Complete Biodegradation Research Articles

Experimental clinical study on the using of adhesive in the obliteration of varicose veins in humans

Introduction. In order to perform endovasal vein lining, the American Rodney D.Raabe developed a system for varicose veins obliteration, consisting of a glue gun and two catheters, called “VenaSeal”. As an occlusant for varicose veins in this system, “Medtronic” company today proposes to use an adhesive compound synthesized on the basis of butyl ether of α-cyanacrylic acid.Materials and methods. Endovasal catheter obliteration of tributaries and main trunks of the great saphenous vein on the tibia was performed in 15 patients with varicose disease (C2 to CEAR) in order to substantiate the possibility of using the adhesive compound Sulfacrylate. Severity of pain, presence or absence of phlebitis and thrombophlebitis, hyper pigmentation, neurological disorders, allergic reaction were clinically evaluated.Results and discussion. All patients after the introduction of the glue Sulfakrilat had a clinic of moderate phlebitis, without the formation of blood clots in the lumen of the vein. No local or general allergic reaction was observed. From day 7 occluded venous segments were palpated in the form of moderate density bands, without infiltration to surrounding tissues. In the absence of blood flow ultrasound examination showed gradual biodegradation of the adhesive strip inside the vein with the development of complete obliteration of the lumen starting from the 4th month. Starting with the 7th day gradually stopped aseptic inflammation in the wall of the vein was observed on histological examination. Monocytic infiltration of the venous wall with the formation of multinucleated cells of foreign bodies was present until the time of complete biodegradation of the glue. The process of diffuse growth of connective tissue with the presence of fibroblasts from the subendothelium and in the middle shell was most actively observed in histological material from 90 to 120 days after occlusion. Within 180 days, the lumen of the veins occluded by “Sulfacrylate” was completely obliterated by mature connective tissue, in the absence of glue particles, which indicated its complete biodegradation.Conclusion. The experimental studies conducted with the assessment of clinical symptoms, ultrasound examination and histological study of morphogenesis in the lumen of blood vessels in different periods up to 6 months allow us to conclude the potential use of the adhesive compound “Sulfacrylate” (produced in Russia) for endovasal obliteration of varicose veins in humans.

Biodegradation Mechanism of Chloramphenicol by <i>Aeromonas Media</i> SZW3 and Genome Analysis

The abuse of chloramphenicol (CAP) due to its low price is detrimental to ecological safety and human health. An earthworm gut content dwelling bacterium, Aeromonas media SZW3, was isolated with capability of CAP biodegradation, and the CAP degradation efficiency reached 55.86% at day 1 and 67.28% at day 6. CAP biodegradation kinetics and characteristic of strain SZW3 determined the factors that affect CAP biodegradation. Thirteen possible biodegradation products were identified, including three novel biodegradation products (CP1, CP2 and CP3), and three potential biodegradation pathway were proposed. Biodegradation reactions include amide bond hydrolysis, nitro group reduction, acetylation, aminoacetylation, dechlorination and oxidation. Genome analysis suggested that the coding gene of RarD (CAP resistance permease), CAP O-acetyltransferase, nitroreductase and haloalkane dehalogenase may be responsible for CAP biodegradation. The proposed complete biodegradation pathway and genome analysis by strain SZW3 provide us new insight of the transformation route and fate of CAP in the environment.

Microplastics in marine environment: a review on sources, classification, and potential remediation by membrane technology

Microplastics are pollutants highly stable to complete biodegradation and require more specific separation processes for their removal. Classification and potential remediation technologies, such as membrane technology, are discussed in this review.

Molecular weight characterization of cellulose using ionic liquids

Cellulose, the most abundant natural polymer on the planet, is the major polysaccharide produced by plant photosynthesis. It has many advantages, such as renewability, tremendous reversibility, complete biodegradability, excellent biocompatibility, high mechanical property and structural designability. The molecular weight and polydispersity index are the key parameters of cellulose materials. Measurement of the molecular weight characteristics of cellulose is of great significance for effectively utilizing cellulose resources and comprehensively understanding the relationship between structure and property. In this review, we summarize the methods used to characterize the molecular weight of cellulose and focus on the detailed applications of ionic liquids for such characterization.

