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.

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.

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.

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.

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。

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 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.

Electricity generation by Pseudomonas putida B6-2 in microbial fuel cells using carboxylates and carbohydrate as substrates

Microbial fuel cells(MFCs)employing Pseudomonas putida B6-2(ATCC BAA-2545)as an exoelectrogen have been developed to harness energy from various conventional substrates,such as acetate,lactate,glucose,and fructose.Owing to its metabolic versatility,P.putida B6-2 demonstrates adaptable growth rates on diverse,cost-effective carbon sources within MFCs,exhibiting distinct energy production characteristics.Notably,the anode chamber’s pH rises with carboxylates’(acetate and lactate)consumption and decreases with carbohydrates’(glucose and fructose)utilization.The MFC utilizing fructose as a substrate achieved the highest power density at 411 mW m^(−2).Initial analysis revealed that P.putida B6-2 forms biofilms covered with nanowires,contributing to bioelectricity generation.These microbial nanowires are likely key players in direct extracellular electron transport through physical contact.This study established a robust foundation for producing valuable compounds and bioenergy from common substrates in bioelectrochemical systems(BESs)utilizing P.putida as an exoelectrogen.

Effects of Surfactant on Solubility and Microbial Conversion of Steroid

Enhancing the dispersion and dissolution of substrate particles in substrate water suspension is a feasible way to improve steroid bioconversion. The aim of the present study is to investigate the effects of applying surfactant to microbial conversion system on the dispersion, solubilization and in turn bioconversion of steroid substrate. The model system is hydroxylation of substrate 19α- 17α-epoxy- 4-pregnene- 3.2It-dine by microbial enzymes from Rhizopus nigricanl. The results show that the presence of substrate leads to an increase in critical micelle concentration （ CMC） of surfactant PSE compared with the normal CMC of PSE in aqueous solution. The grinding time during substrate suspension preparation affects the substrate aqueous solubility differently with the varied surfactant concentrations while barely making any difference in substrate solubility in the absence of surfactant. The properly prolonged grinding time can make up for the loss in substrate solubility arising from the reduction in surfactant concentration. The surfactant complexes composed of surfactants PSE and MGE at appropriate ratios are screened out with orthodoxy experiment method. the interaction between PSE and MGE exerts the most prominent effects on substrate bioconversion, and the surfactant complexes show more beneficial effects on steroid bioconversion than the surfactant PSE used alone.

微生物絮凝剂M-25在酱油废水处理中的应用

利用高效絮凝剂产生菌M-25所产生的微生物絮凝剂处理酱油废水,处理结果与Al2(SO4)3和PAM的处理结果作对比。结果表明,微生物絮凝剂M-25单独处理酱油废水的效果优于Al2(SO4)3,与PAM效果接近,而且,所需沉降时间最短,仅为30min。M-25与Al2(SO4)3复配后,可提高处理效率,絮凝率和COD去除率分别达到77.2%和79.8%。

青霉菌HHE-P7利用酱油废水产生微生物絮凝剂的研究

研究了微生物絮凝剂产生菌HHE-P7在酱油废水中产生微生物絮凝剂的絮凝特性。实验表明，酱油废水由于碳源丰富，是一种良好的培养基。HHE-P7菌最佳培养条件为：COD20000mg／L，K2HP041．0g／L，培养3d。最佳絮凝条件为在1L高岭土水中投加10～15mL微生物絮凝剂（MBF7），pH调至9，则絮凝率为90％以上；微生物絮凝荆在水系中主要起吸附架桥的作用。

微生物絮凝剂产生菌NX-2的筛选和合成条件的研究

从土壤中筛选分离到 1株高效絮凝剂产生菌NX 2 ,鉴定为枯草芽孢杆菌 (Bacillussub tilis)。在含谷氨酸和葡萄糖的培养基中培养 ,其发酵产物粘度高 ,对高岭土、活性炭等固体悬浮颗粒具有显著的絮凝作用 ,而缺少谷氨酸和额外碳源则不能产生絮凝活性。NX 2培养并产生絮凝活性的碳源可采用葡萄糖、蔗糖、麦芽糖、甘油、可溶性淀粉和果糖 ,氮源采用酵母膏、蛋白胨等有机氮源或铵盐等无机氮源。通过核磁共振等手段对分离提纯的样品进行结构表征 ,鉴定其为γ 聚谷氨酸。

青霉菌HHE-P7利用桔水培养微生物絮凝剂的研究

研究了微生物絮凝剂产生菌HHE-P7在桔水废水中产生微生物絮凝剂的絮凝特性,实验表明:桔水由于C源丰富,是一种良好的培养基,最佳培养件条为COD=20000 mg/L,投加KHPO 1.0g,培养3天,则絮凝率24为90.50%,采用与马铃薯培养基混合制成的合成培养基絮凝效果好,而且成本最低。

