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1.
Int J Biol Macromol ; 209(Pt A): 9-30, 2022 Jun 01.
Article in English | MEDLINE | ID: mdl-35381280

ABSTRACT

Bacterial cellulose (BC), an extracellular polysaccharide, is a versatile biopolymer due to its intrinsic physicochemical properties, broad-spectrum applications, and remarkable achievements in different fields, especially in the biomedical field. Presently, the focus of BC-related research is on the development of scaffolds containing other materials for in-vitro and in-vivo biomedical applications. To this end, prime research objectives concern the biocompatibility of BC and the development of three-dimensional (3D) BC-based scaffolds. This review summarizes the techniques used to develop 3D BC scaffolds and discusses their potential merits and limitations. In addition, we discuss the various biomedical applications of BC-based scaffolds for which the 3D BC matrix confers desired structural and conformational features. Overall, this review provides comprehensive coverage of the idea, requirements, synthetic strategies, and current and prospective applications of 3D BC scaffolds, and thus, should be useful for researchers working with polysaccharides, biopolymers, or composite materials.


Subject(s)
Cellulose , Tissue Scaffolds , Bacteria , Biocompatible Materials/chemistry , Cellulose/chemistry , Tissue Engineering/methods , Tissue Scaffolds/chemistry
2.
Int J Biol Macromol ; 137: 247-252, 2019 Sep 15.
Article in English | MEDLINE | ID: mdl-31260774

ABSTRACT

Bacterial cellulose (BC), representing the highly purified form of cellulose, possesses better nanofibrous morphology and superior mechanical properties than plant cellulose (PC). However, the regeneration process, which produces intermediate structures, significantly alters the original properties of native cellulose and result in varied structural and physico-mechanical features. Therefore, it is important to estimate the degree of variations in the structures and properties of both PC and BC during their regeneration. Herein, we conducted a detailed comparative study by dissolving BC and PC in N-methylmorpholine N-oxide (NMMO) and synthesizing their regenerated gels, namely regenerated bacterial cellulose (RBC) and regenerated plant cellulose (RPC), respectively. The structural features of BC, PC, RBC, and RPC were comparatively evaluated via field-emission scanning electron microscopy, X-ray diffraction, porosity analyses, as well as analyzed their mechanical, thermal, and liquid-holding capabilities. The results showed inferior mechanical, thermal, and crystalline features of RBC and RPC to their respective counterparts. However, RBC showed better porosity, water absorption capability, and water retention time than RPC. The overall mechanical, thermal, and physiological features of RBC were better than those of RPC. These findings may facilitate the use of RBC in composite synthesis for various applications.


Subject(s)
Bacteria/chemistry , Cellulose/chemistry , Plants/chemistry , Cellulose/ultrastructure , Chemical Phenomena , Mechanical Phenomena , Polymers/chemistry , Porosity , Solubility , Spectrum Analysis
3.
Int J Biol Macromol ; 117: 1200-1210, 2018 Oct 01.
Article in English | MEDLINE | ID: mdl-29894790

ABSTRACT

This study reports the fabrication of porogen-induced, surface-modified, 3-dimensionally microporous regenerated bacterial cellulose (rBC)/gelatin (3DMP rBC/G) scaffolds for skin regeneration applications. Round shaped gelatin microspheres (GMS), fabricated using a water-in-oil emulsion (WOE) method, were utilized as the porogen. The dissolution of GMS from the solution casted BC scaffolds led to surface-modified microporous rBC. The scaffolds were characterized using field emission scanning electron microscopy (FE-SEM) and elemental analysis. FE-SEM analysis confirmed the regular microporosity of the 3DMP rBC/G scaffolds, while elemental analysis confirmed the successful surface modification of cellulose with gelatin. In vitro tests showed good adhesion and proliferation of human keratinocytes (HaCaT) on the 3DMP rBC/G scaffolds during 7 days of incubation. Confocal microscopy showed penetration of HaCaT cells into the scaffolds, up to 300 µm in depth. In vivo wound healing and skin regeneration experiments, in experimental mice, showed complete skin regeneration within 2 weeks. The wound closure efficacy of the 3DMP rBC/G scaffolds was much higher (93%) than that of the control (47%) and pure BC-treated (63%) wounds. These results indicated that our 3DMP rBC/G scaffolds represent future candidate materials for skin regeneration applications.


