产耐酸性α-淀粉酶菌株的分离、鉴定、酶学特性研究及发酵培养基的优化

从富含淀粉的土壤中筛选获得多株产耐酸性α-淀粉酶的菌株,将酶活最高的一株经16S rDNA鉴定为枯草芽孢杆菌(Bacillus subtilis),命名为Bacillus subtilis A-7,其所产的耐酸性α-淀粉酶最适温度和pH分别为60℃和4.5。通过单因素筛选及正交试验优化发酵培养基,得到最佳配方为可溶性淀粉2%,蛋白胨2%,CaCl20.07%,Na2HPO40.8%,在此条件下耐酸性α-淀粉酶活力达到221 U/mL,是未优化条件下的2.3倍。     

一株中温淀粉酶菌株的分离鉴定及其产酶条件分析

利用固体淀粉筛选培养基,从安阳市郊区面粉厂附近的土壤里分离筛选出1株产淀粉酶的菌株,编号为MF-3-2.经过菌株形态、革兰氏染色、16S rDNA鉴定及系统进化树分析,初步确定其为枯草芽孢杆菌(Bacillus subtilis).摇瓶培养后对其酶学性质研究发现,该菌株淀粉酶的最适温度为65℃,最适pH值为6.0,在pH值4.8～6.0范围内仍能残余70％以上的酶活力.该菌株的最适生长温度为40℃,最适生长pH值为6.5.产酶条件优化结果表明:最适碳源为马铃薯淀粉,最适氮源为豆粕粉,最适碳氮比为1∶15,发酵温度30℃,发酵pH值6.0,装液量10％,种龄10h,接种量5％,转速200 r/min,48 h达到产酶高峰.通过发酵产酶条件优化,其淀粉酶活性达到86.8 U/mL,是优化前的35倍.另外,在酸性条件下还具有较好的活性.因此,该菌株的淀粉酶具有潜在的工业应用前景.     

产纤维素酶菌株的分离、鉴定及其酶学性质研究

利用刚果红变色圈法从土壤中分离得到1株产纤维素酶活较高的细菌YL07.通过分析其生理生化性质和16S rDNA序列的同源性,将菌株YL07鉴定为解淀粉芽胞杆菌(Bacillus amyloliquefaciens).同时.对菌株YL07所产纤维素酶的酶学性质进行了研究.结果表明:酶反应的最适pH值为6～7,在PH 6.0～9.0的范围内较稳定,酶反应的最适温度为40℃,30℃以下酶的热稳定性较好.K 、Ca2 对CMCage有激活作用,Fe2 、Na 、K 、Ca2 、Mg2 对滤纸酶活(FPase)有激活作用.     

生淀粉糖化酶产生菌Cellulosimicrobium sp.SDE的分离鉴定及酶学性质研究

从淀粉制品厂周围土壤中分离到一株高产生淀粉糖化酶的菌株SDE,经形态、生理生化及16S rDNA序列分析将其鉴定为Cellulosimicrobium sp..SDE菌株的最适产酶条件为pH7.0,培养温度为30℃.培养42h粗酶液的酶活达175.3U/mL.该酶以生玉米淀粉为底物时,最适作用pH6.0,最适作用温度40℃,pH6.0-7.0范围内酶活力稳定.在Ca2 存在下,酶的热稳定性很高,80℃保温1 h后,酶活力仍保持50%.Ba2 、Cu2 对酶活有强烈的抑制作用,Ca2 、Zn2 有很强的激活作用.     

牦牛源木聚糖酶产生菌的筛选和鉴定

目的以牦牛粪便为样本,筛选并鉴定产木聚糖酶菌株。方法利用碱提取法从玉米芯中提取木聚糖,以自制木聚糖为唯一碳源,从牦牛牛粪中筛选产木聚糖酶细菌,利用16S rDNA基因序列分析鉴定菌种,3,5-二硝基水杨酸法(DNS)测定其产酶能力并分析所产酶的酶学特性。结果筛选获得牦牛源产木聚糖酶类芽胞杆菌,所产木聚糖酶的最适反应条件为50℃、pH 8.0,在pH值为7.0或8.0以及温度50℃条件下,表现出较好的稳定性,Mn~(2+)对酶活力具有显著抑制作用,该菌最佳发酵时间为12 h,酶活最高达到1.2 U/mL。结论该菌所产木聚糖酶能够针对性地降解玉米芯木聚糖,在畜牧业和工业上有一定的应用价值。     

