Hydrogen Production with High Evolution Rate and High Yield by Immobilized Cells of Hydrogen-producing Bacteria Strain B49 in a Column Reactor

To improve the hydrogen evolution rate in continuous hydrogen production of a fermentative hydrogen-producing bacteria strain B49 (AF481148 in EMBL), 4% immobilized cells by polyvinyl alcohol-boric acid method, with the addition of a small amount of calcium alginate in a column reactor obtain hydrogen yield of 2.31 mol H2/mol glucose and hydrogen evolution rate of 1435.4 ml/L culture&middoth respectively at medium retention time of 2 h with a medium containing l0 g glucose/L. As the cell density in gel beads is increased to 8%, hydrogen yield and hydrogen evolution rate for l0 g glucose/L are 2.34 mol H2/mol glucose and 2912.4 ml/L culture &middot h respectively at medium retention time of 1 h, and for molasses wastewater COD of 7505.9 mg/L hydrogen production potential of 205.6 ml/g COD and hydrogen evolution rate of 2057.7 ml/L culture&middoth at hydraulic retention time of 0.75 h are observed. In the continuous culture pH value keeps around 3.9 by self regulation.

Isolation and identification of a bacteria strain Enterobacter cloacae I7 for degradation of hydrolyzed polyacrylamide

A bacteria strain for the degradation of hydrolyzed polyacrylamide （HPAM） was isolated from a curing pot in HPAM distribution station of Daqing Oilfield using Hungate anaerobic technique. The isolate was investigated from morphological, physiological, biochemical and molecular characterization. It is a Gram-negative, shortbacillus, non-spore-forming anaerobic bacteria with an optimum growth at 8.0 pH at 40℃. It can reduce sulfate to I-I2S. Alignment of 16S ribosomal DNA and 16S-23S ribosomal DNA intergenic spacer sequences suggests that this isolate is closely related to the Enterobacter cloacae. The isolate is identified as a new strain belonging to Enterobacter genus, temporarily named as Enterobacter cloacae 17. Analysis results of infrared spectroscopy （IR） show that the bacteria can use HPAM as the only carbon source, change the structure of HPAM polymer surface, and realize the hydrolysis of amide to carboxyl group by hydrolysis mechanism. It can degrade the side chain and change some functional groups, which obviously decreases the viscosity. GC-MS analysis indicates that the determined low-molecular weight degradation products of HPAM are polyacrylamide fragments with duplet bond, epoxy as well as carbonyl group, but most of them are acrylamide oligomer derivatives.

Bio-control of Some Food-Borne Pathogenic Bacteria by Bacteriophage

In recent years, researchers tended to bring new alternative to biological protective systems used in conservation of food and production of safe food. Use of bacteriophage against to pathogen bacteria in food was the most hopeful system in these methods about bio-control. Controls of bacteriophage for each pathogen species and subspecies and determination of phage-host originality are important because efficient bio-control was achieved. Researches concentrated on some food-borne pathogen bacteria such as E. coli O157：H7, Campylobacter, Salmonella and Listeria. In a consequence of these studies made as in vitro and in vivo, first commercial production of phage which will be used in foods was made in Netherlands. Also, it has been informed that use of phage is cost-efficient alternative as compared with other preservatives. This review, discussed application of bacteriophages as bio-control agents in food and advantages and disadvantages about uses of bacteriophages by taking into account antimicrobial characteristics of them.