Subject(s)
Bacteria/chemistry , Biocompatible Materials/chemistry , Cellulose/chemistry , Cellulose/isolation & purification , Microspheres , Tissue Scaffolds/chemistry , Cell Adhesion , Cell Culture Techniques , Cell Line , Cell Survival , Humans , Keratinocytes , Materials Testing , Porosity , Printing, Three-Dimensional , Regeneration , Skin/cytology , Skin Physiological Phenomena , Tissue Engineering , Wound Healing
4.
Int J Biol Macromol ; 113: 526-533, 2018 Jul 01.
Article in English | MEDLINE | ID: mdl-29477541

ABSTRACT

The current study was designed to prepare surface modified BC matrices loaded with model drugs selected on the basis of their aqueous solubility, i.e., poorly water soluble famotidine and highly water soluble tizanidine. Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) confirmed the successful drug loading and thermal stability of the BC matrices. In-vitro dissolution studies using USP type-II dissolution apparatus showed that most of the drug was released in 0.5-3h from famotidine loaded matrices and in 0.25-0.5h from tizanidine loaded matrices. The chemical structure, concentration of the loaded drug, concentration of the surface modifier, and pre- and post-drug loading modifications altered the physicochemical properties of BC matrices, which in turn affected the drug release behavior. In general, surface modification of the BC matrices enhanced the drug release retardant properties in pre-modification drug loading. Surface modification was found to be effective for controlling the drug release properties of BC. Therefore, these modified BC matrices have the potential for applications in modified drug delivery systems.


Subject(s)
Cellulose/chemistry , Drug Carriers/chemistry , Gluconacetobacter xylinus/chemistry , Clonidine/analogs & derivatives , Clonidine/chemistry , Drug Liberation , Famotidine/chemistry , Kinetics , Solubility , Surface Properties , Water/chemistry
5.
Int J Biol Macromol ; 107(Pt A): 865-873, 2018 Feb.
Article in English | MEDLINE | ID: mdl-28935538

ABSTRACT

This study reports the fabrication of highly conducting and biocompatible bacterial cellulose (BC)-gold nanoparticles (AuNPs)-poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) (BC-AuNPs-PEDOT:PSS) composites for biology-device interface applications. The composites were fabricated using ex situ incorporation of AuNPs and PEDOT:PSS into the BC matrix. Structural characterization, using scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and x-ray diffraction (XRD) analysis, confirmed the uniform nature of the synthesized BC-AuNPs and BC-AuNPs-PEDOT:PSS composites. Four-point probe analysis indicated that the BC-AuNPs and BC-AuNPs-PEDOT:PSS films had high electrical conductivity. The composites were also tested for biocompatibility with animal osteoblasts (MC3T3-E1). The composite films supported adhesion, growth, and proliferation of MC3T3-E1 cells, indicating that they are biocompatible and non-cytotoxic. AuNPs and PEDOT:PSS, imparted a voltage response, while BC imparted biocompatibility and bio-adhesion to the nanocomposites. Therefore, our BC-AuNPs-PEDOT:PSS composites are candidate materials for biology-device interfaces to produce implantable devices in regenerative medicine.