Recent progress on chemical modification of cellulose for high mechanical-performance Poly(lactic acid)/Cellulose composite: A review

Cellulose is one of the most promising fillers used for poly(lactic acid) (PLA) composites owing to its natural abundance, complete biodegradability, and superb properties. Improving the compatibility between hydrophilic cellulose and hydrophobic PLA is a hot topic in literature for a long time, wherein surface chemical modification of cellulose have attracted the most attention. In this review, we summarized the research activities of recent five years that focus on the chemical modification strategies of cellulose used in PLA/cellulose composites. Two major classifications are carefully discussed, i.e., the reactions of small molecules modified cellulose such as esterification, oxidation/amidation and silanization, and reactions of polymers modified cellulose including PLA and other polymers. The discussion mainly focuses on the relationship between the structure of grafted small molecule/polymers and mechanical properties of PLA composites and addresses the current common problems that hinder the chemical modified cellulose from developing high-performance PLA/cellulose composites. We hope this review provide some possible inspiration for researchers to develop PLA/cellulose products with industrial value in the future.

Complete biodegradation of di-n-butyl phthalate (DBP) by a novel Pseudomonas sp. YJB6

Phthalate acid esters (PAEs) are environmentally ubiquitous and have aroused a worldwide concern due to their threats to environment and human health. Di-n-butyl phthalate (DBP) is one of the most frequently observed PAEs in the environment. In this study, a novel bacterium identified as Pseudomonas sp. YJB6 that isolated from PAEs-contaminated soil was determined to have strong DBP-degrading activity. A complete degradation of DBP in 200 mg/L was achieved within 3 days when YJB6 was cultivated at 31.4 °C with an initial inoculation size of 0.6 (OD600) in basic mineral salts liquid medium (MSM), pH 7.6. The degradation curves of DBP (50–2000 mg/L) fitted well the first-order kinetics model, with a half-life (t1/2) ranging from 0.86 to 1.88 d. The main degradation intermediates were identified as butyl-ethyl phthalate (BEP), mono-butyl phthalate (MBP), phthalic acid (PA) and benzoic acid (BA), indicating a new complex and complete biodegradation pathway presented by YJB6. DBP might be metabolized through de-esterification, β-oxidation, and hydrolysis, followed by entering the Krebs cycle of YJB6 as a final step. Strain YJB6 was successfully immobilized with sodium alginate (SA), polyvinyl alcohol (PVA), and SA-PVA. The immobilization significantly improved the stability and adaptability of the cells thus resulting in high volumetric DBP-degrading rates compared to that of the freely suspended cells. In addition, these immobilized cells can be reused for many cycles with well conserved in DBP-degrading activity. The ideal DBP degrading ability of the free and immobilized YJB6 cells suggests that strain YJB6, especially the SA-PVA+ YJB6 promises great potential to remove hazardous PAEs.

Assessment of Soil and Fungal Degradability of Thermoplastic Starch Reinforced Natural Fiber Composite

High water absorption capacity and low biodegradation of fiber reinforced composites are the major drawbacks, which limit their applications in different sectors. Development of composites with complete biodegradability is challenging as biodegradability may be incomplete by lowering of its water adsorption capacity. In this work, a series of thermoplastic starch (TPS) reinforced jute (10–40 wt%) composites were developed by compression molding and measured by their mechanical properties. The composite with 30% jute showed the maximum tensile strength (27.3 MPa). Contact angle, and water absorption measurements exposed that composites are moderately hydrophobic in nature. Both soil burial and fungal degradation testing showed biodegradability of composites. Characterizations of optimized composite before and after biodegradation test, were carried out by FTIR, SEM and optical microscope. The present study showed promise on feasible applications of jute-starch composites in packaging, automobile sector, cutlery, indoor furnishing, etc. as a substitute of plastic-based composites.