Screening of Antagonistic Bacteria against Phytophthora infestans and Its Inhibition Effect

[ Objective ] The paper was to screen bacterial strain with significant antagonistic effect against Phytophthora infestans, so as to provide basis for further development and utilization of antagonistic bacteria to inhibit P. infestans and control potato late bright. [ Method] Plate dual culture and filter paper method were used to determine the inhibition effect of strains in vivo, fermentation broth and bacterial liquid of 61 strains against P. infestans and the resistance-induction effect of SR13-2 strain. [ Result] The inhibition rate of 24 strains among 61 tested strains against mycelial growth of P. infestans was greater than 60%, and the inhibi- tion effect of HT-6 strain was the strongest with the inhibition rate of 89.92%. However, fermentation broth of all tested strains had no significant inhibition effect against P. infestans, while the inhibition effect of bacterial liquid of most strains was significantly higher than strain in vivo; the inhibition effect of $34-1 strain was the strongest with inhibition rate of 91.50%. The bacterial liquid of SR13-2 strain was found to have significant resistance-induction effect with protective rate of 60%. [ Conclusion] The inhibition effect of strains in vivo and fermentation broth of antagonistic strains S34-1 and SR13-2 had no relationship with each other, while bacterial liquid had great application potential in controlling potato late bright.

Isolation and Phylogenetic Analysis of Plant Pathogen-Inhibiting Strains from Southern Ocean

[Objective] The aim was to isolate the strains resistant to plant pathogenic fungi from Southern Ocean and study their phylogenetic relationship and antimicrobial spectrum. [Method] Agar diffusion method was adopted to screen antimicrobial strains and determine the antimicrobial spectrum. Phylogenetic relationship of the strains was analyzed by neighbor-joining method of the Mega 4.0 software. [Result] Twenty antimicrobial strains were screened from seawater of Southern Ocean collected during the 27^th Chinese Antarctic Scientific Expedition. Molecular identification and phyloge- netic analysis indicated that two antimicrobial strains were members of Pseu- domonas, two strains were members of Psychrobacter, and the other 16 trains were members of Pseudoalteromonas. The antimicrobial spectrum of four strains which had higher antimicrobial activity indicated that the strains 312, 83-1 and 195 greatly inhibited the growth of Fusarium oxysporum, Rhizoctonia solani K（Jhn, Phytophthora capsici Leonian, Verticillium dahliae, Alternaria solani, Thanatephoru scucumeris and Phomopsis asparagi （Sacc）; strain 312-1 had obvious antimicrobial effect on the six of the plant pathogens except R. solani. [Conclusion] Four strains which had higher antimicrobial effect were obtained and should be further studied for development and application.

Screening and characterization of extracelluar L-asparaginase producing Bacillus subtilis strain hswx88,isolated from Taptapani hotspring of odisha,India

Objective:To screen and isolate an eco-friendly,u thermophilic and potent L-asparaginase producing bacterium,with novel immunological properties that may obviates hypersensitivity reactions.Methods:In the present study baclerial strain isolated for extracellular L-asparaginase production from hotspring,identified by morphological,biochemical and physiological tests followed by t6S rDNA technology and the L-asparaginase production ability was tested by both semi quantitative and quantitative enzymatic assay.Result:The bacterial strain was identified as Bacillus sublilis strain hswx88(GenBank Accession Number JQ237656.1).The extracellular enzyme yielding capacity isolate Bacillus subtilis strain hswx88(23.8 IU/mL)was found to be 1.7 and 14.5 limes higher than the reference organism Pectobacterium carotovorum MTCC 1428(14.2 IU/mL)and Bacillus sp.BCCS 034(1.64 IU/mL).Conclusion:The isolate is eco-friendly and useful to produce bulk quantity of extracellular,thermophilic L-asparaginase for the treatment of various tumor cases and for preparation of acrylamide free fry food preparation.

Isolation of Soil Bacteria Species for Degrading Dibenzothiophene

Five bacterial strains, which are able to grow and to disintegratedibenzothiophene (DBT) and diben- zothiophene sulfone (DBTO_2) infossil fuels, are isolated. Analysis of products of DBT metabolizedby these strains shows that different bacteria strains oxidized DBTby different pathways. The isolated strains R-6, $-16, $-9 and R-8can metabolize DBT to DBTO_2 and 3-hydroxybiphenyl (HBP), which areidentified as Bacillus brevis, Bacillus Sphaericus, Nocardiagloberula and Pseudomonas delafieldii respectively.

