Production and characterization of a bioflocculant by Proteus mirabilis TJ-1

A bioflocculant TJ-F1 with high flocculating activity, produced by strain TJ-1 from a mixed activated sludge, was investigated with regard to its production and characterization. By 16S rDNA sequence and biochemical and physiological characteristics, strain TJ-1 was identified as Proteus mirabilis. The most preferred carbon source, nitrogen source and C/N ratio (w/w) for strain TJ-1 to produce the bioflocculant were found to be glucose, peptone and 10, respectively. TJ-F1 production could be greatly stimulated by cations Ca(2+), Mg(2+) and Fe(3+). The optimal conditions for TJ-F1 production were inoculum size 2 per thousand (v/v), initial pH 7.0, culture temperature 25 degrees C, and shaking speed 130r/min, under which the flocculating activity of the bioflocculant reached 93.13%. About 1.33 g of the purified bioflocculant, whose molecular weight (MW) was 1.2 x 10(5) Da, could be recovered from 1.0 l of fermentation broth. Chemical analysis of bioflocculant TJ-F1 indicated that it contained protein (30.9%, w/w) and acid polysaccharide (63.1%, w/w), including neutral sugar, glucuronic acid and amino sugar as the principal constituents in the relative weight proportions of 8.2:5.3:1. Scanning electron microscopy (SEM) image of the purified solid-state TJ-F1 showed that it had a crystal-linear structure. Spectroscopic analysis of the bioflocculant by Fourier-transform infrared (FTIR) spectrometry indicated the presence of carboxyl, hydroxyl and amino groups preferred for the flocculation process.     

Production of a Bioflocculant by Rhodococcus erythropolis S-1 Grown on Alcohols

Rhodococcus erythropolis strain S-1, which was isolated from soil, produces a bioflocculant. We have found that alcohols are useful carbon sources for its flocculant production. Ethanol was best for flocculant production and culture time. The bioflocculant produced on ethanol medium flocculated a wide range of suspended soils, alkaline and acid.     

Characterization and application of bioflocculant prepared by Rhodococcus erythropolis using sludge and livestock wastewater as cheap culture media

A new bioflocculant was produced by culturing Rhodococcus erythropolis in a cheap medium. When culture pH was 7.0, inoculum size was 2 % (v/v), Na₂HPO₄ concentration was 0.5 g L^?1, and the ratio of sludge/livestock wastewater was 7:1 (v/v), a maximum flocculating rate of 87.6 % could be achieved. Among 13 different kinds of pretreatments for sludge, the optimal one was the thermal-alkaline pretreatment. Different from a bioflocculant produced in a standard medium, this bioflocculant was effective over a wide pH range from 2 to 12 with flocculating rates higher than 98 %. Approximately, 1.6 g L^?1 of crude bioflocculant could be harvested using cold ethanol for extraction. This bioflocculant showed color removal rates up to 80 % when applied to direct and disperse dye solutions, but only 23.0 % for reactive dye solutions. Infrared spectrum showed that the bioflocculant contained functional groups such as –OH, –NH₂, and –CONH₂. Components in the bioflocculant consisted of 91.2 % of polysaccharides, 7.6 % of proteins, and 1.2 % of DNA. When the bioflocculant and copper sulfate (CuSO₄) were used together for decolorization in actual dye wastewater, the optimum decolorization conditions were specified by the response surface methodology as pH 11, bioflocculant dosage of 40 mg/L, and CuSO₄ 80 mg/L, under which a decolorization rate of 93.9 % could be reached.     

Production of a novel bioflocculant by fed-batch culture of Citrobacter sp.

Production of a novel bioflocculant by a fed-batch culture of Citrobacter sp. TKF04 was investigated using acetic acid as a sole carbon source. Synthesis of the bioflocculant was favored by dissolved O₂ tension at 20% of air saturation and C/N ratio (mol acetic acid/mol ammonium) of 10:1 in the feed solution. Under optimal conditions, 4.6 g crude bioflocculant per liter broth was produced, whose flocculating activity was 22 300 units. This activity was 9 times higher than that of the control (only acetic acid was supplied).     

