Immobilization Of Microorganisms Research Articles

New Biocomposite Electrospun Fiber/Alginate Hydrogel for Probiotic Bacteria Immobilization

Biotechnological use of probiotic microorganisms involves providing them with appropriate conditions for growth, but also protection against environmental changes caused by an exchange of the medium, isolation of metabolites, etc. Therefore, the research on effective immobilization of probiotic microorganisms should be focused in this direction. The present study aimed to evaluate the effectiveness of an innovative hybrid immobilization system based on electrospun nanofibers and alginate hydrogel. The analyses carried out included the study of properties of the initial components, the evaluation of the degree and durability of cell immobilization in the final material, and their survival under stress conditions. Effective binding of microorganisms to the hydrogel and nanofibers was confirmed, and the collected results proved that the proposed biocomposite is an efficient method of cell protection. In addition, it was shown that immobilization on electrospun nanofibers leads to the preservation of the highest cell activity and the least cell growth restriction as compared to free or lyophilized cells only. The completed research opens new perspectives for the effective immobilization of microorganisms of significant economic importance.

Effect of bioaugmentation combined with activated charcoal on the mitigation of volatile fatty acids inhibition during anaerobic digestion

Volatile fatty acids (VFAs) accumulation is a common problem in anaerobic digestion, which is constraining the process. In this study, bioaugmentation was initially adopted as a measure to tackle the acidification problem in a continuous anaerobic digester. However, after bioaugmentation stopped, the promotive effect of bioaugmentation was hard to sustain. In comparison, the combination of bioaugmentation and Activated charcoal (AC) enabled a better reactor performance. The positive impact of AC on recovery from acidification in sequential batch reactors was thus investigated by feeding either propionate or acetate. The results implied that the addition of AC significantly increased the degradation rate of propionate, thus accelerating the biogas production rate (104 ~ 371%). Moreover, the role of AC is mainly in the immobilization of microorganisms to form bio-AC owing to AC’s physical characteristics (high-surface-area and large number of pores enables adsorption of microorganisms). The biofilms on the AC decreased the distance between the microbes and delayed the washout effect of microorganisms, enabling a longer-lasting effect of bioaugmentation. The 16S-rRNA analysis showed that the addition of AC led to the enrichment of syntrophic microbial guilds (syntrophic VFAs oxidizing bacteria and hydrogenotrophic methanogens). The potential function analysis (PICRUSt2) indicated the significant enhancement of formylmethanofuran dehydrogenase (EC 1.2.7.12) and coenzyme F420 hydrogenase (EC 1.12.98.1) by AC. The results suggested that the addition of AC promoted interspecies electron transfer.

The Decolorization of Synthetic Dyes with Immobilized Bacillus species

Although, synthetic dyes have toxic effects on to environment, are very important for coloration of large number of materials and lead to increasing concerns about color removal worldwide. Immobilization of microorganisms is one of the promising techniques for biological treatment of wastewater with the many advantages for industrial usage. This study aimed to determine the efficiency of immobilized four different Bacillus species (B. cereus, B. megaterium, B. subtilis and B. thuringiensis) on decolorization of dyes (maxilon red, methyl red and doracryl blue) at different Na-alginate concentrations. B. megaterium and B. thuringiensis were most effective and decolorized the maxilon red 92.63% and 90.74%, respectively, with the Na-alginate concentration of 2.5%. B. megaterium was the most effective strain in decolorization of doracryl blue with 75.91% decolorization value and with beads at 10% Na-alginate concentration. B. megaterium was the most effective strain in decolorization of methyl red with 64.99% decolorization and the beads were prepared with 10% Na-alginate concentration. Among the four Bacillus species, B. megaterium was the most effective in the decolorization experiments of all three dyes. Results of this study could be used as a reference for the development of effective removal technique for dyes in textile wastewater.

Polymeric Materials Used for Immobilisation of Bacteria for the Bioremediation of Contaminants in Water.

