Carrier For Bacteria Research Articles

Study on Active Recovery of Anaerobic Ammonia Oxidation and Start-Up of ASBR Reactor

In order to prevent the loss of microbes, added anaerobic ammonia oxidation to (ASBR) reactor plus membrane as the growth of anaerobic ammonia oxidation bacteria carrier. After 30d cultivate, the activity of anammox bacteria restore to the original level, and improve TN volume load train anammox bacteria. The whole process of NH4+-N and NO2--N removal rate has remained at more than 90%.After the activity recovery of anammox NH4+-N, NO2--N the ratio of consumption to the NO3--N generation finally tends to a certain value (1. 00b 1. 30 b 0. 25).In the process of cultivate, the sludge was gradually changed from black to red brown color .Results show that the ASBR is well suited for anammox enrichment culture of bacteria.

A comparative study in bacteriological analysis between re-used and disposable oxygen humidification devices

Objective To carry out bacteriological analysis between re-used and disposable oxygen humidification devices. Methods Reused oxygen equipment and disposable oxygen moisture bottles from 6 randomly selected elderly wards were collected, patients who used oxygen will be randomized into 3 groups, group A used cold water as the oxygen humidification liquid, group B used distilled water as humidification liquid, group C used AQUAPAK disposable oxygen humidification devices, sample taking in group A and group B happened on every Monday and Thursday before the replacement of sample moisture bottles, sample was taken in group C after the use of disposable oxygen humidification devices, according to disinfection health standards (GB5982-1995)sampling method of disinfection liquid sample was taken and sent to test in the disinfectant laboratory. Results Of 61 samples in group A bacteria cartier rate was 81.97%, bacteria carrier rate of 71 samples in group B was 47.89%, of 52 samples in group C the carrier rate was 0. The comparing of bacterial contamination rate of three kinds of oxygen moisture bottles after using was statistically significant. Take group A, B for comparison, the average severity level of bacteria in group A is higher than group B. In group A, the level of the Gram-negative bacteria as well as Gram-positive bacteria colonization was higher than group B. Conclusions Whether use of cold water or distilled water, oxygen humidification liquids have different degrees of pollution. Currently there is no general criteria and norms in the context of sterilization of oxygen humidification, for patients on long-term oxygen using, to choose disposable oxygen humidification device to reduce the incidence of hospital infections is recommended. Key words: Oxygen moisture bottle; Bacterial monitor; , Humidification fluid; Disinfection method; Therapeutic observation

Probiotic ice cream: viability of probiotic bacteria and sensory properties

Ice cream is a dairy product with good potential to act as a food carrier for probiotic bacteria. The incorporation of probiotic bacteria into ice cream is highly advantageous since, in addition to making a functional healthy food, ice cream in itself contains beneficial substances such as dairy raw materials, vitamins and minerals, and is consumed by the general population. Also, compared with fermented milks as a vehicle, ice cream supports considerably greater viability of probiotic strains during production and especially storage. However, losses in the viability of probiotic bacteria in ice cream unavoidably occur during product formulation, processing, storage and melting. During these stages, probiotic cells are subjected to different stresses related to pH, acidity, redox potential, freezing, oxygen (especially in overrun processing), sugar concentration and osmotic effects, hydrogen peroxide, antagonistic impact of co-cultures (in fermented ice creams), and mechanical shearing. It seems that the rate of loss of probiotic cells is greater during the freezing process than during storage. Practicing methods such as selection and application of oxygen-resistant probiotic strains, elimination of molecular oxygen (using oxygen-scavenging components, packaging material that is impermeable to oxygen as well as thicker packaging materials and active packaging systems), applying severe heat treatment, using microencapsulation techniques, and adjusting the product formulation (e.g., fortification of milk with nutrients and prebiotics) can increase the viability of probiotics in the final product. Supplementation of ice cream with probiotic bacteria has been found to have little effect on its flavor, texture or other sensory characteristics. There are also many ways to improve the sensory attributes of the product to compensate for any changes that do occur. This article reviews the viability of probiotic bacteria in ice cream and the main methods used to improve their viability and the sensory characteristics of probiotic ice cream.

