海带发酵降解中相关海洋功能菌的分离、鉴定与筛选CSCD

目的从海带养殖环境中筛选有效降解海带的海洋功能菌,对海带进行降解处理,提高利用率,增加海带原料价值。方法采用以果胶或海藻酸钠为唯一碳源的选择性培养基挑选含有果胶酶、褐藻酸裂解酶的菌株;测定海带发酵液中海藻酸含量,复筛降解效果好的单菌及复合菌;16S rDNA测序对菌种进行鉴定。结果使用含10%鲜海带的富集培养基培养48 h,其中降解效果较好的为1-2和3-10菌种的组合,其降解量为95%。结论经上述研究选出有效的降解海带功能菌1-2和3-10,其降解海带效果较好,对海带利用率高。     

刺参海带饲料原料褐藻胶降解菌的分离与鉴定

从海带及刺参养殖环境中筛选有效降解褐藻胶,且对刺参无致病性的微生物,对海带饲料原料进行降解处理,以降低海带饲料中刺参难以消化的褐藻胶成分,显著提高饲料利用率,增加海带原料价值。以褐藻胶为唯一碳源选择培养基初筛;DNS法测定褐藻胶裂解酶酶活;16S r DNA测序及生理生化试验对菌种进行鉴定;高浓度腹腔攻毒试验考察筛选所得菌株对刺参的潜在致病性;分子排阻色谱及高效凝胶色谱法对微生物酶解褐藻胶的终产物进行分析。系统发育树分析表明,菌株WB1与Bacillus amyloliquifaciens有最高同源性,对刺参无潜在致病性;其褐藻胶裂解酶酶解褐藻胶的终产物主要为二糖和三糖,相对含量分别为74.1%和25.9%,平均分子量为516 Da。解淀粉芽胞杆菌WB1可作为一种安全的有益微生物用于刺参海带饲料原料中褐藻胶成分的降解。     

耐高温木质素降解菌筛选及降解效果研究

为提高育苗基质中废弃物木质素降解速率,在废弃物堆腐生产育苗基质高温阶段取样,筛选耐高温木质素降解菌,并对菌种进行鉴定,同时测定其对秸秆木质素和菌糠木质素的降解效果。获得了1株较好的木质素高温降解菌HZ11,鉴定为解淀粉芽胞杆菌（Bacillus amyloliquefaciens）,结果显示,该菌株对秸秆木质素和菌糠木质素降解效果较好,50 ℃条件下,20 d木质素降解率分别为46.7%和42.4%。菌株HZ11在降解秸秆和菌糠方面具有很好的应用潜力,为利用农业废弃物生产育苗基质提供更加丰富的菌种资源,具有重要的参考价值。     

有机磷降解菌的筛选及其促生特性

【目的】从环境中筛选高效有机磷降解菌及研究其促生机制。【方法】利用蒙金娜有机磷培养基筛选有机磷降解菌,用生化实验对其促生特性进行研究,且通过盆栽实验筛选对黄瓜苗有促生作用的高效有机磷降解菌。【结果】从草坪根周筛选到35株有机磷降解菌,选择5株代表性菌进行黄瓜盆栽实验。结果表明G3-6有机磷降解能力最强,溶磷圈直径(HD)与菌落直径(CD)比值为3.28,且对黄瓜苗的促生效果优于其他菌株。与CK相比,G3-6可提高黄瓜苗鲜重71.53%、干重69.78%和株高33.55%;与阳性对照枯草芽孢杆菌F-H-1相比,G3-6可提高黄瓜苗鲜重2.52%、干重21.14%和株高8.27%。相关分析结果表明降解有机磷能力在促进植物生长过程中可能发挥着比其他功能更重要的作用。16S r RNA序列分析初步鉴定G3-6为假单胞菌属。【结论】假单胞菌G3-6除具有较强的有机磷降解、分泌IAA和铁载体能力,对黄瓜苗也有较好的促生作用,是1株潜在的具有广阔市场应用价值的高效促生菌。     

高盐含油废水中微生物筛选及系统发育研究

对舟山港口的油轮冲洗水样品嗜盐微生物进行筛选,得到7株菌株,其中DG30-2b、T37-2b和DG30-3b对体积分数为1.0%的稠油降解效果较好,降解率分别为28.5%、24.1%和18.7%。这3株菌分别为Bacillus cereus(蜡状芽胞杆菌)、Lysinibacillus xylanilyticus(木糖短小芽胞杆菌)和Thauera aminoaro-matica(氨基脂陶厄氏菌)。对这3株菌进行了降解条件优化,发现其在原油中的最适降解温度均为30℃,最适pH为7.0,最适原油降解浓度为体积分数0.5%。菌株DG30-2b和T37-2b的最适降解盐度均为质量分数2.0%,而菌株DG30-3b最适降解盐度为质量分数3.0%。将该3株菌按照体积比1:1:1混合后组成DGT菌群,对体积分数为1.0%的石油污染的土壤进行处理,并进行GC/MS色谱测定后,对污染物的迁移规律做了初步分析,结果显示C25以上的烷烃含量降低,C18左右的烷烃含量增多,表明菌群DGT有较好的降解效果,具有将长链烷烃降解为短链烷烃的能力。     