Advanced biodegradation process of atrazine in the peroxidase-mediated sequencing batch reactor (SBR) and moving-bed SBR (MSBR): mineralization and detoxification.

The advanced biodegradation process of atrazine was stimulated with hydrogen peroxide (H2O2) in a sequencing batch reactor (SBR) under different operational conditions due to in situ generation of H2O2-peroxidase. The complete biodegradation and mineralization of 50mg/L atrazine was achieved in the SBR with a biomass concentration of 328mg/L stimulated with 10mM of H2O2. The presence of H2O2 in the SBR induced the generation of H2O2-peroxidase resulted in acceleration of atrazine biodegradation. Adding moving media to the SBR system and converting it to the MSBR considerably improved the rate of atrazine biodegradation and mineralization under H2O2 mediation. The highest specific utilization rate of atrazine in the SBR operated at the biomass concentration of 55mg/L was 19.4mg/gbiomass.h, while it was 33.5mg/gbiomass.h in the MSBR operated at the biomass concentration of 37mg/L. The low ATZ removal along with no peroxidase activity in the bioreactor in absence of H2O2 clearly ideated that the biodegradation and mineralization of ATZ was considerably mediated by H2O2-peroxidase enzyme. The toxicity of atrazine solution decreased markedly when treated in the MSBR under optimum conditions. Accordingly, the MSBR stimulated with H2O2 is an efficient and thus promising process for biodegradation of recalcitrant compounds.

Low-temperature thermochronology and diagenesis of the Amagá Basin: insights into hydrocarbon generation and its relationship with tectonothermal and hydrothermal processes

The mineralogical characterization of dark green cements of intraclasts and their host sandstones, developed using optical petrography, X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) and organic petrography, provides new insights about the diagenetic evolution and depositional conditions of the late Oligocene-middle Miocene Amagá Formation, northwestern Colombia. Dark green intraclasts are found as medium-grained, slightly feldspathic sandstones, in which the main authigenic mineral is pyrite that formed during a mesogenetic (burial diagenesis) stage. The host sandstones of the dark green intraclasts were deposited in a meandering river environment and are related to point bar deposits over swampy areas. These strata are medium-grained quartzose sandstones cemented by ankerite as a product of replacement of early calcite through hydrothermal alteration. Solid hydrocarbons analysis together with new low-tempereture thermocronology apatite (U–Th)/He data, available apatite fission-track (AFT), zircon fission-track (ZFT) and vitrinite reflectance (%Ro) data, indicate maximum burial temperatures of ca., 100°C for the deeper parts of the basin. Solid hydrocarbons were emplaced in the late stages of the diagenetic history and occur in a porous system where fractures played an important role. They constitute the first evidence of migration and accumulation of hydrocarbons in the Amagá Basin. However, the latest event of fracturing during a major cooling event associated with basin inversion at ca., 4 Ma, caused complete hydrocarbon biodegradation and seepage, and increased the effect of meteoric water inflow during the telogenetic stage.

Impact of volatile fatty acids to alkalinity ratio and volatile solids on biogas production under thermophilic conditions.

