High Biodegradation Potential Research Articles

Exploring Prenatal Exposure to Halogenated Compounds and Its Relationship with Birth Outcomes Using Nontarget Analysis.

Halogenated organic compounds (HOCs) are a class of contaminants showing high toxicity, low biodegradability, and high bioaccumulation potential, especially chlorinated and brominated HOCs (Cl/Br-HOCs). Knowledge gaps exist on whether novel Cl/Br-HOCs could penetrate the placental barrier and cause adverse birth outcomes. Herein, 326 cord blood samples were collected in a hospital in Jinan, Shandong Province from February 2017 to January 2022, and 44 Cl/Br-HOCs were identified with communicating confidence level above 4 based on a nontarget approach, covering veterinary drugs, pesticides, and their transformation products, pharmaceutical and personal care products, disinfection byproducts, and so on. To our knowledge, the presence of closantel, bromoxynil, 4-hydroxy-2,5,6-trichloroisophthalonitrile, 2,6-dibromo-4-nitrophenol, and related components in cord blood samples was reported for the first time. Both multiple linear regression (MLR) and Bayesian kernel machine regression (BKMR) models were applied to evaluate the relationships of newborn birth outcomes (birth weight, length, and ponderal index) with individual Cl/Br-HOC and Cl/Br-HOCs mixture exposure, respectively. A significantly negative association was observed between pentachlorophenol exposure and newborn birth length, but the significance vanished after the false discovery rate correction. The BKMR analysis showed that Cl/Br-HOCs mixture exposure was significantly associated with reduced newborn birth length, indicating higher risks of fetal growth restriction. Our findings offer an overview of Cl/Br-HOCs exposome during the early life stage and enhance the understanding of its exposure risks.

Insights into bacterial resistance to contaminants of emerging concerns and their biodegradation by marine bacteria

Contaminants of Emerging Concern (CECs) are human-made chemicals that remain unregulated. The continuous detection of CECs in aquatic ecosystems, due to their incomplete removal, emphasizes the importance of understanding their fate and impact on the environment and human health. The detrimental effects of CECs on marine eukaryotes are well documented in multiple studies. However, their impact on marine bacteria and their biodegradation by these organisms are not well understood. In this study, two marine bacteria, Priestia sp. 35 ODPABA G14 and Rhodococcus sp. 23 AHTN G14, previously isolated from submarine sediments, were used. These two strains were tested for their resistance as well as their capacity to degrade different classes of hydrophobic and hydrophilic CECs, including synthetic musks, UV filters, pesticides and pharmaceuticals. Both strains showed high resistance to all of the hydrophobic tested CECs even up to 500 mg L−1. Only Ketoprofen was toxic to bacterial cells, particularly to Rhodococcus sp. starting at concentration as low as 4 mg L−1. Furthermore, Priestia sp. and Rhodococcus sp. strains exhibited high biodegradation potential, especially for hydrophobic compounds. Although this may not apply to all pollutants, the data presented in this study suggest a positive correlation between marine bacterial resistance to CECs and their high biodegradation potentials.

Collagen Matrix to Restore the Tympanic Membrane: Developing a Novel Platform to Treat Perforations.

Modern otology faces challenges in treating tympanic membrane (TM) perforations. Instead of surgical intervention, alternative treatments using biomaterials are emerging. Recently, we developed a robust collagen membrane using semipermeable barrier-assisted electrophoretic deposition (SBA-EPD). In this study, a collagen graft shaped like a sponge through SBA-EPD was used to treat acute and chronic TM perforations in a chinchilla model. A total of 24 ears from 12 adult male chinchillas were used in the study. They were organized into four groups. The first two groups had acute TM perforations and the last two had chronic TM perforations. We used the first and third groups as controls, meaning they did not receive the implant treatment. The second and fourth groups, however, were treated with the collagen graft implant. Otoscopic assessments were conducted on days 14 and 35, with histological evaluations and TM vibrational studies performed on day 35. The groups treated with the collagen graft showed fewer inflammatory changes, improved structural recovery, and nearly normal TM vibrational properties compared to the controls. The porous collagen scaffold successfully enhanced TM regeneration, showing high biocompatibility and biodegradation potential. These findings could pave the way for clinical trials and present a new approach for treating TM perforations.