Siliceous Materials for Immobilization of Photoheterotrophic Bacteria

ABSTRACTPreparation of transparent silica as potential carrier for photocatalysts and photosynthetic bacteria is presented. SiO2 was obtained by sol-gel techniques using tetraethyl orthosilicate as precursor. Glycol and glycerol were used as solvents. The increase of porosity of the studied materials was reached by application of soluble and commercial potato starch as a filler. Calcinations at 825 K for 6 hours removed all organic compounds. The rate of gelation was enhanced applying hydrochloric acid. Different materials were obtained in a series of syntheses with different concentrations of individual components. Transparency of the obtained materials varied between 50 and 97% (in range of λ 350 - 800 nm). Surface area varied between 300 and 400 m2/g and pore diameter was 5 – 18 nm. Samples were studied with SEM, nitrogen sorption at 77 K and UV-Vis spectroscopy. The obtained transparent materials with occluded TiO2 or CaTiO3 were tested in photocatalytic splitting of water.

Survival, growth characteristics and bioactive potential of Lactobacillus acidophilus in a soy‐based cream cheese

AbstractBACKGROUND: Soy‐based products have received much attention lately as dairy replacers and carriers for probiotics, without the cholesterol and lactose intolerance factors. We have previously developed a soy cream cheese product and would like to evaluate its suitability as a carrier for probiotic microorganisms. Soy cream cheese is commercially uncommon, while a probiotic soy cream cheese is yet to be available in the market.RESULTS: Five strains of probiotics were screened for their α‐galactosidase activity. Lactobacillus acidophilus FTCC 0291 showed the highest α‐galactosidase‐specific activity and was incorporated into soy cream cheese for a storage study of 20 days at 25 and 4 °C. L. acidophilus FTCC 0291 in soy cream cheese at both storage temperatures maintained a viability exceeding 107 CFU g−1 over storage. Oligosaccharide and reducing sugar analyses indicated that L. acidophilus FTCC 0291 was capable of utilizing the existing reducing sugars in soymilk and concurrently hydrolyzing the oligosaccharides into simpler sugars for growth. L. acidophilus FTCC 0291 also produced organic acids, leading to decreased pH. Under low pH and high organic acid concentration, the growth of total aerobes and anaerobes was significantly (P < 0.05) suppressed compared to the control. The hydrolysis of protein in soymilk produced essential growth factors such as peptides and amino acids that may have promoted the growth of L. acidophilus FTCC 0291 and the release of bioactive peptides with in vitro angiotensin I‐converting enzyme inhibitory activity.CONCLUSION: This study showed that soy cream cheese could be used as a carrier for probiotic bacteria, with potential antihypertensive property. Copyright © 2009 Society of Chemical Industry

Influence of Lactobacillus E1 on the storage stability in emulsion immobilization

A coacervation method with double emulsion strategy (w/o/w) was used to prepare immobilized Lactobacillus E1. Diatomite was chosen as the carrier for bacteria. Sodium alginate, dextrin and gelatin were used as protective solutes for the preservation of Lactobacillus E1 and their effects on the storage viability during storage were discussed. The influence of storage temperature on the storage viability was also examined. The results show that high bacteria viable count over 109 cfu/g for an extended shelf life of 37 d can be achieved with 2% sodium alginate, 5% dextrin and 4% gelatin as protective solutes, at 10°C of the storage temperature. This immobilized Lactobacillus E1 has potential use as functional food ingredient for both human dairy food and animal feedstuff.

Secretory delivery of heterologous proteins in attenuated Vibrio anguillarum for potential use in vaccine design

To synthesize and secrete heterologous proteins in an attenuated Vibrio anguillarum strain for potential multivalent live vaccine development, different antigen-delivery systems based on bacterial-originated secretion signal peptides (SPs) were designed and identified in this work. Four SPs were derived from hemolysin of Escherichia coli, RTX protein of V. cholerae, hemolysin of V. anguillarum, zinc-metalloprotease of V. anguillarum, respectively, and their abilities to support secretion of green fluorescent protein (GFP) in an attenuated V. anguillarum strain MVAV6203 were assayed. Immunodetection of GFP showed that the capability of the tested signal leaders to direct secretion of GFP varied greatly. Although all the four signal peptide-fused GFPs could be expressed correctly and trapped intracellularly in recombinant strains, only the EmpA signal peptide could confer efficient secretion to GFP. For the investigation of its potential application in live bacteria carrier vaccines, a heterologous protein EseB of Edwardsiella tarda was fused to the SP(empA) antigen-delivery system and introduced into the strain MVAV6203. Further analysis of EseB demonstrated that the constructed SP(empA) antigen-delivery system could be used to secrete foreign protein in attenuated V. anguillarum and be available for carrier vaccines development.