The study assessed the impact of volatile fatty acids (VFA) to total alkalinity (TA) ratio (VFA/TA), and percentage volatile solids (VS) reduction of batch and semi-continuous anaerobic co-digestion of palm nut paste waste (PNPW) and anaerobic-digested rumen waste (ADRW) on digester stability and biogas production under the environmental condition of 50 ± 1°C and hydraulic retention time of 21 days for the batch studies and 14 days for semi-continuous co-digestion. The co-digestion ratios were based on percentage digester volume corresponding to 90%:10%, 75%:25% and 50%:50%. During batch and semi-continuous anaerobic co-digestion, VFA/TA of 0.32-1.0 and VS reduction of 53-67% were observed as the stable range at which biogas production was maximum. In terms of semi-continuous anaerobic digestion (AD), except for the 50%:50% ratio where biogas production progressed steadily from the first to fourteenth days, biogas production initially dropped from 180.1 to 171.3 mL between the first and third days of the 90%:10% reaching a maximum of 184 mL on the fourteenth day. Biogas production declined from 198.8 to 187.5 mL on the second day and then increased to 198.8 ± 0.5 mL in the case of the 75%:25% with a significant difference between the treatment ratios at p < 0.05. Therefore, the study can confirm that the 50%:50% ratio (PNPW:ADRW) is a suitable option for managing crude fat-based waste under thermophilic AD due to its potential for rapid start-up and complete biodegradation of active biomass within a 21-day period. This presupposes that residual methane as greenhouse gas will be void in the effluent if disposed of.

Biodegradable Polymer Blends Based on Thermoplastic Starch

This work considered the utilisation of environmentally friendly biodegradable materials instead of conventional polymeric materials, in order to prevent further environmental endangerment by accumulation of non-biodegradable materials. Thermoplastic starch (TPS) is an exemplary environmentally friendly biodegradable material. Blending TPS with other biodegradable polymers such as biodegradable polyesters; polylactic acid (PLA) and polycaprolactone (PCL), was recognised as a successful strategy to provide a renewable, fully biodegradable and cost-effective materials. Namely, PLA, PCL and TPS polymeric materials individually show some shortcomings, which can be surpassed by blending. Using economically viable procedure, one can produce multicomponent polymeric materials complying with functional performance requirements while achieving complete biodegradation. Accordingly, PLA/PCL/TPS ternary blends with compositional variations were prepared and investigated in terms of structural, morphologic, mechanical, thermal, physicochemical (water absorption, contact angle) and processing properties in order to discuss and elucidate optimal performance of the overall material. In summary, this study could lead to a better understanding of performance behind different blends and ensure producing and using a new generation of biodegradable plastics that will not burden our environment.

Collagen–iron oxide nanoparticle based ferrogel: large reversible magnetostrains with potential for bioactuation

Smart materials such as stimuli responsive polymeric hydrogels offer unique possibilities for tissue engineering and regenerative medicine. As, however, most synthetic polymer systems and their degradation products lack complete biocompatibility and biodegradability, this study aims to synthesize a highly magnetic responsive hydrogel, based on the abundant natural biopolymer collagen. As the main component of vertebratal extracellular matrix, it reveals excellent biocompatibility. In combination with incorporated magnetic iron oxide nanoparticles, a novel smart nano-bio-ferrogel can be designed. While retaining its basic biophysical properties and interaction with living cells, this collagen-nanoparticle hydrogel can be compressed to 38% of its original size and recovers to 95% in suitable magnetic fields. Besides the phenomenology of this scenario, the underlying physical scenarios are also discussed within the framework of network models. The observed reversible peak strains as large as 150% open up possibilities for the fields of biomedical actuation, soft robotics and beyond.

Removal mechanisms of β-blockers by anaerobic digestion in a UASB reactor with carbon feeding

Efficient removal of medical wastewater and pharmaceutical production wastewater containing Beta-blockers is currently the focus and difficulty of research. In this study, the UASB reactor was used to achieve efficient removal of Beta-blockers. The removal rate of atenolol, metoprolol and propranolol is about 80%, 60% and 60%, respectively. The relevant functional microorganisms were Thermotogae, Anaerolineae and Bacteroidetes. Beta-blockers interfered with the metabolism of bacteria and methanogens, resulting in reduction of methane production and accumulation of acetic acid, which in turn affected the performance of UASB reactor. Metoprolol, atenolol and propranolol are mainly removed by anaerobic co-metabolism with starch, of which oxidative degradation is the main route. This study provides a new idea for the complete and efficient biodegradation of Beta-blockers wastewater.