Isolation and characteristics of Arthrobacter sp.strain CW-1 for biodegradation of PAEs

Isolation of new bacterial strains and recognition of their metabolic activities are highly desirable for sustainability of natural ecosystems. Biodegradation of dimethyl phthalate （DMP） under anoxic conditions has been shown to occur as a series of sequential steps using strain CW-1 isolated from digested sludge of Sibao Wastewater Treatment Plant in Hangzhou, China. The microbial colony on LB medium was yellowish, 3-5 mm in diameter, convex in the center, and embedded in mucous externally. The individual cells of strain CW-1 are irregular rods, measuring （0.6-0.7）×（0.9-1.0） pm, V-shaped, with clubbed ends, Gram positive and without any filaments. 16S rDNA （ 1438 bp） sequence analysis showed that the strain was related to Arthrobacter sp. CW-1 and can degrade PAEs utilizing nitrate as electron acceptor, but cannot mineralize DMP completely. The degradation pathway was recommended as： dimethyl phthalate （DMP）→monomethyl phthalate （MMP）--,phthalic acid （PA）. DMP biodegradation was a first order reaction with degradation rate constant of 0.3033 d 1 and half-life 2.25 d. The DMP conversion to PA by CW-1 could be described by using sequential kinetic model.

苹果酵素混菌发酵工艺优化

该研究以费比恩塞伯林德纳氏酵母(Cyberlindnera fabianii)、酿酒酵母(Saccharomyces cerevisiae)、戊糖乳植物杆菌(Lactiplantibacillus pentosus)、肠膜明串珠菌(Leuconostoc mesenteroides)为发酵菌种制备苹果酵素,研究不同菌种组合发酵对苹果酵素可溶性固形物、pH、总酸、还原力、超氧化歧化酶(SOD)活性和感官评分的影响,并采用单因素和响应面试验对苹果酵素酵母菌发酵阶段和乳酸菌发酵阶段的工艺进行优化。结果表明,多菌种发酵苹果酵素酵母菌发酵阶段最佳工艺条件为费比恩塞伯林德纳氏酵母∶酿酒酵母1∶0.2,接种量3.3%,发酵温度23℃,初始pH4.7,乳酸菌发酵阶段最佳工艺条件为戊糖乳植物杆菌∶肠膜明串珠菌1∶1,接种量5.2%,发酵温度33℃,初始pH 5.1,在此优化条件下,多菌种发酵苹果酵素的感官评分为9.82,SOD活性为55.83 U/m L、总酸含量为4.96 g/L、还原力为6.83、可溶性固形物含量3.14°Bx、p H为2.96。该研究为苹果酵素产品工业化产生提供了理论依据。

一株旱稻联合固氮菌株的分离鉴定及促生作用

[目的]旱稻是一种重要的种质资源,对成熟期旱稻根系内生固氮菌进行筛选与鉴定,以获得对旱稻有较好促生作用的菌株。[方法]采用联合固氮固体培养基培养方法,从成熟期旱稻根系中分离出内生固氮菌,通过扩增固氮酶nifH基因和16S rRNA基因进行分子鉴定和系统进化分析生化指标测定和形态学鉴定;采用透明圈法进行溶磷、产铁载体能力验证;以褐球固氮菌为阳性对照,利用ELISA测定试剂盒测定菌株分泌固氮酶活性、1-氨基环丙烷-1-羧酸(ACC)脱氨酶,采用Salkowski比色法测定生长素(IAA)含量,并研究其生长特征。将分离的固氮菌株以1%浓度(约8×10~7CFU/mL)浸泡旱稻谷种进行催芽,研究其促生效果。[结果]分离的菌株URR45为固氮菌,属于嗜温型微生物,最适生长温度为32~50℃,最适pH为6.0~6.5,不耐盐。其分泌的固氮酶含量为220.15 U/L,ACC含量为898.69 ng/mL,生长素含量为14.91 mg/L,固氮酶含量和ACC含量显著高于对照组褐球固氮菌。该菌株能够利用葡萄糖、麦芽糖等碳源,属于发酵型细菌,具有水解明胶、溶磷和产铁载体特性。该菌株经16S rRNA基因测序后通过NCBI BLAST比对,鉴定为Herbaspirillum seropedicae,隶属于Pseudomonadota门、Betaproteobacteria纲、Burkholderiale目、Oxalobacteraceae科、Herbaspirillum属,革兰氏染色呈阴性。促生试验结果表明,在主根长度、侧根长度以及测根数方面均显著高于对照组。[结论]该菌株对旱稻幼苗具有一定的促生作用,在农业上产上可作为功能性内生固氮菌开发利用。