Comparative Assessment of Biodegradability Potential of Pseudomonas putida and Bacillus amyloliquefaciens on Oil Spill Dispersant (Aquabreak and Teepol) in Freshwater

To compare and assessment of Biodegradability Potential of Pseudomonas putida and Bacillus amyloliquefaciens on oil spill dispersant (Aquabreak and Teepol) in Freshwater. Fresh water sample were collected from Biara, Gokana L.G.A, and were transported to the Microbiology Laboratory of Rivers State University, Port Harcourt, Nigeria for analyses while Oil spill dispersant (OSD/Aquabreak) was purchased from Barker and Hughes, all in Rivers state. Nine experimental set up were carried out using Bacillus and Pseudomonas species as the bio-augmenting organism. Controls were made without organisms. Its bioremediation potential on the pollutants and two types of test organisms were monitored for 28 days at an interval of 7day period. The setup was aerated twice a week to provide more oxygen for the organisms to thrive. Analysis of samples were carried out using standard analytical procedures. The resultsphysiochemical property of the water shows that as follows: pH 6.5, Temperature 30.0 ºC, Electric conductivity 15 µs/cm, Total dissolved solid 7 mg/l ,Chlorine 0.1 mg/l, Bromine 0.2 mg/l, Salinity (0.01 mg/l), Dissolved oxygen 1.5 mg/l , Biological Oxygen Demand 0.3 mg/l, Nitrate 0.01 mg/l, Sulphate 4.18 mg/l Phosphate 0.10 to 1.5mg/l, Total Hydrocarbon content 24mg/l. Percentage (%) Ultimate biodegradability of the two oil spill dispersant OSD/teepol and OSD/aquabreak revealed that control set-up recorded the 79.3 and 86.7 % , bioremediation set-up augmented with Bacillus amyloliquefaciens recorded 93.7 and 99.1% while the set-up augmented with P. putida had 98.0 and 94.7% respectively . It was observed that P. putida degrade Teepol than Bacillus amyloliquefaciens while aquabreak is more degraded by Bacillus amyloliquefaciens than P. putida. Nevertheless both dispersant shown high level of degradability by the test organisms. Therefore It is recommended that oil companies and government parastatals carrying out remediation in the Niger Delta should be encouraged and OSD/Teepol and OSD/aqubreak due to their high biodegradation potential.

Potential of Advanced Oxidation as Pretreatment for Microplastics Biodegradation

In the last two decades, microplastics (MP) have been identified as an emerging environmental pollutant. Due to their small size, MP particles may easily enter the food chain, where they can have adverse effects on organisms and the environment in general. The common methods for the removal of pollutants from the environment are not fully effective in the elimination of MP; thus, it is necessary to find a more suitable treatment method(s). Among the various approaches tested, biodegradation is by far the most environmentally friendly and economically acceptable remediation approach. However, it has serious drawbacks, generally related to the rather low removal rate and often insufficient efficiency. Therefore, it would be beneficial to use some of the less economical but more efficient methods as pretreatment prior to biodegradation. Such pretreatment would primarily serve to increase the roughness and hydrophilicity of the surface of MP, making it more susceptible to bioassimilation. This review focuses on advanced oxidation processes (AOPs) as treatment methods that can enhance the biodegradation of MP particles. It considers MP particles of the six most commonly used plastic polymers, namely: polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyethylene terephthalate and polyurethane. The review highlights organisms with a high potential for biodegradation of selected MP particles and presents the potential benefits that AOP pretreatment can provide for MP biodegradation.

Control of Pre-formed Halogenated Disinfection Byproducts with Reuse Biofiltration.

Disinfection byproduct (DBP) pre-formation is a major issue when prechlorination is used before or during advanced treatment of impacted drinking water sources. Control strategies for pre-formed DBPs before final disinfection, especially for currently nonregulated although highly toxic DBP species, are not yet established. This study evaluated the biodegradation potential of pre-formed DBPs, including haloacetonitriles (HANs), haloacetamides (HAMs), and haloacetaldehydes (HALs), during biofiltration with sand, anthracite, and biological activated carbon of three wastewater effluents under potable reuse conditions. Up to 90%+ removal of di- and trihalogenated HANs, HAMs, and HALs was observed, and removal was associated with active heterotrophic biomass and removal of biodegradable organic carbon. Unlike the microbial dehalogenation pathway of haloacetic acids (HAAs), removal of HANs and HAMs appeared to result from a biologically mediated hydrolysis pathway (i.e., HANs to HAMs and HAAs) that may be prone to inhibition. After prechlorination, biofiltration effectively controlled pre-formed DBP concentrations (e.g., from 271 μg/L to as low as 22 μg/L in total) and DBP-associated calculated toxicity (e.g., 96%+ reduction). Abiotic residual adsorption capacity in biological activated carbon media was important for controlling trihalomethanes. Overall, the toxicity-driving DBP species exhibited high biodegradation potential and biofiltration showed significant promise as a pre-formed DBP control technology.

Biological, surface, and wetting behavior of bio-surfactants tank-mixed with trifloxysulfuron-sodium on Sorghum halepense.