Properties and behavior under environmental factors of isosorbide-plasticized starch reinforced with microcrystalline cellulose biocomposites

Green biocomposites based on corn starch plasticized with isosorbide and glycerol and filled with microcrystalline cellulose (MCC) were processed. The structural interactions, dynamomechanical properties, water absorption, and soil biodegradability were investigated by different techniques considering the effect of the type and amount of plasticizer and the MCC addition. The changes along the time of the structural interactions and the dynamomechanical properties of these materials and the influence of the retrogradation phenomenon were also studied.The use of isosorbide as plasticizer instead of glycerol improved the stiffness, the water absorption and the biodegradation rate of thermoplastic starch (TPS). Moreover, no evidence of retrogradation for isosorbide was observed. An isosorbide content of 35% and the addition of MCC filler enhanced in a greater extent these properties with a complete biodegradability in 7 month. These green biocomposites can be an alternative for food packaging applications.

Rapid and Complete Biodegradation of Acrylic Acid by a Novel Strain Rhodococcus ruber JJ-3: Kinetics, Carbon Balance, and Degradation Pathways

Acrylic acid is used in various industrial applications but inflicts harm to human health and causes environmental pollution. A new bacterium, identified as Rhodococcus ruber JJ-3, was isolated, which can degrade high concentrations of acrylic acid rapidly and completely. Experimental results showed that the strain can achieve complete degradation of 1000 mg·L−1 acrylic acid in 11 h under the following conditions: pH 7, temperature 35°C, and inoculation quantity 15%. A high concentration of acrylic acid (2000 mg·L−1) can be completely removed in 28 h. According to the Monod model, the maximum specific degradation rate (vmax) and half saturation rate constant (KS) of the strain were 0.85 h−1 and 101.83 mg·L−1, respectively. The results of carbon balance revealed that 54.6% carbon was assimilated by R. ruber JJ-3 as biomass, and 43.0% carbon was mineralized into CO2. Furthermore, glycerol and lactic acid were measured as intermediates, and the possible degradation pathway was proposed during the biodegradation of acrylic acid. These results suggested that R. ruber JJ-3 completely degrades acrylic acid and might have a potential environmental implication in the purification of acrylic acid-contaminated environments.

POTENTIAL EVALUATION OF YELLOW COTTON (COCHLOSPERMUM REGIUM) PIGMENTS FOR DYE SENSITIZED SOLAR CELLS APPLICATION

Recently, dye-sensitized solar cells (DSSC) have concerned significant attention attributable to their material preparation process, architectural and environmental compatibility, also low cost and effective photoelectric conversion efficiency. Therefore, this study aimed to use potential plant materials for DSSC. This research presents the extraction of natural pigments from yellow cotton flowers (Cochlospermum regium). In addition, the natural pigments were revealed that outstanding advantages, including a wide absorption range (visible light), easy extraction method, safe, innocuous pigments, inexpensive, complete biodegradation and ecofriendly. Methanol was used as a solvent extraction for the yellow cotton flower. The chlorophylls and carotenoid pigments extractions were estimated by a UV-visible spectrometer. The chlorophyll-a, chlorophyll-b, and carotenoid yield were 0.719±0.061 µg/ml, 1.484±0.107 µg/ml and 7.743±0.141 µg/ml, respectively. Thus, this study results suggested that yellow cotton flowers containing reasonable amounts appealable in the DSSC production.

Effect of Different Operational Parameters on Bio-degradation of Chicken Feathers by Aspergillus niger: Investigation Under Submerged Fermentation Process

Fungal strain, Aspergillus niger (ATCC 1015) has ability to grow on keratinous material therefore, it was selected for the investigating bio-degradation of chicken feathers. Different operational parameters were studied under submerged fermentation process i.e. effect of substrate concentration, effect of pH, effect of incubation temperature, effect of yeast extract concentration and effect of volume of fermentation medium. A. niger was grown on solid medium of malt extract and agar, due to its ability of rapid growth on it. Complete bio-degradation of the substrate was achieved after 5 days (0.70±0.03 U/mL) under standard optimized conditions. Investigation of different operational parameters on bio-degradation of chicken feathers revealed, maximum keratinolytic was observed at 40 °C incubation temperature, at 0.5 g/100 mL of substrate concentration, 8 g/100 mL concentration of yeast extract, at 7 pH of the fermentation medium and at 50 mL volume of fermentation medium. The present study suggests that A. niger could prove to be a potential candidate for production of keratinase and bio-degradation of chicken feathers.&#x0D;