Bioremediation is a key process for reclaiming polluted soil and water by the use of biological agents. A commonly used approach aims to neutralise or remove harmful pollutants from contaminated areas using live microorganisms. Generally, immobilised microorganisms rather than planktonic cells have been used in bioremediation methods. Activated carbon, inorganic minerals (clays, metal oxides, zeolites), and agricultural waste products are acceptable substrates for the immobilisation of bacteria, although there are limitations with biomass loading and the issue with leaching of bacteria during the process. Various synthetic and natural polymers with different functional groups have been used successfully for the efficient immobilisation of microorganisms and cells. Promise has been shown using macroporous materials including cryogels with entrapped bacteria or cells in applications for water treatment and biotechnology. A cryogel is a macroporous polymeric gel formed at sub-zero temperatures through a process known as cryogelation. Macroporous hydrogels have been used to make scaffolds or supports for immobilising bacterial, viral, and other cells. The production of composite materials with immobilised cells possessing suitable mechanical and chemical stability, porosity, elasticity, and biocompatibility suggests that these materials are potential candidates for a range of applications within applied microbiology, biotechnology, and research. This review evaluates applications of macroporous cryogels as tools for the bioremediation of contaminants in wastewater.

A Non-Destructive, Tuneable Method to Isolate Live Cells for High-Speed AFM Analysis.

Suitable immobilisation of microorganisms and single cells is key for high-resolution topographical imaging and study of mechanical properties with atomic force microscopy (AFM) under physiologically relevant conditions. Sample preparation techniques must be able to withstand the forces exerted by the Z range-limited cantilever tip, and not negatively affect the sample surface for data acquisition. Here, we describe an inherently flexible methodology, utilising the high-resolution three-dimensional based printing technique of multiphoton polymerisation to rapidly generate bespoke arrays for cellular AFM analysis. As an example, we present data collected from live Emiliania huxleyi cells, unicellular microalgae, imaged by contact mode High-Speed Atomic Force Microscopy (HS-AFM), including one cell that was imaged continuously for over 90 min.

Immobilization of nitrifying bacteria on composite based on polymers and eggshells for nitrate production

Nitrification is a key step in biological nitrogen transformation which depends on the performance of specialized microorganisms. Generally, nitrifying bacteria present a low growth rate and performance which can be improved when immobilized as a biofilm. The development of new materials suitable for the immobilization of nitrifying microorganisms is very important in nitrification and wastewater treatment. In this study, the effect of eggshell powder on biofilm formation by Nitrosomonas europaea an ammonium-oxidizing bacteria and Nitrobacter vulgaris a nitrite-oxidizing bacteria, on new polymeric supports were analyzed. Polylactic acid, polyvinyl chloride and polystyrene were tested to produce polymer-eggshells powder composites and used as biofilm supports for nitrifying bacteria. The support material was characterized to identify the most suitable polymer-eggshells powder combination for the cell adhesion and biofilm formation. The nitrification results showed a highest nitrate production of 42mg NO3--N/L with polylactic acid-eggshell composite, with the best surface properties for cellular adhesion. Finally, scanning electron microscopy micrographs confirmed the best biofilm formed on polylactic acid-eggshell.

Treatment of 1,4-dioxane-containing water using carriers immobilized with indigenous microorganisms in landfill leachate treatment sludge: A laboratory-scale reactor study

1,4-Dioxane (DX) is a contaminant of emerging concern in aquatic environments, and is frequently found in landfill leachate. As a biological method applicable to landfill leachate treatment facilities, the feasibility of DX treatment using carriers immobilized with microorganisms indigenous to landfill leachate treatment sludge was explored through laboratory-scale reactor experiments by introducing carriers prepared via microorganism immobilization in the aeration tank of a leachate treatment facility. Three different carrier materials were used to immobilize microorganisms, and a model DX-containing water (10 mg/L) was treated under continuous feeding. Biological DX removal to < 0.5 mg/L was achieved using all carrier types, thereby adhering to the effluent standard for landfill leachate in Japan, which confirms the usefulness of the proposed method. However, weaker aeration and enhanced DX loading drastically impaired the DX removal performance depending on the carrier materials. This suggests the importance of carrier selection and control of the operational variables to ensure stable and effective DX removal. Microbial community analyses revealed that Pseudonocardia with thm genes may largely contribute to the initial oxidation of DX, irrespective of the carrier type, suggesting the importance of this population for the continuous treatment of low DX concentrations with mixed microbial consortia.