There is a public interest in developing bio-surfactants due to their low toxicity and high biodegradation potential. However, their biological, surface, and behavior to use with agrochemicals has not been investigated. Critical micelle concentrations (CMCs) for the synthetic surfactant dioctyl sodium sulfosuccinate (DOSS), the bio-surfactant rhamnolipid (RL), and the bio-surfactant surfactin (SF) were 1200, 50, and 50 mg L-1 , respectively. Based on the ability of the surfactants to reduce the surface tension of trifloxysulfuron-sodium spray solution at 0.25 to 1× CMC, they are ranked SF > RL > DOSS, while at 1.5 to 4× CMC, they are ranked SF=RL > DOSS. Without surfactant, trifloxysulfuron-sodium at 10.04 g ha-1 reduced johnsongrass growth up to 50% (ED50 ). At best, SF at 1 to 4× CMC halved ED50 . Unlike DOSS, which increased ED50 (12.89 g ha-1 ) due to a phytotoxic effect, SF and RL at 4× CMC decreased ED50 (5.19 and 6.50 g ha-1 , respectively) without a phytotoxic effect. A 5-μl droplet containing SF dried faster due to greater spread on the leaf surface than other surfactants. Although the wetted area of the leaf with the droplet containing RL was wider than that of DOSS, it took longer to dry. This observation contradicts the previous theory. In terms of dosage, safety, and efficacy, the RL and SF were comparable to DOSS in other tank-mix with trifloxysulfuron-sodium. It seems that RL also works as a humectant, while SF likely works as a wax solubilisant. © 2023 Society of Chemical Industry.

Attempt to Extend the Shelf-Life of Fish Products by Means of Innovative Double-Layer Active Biodegradable Films.

In this study, we aimed to produce, innovative and, at the same time, environmentally-friendly, biopolymer double-layer films with fish processing waste and active lingonberry extract as additives. These double-layered films were based on furcellaran (FUR) (1st layer) and carboxymethyl cellulose (CMC) with a gelatin hydrolysate (HGEL) (2nd layer). The aim of the study was to assess their impact on the durability of perishable salmon fillets during storage, and to evaluate their degree of biodegradation. The fillets were analyzed for changes in microbiological quality (total microbial count, yeast and molds, and psychrotrophic bacteria), biogenic amine content (HPLC), and lipid oxidation (peroxidase and acid values, TBARS). The degree of biodegradation includes analysis of film and compost chemical composition solubility, respiratory activity, and ecotoxicity testing. The obtained results allow to suggest that active films are not only bacteriostatic, but even bactericidal when they used to coat fish fillets. Concerning the group of samples covered with the double-layer films, a 19.42% lower total bacteria count was noted compared to the control samples. Furthermore, it can be observed that the applied double-layer films have a potentially strong inhibitory effect on the accumulation of biogenic amines in fish, which is correlated with its antimicrobial effect (the total biogenic amine content for control samples totaled 263.51 mg/kg, while for the double-layer samples, their value equaled: 164.90 mg/kg). The achieved results indicate a high biodegradation potential, however, a too low pH of the film results in limiting seed germination and growth. Despite that, of these, double-layer films are a technology that has applicative potential.

Biosurfactants: Sustainable and Versatile Molecules

Biosurfactants are amphipathic molecules produced by plants, animals, and microorganisms, that present emulsifying properties and may act reducing surface and interfacial tensions. When compared to synthetic surfactants, these biological analogues have high biodegradability potential, and may be produced from renewable raw materials within overall biotechnological processes involving low generation of residues. The production and application of microbial surfactants have been recently considered in several industrial sectors, as these low toxicity versatile compounds find applications in food, pharmaceutical, cosmetic, and petrochemical products, in nanotechnology and agriculture, and in the bioremediation of xenobiotic-contaminated areas. Herein, the main conceptual aspects and physicochemical properties, as well as the classifications of biosurfactants according to their origin and their chemical structures, are addressed. The production of microbial biosurfactants through sustainable processes are also described, with particular focus on new applications and on the increasing relevance of such bioproducts for the sustainable development of modern society.

Immobilization of Sporothrix schenckii 1099-18 exo-polygalacturonase in magnetic mesoporous silica yolk-shell spheres: Highly reusable biocatalysts for apple juice clarification

In this study, a heterologously expressed exo-polygalacturonase from Sporothrix schenckii 1099-18 was purified and then its two magnetic immobilized counterparts were prepared in yolk–shell-structured mesoporous silica. The exo-polygalacturonase was initially precipitated on porous calcium carbonate in the presence of Fe3O4 magnetic nanoparticles. Then, a silica layer was created on the surface of the precipitated particles. The obtained immobilized exo-polygalacturonase (silica@Fe3O4/SsExo-PG) was further treated with glutaraldehyde (silica@Glu- Fe3O4/SsExo-PG). Fourier-transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy techniques were used to confirm the immobilization of polygalacturonase. The optimum pH and temperature of all the exo-polygalacturonase preparations were determined to be 4.0 and 60 °C, respectively which are also optimum conditions for apple juice clarification. The silica@ Fe3O4/SsExo-PG and silica@Glu- Fe3O4/SsExo-PG showed 3- and 3.7-fold much stability, respectively than the free exo-polygalacturonase at 60 °C. The free and immobilized SsExo-PG preparations were used for the clarification of apple juice and the result showed that the turbidity of apple juice was reduced by 82% after 1 h treatment time. After ten consecutive uses, silica@Fe3O4/SsExo-PG and silica@Glu-Fe3O4/SsExo-PG retained 80% and 90% of their initial activities, respectively. Altogether, biochemical, thermal-stability, and apple juice clarification characteristics of the immobilized SsExo-PG suggest a high potential for biodegradation of pectin.

