Screening and field application of microbial-flooding activator systems

This study aims to further enhance the oil recovery of reservoirs in the Zhong-2 Block of the Gudao Oilfield by identifying the most effective microbial-flooding activator systems and applying them in the field.We began by analyzing the structure of the reservoirs'endogenous microbial communities to understand the potential impact of microbial flooding.This was followed by determining commonly used activator systems based on their abilities to stimulate oil-displacement functional bacteria.Through laboratory experiments on oil displacement efficiency and sweep characteristics,we determined the optimal activator injection method(injection ratio)and the requisite bacterial concentration for maximal microbial-flooding efficacy.Finally,we selected the optimal activator systems and applied them to field tests.Our findings suggest the target block is highly receptive to microbial-flooding.In terms of performance,the activator systems ranked as No.3>No.4>No.1>No.2.Interestingly,a deep activator system,when compared to the top-performing No.3 system,exhibited a higher bacterial concentration peak and longer peaking duration.Optimal oil displacement effects were observed at a 1:4 vol ratio between the No.3 activator and deep activator systems,with bacterial concentrations of up to 106 cells/mL or above.Field tests with the selected activator systems,following a specific injection protocol,demonstrated a notable increase in oil production and a reduction in water cut.

Screening of One Microbial Flocculant for Treatment of Methyl Orange Wastewater and its Decolorization Effect

[Objective] To screen out a microbial flocculant with good decolorization effect on methyl orange wastewater,and study the effect of different cultural conditions on decolorization effect of methyl orange.[Method] Absorbance of methyl orange solution before and after decolorization was determined by spectrophotometer,and the decolorization rate was calculated to compare the effects of different cultural conditions on removal rate of methyl orange.[Result]An optimal actinomycete stain（F-1-2） was screened out,and the best cultural condition was as follows：with sucrose as carbon source and NaNO3 as nitrogen source,cultured in constant temperature oscillator at 150 r/min,30℃ for 72 h.Under the optimal condition,the removal rate against methyl orange could reach 68.4%.[Conclusion]Different culture conditions have great impact on decolorization effect of strain.

Screening of Bioflocculant-Producing Strains and Characteristics of Microbial Flocculation

A high effective bioflocculant-producing strain named LB1 was isolated and screened from the leachate by routine micro- method. The strain was identified as genus Pseudomonas according to the morphologic and physiological-biochemical characteristics of the strain. The biological characteristics of the microbial flocculants produced by LB1 were investigated. The results show that the optimal production period of microbial flocculant using LB1 is 96 h; and the products, found in the fermentation liquor, comprise the extracellular organic matter （EOM） of LB1 generated during LB1 growth and the secondary metabolites in the anaphase of LB1. Meanwhile, the mycelia can improve the performance of the microbial flocculants. Because heat has a greater influence on the active substance in the microbial flocculants than other factors, the activity of the flocculants decreases with increasing temperature and the time of heating. The flocculants can flocculate mud-containing and melanin-containing wastewater effectively with a flocculation ratio of 85.1% and 92.2%, respectively. The optimal heating temperature varies from 20 to 45 ℃. When flocculating the two wastewater, the flocculating activity of the flocculants is above 57.7% and 70.9%, respectively, in a wide pH range from 3 to 11.

Security evaluation of compounded microbial flocculant

A new kind of compounded microbial flocculant (CMBF) for water and wastewater treatment has been developed through biological technology. In order to discuss its biological security, four groups of experiments, rat acute toxicity test via mouth, salmonella assay in vitro, mouse micronucleus in vivo test and teratogenesis test were conducted to evaluate its general toxicity, genotoxicity and generative toxicity. The experimental results showed that this type of compounded microbial flocculant was a substantial non-toxic substance based on the fact that LD50 value was over 10 mg/kg. The results from salmonella in vivo test and mouse micronucleus in vivo test revealed that the compounded microbial flocculant is a genetically non-toxic substance. Furthermore, compounded microbial flocculant has little effect on the growth of all the rats, and any morphologic abnormal phenomenon hasn’t appeared.