The production of bioflocculants by Bacillus licheniformis using molasses and its application in the sugarcane industry

A bioflocculant produced by B. licheniformis was investigated with regard to a low-cost culture medium and its industrial application. Molasses replaced sucrose as the sole carbon source in bioflocculant fermentation. The optimum low-cost culture medium was determined to be composed of 20 g/L molasses, 0.4 g/L urea, 0.4 g/L NaCl, 0.2 g/L KH₂PO₄, 1.6 g/L K₂HPO₄, and 0.2 g/L MgSO₄. The bioflocculant from B. licheniformis was then applied to treat sugarcane-neutralizing juice to remove colloids, suspended particles, and coloring matters in a sugar refinery factory. The optimal operation conditions were a bioflocculant dosage of 21 U/mL, pH 7.3 and a heating temperature of 100°C. The color and turbidity of the sugarcane juice reached IU 1267 and IU 206, respectively, after clarification with the bioflocculant; these values were almost the same as those acquired following treatment with polyacrylamide (PAM), the most widely applied flocculant in sugar industries. These results suggest the great potential for use of bioflocculants in the sugar refinery process.     

Phormidium J-1 bioflocculant: production and activity

Phormidium J-1, a benthic filamentous cyanobacterium, isolated from a drainage channel, was found to produce a high molecular weight polymer. This substance can flocculate bentonite particles from suspensions. At the stationary phase of growth the cells excreted this bioflocculant into the surrounding medium. Production was enhanced by reduction of the calcium content in the growth medium or by increasing its EDTA content. Above the isoelectric point (pH 3.5) the bioflocculant is negatively charged. The presence of minimal concentrations of divalent cations in the reaction mixture is required for its flocculating activity. The production of bioflocculant could be of great importance in clarification of turbid water bodies, thus allowing light penetration to the sediment/water interface. Bioflocculant production and excretion was not found in several other benthic cyanobacteria.Dedicated to Prof. Dr. H.-G. Schlegel on the occasion of his 60th birthday     

Novel bioflocculant produced by salt-tolerant,alkaliphilic strain Oceanobacillus polygoni HG6 and its application in tannery wastewater treatment

The optimized production of MBF-HG6, which is a novel salt-tolerant alkaliphilic bioflocculant produced by Oceanobacillus polygoni with its application in tannery wastewater treatment was investigated in this study. It was found the optimal carbon source, nitrogen source, cation, and initial pH of the medium for bioflocculant production were starch, urea, Fe²⁺, and pH 9.0, respectively. The best stability in the temperature range was from 0 to 80°C and the purified MBF-HG6 contained polysaccharides of 81.53% and proteins of 9.98%. The carboxyl, hydroxyl, and amino groups were determined in bioflocculants, while the optimized bioflocculating activity was observed as 90.25% for the dosages of 6.96mL MBF-HG6, 4.77mL CaCl₂ (1%, m/v), and 19.24g/L NaCl using response surface methodology. In addition, SS and turbidity removal rates of the tannery wastewater (4g/L MBF-HG6) could, respectively, reach 46.49% and 91.08%, indicating that the great potential was emerged in enhancement of tannery wastewater treatment by MBF-HG6.     

Evaluation of the flocculation potential and characterization of bioflocculant produced by Micrococcus sp. Leo

Bioflocculants are safe, biodegradable and environmentally friendly biopolymeric materials. These merits portend it as preferred alternative to inorganic and organic synthetic polymeric flocculants. The culture conditions optimal for the production of bioflocculant by Micrococcus sp. Leo with subsequent evaluation of the properties of the produced compound were investigated. Optimum culture conditions for bioflocculant production included 2% (vol/vol) inoculum size, incubation temperature of 28°C, agitation speed of 160 rpm and initial pH of 4.0. Glucose and (NH₄)₂SO₄ and Al³⁺ were the best as sole carbon, nitrogen and cation sources, respectively. The purified bioflocculant flocculated kaolin suspension optimally at a dosage of 0.2 mg/mL following jar test, and flocculating activity of about 70% was retained after heat treatment of 100°C. Chemical analysis showed that the bioflocculant was composed of 28.4% polysaccharide, 2.6% protein and 9.7%. uronic acid. Thermogravimetric analysis demonstrated that the bioflocculant could not decompose completely at 400°C. FTIR spectra revealed the presence of hydroxyl, carboxyl and amino groups as the main functional groups. The bioflocculant produced by Micrococcus sp. Leo appears to hold promise as an alternative to conventional flocculants commonly used in water/wastewater treatment.     