一株高效解钾菌的筛选、鉴定及培养条件的优化

以黑土水稻田中解钾菌为研究目标,共分离筛选出5株解钾菌,通过其形态特征以及测定菌株解钾能力筛选出1株高效解钾菌株S1。利用16S rDNA鉴定S1的种属,并通过单因素试验和正交试验优化该菌株的培养条件。结果表明,分离筛选得到的5株解钾菌均能有效分解钾长石,菌株S1解钾能力最强,解钾率为57.03%,发酵液中解钾量为3.852 mg/L,为最优解钾菌。初步鉴定解钾菌S1为伯克霍尔德菌(Burkholderia ambifaria)。经单因素试验和正交试验优化后的培养组分为碳源1.0%甘露醇、氮源1.0%蛋白胨、无机盐0.5%K_(2)HPO_(4),培养条件为温度30℃、时间48 h、培养基装液量(培养瓶250 mL)80 mL、初始pH 6.5、接种量5.0%。

一株苜蓿缩合单宁降解菌的筛选及其鉴定

研究旨在筛选鉴定缩合单宁降解菌,为缩合单宁生物降解提供微生物资源支持,并为扩大紫花苜蓿的利用提供参考。以苜蓿根部土壤为菌源,以缩合单宁为唯一碳源的耐受培养基筛选得到一株降解缩合单宁的菌株,对其进行形态学观察、生理生化特征测定、16S rDNA基因序列比对,测定生长曲线,观察菌种固态发酵紫花苜蓿的效果。结果显示:确定筛选出的菌株为Klebsiella sp.,命名为DN-2。菌株DN-2在肉汤培养基上约3 h进入对数期,24 h时菌液在600 nm的光密度(OD_(600 nm)值)为2.405;在含有缩合单宁的营养肉汤培养基上约4.5 h进入对数生长期,20 h达最大OD_(600 nm)值2.35,整体表现为菌株生长的迟缓期延长而稳定期缩短。正丁醇盐酸检测结果显示,菌株DN-2生长36 h对菌液中的缩合单宁降解率高达94.2%。DN-2菌株固态发酵苜蓿结果显示,发酵处理5 d时,缩合单宁降解率达59.73%,可见DN-2菌株对苜蓿中缩合单宁具有良好的降解效果。研究表明,菌株DN-2的筛选对于植物来源的缩合单宁的生物降解及微生物资源的开发具有一定的实践意义,并为苜蓿在动物生产中的扩大应用提供参考。

产酸乳酸菌红酸汤发酵研究

采用传统发酵红酸汤分离产酸乳酸菌菌株,开展红酸汤发酵研究。将辣椒和番茄切碎后等量混匀为发酵基质,按照1×10^(6)cfu/g接种产酸乳酸菌菌株到其中。首先采取单菌株发酵实验,挑选发酵风味好的菌株,再开展多菌株组合发酵实验,发酵结束后均记录发酵终点pH及其风味。单菌株发酵得到6株红酸汤发酵风味好的菌株,分别为:ST23-2、ST7-15、ST7-14、ST7-1、ST11-2和ST7-20;多菌株组合发酵风味最佳的是组合3与组合20发酵组;多菌株发酵风味优于单菌株。