Novel Bacterial Surface Display Systems Based on Outer Membrane Anchoring Elements from the Marine Bacterium Vibrio anguillarum

Surface display of heterologous peptides and proteins such as receptors, antigens, and enzymes on live bacterial cells is of considerable value for various biotechnological and industrial applications. In this study, a series of novel cell surface display systems were examined by using Vibrio anguillarum outer membrane protein and outer membrane lipoprotein as anchoring motifs. These display systems consist of (i) the signal sequence and first 11 N-terminal amino acids of V. anguillarum outer membrane lipoprotein Wza, or the signal sequence and first 9 N-terminal amino acids of the mature major Escherichia coli lipoprotein Lpp, and (ii) transmembrane domains of V. anguillarum outer membrane proteins Omporf1, OmpU, or Omp26La. In order to assay the translocation efficiency of constructed display systems in bacteria, green fluorescent protein (GFP) was inserted to the systems and the results of GFP surface localization confirmed that four of the six surface display systems could successfully display GFP on the E. coli surface. For assaying its potential application in live bacteria carrier vaccines, an excellent display system Wza-Omporf1 was fused with the major capsid protein (MCP) of large yellow croaker iridovirus and introduced into attenuated V. anguillarum strain MVAV6203, and subsequent analysis of MCP surface localization proved that the novel display system Wza-Omporf1 could function as a strong tool in V. anguillarum carrier vaccine development.

Production of gaseous nitrogen compounds in a novel process for ammonium removal

The production of gaseous nitrogen compounds, particularly the greenhouse gas nitrous oxide, was investigated in a novel process for ammonium removal from wastewater. The process is based on the adsorption of ammonium on zeolite followed by bioregeneration. The zeolite serves the dual purpose of an ion exchanger and a physical carrier for nitrifying bacteria which bio-regenerate the ammonium saturated mineral. An analysis of the nitrifying population composition in the reactor fed with simulated secondary effluent (NH4+ = 50 mg/l) revealed that about half of the bacteria in the biofilm were common ammonium oxidizers Nitrosococcus mobilis and Nitrosomonas, while the other half were nitrite oxidizers. The amount of nitrogen losses, under different conditions, and the identification of the emitted gases (N2 or N2O) were investigated in two sets of experiments: (I) batch experiments using biomass originating from the ion exchange reactor with and without the addition of nitrite, and (II) continuous experiments using the ion exchange reactor with zeolite as the biomass carrier. In the batch experiments, nitrite and oxygen concentrations were determined as the major parameters responsible for the formation of gaseous nitrogen gas during ammonia oxidation by autotrophic bacteria. Continuous experiments showed that the major parameter significantly affecting nitrogen losses was the amount of ammonium adsorbed by the zeolite during the ion exchange phase. The amount of ammonium adsorbed determines the ammonium concentration during the initial period of bioregeneration, which in turn directly influences oxygen demand and the resulting concentrations of oxygen and nitrite. It was concluded that the formation of nitrogen gas compounds in the ion exchange/bioregeneration process can be eliminated by adjusting the operational regime to have a shorter adsorption phase resulting in smaller amounts of ammonium adsorbed per cycle.

Alginate microbeads as inoculant carriers for plant growth-promoting bacteria

A method of inoculating wet and dry seeds with plant growth-promoting bacteria (PGPB) using alginate microbeads as a substrate and Azospirillum brasilense as the model PGPB was developed. The microbeads were produced by low pressure spraying of an alginate solution mixed with liquid bacterial culture suspended in a very rich medium through a small nozzle resulting in small-diameter droplets. These droplets, when sprayed into a slowly stirred solution of CaCl2, immediately hardened into microbeads at diameters ranging between 100 and 200 µm. Although the process killed part of the entrapped bacteria, the remaining bacteria residing in the microbeads were sufficient [>1011 colony-forming units (CFU) g–1 inoculant] for seed inoculation. Further, it was found that the bacterial population in the inoculant could be enhanced by secondary multiplication in the same medium for an additional 16 h. It was found that the microbeads could be used either wet or dry. Dry inoculant was produced using dry air at 38°C, creating a powdery substance loaded with >109 CFU g–1 beads. Alternatively, dry microbeads were produced using a standard freeze-drying procedure. This dry preparation was easily attached to dry seed surfaces with the addition of 1% alcohol-diluted lecithin or with 0.5% synthetic paper adhesive (Resistol). The bacteria were slowly released from the microbeads in amounts ranging from 104 to 106 CFU g–1 depending on the type (wet or dry, with or without skim milk) and the time of incubation (the longer the incubation period, the smaller the amount of bacteria released with time). The wet and dry inoculants enhanced the development of wheat and tomato seedlings growing in unfertile soil, and biodegraded within 15 days in moist soil.