α-葡萄糖苷酶菌株的选育及发酵条件的研究

从2株芽胞杆菌中通过筛选获得了一株产α-葡萄糖苷酶活力较高的嗜热脂肪芽孢杆菌U2,以嗜热芽孢杆菌U2为菌种,优化发酵培养基后,在温度45℃、初始pH6.8、转速200r/min和10%接种量条件下,发酵20h,菌株U2产酶水平可达到2.62U/mL,比出发菌提高了4倍。     

南极海冰细菌中产低温 α-淀粉酶菌株的发酵和酶学特性的初步研究

从147株南极海冰细菌中筛选出一株高产低温a-淀粉酶的菌株Pseudoalteromonas sp.AN175。生长发酵单因素试验表明,菌株AN175在1%麦芽糖、0.5%酵母粉、0.01%磷酸铁、0.5%氯化钙、1%可溶性淀粉、5%NaCl、pH 6.0的培养基,10℃,30%装液量,130 r/min条件下振荡培养9 d可达到最大酶活132.5 U/mL,为优化前的2倍多。生长和产酶试验表明,该菌生长较常温菌缓慢,酶分泌时间滞后。粗酶特性研究显示,该酶催化的最适条件为温度30℃,pH值8.0。     

产弹性蛋白酶菌种的筛选及发酵条件优化研究

从合肥肉联厂附近的土壤和污水中分离得到19株产弹性蛋白酶菌株,初步鉴定该菌株属于假单胞菌属.经过发酵复筛有三株产酶能力超过15u/mL.实验对菌株最佳产酶发酵条件进行了优化2%干酪素、0.5%葡萄糖、0.4%酵母膏、0.2% K2HPO4、0.01% MgSO4·7H2O;起始pH值7.0;最适发酵温度为30℃;装液量为25mL/250mL;该菌株在28h左右产弹性蛋白酶的量达18u/mL.     

一株产生淀粉酶杆菌Bacillus sp. GEL-09的筛选、鉴定及发酵条件优化

【背景】生淀粉酶可以水解生淀粉颗粒,在酒精发酵、白酒、黄酒和食醋的生料酿造工业中具有广阔的应用前景。【目的】从自然环境中筛选产生淀粉酶的菌,对其发酵条件及酶性能进行考察,为淀粉生料发酵过程提供优良菌种和酶资源。【方法】取木薯田土壤,经过稀释、热处理、富集培养以及木薯淀粉平板筛选培养基初筛,摇瓶复筛得到产高效降解生淀粉酶的菌株;经过菌落形态、细胞染色观察以及16S rRNA基因序列比对进行鉴定;对筛选菌株的发酵培养基和发酵条件进行优化,并对酶蛋白进行分离纯化和酶学性质分析。【结果】分离到一株具有较高生淀粉酶水解活力的菌株GEL-09,经鉴定为芽胞杆菌Bacillus sp.GEL-09;该菌在最优发酵条件下培养96 h,胞外酶活力达到430.6 U/m L,是优化前的2.8倍;酶学性质分析发现该酶为中温、中性酶,最适温度和p H为50°C和7.0;生淀粉降解能力对比发现,该酶的生淀粉降解能力值为62.3%,显著高于细菌α-淀粉酶、生麦芽糖淀粉酶和甘薯β-淀粉酶对生淀粉的降解能力。【结论】Bacillus sp.GEL-09在生淀粉酶生产方面具有良好的开发应用前景。     

脂肪酶假单胞菌的分离培养及最佳产酶条件研究

以麻疯树油为唯一碳源,从以粉碎的麻疯树种子处理过的土壤中分离筛选出1株脂肪酶活性较高的菌株,初步鉴定为假单胞菌属(Pseudomonas).实验观察了碳源、氮源、无机盐及发酵工艺对产酶的影响,摇瓶发酵结果表明.该菌株最适产酶培养基的组成是(%,w/v):橄榄油2,酵母膏0.5,(NH4)2SO4 0.5,MgCl2·6H2O 0.5,最适产酶温度为30℃,最佳产酶pH为6.5,转速180r/min,发酵培养36h酶活达到最高,为14.17U/mL.本研究为以麻疯树油为原料酶法生产生物柴油奠定了一定的基础.     