Polyurethane Foams for Domestic Sewage Treatment.

The aim of the study was to assess the possibility of using polyurethane foams (PUF) as a filling of a foam-sand filter to directly treat domestic sewage with increased content of ammonium nitrogen and low organic carbon to nitrogen ratio (C/N). The study compared performance of two types of flexible foams: new, cylinder-shaped material (Novel Foams, NF) and waste, scrap foams (Waste Foams, WF). The foams serving as a filling of two segments of a foam-sand filter were assessed for their hydrophobic and physical properties and were tested for their cell structure, i.e., cell diameter, cell size distribution, porosity, and specific surface area. The study accounted also for selected application-related properties, such as hydrophobicity, water absorption, apparent density, dimensional stability, amount of adsorbed biomass, and the possibility of regeneration. Cell morphology was compared in reference foams, foams after 14 months of the filter operation, and regenerated foams. The experimental outcomes indicated WF as an innovative type of biomass carrier for treating domestic sewage with low C/N ratio. SEM images showed that immobilization of microorganisms in NF and WF matrices involved the formation of multi-cellular structures attached to the inner surface of the polyurethane and attachment of single bacterial cells to the foam surface. The amount of adsorbed biomass confirmed that the foam-sand filter made up of two upper layers of waste foams (with diameters and pore content of 0.50–1.53 mm and 53.0–63.5% respectively) provided highly favorable conditions for the development of active microorganisms.

Solution of environmental problems of livestock breeding through intensification of waste treatment processes

Intensification of anaerobic processing of animal waste has a significant effect in comparison with other methods, which is expressed in a significant reduction in the pollution of environmental objects (air, water and soil) with chemicals and pathogenic microflora. The paper shows the developed technology of anaerobic processing of animal products, which allows one, on the one hand, to solve the environmental problems of animal husbandry, and on the other hand, to produce biogas fuel. The design features of the experimental setup for research are considered. The main indicators of the initial and re-loading manure and the properties of the resulting biogas have been analyzed. It was concluded that a promising direction for increasing the yield of biogas, as well as methane in its composition, it is advisable to improve the design of the bioreactor, to increase the productivity of the bioreactor and reduce the HRT through the use of a leaching layer and immobilization of microorganisms. At the same time, preliminary grinding of the raw material allows one to obtain a relatively better result.

Study on the preparation conditions and degradation performance of an efficient immobilized microbial agent for marine oil pollution

ABSTRACT In the process of handling marine oil spills accidents, the biological method has attracted wide attention due to its low cost and no secondary pollution. However, in the process of practical application, there are problems such as low microbial density and great influence of environmental factors when the oil is treated by spraying microorganisms on the sea surface. This study used immobilized microorganism technology to solve the above-mentioned problems. In this study, the bacteria immobilized on cinnamon shell (CS) with good degradation performance were obtained by optimizing preparation conditions. Under the optimal conditions of sodium alginate (SA) concentration of 4.57%, CS concentration of 1.28%, and the CaCl2 concentration of 2.45%, the degradation rate of diesel in 5 days reached 74.04%. The reusability of immobilized microbial agents was further studied. The study designed three cycles of repeated degradation experiments. The results showed that the degradation rate of diesel can still reach 60.12% after three times of reuse, which indicated the reusability of the immobilized microbial agents was excellent. The decrease in degradation rate of diesel was mainly related to the fragmentation of immobilized microbial agents and the decrease in microbial biomass.

Antagonistic effect of Frankia F1 on Ginseng crops soil-borne diseases and microbial community soil structure

ABSTRACT Root and rust rot are common fungal diseases that decrease both the yield and quality of ginseng, resulting in severe economic losses for the ginseng industry. In this study, we explored the bacteriostatic and greenhouse control effects that the actinomycetes strain Frankia F1, extracted from the ginseng-rhizosphere soil, has on the pathogenic fungi that cause ginseng root rot (Fusarium solani) and rust rot (Cylindrocarpon destructans). We found that F1 fermentation broth inhibited the rate of mycelia growth by 80.6% and 71.1%, as well as the rate of spore germination by 87.0% and 78.6%, in F. solani. and C. destructans, respectively. Moreover, the antagonistic mechanism of F1 crude extract damaged the cell membranes of pathogens and led to a decreased ability to reduce sugar and soluble protein. The immobilised microorganisms of germ bran and germ bran charcoal improved the physical and chemical properties and soil fertility, improved the microbial community structure, increased the relative abundance of Proteobacteria, and reduced the relative abundance of Acidobacteria. An F1 biocontrol strategy could reduce economic and agricultural losses within the ginseng industry if implemented.