Characteristics of a bioflocculant produced by <Emphasis Type="Italic">Bacillus mucilaginosus</Emphasis> and its use in starch wastewater treatment

A bioflocculant, MBFA9, was produced from a strain of bioflocculant-producing bacteria isolated from a soil sample and identified as Bacillus mucilaginosus. MBFA9 had a good flocculating capability and could achieve a flocculating rate of 99.6% for kaolin suspension at a dosage of only 0.1 ml/l. The major component of MBFA9 was found to be polysaccharide composed mainly of uronic acid (19.1%), neutral sugar (47.4%) and amino sugar (2.7%). Infrared spectrum analysis showed the presence of carboxyl and hydroxyl groups in the bioflocculant. MBFA9 is nontoxic and can be used in food industries for suspended solids (SS) recovery. When applied to starch wastewater treatment, MBFA9 greatly accelerated the formation of flocs and the settling of organic particles in the presence of Ca(2+) salt. After 5 min of settling, the removal rate of SS and chemical oxygen demand were up to 85.5% and 68.5%, respectively, which is better than traditional chemical flocculants.     

Production and characteristics of a bioflocculant produced by Bacillus sp. F19

A bioflocculant-producing bacterium isolated from soil was identified as Bacillus sp. and the bioflocculant produced was named MBFF19. Effects of physico-chemical conditions including pH, carbon sources and nitrogen sources on MBFF19 production were studied. Chemical analyses of the purified bioflocculant MBFF19 indicated that it was a sugar-protein derivative, composed of neutral sugar (3.6%, w/w), uronic acid (37.0%, w/w), amino sugars (0.5%, w/w) and protein (16.4%, w/w). The two neutral sugar components were mannose and glucose and the molar ratio was 1.2:1. Infrared spectrophotometry analysis revealed that MBFF19 contained carboxyl, hydroxyl and methoxyl groups in its structural. Flocculating properties of bioflocculant MBFF19 was examined using kaolin, activated carbon and fly coal suspension. Cation supplement had no positive effects on the flocculating activity whereas the presence of Fe3+ inhibited flocculation. Influences of pH and bioflocculant dosage on the flocculation were also examined.     

三唑磷降解菌株GS-1的分离鉴定及其降解特性的研究

从有机磷农药污水处理池污泥中分离到一株能高效降解三唑磷的菌株GS-1, 通过生理生化实验和16S rDNA序列同源性分析, 将该菌株鉴定为Diaphorobacter sp.。菌株GS-1能以三唑磷为唯一碳源生长, 能在12 h内降解100 mg/L的三唑磷至检测不出的水平。菌株GS-1降解三唑磷的过程中会产生中间代谢产物苯唑醇(1-苯基-3-羟基-1,2,4-三唑), 36 h后苯唑醇被完全转化。菌株GS-1降解三唑磷的最适pH值为8.0, 最适温度为30°C, 且对杀螟硫磷、辛硫磷、毒死蜱和甲基对硫磷     

抗草甘膦酵母菌ZM-1的分离鉴定及其生长降解特性

以福州市郊区的耕作土壤为研究材料, 利用草甘膦为选择压力, 通过富集、驯化培养, 分离出一株对草甘膦具有高耐受和降解作用的酵母菌菌株ZM-1, 结合生理生化特征及26S rDNA D1/D2区序列分析将其初步鉴定为胶红酵母菌(Rhodotorula mucilaginosa)。菌株ZM-1能以草甘膦为唯一碳、氮源生长, 对草甘膦的最高耐受浓度为50 g/L。在草甘膦初始浓度为1 g/L的无机盐培养基中, 30°C、150 r/min 摇床振荡培养7 d, 草甘膦降解率为85.38%。适合菌株ZM-1生长及降解草甘膦的最佳条件为: 草甘膦初始浓度1 g/L, 接种量4%, 温度30°C, pH 值5.5-6.0, 装料量50 mL/250 mL。菌株ZM-1是一株良好的草甘膦耐受菌, 可用于草甘膦污染环境的生物修复, 也可能成为转基因抗草甘膦作物的一个很好资源。     

New olivosyl derivatives of methymycin/pikromycin from an engineered strain of Streptomyces venezuelae

A mutant strain of Streptomyces venezuelae was engineered by deletion of the entire gene cluster related to biosynthesis of the endogenous deoxysugar (TDP-D-desosamine) and replacement with genes required for biosynthesis of an intermediate sugar (TDP-4-keto-6-deoxy-D-glucose) or an exogenous sugar (TDP-D-olivose), from the oleandomycin and urdamycin deoxysugar pathways. The 'sugar-flexible' glycosyltransferase (DesVII) was able to attach the intermediate sugar and the new sugar to both 12- and 14-membered macrolactones thus producing quinovose or olivose glycosylated 10-deoxymethynolide and narbonolide, respectively. In addition, hydroxylated analogs of the new metabolites were detected. These results demonstrate a successful attempt of engineering the deoxysugar pathway for generation of novel hybrid macrolide antibiotics.     