津巴布韦烟叶中淀粉酶和蛋白酶产生菌的分离及鉴定

目的:从津巴布韦烟叶中分离产蛋白酶菌和产淀粉酶能力最高的菌株,并对其进行鉴定。方法:采用淀粉富集培养基和酪蛋白富集培养基分别分离津巴布韦烟叶中的产淀粉酶和产蛋白酶菌株,通过生理生化实验和16SrRNA序列分析鉴定分离的菌株。结果:产蛋白酶菌株菌体不透明、表面有褶皱,蛋白酶酶活为52.10±0.13 U/mL;产淀粉酶菌株菌体表面呈黏状,淀粉酶酶活为3.69±0.07 U/mL;产蛋白酶与产淀粉酶的2株菌均与枯草芽孢杆菌的16S rRNA序列有100%的相似性,结合生理生化指标初步鉴定为枯草芽孢杆菌。结论:获得的2株菌在降解烟叶的蛋白质和淀粉过程中可能起重要作用。     

Thermophilic amylase-producing bacteria from Vietnamese soils

Of 25 bacterial isolates from Vietnamese soils, two were identified asBacillus stearothermophilus and one asThermoactinomyces thalpophilus, both thermophilic, amylase-producing bacteria. Amylase activity was highest in the presence of cassava starch as carbon source and (NH₄)₂HPO₄ as nitrogen source. The strains exhibit a high amylase productivity within the first 5 to 7 h of cultivation at 55°C. The crude enzyme had optima of pH 6.5 and 70°C.     

Lead inhibition of enzyme synthesis in soil.

Addition of 2 mg of Pb2+/g of soil concident with or after amendment with starch or maltose resulted in 75 and 50% decreases in net synthesis of amylase and alpha-glucosidase, respectively. Invertase synthesis in sucrose-amended soil was transiently reduced after Pb2+ addition. Amylase activity was several times less sensitive to Pb2+ inhibition than was enzyme synthesis. In most cases, the rate of enzyme synthesis returned to control (Pb2+) values 24 to 48 h after the addition of Pb. The decrease in amylase synthesis was paralleled by a decrease in the number of Pb-sensitive, amylase-producing bacteria, whereas recovery of synthesis was associated with an increase in the number of amylase-producing bacteria. The degree of inhibition of enzyme synthesis was related to the quantity of Pb added and to the specific form of lead. PbSO4 decreased amylase synthesis at concentrations of 10.2 mg of Pb2+/g of soil or more, whereas PbO did not inhibit amylase synthesis at 13 mg of Pb2+/g of soil. Lead acetate, PbCl2, and PbS reduced amylase synthesis at total Pb2+ concentrations of 0.45 mg of Pb2+/g of soil or higher. The results indicated that lead is a potent but somewhat selective inhibitor of enzyme synthesis in soil, and that highly insoluble lead compounds, such as PbS, may be potent modifiers of soil biological activity.     

Lytic Enzyme toward Aniline-assimilating Rhodococcus erythropolis AN-13: Screening and Production

A bacterial strain, SH-548, that produces a lytic enzyme toward intact cells of aniline-assimilating Rhodococcus erythropolis AN-13, was isolated from soil. The isolated bacterium was identified as a Flavobacterium species. The growth conditions for the enzyme production by Flavobacterium sp. SH-548 were examined; organic nitrogen compounds, such as meat extract and Polypepton, were effective for its production. The lytic enzyme of this strain lysed intact cells of Rhodococcus, Bacillus, Nocardia, Corynebacterium, Brevibacterium, Streptococcus, Micrococcus, Cellulomonas and DAB (diaminobutyric acid)-type coryneform bacterial strains. However, it did not act on those of Staphylococcus aureus or gram-negative bacteria, Enterobacter, Escherichia, Klebsiella, Proteus or Pseudomonas strains. Bacterial strains having cell walls of the glycolyl type were readily lysed by this enzyme.     

Isolation and characterization of actinomycetes strains that produce phospholipase D having high transphosphatidylation activity

The present study was conducted to screen microorganisms that produce phospholipase D (PLD), and we especially focused on the strains having high transphosphatidylation activity. Eighty bacterial strains were isolated from soil samples by a screening method utilizing a preliminary selection medium with phosphatidylcholine (PC) as the sole carbon source. The culture supernatants were then assayed for PLD activity. The finding of dual PLD activities in cultures revealed that the hydrolytic and transphosphatidylation activities were correlated. Consequently, six strains were selected as stably producing PLD enzyme(s) during continuous subcultures. The culture supernatants of selected strains synthesized phosphatidylglycerol, phosphatidylserine and phosphatidylethanolamine from PC with high conversion rates. These isolated strains will be made available to carry out phospholipid modification through the efficient transphosphatidylation activity of the PLD that they produce.     