Subject(s)
Biocompatible Materials/chemistry , Cellulose/chemistry , Metal Nanoparticles/chemistry , Polymers/chemistry , Animals , Bacteria/chemistry , Cellulose/ultrastructure , Electric Conductivity , Gold/chemistry , Metal Nanoparticles/ultrastructure , Microscopy, Atomic Force , Microscopy, Electron, Scanning , Microscopy, Electron, Transmission , Polystyrenes/chemistry , Regenerative Medicine , Spectroscopy, Fourier Transform Infrared , Thiophenes/chemistry , X-Ray Diffraction
6.
Int J Biol Macromol ; 102: 1166-1173, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28487196

ABSTRACT

Bacterial cellulose (BC) has received substantial attention because of its high purity, mechanical strength, crystallinity, liquid-absorbing capabilities, biocompatibility, and biodegradability etc. These properties allow BC to be used in various fields, especially in industries producing medical, electronic, and food products etc. A major discrepancy associated with BC is its high production cost, usually much higher than the plant cellulose. To address this limitations, researchers have developed several strategies for enhanced production of BC including the designing of advanced reactors and utilization of various carbon sources. Another promising approach is the production of BC from waste materials such as food, industrial, agricultural, and brewery wastes etc. which not only reduces the overall BC production cost but is also environment-friendly. Besides, exploration of novel and efficient BC producing microbial strains provides impressive boost to the BC production processes. To this end, development of genetically engineered microbial strains has proven useful for enhanced BC production. In this review, we have summarized major efforts to enhance BC production in order to make it a cost-effective biopolymer. This review can be of interest to researchers investigating strategies for enhanced BC production, as well as companies exploring pilot projects to scale up BC production for industrial applications.


Subject(s)
Biotechnology/economics , Cellulose/biosynthesis , Cost-Benefit Analysis , Bioreactors/microbiology , Biotechnology/instrumentation
7.
Environ Sci Pollut Res Int ; 24(14): 12713-12722, 2017 May.
Article in English | MEDLINE | ID: mdl-28378308

ABSTRACT

Nanotechnology is a fast-emerging field and has received applications in almost every field of life. Exploration of new synthetic technologies for size and shape control of nanomaterials is getting immense consideration owing to their exceptional properties and applications. Magnetic nanoparticles (MNPs) are among the most important group of nanoparticles thanks to their diverse applications in medical, electronic, environmental, and industrial sectors. There have been numerous synthetic routes of MNPs including thermal decomposition, co-precipitation, microemulsion, microwave assisted, chemical vapor deposition, combustion synthesis, and laser pyrolysis synthesis. The synthesized MNPs have been successfully applied in medical fields for therapy, bioimaging, drug delivery, and so on. Among environmental aspects, there has been great intimidation of organic pollutants in air and water. Utilization of various wastes as adsorbents has removed 80 to 99.9% of pollutants from contaminated water. MNPs as adsorbents compared to coarse-grained counterparts have seven times higher capacity in removing water pollutants and degrading organic contaminants. This study is focused to introduce and compile various routes of MNP synthesis together with their significant role in water purifications and degradation of organic compounds. The review has compiled recent investigation, and we hope it will find the interest of researchers dealing with nanoparticles and environmental research. Graphical abstract Synthesis and applications of magnetic nanoparticles.


Subject(s)
Magnetics , Magnetite Nanoparticles/chemistry , Adsorption , Nanoparticles/chemistry , Nanotechnology , Water Purification
8.
Recent Pat Nanotechnol ; 10(3): 169-180, 2016.
Article in English | MEDLINE | ID: mdl-27136931

ABSTRACT

BACKGROUND: Cellulose being the most abundant polymer has been widely utilized in multiple applications. Its impressive nanofibril arrangement has provoked its applications in numerous fields. Recent trends have been shifted to produce composites of nanocellulose for numerous applications among which the most important ones are its use in medical and environmental prospective. This review has basically focused the development of nanocellulose composites and its applications in resolving environmental hazards. METHODS: We have reviewed large number of research and review articles from famous journals using a focused review question. The quality of retrieved papers was assessed through standard tools. The contents from reviewed articles were described in scientific way. RESULTS: We included 85 papers including research and review articles and patents in this review. 18 papers introduced the theme of current review. More than 10 papers were used to describe the approaches used for synthesizing cellullose nanocomposites. Composite synthesis strategies included the in situ addition, ex situ penetration, solution mixing, and solvent casting etc. Around 60 manuscripts including 6 patents were used to demonstrate various applications of nanocellulose composites. Nanocellulose based materials offer several applications in the development of antimicrobial filters, air and water filters, filters for removal of heavy metals, pollutant sensors as well as applications in catalysis and energy sectors. Such products are more efficient, robust, reliable, and environment-friendly. CONCLUSION: This review gives a comprehensive picture of ongoing research and development on environmental remediation by nanotechnology. We hope that the contents reviewed herein will catch the reader's interest and will provide interesting background to extend future research activities regarding cellulose based materials.