一株苯系物降解真菌筛选及降解特性

采用逐量分批驯化的方法以污水处理厂污泥作为菌源,苯、甲苯、二甲苯为唯一碳源,驯化、分离、筛选能够有效降解苯系物的真菌,命名为B1。采用单因素以及正交实验方法并对真菌降解环境影响因素及降解效率进行了测定和研究。结果表明:真菌B1对苯系物降解的最佳条件为C:N=5:1,pH5,温度30℃,菌种接种量为5.5ml(50ml培养基)。采用GC对初始液相浓度0~90mg/L范围内的苯系物降解效果进行测定,未发现苯系物对真菌降解活性产生抑制作用。真菌对苯系物的降解效率为:甲苯>苯>二甲苯,最高降解效率分别达到87.39%,85.21%,81.47%。混合物降解效果略高于单一底物的降解效果。     

一株甲醛降解菌鉴定及其降解性能研究

目的:从实验室的动物肝脏浸置标本分离得到一株甲醛降解菌CSLG1,并考察其对甲醛的降解特性。方法:通过形态学和18S rDNA测序鉴定菌种,改变液体培养基中甲醛浓度确定该菌株的甲醛抗性,并在较高甲醛浓度的培养基中测定菌株CSLG1的生长曲线,证实其对甲醛具有降解能力。结果:鉴定结果显示,该菌CSLG1属于拟青霉属(Paecilomyces daclylethromorphus),其能在6.52 g/L的高甲醛浓度下生长;当甲醛初始浓度为3.73 g/L时,菌株CSLG1能在60 h内彻底降解。结论:菌种CSLG1对甲醛具有良好的降解效率,研究结果对甲醛污染环境的生物降解具有较好的科学意义和应用价值。     

土壤中聚乙烯降解菌的筛选、鉴定及降解特性

[目的] 农用地膜主要成分为聚乙烯（polyethylene,PE）,因其难以被降解,其废弃物常造成“白色污染”,本研究从常年覆盖农用地膜的土壤中筛选PE降解菌,并探究其对PE制品的降解效能。[方法] 采集的土壤样品用PE为唯一碳源的无机盐培养基进行富集,筛选、纯化PE降解菌,分离菌通过形态染色、生理生化特征、16S rRNA基因序列分析进行鉴定,检测其在不同PE浓度（0%、0.05%、0.10%、0.25%、0.50%、1.00%、2.00%、3.00%）的无机盐培养基中的生长曲线,最后通过扫描电镜、光镜观察,检测分离菌对农用地膜的降解效能。[结果] 从土壤中筛选获得一株能够降解PE的分离菌株（命名为SW1）,初步鉴定其为放线菌的诺卡氏菌属Nocardia sp.。SW1的生长对PE具有明显浓度依赖,在含2% PE的无机盐培养基中生长最快,在培养的第48 h菌液浓度开始明显增加,第60 h达到最大,而在不含PE的无机盐培养基中未见生长。形态生理学观察表明,35℃培养15 d后,扫描电镜观察可见有大量菌嵌入膜内或附于膜表面生长,膜表面粗糙,并开始出现破损;培养60 d后,光镜观察可见膜大面积破损,并出现空洞。[结论] 从土壤中筛选获得了一株能够有效降解PE制品的放线菌菌株Nocardia sp. SW1。该研究丰富了PE制品降解微生物的菌种资源,为PE塑料废弃物的生物降解提供了科学数据与参考。     