Iron metabolism in anoxic environments at near neutral pH.

Anaerobic dissimilatory ferric iron-reducing and ferrous iron-oxidizing bacteria gain energy through reduction or oxidation of iron minerals and presumably play an important role in catalyzing iron transformations in anoxic environments. Numerous ferric iron-reducing bacteria have been isolated from a great diversity of anoxic environments, including sediments, soils, deep terrestrial subsurfaces, and hot springs. In contrast, only few ferrous iron-oxidizing bacteria are known so far. At neutral pH, iron minerals are barely soluble, and the mechanisms of electron transfer to or from iron minerals are still only poorly understood. In natural habitats, humic substances may act as electron carriers for ferric iron-reducing bacteria. Also fermenting bacteria were shown to channel electrons to ferric iron via humic acids. Whether quinones or cytochromes released from cells act as electron transfer components in ferric iron reduction is still a matter of debate. Anaerobic ferrous iron-oxidizing phototrophic bacteria, on the other hand, appear to excrete complexing agents to prevent precipitation of ferric iron oxides at their cell surfaces. The present review evaluates recent findings on the physiology of ferric iron-reducing and ferrous iron-oxidizing bacteria with respect to their relevance to microbial iron transformations in nature.

Iron metabolism in anoxic environments at near neutral pH

Anaerobic dissimilatory ferric iron-reducing and ferrous iron-oxidizing bacteria gain energy through reduction or oxidation of iron minerals and presumably play an important role in catalyzing iron transformations in anoxic environments. Numerous ferric iron-reducing bacteria have been isolated from a great diversity of anoxic environments, including sediments, soils, deep terrestrial subsurfaces, and hot springs. In contrast, only few ferrous iron-oxidizing bacteria are known so far. At neutral pH, iron minerals are barely soluble, and the mechanisms of electron transfer to or from iron minerals are still only poorly understood. In natural habitats, humic substances may act as electron carriers for ferric iron-reducing bacteria. Also fermenting bacteria were shown to channel electrons to ferric iron via humic acids. Whether quinones or cytochromes released from cells act as electron transfer components in ferric iron reduction is still a matter of debate. Anaerobic ferrous iron-oxidizing phototrophic bacteria, on the other hand, appear to excrete complexing agents to prevent precipitation of ferric iron oxides at their cell surfaces. The present review evaluates recent findings on the physiology of ferric iron-reducing and ferrous iron-oxidizing bacteria with respect to their relevance to microbial iron transformations in nature.

Growth and survival of phosphate-solubilizing bacteria in calcium alginate

Calcium alginate was superior to conventional charcoal-soil (3:1) carrier for phosphate-solubilizing bacteria (PSB). H1gh populations of Pseudomonas striata (27) and Bacillus polymyxa (H-5) could be maintained in this polymer dunng storage. Incorporation of charcoal-soil (3:1) adversely affected the initial loading of these organisms in alginate gel. Alginate alone supported maximum survival of these organisms at elevated storage temperature (40°C).

A Kinetic Approach to Modeling Mobile Bacteria‐Facilitated Groundwater Contaminant Transport