Subject(s)
Cellulose/chemistry , Environmental Restoration and Remediation , Nanocomposites/chemistry , Patents as Topic
9.
Carbohydr Polym ; 136: 908-16, 2016 Jan 20.
Article in English | MEDLINE | ID: mdl-26572428

ABSTRACT

This study was aimed to characterize the structural and physico-mechanical properties of bio-cellulose produced through cell-free system. Fourier transform-infrared spectrum illustrated exact matching of structural peaks with microbial cellulose, used as reference. Field-emission scanning electron microscopy revealed that fibrils of bio-cellulose were thicker and more compact than microbial cellulose. The specific positions of peaks in the X-ray diffraction and nuclear magnetic resonance spectra indicated that bio-cellulose possessed cellulose II polymorphic structure. Bio-cellulose presented superior physico-mechanical properties than microbial cellulose. The water holding capacity of bio-cellulose and microbial cellulose were found to be 188.6 ± 5.41 and 167.4 ± 4.32 times their dry-weights, respectively. Tensile strengths and degradation temperature of bio-cellulose were 17.63 MPa and 352 °C, respectively compared to 14.71 MPa and 327 °C of microbial cellulose. Overall, the results indicated successful synthesis and superior properties of bio-cellulose that advocate its effectiveness for various applications.


Subject(s)
Cellulose/chemistry , Gluconobacter/enzymology , Polysaccharides, Bacterial/chemistry , Cell-Free System/metabolism , Cellulose/metabolism , Gluconobacter/metabolism , Hydrolysis , Hydrophobic and Hydrophilic Interactions , Industrial Microbiology/methods , Polysaccharides, Bacterial/metabolism , Tensile Strength
10.
J Food Sci Technol ; 52(12): 8343-9, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26604413

ABSTRACT

Bacterial cellulose (BC) has been given an ample attention due to its high potential for many industrial applications. However, the high cost of production medium has hindered the commercialization of BC. Several efforts have been made to explore cheep, raw and waste sources for BC production. The current study aims at investigating the BC production from a waste source; the scum obtained during preparation of sugarcane jaggery or gur (JS). JS was five-fold diluted with distilled water and used as culturing medium without any additional nutrients. The production of BC was monitored till 10th days of cultivation both at static and shaking culturing conditions. A maximum of 2.51 g/L and 2.13 g/L BC was produced in shaking and static cultures, respectively, after 10 days. The structure features of BC were confirmed through FTIR, XRD and SEM analysis. The chemical structure and physical appearance strongly resembled the BC produced form synthetic media. It was noteworthy that the BC produced from JS showed higher mechanical and thermal properties. The cell adhesion and proliferation capabilities of produced BC were observed that depicted definite animal cell adhesion without any considerable cytotoxicity. Besides providing an economically feasible way for BC production, the high level of physico-mechanical and biological properties insured the importance in medical fields.

11.
Biotechnol J ; 10(12): 1847-61, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26395011

ABSTRACT

Bacterial cellulose (BC), owing to its pure nature and impressive physicochemical properties, including high mechanical strength, crystallinity, porous fibrous structure, and liquid absorbing capabilities, has emerged as an advanced biomaterial. To match the market demand and economic values, BC has been produced through a number of synthetic routes, leading to slightly different structural features and physical appearance. Chemical nature, porous geometry, and 3D fibrous structure of BC make it an ideal material for composites synthesis that successfully overcome certain deficiencies of pure BC. In this review, we have focused various strategies developed for synthesizing BC and BC composites. Reinforcement materials including nanoparticles and polymers have enhanced the antimicrobial, conducting, magnetic, biocompatible, and mechanical properties of BC. Both pure BC and its composites have shown impressive applications in medical fields and in the development of optoelectronic devices. Herein, we have given a special attention to discuss its applications in the medical and electronic fields. In conclusion, BC and BC composites have realistic potential to be used in future development of medical devices, artificial organs and electronic and conducting materials. The contents discussed herein will provide an eye-catching theme to the researchers concerned with practical applications of BC and BC composites.