中国东北地区三种蜜环菌的生物学特性及奥氏蜜环菌人工培养

蜜环菌属Armillaria真菌具有较高的食药用价值。由于蜜环菌的生长发育过程较复杂,还未完全实现商业化栽培,野生资源的供应受到季节性和地域性的影响。本研究以采自东北地区蜜环菌属的3个菌株为研究对象,通过培养物的形态特征及分子标记确定菌株JG19016为奥氏蜜环菌A. ostoyae,菌株JG19017为高卢蜜环菌A. gallica,菌株JG19018为中国蜜环菌生物种C。奥氏蜜环菌JG19016最适生长温度为25 ℃,高卢蜜环菌JG19017的最适生长温度为22 ℃,中国蜜环菌生物种C JG19018则在22-25 ℃时菌丝生长速度最快;3个菌株最适pH为5-6。奥氏蜜环菌JG19016对葡萄糖和蔗糖利用率较好,高卢蜜环菌JG19017对葡萄糖利用率较好,中国蜜环菌生物种C JG19018对葡萄糖和淀粉利用率较好;蛋白胨对3个菌株促进作用最强,为最适氮源。培养基中加入VB₁,对3个菌株的菌丝生长均有明显的促进作用。奥氏蜜环菌JG19016菌丝生长的最优培养基配方为：葡萄糖20 g,蛋白胨3 g,磷酸二氢钾2 g,硫酸镁1.5 g,VB₁ 10 mg,琼脂20 g,水1 L。在木屑基质中培养,其配方的最优碳氮比为38:1,最佳木屑粗细比为3:1以上。出菇条件探索结果显示,菌丝及菌索长满菌袋(17 mm×33 mm×5 mm丝聚乙烯袋)需要50-60 d,之后在18 ℃、60%湿度和12 h散射光的环境中,10 d左右可观察到原基产生。增加菇房湿度到90%-95%,2-3 d可观察到1-3 cm的幼子实体,7 d左右菌柄和菌盖完全分化,10 d左右观察到菌盖展开。     

褐藻胶降解菌株S10鉴定及产酶条件优化

探讨了褐藻胶降解菌株S10的生长条件及其对产褐藻胶降解酶活力的影响。以分离自海参肠道的褐藻胶降解菌株S10为研究对象，采用形态学观察结合16S rDNA序列分析，对菌株S10进行菌种鉴定并对其生理生化特性进行测定。以降解酶活力为指标，利用单因素、Plackett-Burman(PB)和响应面法对培养基成分和培养条件进行优化；最后对优化前后的菌株生长量、产酶活力和粗酶液稳定性进行分析。结果表明，菌株S10属于溶藻孤菌(Vibrio algindyticus);当pH 7、接种量2%(体积分数)、装液量150 mL、温度26℃、转速150 r/min、NaCl 3%(质量分数，下同)、海藻酸钠含量1.12%、硫酸铵含量0.44%、培养时间35.95 h条件下，褐藻胶降解酶活力最大(188.18 U/min)。优化后产酶活力提高30%;4℃低温更有利于该酶保存。综上，优化后的菌株S10产褐藻胶降解酶活力较高，能更好地用于降解褐藻胶，可为提高褐藻胶的利用率和进一步发掘褐藻胶寡糖的利用价值提供参考。     

Degradations of 4-cholesten-3-one and 1,4-androstadiene-3,17-dione by cholesterol-degrading bacteria

Degradations of 4-cholesten-3-one and 1,4-androstadiene-3,17-dione, which are intermediates of microbial conversion of cholesterol, by cholesterol-degrading bacteria (12 strains of the genus Rhodococcus isolated from food of animal origin and 12 culture collection strains) were examined. All strains had the ability to degrade 4-cholesten-3-one without necessarily being able to degrade cholesterol. On the other hand, the bacteria were divided into three groups with little or no (0-10%), intermediate (10-70%) and high (70-100%) degradation abilities for 1,4-androstadiene-3,17-dione.     

Mechanism of Isolated Hemicellulose and Xylan Degradation by Cellulolytic Rumen Bacteria

Although certain strains of cellulolytic rumen bacteria cannot utilize isolated hemicelluloses or xylan as a source of energy, all strains examined can degrade or solubilize these materials from an 80% ethyl alcohol insoluble to a soluble form. Centrifugation and washing of the cellobiose-grown bacterial cells did not affect the rate or extent of utilization or degradation or both. When the level of a nonutilizing culture inoculum (either normal or washed) was doubled, a corresponding increase in the initial rate of degradation was observed. With a nitrogen-free medium, utilization of xylan was almost completely inhibited for a utilizing strain, whereas degradation by either type of organism was not markedly affected. Cellobiose medium cell-free culture filtrates from a nonutilizing strain were able to degrade or solubilize xylan. The percentage of degradation increased with the volume of cell-free filtrate, and all activity was lost when the filtrate was boiled. No utilization (loss in total pentose) was observed with cell-free filtrates from utilizing or nonutilizing strains. The release of free hexose from insoluble cellulose by culture filtrates from a nonutilizing strain was very limited. On the other hand, carboxymethylcellulose (CMC-70L) and cellulodextrins were degraded to an 80% ethyl alcohol soluble form by filtrates from both types of organisms. Similar enzyme activity was obtained in cell-free culture filtrates from four additional strains of cellulolytic rumen bacteria (one xylan utilizer and three nonutilizers). When the assays were carried out aerobically, CMC-70L solubilization was reduced to a much greater extent than xylan or cellulodextrin solubilization. The enzyme or enzymes responsible for the degradation of hemicellulose by cellololytic rumen bacteria unable to utilize the hemicellulose as an energy source appear to be constitutive in nature, and this activity may be a nonspecific action of a beta-1, 4-glucosidase or -cellulase.     