Influence of polymer type and carbon nanotube properties on carbon nanotube/polymer nanocomposite biodegradation

The interaction of anaerobic microorganisms with carbon nanotube/polymer nanocomposites (CNT/PNC) will play a major role in determining their persistence and environmental fate at the end of consumer use when these nano-enabled materials enter landfills and encounter wastewater. Motivated by the need to understand how different parameters (i.e., polymer type, microbial phenotype, CNT characteristics) influence CNT/PNC biodegradation rates, we have used volumetric biogas measurements and kinetic modeling to study biodegradation as a function of polymer type and CNT properties. In one set of experiments, oxidized multiwall carbon nanotubes (O-MWCNTs) with a range of CNT loadings 0–5% w/w were incorporated into poly-ε-caprolactone (PCL) and polyhydroxyalkanoates (PHA) matrices and subjected to biodegradation by an anaerobic microbial community. For each CNT/PNC, complete polymer biodegradation was ultimately observed, although the rate of biodegradation was inhibited above certain critical CNT loadings dependent upon the polymer type. Higher loadings of pristine MWCNTs were needed to decrease the rate of polymer biodegradation compared to O-MWCNTs, an effect ascribed principally to differences in CNT dispersion within the polymer matrices. Above certain CNT loadings, a CNT mat of similar shape to the initial PNC was formed after polymer biodegradation, while below this threshold, CNT aggregates fragmented in the media. In situations where biodegradation was rapid, methanogen growth was disproportionately inhibited compared to the overall microbial community. Analysis of the results obtained from this study indicates that the inhibitory effect of CNTs on polymer biodegradation rate is greatest under conditions (i.e., polymer type, microbial phenotype, CNT dispersion) where biodegradation of the neat polymer is slowest. This new insight provides a means to predict the environmental fate, persistence, and transformations of CNT-enabled polymer materials.

Chitin, Characteristic, Sources, and Biomedical Application.

Chitin stands at second, after cellulose, as the most abundant polysaccharide in the world. Chitin is found naturally in marine environments as it is a crucial structural component of various marine organisms. Different amounts of waste chitin and chitosan can be discovered in the environment. Chitinase producing microbes help to hydrolyze chitin waste to play an essential function for the removal of chitin pollution in the Marine Atmosphere. Chitin can be converted by using chemical and biological methods into prominent derivate chitosan. Numerous bacteria naturally have chitin degrading ability. Chitin shows promise in terms of biocompatibility, low toxicity, complete biodegradability, nontoxicity, and film-forming capability. The application of these polymers in the different sectors of biomedical, food, agriculture, cosmetics, pharmaceuticals could be lucrative. Moreover, the most recent achievement in nanotechnology is based on chitin and chitosan-based materials. In this review, we examine chitin in terms of its natural sources and different extraction methods, chitinase producing microbes and chitin, chitosan together with its derivatives for use in biomedical and agricultural applications.

Environment-friendly Fully Biodegradable Jute-Poly(vinyl Alcohol) Modified Soy Composite Development as Plastic Substitute

ABSTRACT The aim of this investigation was to develop composites with high mechanical strength and complete biodegradation property. Mild alkali-treated jute and poly(vinyl alcohol)-modified nanoclay-based soy resins were used to develop jute-modified soy composites. The tensile strength of composite was enhanced up to 75% and impact strength by 30% as compared to that of normal jute–soy composite. Biodegradation study was carried out by soil burial condition. These composites can be used in different sector as replacement of nonbiodegradable plastic.