Mobile bacterial particles can act as carriers and enhance the transport of hydrophobic contaminants in groundwater by reducing retardation effects. Because of their colloidal size and favorable surface conditions, bacteria act as efficient contaminant carriers. When such carriers exist in a water‐saturated porous medium, the system can be thought of as three phases: an aqueous phase, a carrier phase, and a stationary solid matrix phase. Contaminant may be present in either or all of these phases. In this study, a mathematical model based on mass balances is developed to describe the simultaneous transport and fate of a biodegradable contaminant and bacteria in a porous medium. The Monod model describes the relation between the growth rate of bacteria and concentration of the contaminant which serves as a growth substrate. The bacterial decay is assumed to be a first‐order reaction. The mechanisms of bacterial mass transfer between aqueous and solid matrix phases, and contaminant mass transfer between aqueous and bacterial phases are represented by kinetic models. Governing equations are nondimensionalized and solved to analyze the bacteria‐facilitated contaminant transport. The model is compared with a similar model obtained with local equilibrium assumption to understand the characteristics of kinetic and local equilibrium descriptions. Results show that the contaminant transport as well as bacterial transport can be described by local equilibrium assumption when Damköhler numbers are larger than 10. Significant sensitivities to model parameters, particularly bacterial growth rate and influent bacterial concentration, were observed. The numerical results of the bacteria carrier effect match favorably with experimental data reported in the literature.

Shelf life of phosphate-solubilizing inoculants as influenced by type of carrier, high temperature, and low moisture

A charcoal–soil mixture, paddy straw compost, and wheat bran were tested to explore their possible use as carriers for phosphate-solubilizing bacteria and fungi. The charcoal–soil mixture was found to be the best carrier for phosphate-solubilizing bacteria, and wheat bran, for phosphate-solubilizing fungi. Higher temperatures during storage markedly influenced the shelf life of phosphate-solubilizing microorganisms. Thermotolerant strains, such as Bacillus subtilis, Bacillus circulans, and Aspergillus niger, were found to survive not only at high storage temperatures (40 and 45 °C), but also at low moisture status in the carrier. Key words: inoculum carriers, thermotolerant strains, shelf life.

A host-dependent hybrid plasmid suitable as a suicidal carrier for transposable elements

Plasmid pAS8Tc s rep-1::Tn7 (abbreviated pAS8Rep-1), a derivative of the RP4-ColE1 hybrid plasmid pAS8 displaying ColE1-dependent replication/maintenance, was found capable of the introduction of transposon Tn7 into the genome of phytopathogenic Pseudomonas. The plasmid is potentially useful as a general purpose suicidal Tn carrier for bacteria that do not support stable replication/maintenance of ColE1 but are within the conjugational host range of RP4.

Influence of Microorganisms on the Flavor of Selected Precooked Frozen Foods

SUMMARY—Macaroni and cheese, blueberry. pie, and beef gravy served as carriers for various bacteria including Escherichia coli, Proteus vulgaris, Pseudomonas fluorescens, Pseudomonas aeruginosa, Pseudomonas geniculata, or a mold, Chrysosporium pannorum. The foods were inoculated with l,000,000 bacterial cells per gram or 250 mg, wet weight, of mold and compared with uninoculated samples after various intervals of frozen storage. Special effort was made to reduce the holding period both previous to freezing and for thawing to a minimum. A taste panel evaluated storage time and types of microorganisms for their effects on flavor and aroma, and found that in a limited number of instances the presence of certain microorganisms appeared to influence the flavor and aroma of food directly. More frequently, however, alterations in flavor or aroma developing during frozen storage seemed to be attributable either partially or wholly to factors other than the presence of or reactions incited by the microorganisms.

The response to inoculation of the three chromosome races of Trifolium ambiguum sown with and without a companion grass. II. The effect of the method of inoculation on the clover and grass

The inoculation of legumes is often carried out using skim-milk as the carrier for the nodule bacteria. Increased germination due to inoculation has often been reported but in this investigation the effects of the skim-milk and the bacteria have been separated. The results indicate that the early establishment of T. ambiguum was stimulated by the skim milk rather than the nodule bacteria. The mechanism of this effect is thought to be due to extra N present in the milk and possibly to an enhanced nitrogen-cycle in the inoculated soil and evidence is produced of increases in certain freeliving nitrogen fixing and nitrifying microorganisms.

BELGIUM

<h3>Prison Reform</h3> In a previous letter, I referred to various hygienic reforms in the Belgian penitentiary system. As a result of statistics published by the anthropologic service, which was established in 1907, the minister of justice has been prevailed upon to consider the immediate creation at Merxplas of a sanatorium for the tuberculous, a hospital for patients with venereal disease, and a home for epileptics. It is certainly the only logical course to take advantage of the time spent by a prisoner in a penitentiary to give him good medical care and improve his health in every way possible. The bacteria carrier who is not sterilized in prison will later resume his place in society. If he is returned to society in the same condition in which he arrived (or possibly in a worse state, for his contagiousness may have increased), he will be the cause of the spread of