Degradations of 4-cholesten-3-one and 1,4-androstadiene-3,17-dione by cholesterol-degrading bacteria

Degradations of 4-cholesten-3-one and 1,4-androstadiene-3,17-dione, which are intermediates of microbial conversion of cholesterol, by cholesterol-degrading bacteria (12 strains of the genus Rhodococcus isolated from food of animal origin and 12 culture collection strains) were examined. All strains had the ability to degrade 4-cholesten-3-one without necessarily being able to degrade cholesterol. On the other hand, the bacteria were divided into three groups with little or no (0–10%), intermediate (10–70%) and high (70–100%) degradation abilities for 1,4-androstadiene-3,17-dione.     

Selective alginate degradation by marine bacteria associated with the algal genusSargassum

Summary Alginase-secreting bacteria associated with actively growing tissues of the marine Phaeophyta speciesSargassum fluitans andS. natans have been isolated and evaluated for their ability to degrade alginate (ALG), carboxymethylcellulose, and agar. Of seven isolates selected for their ability to grow on 2% agar containing 1% sodium alginate, none were able to grow on either 2% agar or 2% agar supplemented with 0.1% carboxymethylcellulose. Two of these with fermentative potential, i.e., ALG-A and ALG-G, showed selective activities with respect to their ability to degrade native alginate and/or take up the products resulting from alginate degradation. The ALG-A isolate was able to rapidly degrade native alginate with the generation of a stable polymer fraction and small oligouronides, most of which were dissimilated for growth. The ALG-G isolate was able to completely degrade native alginate with the accumulation of significant quantities of unsaturated dimeric and trimeric oligouronides. A limit polymer was generated from the action of a polymannuronan-specific extracellular alginate lyase purified from exponential cultures of the ALG-A organism. This product proved to be an effective substrate for the alginate lyase activity obtained from the medium of exponential phase cultures of the ALG-G isolate, and upon incubation with concentrated and dialyzed ALG-G medium was converted to the products that were observed to accumulate in the medium of the ALG-G isolate grown on native alginate. These organisms represent examples of the microflora associated with actively growingSargassum tissues, each with a selective ability to degrade and dissimilate the biomass of the marine brown algae.     

Biodegradation of the mixture of 2,4,6-trichlorophenol, 4-chlorophenol,and phenol by a defined mixed culture

Two new strains, Pseudomonas sp. TCP114 degrading 2,4,6-trichlorophenol (TCP) and Arthrobacter sp. CPR706 degrading 4-chlorophenol (4-CP), were isolated through a selective enrichment procedure. Both strains could also degrade phenol. The degradability of one component by a pure culture was strongly affected by the presence of other compounds in the medium. For example, when all three components (TCP, 4-CP, and phenol) were present in the medium, a pure culture of CPR706 could not degrade any of the components present. This restriction on degradability could be overcome by employing a defined mixed culture of the two strains. The mixed culture could degrade all three components in the mixture through cooperative activity. It was also demonstrated that the mixed culture could be immobilized by using calcium alginate for the semi-continuous degradation of the three-component mixture. Immobilization not only accelerates the degradation rate, but also enables reuse of the cell mass several times without losing the cells' degrading capabilities.     

降解尿酸乳酸菌复合菌系的筛选与菌株组合提升降解效果

【背景】高尿酸症由血液中尿酸含量明显升高而导致,利用乳酸菌对人体的益生作用缓解高尿酸血症越来越受到关注。【目的】获得具有降解尿酸能力的乳酸菌复合菌系与纯培养菌株。【方法】以泡菜为样品来源,以尿酸为底物,采用MRS培养基筛选降解尿酸的乳酸菌复合菌系,通过高效液相色谱法测定复合菌系对尿酸的降解能力。【结果】得到一组乳酸菌复合菌系,当培养温度为37 °C、pH值为6.20、静置培养72 h后复合菌系对尿酸的降解率为12.08%;通过优化培养条件,当该菌系在以牛肉膏为单一氮源、初始pH值为5.00、温度为35 °C的条件下培养72 h,尿酸降解率上升至17.19%,降解率比优化前提高了42.3%;从该菌系中分离出两株具有尿酸降解能力的菌株UA-1与UA-2,它们的尿酸降解率分别为10.85%和8.65%;通过形态学观察和16S rRNA基因序列分析,经鉴定两株菌均为布氏乳杆菌(Lactobacillus buchneri)。将两株单菌组合降解尿酸试验发现,UA-1与UA-2比例为2:1的尿酸降解率为20.2%,比原复合菌系的降解能力提高了67.22%。【结论】研究证明了乳酸菌复合菌系对尿酸的降解能力优于单个菌株,为后续利用乳酸菌复合菌系应用提供了数据支持。     