芽孢杆菌蛋白酶在食品工业中的应用研究进展

芽孢杆菌蛋白酶是一种重要的微生物源蛋白酶,其种类多样、活性显著、研究较为深入,已被广泛应用于食品行业。本文综述了产蛋白酶芽孢杆菌的筛选、高产蛋白酶菌株的选育与工程菌株的构建、蛋白酶发酵条件的优化,分别以植物蛋白和动物蛋白为作用对象介绍了芽孢杆菌蛋白酶在食品行业中的应用情况,并对将来的研究方向和发展趋势进行了展望,旨在为芽孢杆菌蛋白酶的深入研究和应用提供参考。

苦草附生细菌的分离鉴定及高效功能菌株筛选

为探究沉水植物附生细菌的功能特性,选取苦草(Vallisneria natans)在室内配置模拟污水进行菌群驯化,分离苦草根、叶际附生细菌进行筛选,结合16S rRNA基因序列分析鉴定结果,共分离纯化和保藏172株菌株(分布于5个门、15个目、42个属),其中根际分离菌107株,叶际分离菌65株.将分离得到的5个门、30个属、47个种的82株代表性菌株进行脱氮、解磷释磷、产吲哚乙酸(IAA)和去除有机物功能验证实验.最终筛选到高效氨氮去除菌10株、硝氮去除菌9株、解无机磷菌12株、解有机磷菌11株、产IAA菌11株及去除有机物菌10株.苦草根、叶际可培养微生物多样性较为丰富,该研究中筛选到的高效功能菌丰富了对苦草附生微生物资源的认识,为沉水植物合成菌群的研制和应用奠定基础.

番茄青枯病拮抗菌的筛选及防治效果

为了筛选出具有抑制青枯雷尔氏菌作用的拮抗菌,采用形态指标、生理生化特征以及16S rRNA序列分析等方法对菌株进行了研究,并且通过阴性对照(CK)、番茄青枯病菌阳性胁迫处理(RB)和拮抗菌K+番茄青枯病菌处理(KRB)3个盆栽番茄土壤样品进行了防卫反应基因的表达研究.结果表明,拮抗菌K5菌落呈乳白色且表面光滑,经革兰氏染色为阳性,初步确定为芽孢杆菌,通过分子鉴定后确定为贝莱斯芽孢杆菌;番茄青枯病的盆栽防治效果达到23.20%,K5菌株在接种48 h后能诱导番茄根部抗病基因表达,CTR、ETR基因的表达量提高,表明K5通过植物抗病相关基因的表达,能诱导植物产生抗病性,并能有效地抑制青枯病菌的繁殖,从而达到防治青枯病的作用.

耐盐碱性蛋白酶菌株LK-3的筛选及酶学性质

为了寻找产碱性蛋白酶活性高且稳定性良好的野生菌株,作者从上海临港区域的东海海水中筛选出一株高产稳定且耐盐的产碱性蛋白酶菌株。对该菌株的形态学特性、生理特性以及16S rDNA基因序列进行测序和分析,确定该菌株为同温层芽孢杆菌(Bacillus stratosphericus),并命名为B. stratosphericus LK-3。酶学性质研究结果显示,该酶的最适作用条件为温度35℃、p H 8.5、最适接种体积分数7%,该酶在上述条件下发酵72 h的酶活力为(581.74±0.81) U/mL。此外该酶具有较好的耐盐性,即使在40 g/dL的高饱和盐质量浓度下仍然保持22.03%的相对原始酶活力。蛋白酶的耐盐性是一个有价值的特性,可将其纯化后作为洗涤剂的生物添加剂应用于工业生产。

