进行了鉴定,发现15株Bt含有cry1基因,4株含有cry2基因,有3株分别含有cry7、cry8、cry9基因.克隆了一个新型的cry2Ab基因,其编码蛋白与现有Cry2Ab型杀虫晶体蛋白的最高同源性为95%.     

Bio-remediation of acephate–Pb(II) compound contaminants by Bacillus subtilis FZUL-33

Removal of Pb~(2+)and biodegradation of organophosphorus have been both widely investigated respectively. However, bio-remediation of both Pb~(2+)and organophosphorus still remains largely unexplored. Bacillus subtilis FZUL-33, which was isolated from the sediment of a lake, possesses the capability for both biomineralization of Pb~(2+)and biodegradation of acephate. In the present study, both Pb~(2+)and acephate were simultaneously removed via biodegradation and biomineralization in aqueous solutions.Batch experiments were conducted to study the influence of p H, interaction time and Pb~(2+)concentration on the process of removal of Pb2+. At the temperature of 25°C, the maximum removal of Pb~(2+)by B. subtilis FZUL-33 was 381.31 ± 11.46 mg/g under the conditions of p H 5.5, initial Pb~(2+)concentration of 1300 mg/L, and contact time of 10 min. Batch experiments were conducted to study the influence of acephate on removal of Pb~(2+)and the influence of Pb2+on biodegradation of acephate by B. subtilis FZUL-33. In the mixed system of acephate–Pb2+, the results show that biodegradation of acephate by B. subtilis FZUL-33 released PO43+, which promotes mineralization of Pb2+. The process of biodegradation of acephate was affected slightly when the concentration of Pb2+was below 100 mg/L. Based on the results, it can be inferred that the B. subtilis FZUL-33 plays a significant role in bio-remediation of organophosphorus-heavy metal compound contamination.     

四环素工业废水生化处理工艺的研究

本文报道了四环素生产废水絮凝处理的最佳组合是１５ｍｇ／ｋｇ聚丙烯酰胺＋３０００ｍｇ／ｋｇ硫酸亚铁；经驯化的接种水测出ＣＯＤ为２７６４ｍｇ／Ｌ时，废水的ＢＯＤ５为１８７３ｍｇ／Ｌ，ＢＯＤ５／ＣＯＤ≈６８％，属易生化处理范畴。生物膜处理可在２ｄ内将ＣＯＤ从４４８８ｍｇ／Ｌ降至５４９ｍｇ／Ｌ，处理中的优势菌群为Ｇ＾＋芽孢杆菌。经γ射线辐射后，废水对细菌不再有抑制作用。     

Combination e ect of pH and acetate on enzymatic cellulose hydrolysis

The productivity and e ciency of cellulase are significant in cellulose hydrolysis. With the accumulation of volatile fatty acids (VFAs), the pH value in anaerobic digestion system is reduced. Therefore, this study will find out how the pH and the amount of acetate influence the enzymatic hydrolysis of cellulose. The e ects of pH and acetate on cellulase produced from Bacillus coagulans were studied at various pH 5–8, and acetate concentrations (0–60 mmol/L). A batch kinetic model for enzymatic cellulose hydrolysis was constructed from experimental data and performed. The base hypothesis was as follows: the rates of enzymatic cellulose hydrolysis rely on pH and acetate concentration. The results showed that the suitable pH range for cellulase production and cellulose hydrolysis (represents e ciency of cellulase) was 2.6–7.5, and 5.3–8.3, respectively. Moreover, acetate in the culture medium had an e ect on cellulase production (KI = 49.50 mmol/L, n = 1.7) less than cellulose hydrolysis (KI = 37.85 mmol/L, n = 2.0). The results indicated that both the pH of suspension and acidogenic products influence the enzymatic hydrolysis of cellulose in an anaerobic environment. To enhance the cellulose hydrolysis rate, the accumulated acetate concentration should be lower than 25 mmol/L, and pH should be maintained at 7.     

冰川环境耐冷菌的冷适蛋白酶分离纯化及酶学性质

采用离交和凝胶层析对“中国冰川1号”耐冷菌BacilluscereusSYPA23所产的蛋白酶进行分离纯化,并进行酶学性质研究.与中温酶相比,该蛋白酶具有较高的低温催化活力,其最适催化温度为42℃,适宜pH为7.0～8.5,SDSPAGE测定的分子量(Mr)为34.2×103.金属离子Mn2 、Ca2 对该酶有激活作用,Cu2 、Hg2 、Pb2 、Co2 对其活性有一定抑制作用.该酶属金属蛋白酶,其活性受EDTA强烈抑制,不受PMSF抑制.该蛋白酶具有低温酶典型的热不稳定性,0℃下半衰期24h,但Ca2 和一些低分子醇类物质能提高其稳定性.动力学数据分析表明,该蛋白酶在低温下对底物亲和能力高,在较宽温度范围内(25～45℃)均保持着较高的催化效能.图7表3参17