Experimental research on Phanerochaete chrysosporium as coal microbial flocculant

The flocculation effect of the Phanerochaete chrysosporium on the coal slurry were studied by orthogonal experimental method in this study.The results of research show that the P.chrysosporium has a good effect on flocculating coal slurry.The optimum combination of the experimental is the P.chrysosporium,which is cultured in 2 days,mixed with 2 mL coagulant and 2 mL broth.The flocculant is a broken liquid with pH value of 6.The hightest flocculation ratio is 93.5%.The result of FTIR shows that the biological extraction of P.chrysosporium contains a lot of acidic polysaccharides that has the effect on flocculation.Microbial flocculant molecules and particles of coal slurry could be flocculated by‘‘absorption bridge’’.

Application Research Status and Development Prospect of Microbial Flocculant

Microbial flocculant （MBF） is a kind of novel flocculant, which is widely used for the food industry, highly concentrated organic waste water treatment and the urban water supply technology. Due to its characteristics of superior flocculation effect, without secondary pollution to the environment and being easily degraded, MBF has been emerging as a hotspot of water treatment research in recent years. In this paper, the latest progress of the preparation of MBFs and the flocculating mechanism were presented. The practical application research of MBFs for water treatment was reviewed. Finally, suggestions and development prospect of research on MBFs were discussed.

Screening and flocculating properties of bioflocculant-producing microorganisms

Screening of bioflocculant-producing microorganisms was carded out. A strain that secreted excellent bioflocculant was isolated from municipal sewage using the spread plate technique, identified as Klebsiella sp. by the analytical profile index （API） identification system, and named A9. Several important factors that had an effect on A9＇s bioflocculant-producing and flocculating activity were studied. A total of 4 g/L Kaolin suspension was used to measure the flocculating activity of the bioflocculant from A9. It was found that maltose and urea were Ag＇s best carbon and nitrogen sources, respectively, and the flocculating activity of the flocculating agent from A9 was markedly increased by the addition of trivalent cations such as Fe^3＋ and Al^3＋; furthermore, the bioflocculant produced by A9 was most effective when the pH value was 6.0.

Screening of flocculant-producing microorganisms and flocculating activity

A strain saccharomycete STSM-1 with high flocculanting activity was isolated from activated sludge with conventional methods. The high production rate and the low cost STSM-1 medium was obtained by selecting different kinds of media, carbon source, nitrogen source and inorganic salt ion. The best flocculant-producing conditions were found by changing medium initial pH, culture temperature and ventilation flow. The best flocculating effect was obtained by changing positive ion types, density and concentration of flocculant.

Non-parallelism between the effect of microbial flocculants on sewerage disposal and the flocculation rate

This paper dealt with non-parallelism between the effect of microbial flocculant (MBF) on sewerage disposal and the flocculation rate, the high flocculation rate doesn’t mean the fine disposal effectiveness, and revealed the problem encountered when the exclusive parameter―flocculation rate is used to evaluate the effect of MBF on sewerage disposal. The results showed that MBF made from different carbon sources have some influence on the effectiveness of sewerage disposal; flocculation rate cannot authentically reflect the status of sewerage disposal. When the exclusive parameter―flocculation rate is used to evaluate the effect of MBF on sewerage disposal, it would be exaggerated, especially in disposing COD-low sewerage. The authors considered that when flocculation rate is used to evaluate the effect of MBF on sewerage disposal, it is better to take COD-removal rate into account.

Progress of Microbial Enhanced Oil Recovery in Laboratory Investigation

This paper describes a simple, easy process for screening microorganisms, and introduces a laboratory simulation device and process of microbial enhanced oil recovery (MEOR) , which is a necessary research step for trial in oilfields. The MEOR mechanism and the influence of adsorption, diffusion, metabolism, nutrition, porosity, and permeability are analyzed. The research indicates that different microbes have different efficiencies in EOR and that different culture types play different roles in EOR. The effect of syrup is better than that of glucose, and larger porosity is favorable to the reproduction and growth of microbes, thereby improving the oil recovery. Using crude oil as a single carbon source is more appreciable because of the decrease in cost of oil recovery. At the end of this paper, the development of polymerase chain reaction (PCR) for the future is discussed.