Subject(s)
Biocompatible Materials/chemical synthesis , Cellulose/chemical synthesis , Polysaccharides, Bacterial/chemical synthesis , Biocompatible Materials/chemistry , Cellulose/chemistry , Electronics, Medical , Equipment and Supplies , Nanocomposites/chemistry , Polysaccharides, Bacterial/chemistry
12.
Carbohydr Polym ; 132: 286-94, 2015 Nov 05.
Article in English | MEDLINE | ID: mdl-26256351

ABSTRACT

The current study was intended to produce bio-cellulose through a cell-free system developed by disrupting Gluconacetobacter hansenii PJK through bead-beating. Microscopic analysis indicated the complete disruption of cells (2.6 × 10(7) cells/mL) in 20 min that added 95.12 µg/mL protein, 1.63 mM ATP, and 1.11 mM NADH into the medium. A liquid chromatography mass spectrometry/mass spectrometry linear trap quadrupole (LC-MS/MS LTQ) Orbitrap analysis of cell-lysate confirmed the presence of all key enzymes for bio-cellulose synthesis. Under static conditions at 30 °C, microbial and cell-free systems produced 3.78 and 3.72 g/L cellulose, corresponding to 39.62 and 57.68% yield, respectively after 15 days. The improved yield based on consumed glucose indicated the superiority of cell-free system. Based on current findings and literature, we hypothesized a synthetic pathway for bio-cellulose synthesis in the cell-free system. This approach can overcome some limitations of cellulose-producing cells and offers a wider scope for synthesizing cellulose composites with bactericidal elements through in situ synthesizing approaches.


Subject(s)
Cell-Free System/metabolism , Cellulose/metabolism , Gluconacetobacter/metabolism , Glucose/metabolism , Industrial Microbiology/methods , Tandem Mass Spectrometry
13.
Carbohydr Polym ; 127: 86-93, 2015.
Article in English | MEDLINE | ID: mdl-25965460

ABSTRACT

Electrically conducting bacterial cellulose (BC) membranes were prepared by ex situ incorporation of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) ( PEDOT: PSS) into BC pellicles. The BC pellicles were immersed into an aqueous solution of PEDOT: PSS for 6, 12, 18, or 24h, and the resultant composites were vacuum dried at ambient temperature. The structural features of the composites were determined using X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), Fourier-transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD). XPS confirmed synthesis of the composites, and SEM showed uniform incorporation of PEDOT: PSS into the BC matrix. The FTIR spectra of the composites exhibited characteristic bands for both BC and PEDOT: PSS, and XRD analysis showed a slight decrease in crystallinity during composite preparation. The electrical conductivity of the composites was 12.17S/cm for incorporation of 31.24 wt% PEDOT: PSS into the BC matrix. These highly conducting BC-PEDOT:PSS composites are expected to find potential applications in optoelectronic devices such as biosensors, organic light-emitting diodes, and solar cells.


Subject(s)
Cellulose/chemistry , Electric Conductivity , Nanotubes/chemistry , Polysaccharides, Bacterial/chemistry , Polystyrenes/chemistry , Thiophenes/chemistry , Cellulose/analogs & derivatives , Gluconacetobacter/chemistry , Polysaccharides, Bacterial/analogs & derivatives
14.
Appl Microbiol Biotechnol ; 98(23): 9561-78, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25359472