两株鱼源降脂乳酸菌的分离、体外筛选及分子鉴定

脂肪肝病是我国人工养殖鱼类中常见的营养性疾病,对水产养殖业造成很大的负面影响。为了筛选具有降脂作用的潜在乳酸菌,利用MRS琼脂培养基,从健康褐篮子鱼(Siganus fuscescens)和卵形鲳鲹(Trachinotus ovatus)肠道中分离得到52株乳酸菌。测定这些菌株的溶血性后得到35株不溶血乳酸菌菌株。经降脂活性复筛(测定菌株体外降胆固醇能力、体外降三酰甘油能力)后从中筛选得到2株具有降脂能力的潜在益生菌,随后测定了这2株菌株对人工模拟胃液、人工模拟肠液的耐受性、菌株的黏附能力(菌株表面疏水活性和自凝集能力)、胞外酶活性及颉颃病原菌活性,最终获得2株具有较强体外降脂能力的潜在益生菌(LZ8和F2),其中,菌株LZ8分离于褐篮子鱼肠道、F2分离于卵形鲳鲹肠道。经16S rRNA鉴定分别为乳酸乳球菌(Lactococcus lactis)和粪肠球菌(Enterococcus faecalis)。

云南白菜根肿病拮抗菌的筛选及鉴定

【目的】获得对云南白菜根肿病具有高效拮抗作用的微生物菌株,为云南白菜根肿病的生物防治提供潜在的菌种资源。【方法】从云南省曲靖市麒麟区三宝乡大棚白菜根肿病发病严重的地块,采集正常生长或发病较轻的白菜植株及其根际土壤,分离筛选抑菌效果较好的菌株,并对其进行形态特征鉴定、生理生化检测及分子序列分析。【结果】经初步筛选共获得46株细菌。土壤样品中共分离出30株细菌,其中抑制效果最好的是TB⁃7菌株,该菌株对白菜根肿病菌休眠孢子萌发抑制率为76.88%;白菜植株内共分离出16株内生细菌,其中抑制效果最好的是EB⁃15菌株,该菌株对白菜根肿病菌休眠孢子萌发抑制率为67.38%。通过对比分析选择抑菌效果最好的TB⁃7菌株作为目标菌株,经鉴定,TB⁃7菌株为革兰氏阳性芽孢杆菌,菌体菌落较小,颜色淡黄色,表面光滑且扁平,菌体湿润,不透明,边缘规则;生理生化指标检测结果显示,TB⁃7菌株是好氧菌,V⁃P、淀粉水解、pH 5.7,生长3项检测指标均呈阳性,柠檬酸盐、丙酸盐、D⁃木糖、L⁃阿拉伯糖、D⁃甘露醇、明胶液化、7%NaCl生长、硝酸盐还原8项检测指标均呈阴性;16S rDNA扩增产物约为1500 bp,测序结果表明,TB⁃7菌株与坚强芽孢杆菌(Cytobacillus firmus)同源性达到100%,鉴定该菌株为芽孢杆菌属的坚强芽孢杆菌。【结论】通过初步筛选及鉴定,获得1株对白菜根肿病菌休眠孢子抑制率达到76.88%的拮抗菌株,该菌株的获得可为解决云南本地日益严重的白菜根肿病的生物防治奠定基础。

产电微生物对SMFC产电及降解性能的影响

目的在以含油污泥为阳极底泥的沉积型微生物燃料电池(SMFC)体系中,通过改变产电微生物种类和分布方式,探究产电微生物对SMFC产电及降解性能的影响。方法通过采集输出电压、功率密度、表观内阻来检测石油去除率,比较了不同单菌-SMFC、不同混合菌-SMFC的产电性能和降解性能,考查了菌种分布对SMFC性能的影响。结果在单菌-SMFC中,弗氏柠檬酸杆菌-SMFC的产电及降解性能均优于其他5种单菌构筑的SMFC;混合菌-SMFC的产电及降解性能较单菌-SMFC有较大提升,且其中蜡样芽孢杆菌+中间苍白杆菌-SMFC的产电及降解性能最优,输出电压可达到515.30 mV;菌种分布在阳极材料中和阳极底泥中都可以降解含油污泥中的有机物,但是菌种分布在阳极材料中更有利于SMFC产电性能及降解性能的发挥。结论混合菌相对于单菌能够显著提升SMFC的产电及降解性能,而且菌种分布在阳极材料中更有益于SMFC产电性能及降解性能的发挥。