微生物絮凝剂-阳离子型无机微粒体系的混凝脱色研究

从啤酒厂废酵母直接提取微生物絮凝剂,与水合氧化铁微颗粒体系集成应用于混凝脱色,其脱色效果与无机微颗粒体系的电荷密度、微生物絮凝剂剂量有关,提出无机微颗粒与染料集合体的“剩余电荷”的概念解释微生物絮凝剂-阳离子型无机微粒体系的混凝机理。结果显示微生物絮凝剂-水合氧化铁微粒体系混凝脱色在试验范围内均有显著的协同效应,直接黄最高脱色率达到95.5%,分别比单独使用水合氧化铁微粒和微生物絮凝剂提高33.6%和82.6%。

阳离子化克雷伯氏菌絮凝剂CMBF-NIII2在生活污水中的应用

微生物絮凝剂具有无毒性,绿色生产等优点,能够安全地用于给水处理及污废水处理.本文通过阳离子改性和与非生物絮凝剂复配的方法,提高MBF-NIII2的絮凝能力.以MBF-NIII2为原料,利用3-氯-2-羟丙基三甲基氯化铵(CHTAC)对其修饰,合成新型阳离子化的微生物絮凝剂(CMBF-NIII2)以CMBF-NIII2为研究主要对象,对校园生活污水进行处理.通过改变投加量、pH值、沉淀时间与温度,探究CMBF-NIII2絮凝能力的变化规律.将改性前的MBF-NIII2与改性后的CMBF-NIII2分别用于校园生活废水的处理,对比发现当CMBF-NIII2投加量为1.3 mL,pH 4.6,温度为60℃,沉降时间为40 min时,絮凝率达到91.5%,且COD去除率为87.8%,絮凝能力明显优于MBF-NIII2(絮凝率为47.61%),能更高效地絮凝生活污水.以MBF-NIII2与三氯化铁复配处理生活污水,结果表明MBF-NIII2和FeCl_3的投加量分别为10 mg·L^(-1)和15 mg·L^(-1)时,絮凝率可达88.06%,不仅比单独使用MBF-NIII2的处理效果好,还相对减少了絮凝剂的投加量.

絮凝剂产生菌HYY-7的培养条件

从生活污水厂的活性污泥中筛选出一株高效微生物絮凝剂产生菌，鉴定为青霉，命名为 ，其产生的微生物絮凝剂命名为MBF7。该茵产生微生物絮凝剂的最佳培养基为葡萄糖培养基，适宜的培养条件为：葡萄糖培养基初始pH值为4．5～6．0，培养温度为30℃；振荡箱的转速为200r／min，培养时间为3～4d。产生的高效絮凝剂MBF7具有良好的絮凝效果，对于实际排放的染料废水、餐厅废水和生活污水浊度去除率分别为92．5％，96．8％，90．2％。

高效微生物絮凝剂产生菌BJ-Ⅰ的筛选鉴定及絮凝特性研究

从活性污泥中筛选出1株高效微生物絮凝剂产生菌BJ-Ⅰ，其絮凝率达87．6％．通过生理生化分析及16S rDNA序列鉴定该菌株为短芽孢杆菌（Bacillus brevis）．该菌产絮凝剂的最适碳源和氮源分别为20g/L的葡萄糖和2．0g／L的蛋白胨；适宜的初始pH和培养温度分别为7．0和30℃；在培养基中添加0．5g／L的Mg^2＋有利于菌体生长，但对絮凝剂合成无影响．对该絮凝剂的特性研究结果表明：菌液投放量3％、pH值在5．9、温度为60℃条件下絮凝效果最好，加入浓度为8％的Ca^2＋可显著提高其絮凝活性．实验证明，该菌起絮凝作用的物质存在于发酵液中，主要成分为杂多糖．

微生物絮凝剂产生菌节杆菌LF-Tou2的培养和絮凝条件研究

CaCl2和ZnCl2对于节杆菌LF-Tou2絮凝剂的产生非常有效。节杆菌LF-Tou2产生絮凝剂的最适温度、最适pH值和最适接种量分别为27℃、7和每mL培养液105个细胞。维生素B9和低浓度的维生素B12能够刺激微生物絮凝剂的产生。实验还发现,在絮凝体系中添加Fe3+、Mn2+和Ca2+能够明显地提高发酵液的絮凝率。对于发酵液展示絮凝剂活性的最合适的pH值为7。在絮凝系统中把定量的助絮剂CaCl2溶液分成2次添加能够非常显著地提高絮凝活性。