Characterization of bioflocculants from biologically aerated filter backwashed sludge and its application in dying wastewater treatment

In this study, the feasibility of bioflocculant extraction from backwashing sludge to reduce its production costs was investigated. Results showed that ultrasound and base treatment could significantly enhance bioflocculant extraction efficiency, however, flocculating activity was affected. It was observed that bioflocculants extracted from sludge of pH 11.0 had no flocculating activity. In contrast, bioflocculants extracted from sludge of pH 5.0, named as M-1, had good flocculating activity. To further study the flocculating activity of M-1, factors such as bioflocculant dosage, temperature and pH of the reaction solution were tested. The optimal conditions were 6.0 mg/l bioflocculant dosage and pH 5.0, at a temperature of 10 °C. Under these conditions, the flocculating rate of kaolin clay was 92.67%. The effectiveness of such bioflocculants in the decolorization of synthetically dyed wastewater was then examined. In flocculating methylene blue and fast blue in aqueous solutions, decolorization efficiency levels were 82.9% and 77.8%, respectively.     

Characterization of moderately halotolerant selenate- and tellurite-reducing bacteria isolated from brackish areas in Osaka

Moderately halotolerant selenate- and tellurite-reducing bacteria were characterized for wastewater treatment applications. A selenate-reducing strain 9a was isolated from the biofilm of a leachate treatment plant at a sea-based waste disposal site. A tellurite-reducing strain Taa was isolated from an enrichment culture derived from brackish sediment. Both bacterial strains were Shewanella species. Strain 9a could anaerobically remove 45–70% of 1.0 mM selenate and selenite from water containing up to 3% NaCl within 4 days, while strain Taa could anaerobically and aerobically remove 70–90% of 0.4 mM tellurite from water containing up to 6% NaCl within 3 days. Globular particles of insoluble selenium were observed both outside and inside the cells of strain 9a. The insoluble tellurium formed by strain Taa was globular under microaerobic conditions but nanorod under aerobic conditions. These bacteria will yield a range of useful selenium and tellurium nanomaterials as well as wastewater treatment applications.     

一种富集高温栅藻Desmodesmus sp. F51的新型生物絮凝剂

[背景]海科贝特氏菌(Cobetia marina)可产生大量具有絮凝活性的胞外产物,可视为一种新型的生物絮凝剂。高温栅藻(Desmodesmus sp.F51)是一种具有较高叶黄素含量的微藻,被认为是一种新兴的叶黄素来源,但利用该生物絮凝剂高效富集高温栅藻的相关研究迄今尚未见报道。[目的]以高温栅藻为对象,研究该新型生物絮凝剂的絮凝效率,并对絮凝机理进行初步探讨。[方法]探索在不同生长阶段微藻培养液添加生物絮凝剂、添加量、絮凝时间、pH对絮凝效率的影响,分析生物絮凝剂的功能基团,并测定在不同pH条件下添加生物絮凝剂前后高温栅藻的Zeta电位变化,以及在显微镜下分析藻细胞在添加生物絮凝剂前后的形态。[结果]在高温栅藻生长至稳定期(pH 8.0)添加2 mL生物絮凝剂,絮凝15 min絮凝效果最佳,达82.1%。傅里叶红外光谱(fourier transform infrared spectroscopy,FTIR)显示了多糖及酰胺结构的特征吸收峰,由此推测生物絮凝剂主要是多糖的混合物,含有少量蛋白质。根据Bradford法测定絮凝剂中蛋白含量约为0.4%(质量比),通过苯酚-硫酸法测定总糖质量分数约为34.5%(质量比),与FTIR分析结果基本相符。生物絮凝剂在pH 4.0-11.0保持60%以上的絮凝效率,说明无论是酸性或是碱性条件下絮凝效率都较高,结合Zeta电位的分析表明,推测生物絮凝剂对高温栅藻的絮凝机理中占主导地位的可能是吸附架桥作用。[结论]该研究对微藻生物絮凝具有重要的理论和实践意义。     