ABSTRACT

Most biomanufacturing systems developed for the production of biocommodities are based on whole-cell systems. However, with the advent of innovative technologies, the focus has shifted from whole-cell towards cell-free enzyme system. Since more than a century, researchers are using the cell-free extract containing the required enzymes and their respective cofactors in order to study the fundamental aspects of biological systems, particularly fermentation. Although yeast cell-free enzyme system is known since long ago, it is rarely been studied and characterized in detail. In this review, we hope to describe the major pitfalls encountered by whole-cell system and introduce possible solutions to them using cell-free enzyme systems. We have discussed the glycolytic and fermentative pathways and their regulation at both transcription and translational levels. Moreover, several strategies employed for development of cell-free enzyme system have been described with their potential merits and shortcomings associated with these developmental approaches. We also described in detail the various developmental approaches of synthetic cell-free enzyme system such as compartmentalization, metabolic channeling, protein fusion, and co-immobilization strategies. Additionally, we portrayed the novel cell-free enzyme technologies based on encapsulation and immobilization techniques and their development and commercialization. Through this review, we have presented the basics of cell-free enzyme system, the strategies involved in development and operation, and the advantages over conventional processes. Finally, we have addressed some potential directions for the future development and industrialization of cell-free enzyme system.


Subject(s)
Enzymes/metabolism , Ethanol/metabolism , Saccharomyces cerevisiae/enzymology , Complex Mixtures , Enzymes/isolation & purification , Enzymes, Immobilized , Fermentation , Glycolysis , Protein Biosynthesis , Transcription, Genetic
15.
Carbohydr Polym ; 98(2): 1585-98, 2013 Nov 06.
Article in English | MEDLINE | ID: mdl-24053844

ABSTRACT

Bacterial cellulose (BC) has received substantial interest owing to its unique structural features and impressive physico-mechanical properties. BC has a variety of applications in biomedical fields, including use as biomaterial for artificial skin, artificial blood vessels, vascular grafts, scaffolds for tissue engineering, and wound dressing. However, pristine BC lacks certain properties, which limits its applications in various fields; therefore, synthesis of BC composites has been conducted to address these limitations. A variety of BC composite synthetic strategies have been developed based on the nature and relevant applications of the combined materials. BC composites are primarily synthesized through in situ addition of reinforcement materials to BC synthetic media or the ex situ penetration of such materials into BC microfibrils. Polymer blending and solution mixing are less frequently used synthetic approaches. BC composites have been synthesized using numerous materials ranging from organic polymers to inorganic nanoparticles. In medical fields, these composites are used for tissue regeneration, healing of deep wounds, enzyme immobilization, and synthesis of medical devices that could replace cardiovascular and other connective tissues. Various electrical products, including biosensors, biocatalysts, E-papers, display devices, electrical instruments, and optoelectronic devices, are prepared from BC composites with conductive materials. In this review, we compiled various synthetic approaches for BC composite synthesis, classes of BC composites, and applications of BC composites. This study will increase interest in BC composites and the development of new ideas in this field.


Subject(s)
Acetobacter/chemistry , Biocompatible Materials/chemistry , Cellulose/chemistry , Gluconacetobacter/chemistry , Polysaccharides, Bacterial/chemistry , Biocompatible Materials/isolation & purification , Chitosan/chemistry , Gels , Humans , Metal Nanoparticles/chemistry , Prostheses and Implants , Skin, Artificial , Tissue Engineering , Tissue Scaffolds
16.
Enzyme Microb Technol ; 53(5): 322-30, 2013 Oct 10.
Article in English | MEDLINE | ID: mdl-24034431

ABSTRACT

Malt hydrolyzing enzymes and yeast glycolytic and fermentation enzymes in the waste from beer fermentation broth (WBFB) were identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). A new 'one-pot consecutive batch strategy' was developed for efficient bio-ethanol production by simultaneous saccharification and fermentation (SSF) using WBFB without additional enzymes, microbial cells, or carbohydrates. Bio-ethanol production was conducted in batches using WBFB supernatant in the first phase at 25-67°C and 50rpm, followed by the addition of 3% WBFB solid residue to the existing culture broth in the second phase at 67°C. The ethanol production increased from 50 to 102.5g/L when bare supernatant was used in the first phase, and then to 219g ethanol/L in the second phase. The amount of ethanol obtained using this strategy was almost equal to that obtained using the original WBFB containing 25% solid residue at 33°C, and more than double that obtained when bare supernatant was used. Microscopic and gel electrophoresis studies revealed yeast cell wall degradation and secretion of cellular material into the surrounding medium. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) supported the existence of enzymes in WBFB involved in bioethanol production at elevated temperatures. The results of this study will provide insight for the development of new strategies for biofuel production.