Isolation and Identification of a Flocculant Producing Strain TS-1

[Objective] The purpose was to select out and identify a flocculant producing strain which could produce high active flocculant.[Method] The strain producing high active flocculant was isolated out and purified through medium culture and the selected strain was identified through observing its culture characters and determining its physiological and biochemical property.[Result] Fourteen strains of bacteria with flocculant producing function were isolated from tested soil samples through isolation,purification and preliminary screening using dilution-spread plate method and plate streaking method.Five strains of flocculant producing bacteria showing higher flocculation activity were selected out after second screening and their flocculation rates were higher than 70%;the flocculation activity of one strain among them was still stable after multiple subculturings,its flocculation rate was always above 90% and it was marked as TS-1.TS-1 was encapsulated Gram-positive bacillus and there was no lipid in it,such as poly-β-hydroxybutyric acid.TS-1 was Bacillus amyloliquefaciens,so it was named Bacillus TS-1.[Conclusion] The strain selected out in this experiment could be used in the flocculation and biochemical treatment of wastewater from starch industry.

Screening and Identification of Strains Converting Trans-anethole to Anisic Acid

[Objectives] This study was conducted to isolate and screen the bacteria that can convert trans-anethole to anisic acid from star anise and its environmental samples, and identify the bacteria. [Methods] According to the traditional microbial culture method, with trans-anethole as the sole carbon source, through enrichment culture and separation and purification, preliminary screening by thin layer chromatography and re-screening by high-performance liquid chromatography, strains that degraded trans-anethole to produce anisic acid were obtained, and 16 S rDNA sequencing and phylogenetic tree construction were performed for genetic analysis. [Results] Eleven strains that degraded trans-anethole to produce anisic acid were obtained, among which strain NT2 that produced anisic acid with a relatively high efficiency was initially identified as Pseudomonas sp. The strain’s trans-anethole degradation rate was 45.41%, and the molar production rate and cumulative concentration of anisic acid were 21.80% and 1.96 g/L, respectively. [Conclusions] Strain NT2 has a strong ability to degrade trans-anethole to produce anisic acid, and can enrich strain resources for degradation of trans-anethole to anisic acid through microbial conversion.

东北酸菜发酵乳酸菌的筛选及评价

为获得适用东北酸菜发酵的乳酸菌菌株,该研究通过对来源于发酵蔬菜10株乳酸菌的生长性能和发酵特性进行评价,发现植物乳植杆菌YJ132和肠膜明串珠菌肠膜亚种UA107显示出显著的发酵潜力:培养16 h后,发酵液OD600值分别升高至1.707和1.672,而pH值分别降低至3.93和3.88,培养24 h后,可滴定酸度(TA)含量为65.62 g/L和63.21 g/L,对亚硝酸盐的降解率达到96.41%和95.78%,在5%NaCl溶液中培养24 h后OD600值仍达到1.51以上,综合评价菌株YJ132和UA107可作为发酵菌种用于东北酸菜发酵。利用YJ132和UA107制备酸菜,发酵末期酸菜样品中TA含量为35.96 g/L,还原糖和可溶性蛋白含量降低至6.51 mg/g和111.27μg/g,并在发酵初期显著降低亚硝酸盐的含量,与对照组相比差异极显著(P<0.01)。接种乳酸菌可抑制有害菌肠杆菌的增殖(P<0.01),增加酸菜中微生物群落的多样性,同时乳杆菌在发酵中后期始终是优势菌群,由此推断YJ132和UA107是通过调控微生物群落来提升东北酸菜的品质。综上所述,YJ132和UA107是适用于东北酸菜发酵的优良乳酸菌菌种。