Characterization and emulsifying property of a novel bioemulsifier by Aeribacillus pallidus YM-1

Aims: Biosurfactants and bioemulsifiers commonly have the advantages of biodegradability, low toxicity, selectivity and biocompatibility over chemically synthesized surfactants. The goal of the study is to present a novel bioemulsifier with great application potential. Methods and Results: Aeribacillus pallidus YM‐1, isolated from crude oil contaminated soil, was found to produce a novel high molecular bioemulsifier with an emulsification index of 60 ± 1% without remarkable surface tension reduction (45·7 ± 0·1 mN m^?1). The number‐average molecular weight was determined as 526 369 Da by gel permeation chromatography analysis. Bioemulsifier was subjected to FT‐IR and a complex of carbohydrates (41·1%), lipids (47·6%) and proteins (11·3%) was determined. Conclusions: The bioemulsifier of A. pallidus YM‐1 was isolated from the glucose‐based culture medium and characterized with the help of chemical analytical techniques. The bioemulsifier exhibited a promising emulsifying property for biotechnology application potential in bioremediation and microbial enhanced oil recovery. Significance and Impact of the Study: This is the first report of the bioemulsifier production by A. pallidus. The potential emulsifying activity of the bioemulsifier in the present study may be explored in various biotechnological and industrial applications.     

Microbial flocculant from Arcuadendron sp. TS-49

Summary A flocculant was purified from the culture broth of Archuadendron sp. TS-49 by a series of precipitations with acetone, 60% ammonium sulfate-butanol, salting-out by dialysis, and cetylpyridinium chloride. The flocculating activity was observed most highly at pH 3.0 and markedly enhanced by the addition of salts, especially in the case of FeCl₃ or FeSO₄. This bioflocculant efficiently flocculated all tested solids, including various microorganisms and organic/ inorganic materials. Qualitative analyses of the bioflocculant showed that it might contain hexosamine, uronic acid, neutral sugar, and protein.     

A Novel Bioflocculant Produced by Cobetia Marina MCCC1113: Optimization of Fermentation Conditions by Response Surface Methodology and Evaluation of Flocculation Performance When Harvesting Microalgae

A preliminary study was carried out to optimize the culture medium conditions for producing a novel microbial flocculant from the marine bacterial species Cobetia marina. The optimal glucose, yeast extract, and glutamate contents were 30, 10, and 2 g/l, respectively, while the optimal initial pH of the culture medium was determined to be 8. Following response surface optimization, the maximum bioflocculant production level of 1.36 g/l was achieved, which was 43.40% higher than the original culture medium. Within 5 min, a 20.0% (v/v) dosage of the yielded bioflocculant applied to algal cultures resulted in the highest flocculating efficiency of 93.9% with Spirulina platensis. The bioflocculant from C. marina MCCC1113 may have promising application potential for highly productive microalgae collection, according to the findings of this study. Open in a separate window     

Optimization of norovirus virus‐like particle production in Pichia pastoris using a real‐time near‐infrared bioprocess monitor

The production of norovirus virus‐like particles (NoV VLPs) displaying NY‐ESO‐1 cancer testis antigen in Pichia pastoris BG11 Mut⁺ has been enhanced through feed‐strategy optimization using a near‐infrared bioprocess monitor (RTBio^® Bioprocess Monitor, ASL Analytical, Inc.), capable of monitoring and controlling the concentrations of glycerol and methanol in real‐time. The production of NoV VLPs displaying NY‐ESO‐1 in P. pastoris has potential as a novel cancer vaccine platform. Optimization of the growth conditions resulted in an almost two‐fold increase in the expression levels in the fermentation supernatant of P. pastoris as compared to the starting conditions. We investigated the effect of methanol concentration, batch phase time, and batch to induction transition on NoV VLP‐NY‐ESO‐1 production. The optimized process included a glycerol transition phase during the first 2 h of induction and a methanol concentration set point of 4 g L^?1 during induction. Utilizing the bioprocess monitor to control the glycerol and methanol concentrations during induction resulted in a maximum NoV VP1‐NY‐ESO‐1 yield of 0.85 g L^?1. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:518–526, 2016