Эффективность анаэробной переработки органических отходов в биофильтрах с использованием кондуктивного носителя

Additional anaerobic treatment of the liquid fraction of the methantenk’s effluent to the content of organic substances that ensure subsequent effective processing under aerobic conditions can be carried out in a biofilter. Processing makes it possible to obtain an additional amount of biogas, reduce the volume of sludge residues. To accelerate the processes of wastewater treatment and optimize the processes of anaerobic processing of wastewater, the use of conductive carriers of inorganic biomass is promising. (Research purpose) The research purpose is in studying the effect of conductive biomass carriers on the efficiency of anaerobic processing of organic waste in biofilters. (Materials and methods) The liquid fraction of the effluent obtained as a result of the gravitational separation of the effluent of the methantenk was used as a substrate for the biofilter. The article describes experimental studies on a test bench that includes two identical bioreactors, in one of which there was placed a biomaterial carrier made of carbon tissue. The article presents a technological scheme and an experimental installation for anaerobic post-treatment of the liquid effluent fraction. (Results and discussion) In the course of experimental studies for 25 days, they showed high stability of the operation of the developed and manufactured experimental installation. In the recycled effluent of a bioreactor with a conductive carrier, the organic substances of the effluent are more fully processed into biogas. The specific (in terms of unit volume of the bioreactor) yields of biogas and methane increased by 14.0 and 22.5 percent; the specific methane yield per gram of raw and decomposed organic matter increased by 22.2 and 7.3 percent. (Conclusions) The use of a biofilter in combination with the immobilization of microorganisms on a conductive carrier allowed to increase the efficiency of fermentation of organic waste by 6 percent, increase the specific yields of biogas and methane, and reduce the volume of sludge residues.

A Biosensor Based Microorganisms Immobilized in Layer-by-Layer Films for the Determination of Biochemical Oxygen Demand

A new approach has been developed for the formation of the biosensor recognition elements via the immobilization of microorganisms in layer-by-layer films in order to determine the biochemical oxygen demand (BOD). Bioreceptor elements of BOD-biosensors have been fabricated based on the bacterial microorganisms Paracoccus yeei, Pseudomonas veronii, and Bacillus proteolyticus isolated from activated sludge. The recognition element was formed with via layer-by-layer deposition; each layer contained cells of one species. A similar multilayered recognition element based on yeast cells of Ogataea angusta, Blastobotrys adeninivorans, and Debaryomyces hansenii was created. In both cases, the cells were immobilized in a hydrogel of polyvinyl alcohol modified with N-vinylpyrrolidone. It was found that layer-by-layer immobilization increases the sensitivity of both the yeast- and bacterial cell–based biosensors. It was surmised that this is due to the lack of competition for substrate within the layer and its greater ability to each of the cell layers. The effects of the composition of the assayed samples (pH, ionic strength, heavy metal compounds) on the oxidative activity of the developed recognition elements have been studied. The analytical and metrological characteristics of the biosensors have been defined. The lower limit of the estimated BOD5 values was 0.5 mg О2/dm3 and 0.7 mg О2/dm3 for bacterial- and yeast cell–based biosensors, respectively. BOD5 was detected in water samples with the fabricated recognition elements. It was shown that the use of these two bioreceptors makes it possible to obtain data that strongly agree with those obtained with traditional method and that biosensing analyzers can act as prototype pilot model of the devices

Batch CGTase Production with Free and Immobilized &amp;lt;i&amp;gt;Bacillus firmus&amp;lt;/i&amp;gt; Strain 37 in Bovine Bone Charcoal