Subject(s)
Beer , Biofuels , Ethanol/metabolism , Bioengineering , Bioreactors , Fermentation , Hot Temperature , Saccharomyces cerevisiae/metabolism , Waste Products/analysis
17.
Bioprocess Biosyst Eng ; 36(6): 737-47, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23377262

ABSTRACT

A number of hydrolyzing enzymes that are secreted from malt during brewing, including cell wall-hydrolyzing, saccharide-hydrolyzing, protein-degrading, lipid-hydrolyzing, and polyphenol and thiol-hydrolyzing enzymes, are expected to exist in an active form in waste from beer fermentation broth (WBFB). In this study, the existence of these enzymes was confirmed by sodium dodecyl sulfate polyacrylamide gel electrophoresis, after which enzyme extract was partially purified through a series of purification steps. The hydrolyzing enzyme activity was then measured under various conditions at each purification step using carboxymethyl cellulose as a substrate. The best hydrolyzing activities of partially purified enzymes were found at pH 4.5 and 50 °C in a citrate buffer system. The enzymes showed highest thermal stability at 30 °C when exposed for prolonged time. As the temperature increased gradually from 25 to 70 °C, yeast cells in the chemically defined medium with enzyme extract lost their cell wall and viability earlier than those without enzyme extract. Cell wall degradation and the release of cell matrix into the culture media at elevated temperature (45-70 °C) in the presence of enzyme extract were monitored through microscopic pictures. Saccharification enzymes from malt were relatively more active in the original WBFB than supernatant and diluted sediments. The presence of hydrolyzing enzymes from malt in WBFB is expected to play a role in bioethanol production using simultaneous saccharification and fermentation without the need for additional enzymes, nutrients, or microbial cells via a cell-free enzyme system.


Subject(s)
Beer , Biofuels , Cell Wall/chemistry , Culture Media , Ethanol/chemistry , Glucosidases , Carboxymethylcellulose Sodium/chemistry , Glucosidases/chemistry , Glucosidases/isolation & purification
18.
Carbohydr Polym ; 92(1): 360-6, 2013 Jan 30.
Article in English | MEDLINE | ID: mdl-23218306

ABSTRACT

The addition of certain supplementary carbon sources to the culture media can influence the production, structural features and mechanical properties of bacterial cellulose (BC). In this study, different concentrations (0, 1, 2 and 4%) of a by-product, single sugar α-linked glucuronic acid-based oligosaccharide (SSGO), were added to the culture media during the production of BC. Production with 1% (BC1), 2% (BC2) and 4% (BC3) SSGO led to increases in BC production of 10.45, 12.74 and 9.01 g/L, respectively, after 10 days of cultivation under static conditions, while it was only 7.4 g/L when no SSGO was added (BC0). The structures of BC0, BC1, BC2, and BC3 were confirmed by XRD and FT-IR analysis. FE-SEM micrographs showed increased fibril thickness and decreased pore size in the SSGO added samples. The tensile strength of the BC0 was 16.73 MPa, while it was 25.05 MPa for BC1. However, with further increases in the concentration of SSGO, the tensile strength decreased to 20.76 and 19.77 MPa for BC2 and BC3, respectively. The results of this study provide further insight into the additive role of SSGO and improvement of the physico-mechanical properties of BC.