新疆传统发酵乳制品调研及其发酵微生物种质资源分析

为挖掘新疆传统发酵乳制品的微生物菌种资源,对不同地区传统发酵乳的制作方式及其发酵微生物进行了调研。采集了全疆12个地州及乌鲁木齐周边共45个县165个乡村483份家庭作坊生产的传统发酵乳制品,并对其进行了发酵微生物筛选。从采集的不涉及任何商品发酵剂的新疆传统发酵乳中,共筛选出497株乳酸菌和364株酵母菌,并首次发现了假肠膜明串珠菌、汉逊德巴利酵母和巴氏醋杆菌等菌。此研究成果可为开发新疆传统发酵乳制品的优质菌种资源提供基础。

ARTP-MMC高通量筛选耐木质纤维素预处理抑制物酿酒酵母的研究

为了提升酿酒酵母(Saccharomyces cerevisiae)对木质纤维素预处理所产生的甲酸、糠醛、5-羟甲基糠醛等抑制物的耐受性,保障酿酒酵母产乙醇能力不受影响,该文以安琪超级酿酒酵母为出发菌株,研究了一种常温常压等离子体(ARTP)诱变和微液滴细胞培养(MMC)相结合的适应性进化和高通量筛选耐木质纤维素预处理抑制物的酿酒酵母方法,获得抗性强的酿酒酵母优势突变株,并评价其耐抑制物、耐高温和产乙醇能力。结果表明,菌株最佳诱变条件为:诱变功率110 W,诱变时间140 s,培养12 h,微液滴微生物培养的适应性进化复合抑制剂梯度组合为CI4~CI6,经过高通量筛选获得最佳的突变株M8;该菌株可耐受体积分数16%乙醇,具有较好的耐高温特性,55℃热激5 min可正常生长;经过10 L发酵罐培养,其最大乙醇产量为56.29 g/L,糖醇转化率为0.49 g/g,达到理论值的96.67%。该研究对木质纤维素高质化利用提供了优良的酿酒酵母,对推动纤维素乙醇具有重要意义。

文库构建与基因簇靶向筛选驱动的微生物天然产物高效发现

微生物天然产物作为小分子药物的主要来源,已被广泛应用于医药与农业等领域。随着全球抗生素耐药性与其他公共健康问题的加剧,新结构、新靶点微生物天然产物发现迫在眉睫。大规模(宏)基因组测序揭示微生物蕴含了巨大的生物合成潜力,相继催生了多种不同类型的天然产物挖掘策略。然而,目前仍然缺乏将天然产物合成基因簇与编码产物快速关联的高效方案。近年来,(宏)基因组文库构建在获取批量天然产物合成基因簇方面展现出明显优势,结合高效的基因簇靶向筛选方法,显著加速了新结构天然产物系统发现。本文综述了三类基于(宏)基因组文库构建与靶向筛选驱动天然产物创新发现的策略,主要从克隆载体类型、文库构建方式、基因簇靶向筛选方法等角度进行了阐述,并对Cosmid/Fosmid文库、BAC/PAC文库、FAC/YAC文库等不同文库类型的优缺点及应用范围进行了对比,最后对这些策略的发展前景进行了展望。未来,基于文库构建与基因簇靶向筛选策略将极大驱动不同生境微生物来源的活性天然产物挖掘,预期大量新靶点、新结构天然产物将不断涌现。

复合菌群构建及其石油烃降解特性

为获得高效降解石油烃复合菌群,对实验室保存的菌株进行石油烃降解效果及原油4组分降解能力分析研究,筛选出了4株菌(A1、A3、Y3、Y4),对其进行ITS和16S rRNA分子鉴定,确认4株菌的分类信息,并优化高效降解菌株的复配方式。结果显示:A1属于不动杆菌属(Acinetobacter)、A3属于芽胞杆菌属(Bacillus)、Y3和Y4均为假丝酵母菌属(Candida);A1、A3、Y3、Y4对石油烃的降解率分别为42.27%、40.95%、62.02%、69.84%;其中Y4对烷烃和芳烃降解效果最佳,降解率分别为65.71%和23.69%,沥青质降解效果最好的是A1,胶质降解效果最好的是Y3,降解率分别为22.74%和21.22%,A3对各组分降解能力均衡;A1、A3、Y4复合的菌群降解效果最佳,其降解率高达83.11%,相较于单一菌株提高了1.19—2.03倍;A1、A3、Y4的最佳接种量比例为0.9∶0.9∶1.5,其降解率可达88.34%。该研究成功筛选出一种新的高效降解石油烃的菌群,对进一步研究和应用于石油污染治理具有重要指导意义。