The present study aimed to study the batch production of CGTase (cyclomaltodextrin-glucanotransferase) with Bacillus firmus strain 37 free and immobilized in bovine bone charcoal in batch mode and in a fluidized bed batch reactor, respectively. The bovine bone charcoal is an innovative support material for the immobilization of microorganisms’ producers of enzymes and the use of this microbial support allows its reuse to a significant cost reduction of the process. The batch fermentation with free cells was investigated for 96 h and reached a CGTase activity equal to 0.77 U/mL. When the microorganism was immobilized on bovine bone charcoal (7 g) and cultivated in fluidized bed batch reactor with air supplementation (1 volume of air/volume of medium * minute), the same activity could be achieved in 24 h. The results of enzymatic activity achieved show the potential of CGTase production in a short time with Bacillus firmus strain 37 immobilized in bovine bone charcoal matrix and using air supplementation in the production medium.

Biofuel generation from high-fat effluent in a biofilm reactor with backwash

ABSTRACT The performance of an up-flow 0.5 m high and 0.076 m diameter fixed-film bioreactor treating lipid-rich synthetic wastewater has been investigated under the present study. The initial porosity of the filter bed using immobilised microorganisms were on the support matrices has been measured to be 0.67. Excess biomass accumulation on the support leads to an increase in biofilm thickness with time. The filter bed has been regenerated by backwashing after the stipulated time to regain its efficiency in terms of COD removal through the revival of the contact surface. A mathematical model has been developed to predict the loss of contact area and decrease in the porosity of bed with operation time. The backwashing time has been correlated to the inlet concentration of substrate. Methanogens like Methanococcus sp. and Methanosarcina sp. are detected in the mixed anaerobic consortia and favourable growth condition for methanogens in the reactor leads to a maximum cumulative methane production at the exit of the reactor estimated to be 785 ml CH4 (STP)/(g VSS added). The originality of the present research lies in investigating erucic acid-rich wastewater in a bioreactor with backwash and proposing an integration of this bioconversion with syngas-based 2G-Biorefinery.

A developed hybrid fixed-bed bioreactor with Fe-modified zeolite to enhance and sustain biohydrogen production

In this study, we describe the development of a hybrid bioreactor with integrated chlorinated polyethylene (CPE) fixed-bed and zeolite as a microorganism nutrition carrier (MNC), aiming at enhancing and sustaining biohydrogen production during the anaerobic digestion (AD) process. In the batch test, the hybrid bioreactor achieved a maximum biohydrogen production of 646.3 mL/L. Accordingly, the hybrid bioreactor significantly enhanced biohydrogen production and maintained a stable performance for 50 days of semi-continuous operation. This result should be attributed to the CPE providing roughness surface and high porosity for microorganism immobilization, resulting in the enhancement of microbial quantity, confirmed by our scanning electron microscope and immobilized biomass analyses. Moreover, the element ratio significantly decreased, indicating that zeolite could provide metal cations for stimulating microbial bioactivity and growth, as well as contributing to superior biohydrogen productivity during the 50-day operation. In order to further enhance and sustain long-term biohydrogen production, raw zeolite was modified with iron. The hybrid-Fe bioreactor (CPE with Fe-modified zeolite) operated mainly following the acetate pathway and exhibited higher sustainability in improving biohydrogen production with a peak value of 1893.0 mL/L during a 72-day-lasting operation. The synergistic mechanism of the Fe-modified zeolite and CPE fixed-bed revealed that it could effectively induce favorable pathways and contribute to the synthesis of essential enzymes, micronutrient supplementation, electoral conductivity, and microbial immobilization for biohydrogen production. Therefore, a hybrid-Fe bioreactor could provide a unique alternative for the enhancement of hydrogen production for practical applications.