高效降解生活污水中COD的根际微生物的分离筛选

采用平板划线法从人工湿地的芦苇、美人蕉的根际土壤中分离出若干细菌、真菌、放线菌菌株,在实验室条件下检测了这些菌株对灭菌生活污水和自然生活污水COD的去除效果,结果表明4株细菌、1株放线菌、1株真菌对灭菌生活污水和自然生活污水COD均具有较高的去除率。4株细菌在降解灭菌生活污水COD的去除率在48 h后依次为75.4%、78.7%、83.5%、69.8%;其在降解未灭菌生活污水COD的去除率在48 h后依次为43.4%、47.8%、50.7%、36.8%;真菌对灭菌和未灭菌生活污水COD的去除率在48 h后分别为60.2%、41.3%;放线菌对灭菌和自然生活污水COD 48 h后的去除率分别为57.8%、46.4%。这几株高效降解COD的湿地根际微生物具有潜在的应用价值。     

一株纤维素降解细菌的筛选、鉴定及产酶条件分析

目的筛选高活性的纤维素降解细菌,并进行初步鉴定和产纤维素酶条件分析。方法采集吉首旗帜山松树林的土壤样品,通过富集培养和刚果红平板染色法筛选分离纤维素降解细菌;通过形态观察、生理生化特性检测和基于16S rRNA基因序列的系统发育分析对分离的菌株进行初步鉴定。利用单因素实验对产纤维素酶条件进行优化。结果分离获得1株高活性纤维素降解细菌JDM11,初步鉴定其为Bacillus velezensis;菌株JMD11产纤维素酶最佳培养温度、最适初始pH和培养时间分别为28℃、7.0～7.5和32h,在该条件下其滤纸酶(FPase)和羧甲基纤维素酶(CMCase)活力分别为260.32U/ml和651.75U/ml。结论菌株JDM11是1株高活性纤维素降解的Bacillus velezensis。     

Isolation and Characterization of Salt-Tolerant Bacterial Strains in Salt-Affected Soils of East Anatolian Region

In the current study, 18 salt-tolerant bacteria were isolated from salt-affected soil in the east Anatolian region. The obtained isolates were identified and characterized by conventional (morphology, physiology, and biochemical tests) and molecular techniques 16 rDNA. Among 18 sequenced isolates, 6 Bacillus, 1 Halomonas, 2 Halobacillus, 2 Zhihengliuella, 2 Oceanobacillus, 1 Virgibacillus, 1 Staphylococcus, 1 Thalassobacillus, 1 Exiguobacterium were identified with high similarity to previously identified strains in the literature. According to the results obtained, investigated bacterial strains have high salt tolerance and significant enzyme activities that can improve soil nutrient cycling and fertility. To the best of our knowledge, the current article is the first study in evaluation and diversity of potential halophlic/halotolerant bacterial strains in salt-affected soils of the east Anatolian region.     

Isolation and Characterization of Thermophilic Bacterial Strains with Inulinase Activity

Nine bacterial strains growing on inulin as the sole carbon and energy source were isolated from soil samples by enrichment culture on a mineral medium. Four of the strains were thermophilic and belong to the genus Bacillus. The thermophilic strains synthesized a β-fructosidase that was active on both inulin and sucrose. The presence of inulin in the culture medium is necessary for enzyme synthesis. Most of the activity on inulin was recovered in the culture medium, and the enzyme was synthesized during cell growth.     

一株产漆酶细菌的分离鉴定及酶学性质研究

[目的]分离获得产漆酶的细菌菌株,研究漆酶的酶学性质并应用于染料脱色.[方法]利用含铜的富集培养基筛选产漆酶细菌;通过形态特征、生理生化试验及16SrDNA序列分析等方法进行鉴定;以丁香醛连氮为底物测定漆酶的酶学性质;通过测定染料在最大吸收波长下吸光值的变化评价漆酶对染料的脱色效果.[结果]从森林土壤中筛选到一株漆酶高产菌株LS05,初步鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens);菌株LS05的芽孢漆酶以丁香醛连氮为底物的最适pH为6.6,最适温度为70℃;该酶具有较好的稳定性,经70℃处理10h或在pH 9.0条件下放置10d后可保留活性.对抑制剂SDS和EDTA具有一定的抗性,在碱性条件下可有效脱色不同的工业染料,RB亮蓝、活性黑和靛红1h内的脱色率达93％以上.[结论]Bacillus amyloliquefaciens LS05的芽孢漆酶在高温和碱性条件下稳定性强,相对于真菌漆酶具有更好的工业应用特性,可有效用于工业染料废水的处理.