高效絮凝菌EbZL-1的筛选鉴定及采收微藻效果评价

从东华大学镜月湖底淤泥样本中筛选到一株高效絮凝菌,采用16S rDNA测序和菌种鉴定试剂盒确定该菌株属于肠杆菌属(Enterobacter),命名为EbZL-1。以高岭土悬液为待絮凝标准液,通过单因素试验和响应面法探究絮凝菌EbZL-1在不同影响因素下的絮凝能力。研究结果表明:以11.69 g/L葡萄糖为碳源,1.04 g/L硝酸铵为氮源,培养基pH=7.8,摇床转速为160 r/min,菌株接种量为45μL(1.2×10^(5)CFU/mL),培养12 h,EbZL-1达到对数生长期;Ca^(2+)作助凝剂,高岭土悬液pH=7.0时,10 min内EbZL-1絮凝率可达96.6%,优于商用絮凝剂聚合氯化铝(120 min,95.0%)。进一步探究菌株絮凝机制,结果表明EbZL-1通过菌体自身紧密吸附待絮凝物实现大颗粒快速沉降。利用EbZL-1沉降小球藻,5 min内其絮凝率高于95%,油镜观察絮凝后小球藻,其胞体未受损。与现有絮凝菌比较,EbZL-1在广泛的pH范围(pH=5~10)内,均可快速沉降微藻,在微藻采收工艺中具有应用前景。EbZL-1絮凝菌不仅有望提升微藻采收效率,且在污水处理等方面也有应用价值,值得进一步开发。

氮高效转化菌筛选及其堆肥应用

旨在筛选氮高效转化菌株并验证其在鸡粪堆肥过程中的效果,为国内畜禽粪污资源化利用与发展提供菌种资源和理论支持。以采集自不同区域的鸡粪和土壤样品为试材,用平板涂布法分离纯化菌株,采用氨氮纳氏比色法和紫外分光光度法检测菌株氮转化能力,并制备微生物菌剂应用于堆肥反应。结果表明:从样品中分离筛选出1株氮高效转化菌,鉴定为布鲁氏杆菌(Brucella tritici NC14)。选择生物炭作为最佳载体制备微生物菌剂并进行堆肥应用。在鸡粪堆肥试验中,施用微生物菌剂能够有效抑制42.3%NH_(3)的释放,减少NH_(4)^(+)-N含量39.78%并增加NO_(3)^(-)-N含量52.3%。研究表明,菌株NC14具有氮高效转化能力且有良好的应用潜力。

浓缩苹果汁中嗜酸耐热菌的分离鉴定及菌群特性研究

为了解和控制浓缩苹果汁中的嗜酸耐热菌,从胀袋浓缩苹果汁中筛选、分离、纯化得到了1株嗜酸耐热菌,并进行菌种鉴定及特性研究。通过菌落形态、显微形态和16S rDNA基因测序以及建立系统发育树分析,初步确定该分离菌与Aiyclobacillus acidoterrestris ATCC 49025标准菌同源度>99.51%,确定该分离菌为酸土脂环酸芽孢杆菌(A.acidoterrestris)。通过热和酸碱处理考察该菌株的热稳定性和酸碱稳定性,在单因素试验的基础上进行正交试验。结果表明,在最优灭菌参数为pH 6.0,105℃热处理20 min的条件下,平板生长菌落数为0,说明该提取条件具有较好的合理性和可靠性,为浓缩苹果汁中嗜酸耐热菌的控制提供了理论依据。