Symbiotic formation of alginate lyase in mixed culture of bacteria isolated from soil

Bacteria having alginate lyase activity were screened by growing cells from various sources in a medium containing alginate as a carbon source. Among the various samples tested, the culture enriched with paddy-field bacteria showed the highest alginate lyase activity, and contained three kinds of bacteria. They were purified and identified to be Flavobacterium, Alcaligenes and Bacillus species. The alginate lyase activity in these strains was low when they were grown separately. The highest alginate lyase activity was obtained when these strains were cultured all together in the same medium.     

秸秆降解菌的筛选及对秸秆的降解效果

作物秸秆作处置不当可能严重影响农村生态环境。目前东北地区的秸秆处置方式主要为直接打碎还田,但秸秆在自然环境中不易腐化,影响春耕。从添加外源微生物促进秸秆原位腐化角度开发新型可培养秸秆降解菌,具有重要意义。本实验通过菌种富集培养、刚果红培养基初筛和滤纸条崩解试验复筛的方法,从腐烂的秸秆和牛肠道中分离筛选潜在的高效纤维素降解菌,测定其最适生长温度和pH,在液态发酵培养条件下考察菌株实际降解能力,共获得具有较高玉米秸秆降解能力的降解菌5株。5种菌株的生长峰值均出现在温度20~30℃,pH值7.5~8.5范围内。液态发酵培养15天后,秸秆失重率为菌株NX9(53.88%)>NF6(51.36%)>JF3(46.97%)>JZ8(45.2%)>JX4(35.79%)>CK(23.88%)。其中,菌株NX9(温度30℃、pH 7.5)对秸秆半纤维素和木质素的降解能力最强,15天降解率分别为48%和37.7%;筛选出的NF6和JF3属于耐冷微生物,特别是菌株NF6在4℃条件下也能生长繁殖,为北方开展"外源微生物促进秸秆原位腐化"技术提供了基础。     

Anaerobic degradation of cellulose by mixed culture

A mixed culture in which cellulose is capable of being converted to methane and carbon dioxide was obtained from an inoculum procured from a sewage-treatment plant and maintained in a synthetic medium containing tissue paper and an inorganic salt and vitamin mixture. The culture was tested for its ability to degrade 12 different paper and cotton products under batch conditions in 3-l anaerobic fermenters. This culture degraded 6-8 mmol/l per week of cellulose, expressed as glucose equivalents, with total gas yields of 0.3 m3/kg of cellulose degraded. The gas produced contained between 56 and 59% of methane. Maximum cellulose degradation occurred at chemical oxygen demand:nitrogen:phosphorus level of 80:5:1 and was adversely affected by high stirring rate. Also the presence of higher proportions of lignin in cellulose products adversely affected the ability of this culture to degrade cellulose.     

Cyclodextrin-linked alginate beads as supporting materials for Sphingomonas cloacae, a nonylphenol degrading bacteria

Calcium alginate beads covalently linked with alpha-cyclodextrin (alpha-CD-alginate beads) were prepared and examined for their ability to serve as a supporting matrix for bacterial degradation of nonylphenol, an endocrine disruptor. Column chromatographic experiment using alpha-CD-alginate beads with diameter of 657+/-82 microm and with degree of CD substitution of 0.16 showed a strong affinity for nonylphenol adsorption. Although addition of alpha-CD (2.7-27 mM) to the culture broth of Sphingomonas cloacae retarded nonylphenol degradation, the immobilized bacteria on the CD-alginate beads were effective for the degradation. Batch degradation tests using the immobilized bacteria on alpha-CD-alginate-beads showed 46% nonylphenol recovery after 10-day incubation at 25+/-2 degrees C, and the recovery reached to about 17% when wide and shallow incubation tubes were used to facilitate uptake of the viscous liquid of nonylphenol on the surface of the medium. Scanning electron microscopic photographs revealed that multiplicated bacteria was present both on the surface and inside the beads and the matrix of CD-alginate was stable and suitable during 10-day incubation.