Crack self-healing of cement-based materials by microorganisms immobilized in expanded vermiculite

Cement-based materials were the most widely used building materials in the world, among which lightweight aggregate could be used in the fields of heat preservation and fire resistance, and had a great development prospect. In this paper, crack self-healing of cement-based materials by microorganisms immobilized in expanded vermiculite was studied. First of all, the adsorption and immobilization of microorganisms by expanded vermiculite was effective, and the microorganisms could be revived and had strong activity after immobilization. Secondly, the expanded vermiculite was wrapped by different methods, such as silicone hydrophobic agent, aqueous epoxy resin and composite paste. The best treatment method was wrapped by composite paste in terms of water absorption rate, and water absorption rate was only 62.7%. The high alkaline environment was not conducive to the survival of microorganisms, and the carrier could provide effective protection for microorganisms. Finally, the mechanical properties of cement-based materials and the effect of crack self-healing were confirmed. Compared with the initial expanded vermiculite specimens, the mechanical properties of the expanded vermiculite specimens wrapped by composite paste were significantly improved. The replaced rate of expanded vermiculite should not be higher than 20% to ensure the mechanical properties of cement-based materials. The effect of cracks repair in cement-based materials gradually improved with the extension of curing age. The cracks with the width of 400 μm were basically repaired after curing for 28 days. The mineralized products were identified as calcite, and they not only blocked the cracks surface, but also filled a certain depth.

Different biochars as microbial immobilization substrates for efficient copper II removal

Immobilization of microorganisms is a widely used strategy to effectively degrade copper II pollution. Microorganisms can be immobilized in synthetic or natural substrates. In this study, different parts of dried corn (root, stalk, leaf, and cob) were used to immobilize microorganism cells and to explore the potential of the carrier to mitigate copper II pollution. Different substrates were pyrolyzed at different temperatures and the obtained biochar was immobilized by Stenotrophomonas maltophilia. The structural characteristics and properties of the biochars were determined using scanning electron microscopy, X-ray diffractometer, energy dispersive spectrometry, and infrared spectrometry and the copper II removal mechanism by the biochar-microbial carriers were analyzed. Corn stalk biochar pyrolyzed at 250 °C had the best pore structure and the best supporting effect on microorganisms; the biochar-microbial carrier also had the strongest copper II removal ability. The control experiment showed that the carrier removal mechanism is composed of biochar adsorption and microbial degradation. Preparation at different conditions will also affect the removal performance of the carrier; when the microorganism inoculation amount is 10%, the immobilization time is 30 hours, the biochar diameter is 0.147–0.074 mm, and the immobilized carrier has the best performance. The precise screening of waste substrates resulted in the preparation of more efficient carriers, which enhanced the removal of copper II while improving waste utilization.

2D Nanocarbons as the Matrix for Immobilized Microbial Preparations

Experimental data on the production of dry powders of immobilized biological preparations intended for treatment of oil-contaminated soil were obtained. The carbonization of biopolymers (starch, lignin) using self-propagating high-temperature synthesis was used as the basic method for obtaining 2D carbon structures used as a matrix for immobilization of oil-destructor microorganisms. Oil-destructor Microorganisms were selected from the accredited collection of the All Russian Institute of Plant Protection. The obtained experimental samples of biological preparations have shown their potential for eliminating the anthropogenic consequences of soil contamination with petroleum products.

Tailoring polymeric composite gel beads-encapsulated microorganism for efficient degradation of phenolic compounds

Phenol and its derivatives are highly toxic pollutants in industrial wastewater for the ecological environments, so there is essential attention to develop effective means of removing these harmful substances from water. In this work, the microorganism was immobilized into polymeric composite gel beads prepared by the effective recombination of natural abundant chitosan (CS) and industrial polyvinyl alcohol (PVA) for treating phenolic compounds. The degradation rate of 99.5% can be achieved to treat 100 mg·L−1 of phenol at 30 °C using the fresh resultant immobilized microorganism, where only 21.1% degradation rate was obtained by the free microorganism under the identical conditions. The recycling experiments of repeated 90 times to treat 100 mg·L‐1 of phenol displayed that the degradation rate of phenol was stable to 99% with the appearance of beads unchanged significantly, indicating the immobilized microorganism possessed excellent operating stability. Moreover, while the phenol derivatives of 100 mg·L−1 were treated catalytically including p-methylphenol, catechol, and o-aminophenol for 24 h by the immobilized microorganism, the degradation rates were all above 95%. The immobilized microorganism into PVA-CS polymeric composite with excellent operating stability and degradation activity would provide a feasible solution for treating phenolic compounds in water in industrial applications.