Subject(s)
Cellulose/chemistry , Glucuronic Acid/chemistry , Polymers/chemistry , Bioreactors , Cellulose/biosynthesis , Culture Media , Gluconacetobacter xylinus/chemistry , X-Ray Diffraction
19.
Bioprocess Biosyst Eng ; 35(1-2): 297-307, 2012 Jan.
Article in English | MEDLINE | ID: mdl-21909678

ABSTRACT

The morphology of gelatin nanoparticles loaded with three different drugs (Tizanidine hydrochloride, Gatifloxacin and Fluconazole) and their characteristics of entrapment and release from gelatin nanoparticles were investigated by the analysis on nanoparticle size distribution, SEM and FT-IR in this study. The particles were prepared by nanoprecipitation using water and ethanol as a solvent and a nonsolvent, respectively. The exclusion of a crosslinking agent from the procedure led the system to have an irregularly-shaped morphology. Nonetheless, the uncrosslinked case of Gatifloxacin loading generally led to a more homogeneous population of nanoparticles than the uncrosslinked case of Tizanidine hydrochloride loading. No loading was achieved in the case of Fluconazole, whereas both Tizanidine hydrochloride and Gatifloxacin are observed of being capable of being loaded by nanoprecipitation. Tizanidine hydrochloride-loaded, blank and Gatifloxacin-loaded nanoparticles yielded, under crosslinked condition, 59.3, 23.1 and 10.6% of the used dried mass. The crosslinked Tizanidine hydrochloride-loaded particles showed the loading efficiency of 13.8%, which was decreased to 1.1% without crosslinking. A crosslinker such as glutaraldehyde is indispensable to enhance the Tizanidine hydrochloride-loading efficiency. To the contrary, the Gatifloxacin-loading efficiency for crosslinked ones was lower by a factor of 2-3 times than that for uncrosslinked ones. This is due to the carboxylic groups of Gatifloxacin and the aldehyde groups of glutaraldehyde competing with each other during the crosslinking process, to react with the amino groups of gelatin molecules. The loading efficiency of gelatin nanoparticles reported by other investigators greatly varies. Nevertheless, the loading efficiency reported by us is in good agreement with the drug-loading data of gelatin nanoparticles reported by other investigators. The 80% of loaded Tizanidine hydrochloride was released around 15 h after start-up of the release experiment, while the 20% of loaded Gatifloxacin was released more rapidly, as free Gatifloxacin, than the loaded Tizanidine hydrochloride and it showed the trend of sustained slow release during the remaining period of its release experiment. Furthermore, the result of comparative FT-IR analysis is consistent to that of the corresponding drug release study.


Subject(s)
Delayed-Action Preparations/chemistry , Drug Compounding/methods , Gelatin/chemistry , Nanocapsules/chemistry , Nanocapsules/ultrastructure , Pharmaceutical Preparations/chemistry , Absorption , Diffusion , Materials Testing , Particle Size
20.
Carbohydr Polym ; 89(4): 1189-97, 2012 Aug 01.
Article in English | MEDLINE | ID: mdl-24750931

ABSTRACT

Polymer composites containing solid clay nanoparticles have attracted immense attention due to the reinforced physico-mechanical properties of the final product. Bacterial cellulose-montmorillonite (BC-MMT) composites were prepared by impregnation of BC sheets with MMT suspension. FE-SEM showed that MMT adsorbed onto the surface as well as penetrated into the matrix of the BC sheets. Peaks for both BC and MMT were present in the FT-IR spectrum of the composite. XRD also showed diffraction peaks for MMT and BC with a slight decrease in the composite crystallinity from 63.22% of pure BC to 49.68% of BC-MMT3. The mechanical and thermal properties of BC-MMT composites were significantly improved compared to those of the pure BC. Tensile strength for composites was increased up to 210 MPa from 151.3 Mpa (BC) while their degradation temperature extended from 232 °C (BC) up to 310 °C. Similarly, the water holding capacity was decreased while the water release rate was improved for the BC-MMT composites as compared to the pure BC.


Subject(s)
Bentonite/chemistry , Cellulose/chemistry , Gluconacetobacter/chemistry , Nanocomposites/chemistry
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