Biodegradation and viability of chitosan-based microencapsulated fertilizers

Enhanced efficiency fertilizers (EEF) are an important subject for sustainable materials. It is fundamental for the released nutrient and biodegradation in the soil to have synergy to ensure material harmlessness. Chitosan, montmorillonite, and KNO3 were considered to develop the EEF because of the high biodegradation potential of the final product. We correlated the material biodegradability and release in water and soil to their formulation. We assume the materials are biodegradable since the biodegradation efficiency achieved over 30 %. As the nutrient diffusion and matrix degradation happen concomitantly, we also observed that the clay delays degradation and the KNO3 improved it. Likewise, the storage period can change the biodegradability properties once the material started to degrade. Hereupon, the amount of nutrient delivered will match the amount consumed by the plant, the matrix will degrade and no residue will be left in the soil.

Biodegradation of atrazine and ligninolytic enzyme production by basidiomycete strains

BackgroundAtrazine is one of the most widespread chlorinated herbicides, leaving large bulks in soils and groundwater. The biodegradation of atrazine by bacteria is well described, but many aspects of the fungal metabolism of this compound remain unclear. Thus, we investigated the toxicity and degradation of atrazine by 13 rainforest basidiomycete strains.ResultsIn liquid medium, Pluteus cubensis SXS320, Gloelophyllum striatum MCA7, and Agaricales MCA17 removed 30, 37, and 38%, respectively, of initial 25 mg L− 1 of the herbicide within 20 days. Deficiency of nitrogen drove atrazine degradation by Pluteus cubensis SXS320; this strain removed 30% of atrazine within 20 days in a culture medium with 2.5 mM of N, raising three metabolites; in a medium with 25 mM of N, only 21% of initial atrazine were removed after 40 days, and two metabolites appeared in culture extracts. This is the first report of such different outcomes linked to nitrogen availability during the biodegradation of atrazine by basidiomycetes. The herbicide also induced synthesis and secretion of extracellular laccases by Datronia caperata MCA5, Pycnoporus sanguineus MCA16, and Polyporus tenuiculus MCA11. Laccase levels produced by of P. tenuiculus MCA11 were 13.3-fold superior in the contaminated medium than in control; the possible role of this enzyme on atrazine biodegradation was evaluated, considering the strong induction and the removal of 13.9% of the herbicide in vivo. Although 88% of initial laccase activity remained after 6 h, no evidence of in vitro degradation was observed, even though ABTS was present as mediator.ConclusionsThis study revealed a high potential for atrazine biodegradation among tropical basidiomycete strains. Further investigations, focusing on less explored ligninolytic enzymes and cell-bound mechanisms, could enlighten key aspects of the atrazine fungal metabolism and the role of the nitrogen in the process.

Methane potential and degradation kinetics of fresh and excavated municipal solid waste from a tropical landfill in Colombia

The optimization of degradation processes and the management of leachate and biogas produced in landfills are key aspects for the establishment of more sustainable municipal solid waste (MSW) disposal in developing countries. In this study, biochemical methane potential (BMP) tests were used to evaluate CH4 production potential and degradation kinetics of fresh waste (FW) and five-year aged excavated waste (EW) samples from a tropical controlled landfill with compositional characteristics of developing countries. BMP tests with reconstituted samples of the biodegradable fraction of both MSW types were performed at three substrate/inoculum (S/I) ratios (0.3, 0.5 and 1.0 g VS substrate g− 1 VS inoculum), and CH4 generation parameters were determined using the first-order and modified Gompertz kinetic models. After 30-d, the best BMP results were reached at S/I ratios of 0.5 and 1.0, with cumulative CH4 productions of 528 and 433 mL CH4 g− 1 VS for FW, respectively; and 151 and 135 mL CH4 g− 1 VS for EW, respectively. The first-order kinetic model provided a good fit to BMP results for FW, whereas the modified Gompertz model showed a better adjustment to the BMP data for EW. Calculated first-order CH4 generation rates for FW and EW were in the range 0.19–0.36 and 0.23–0.25 d− 1, respectively. These results evidence the high biodegradability and CH4 potential of FW disposed of in a tropical landfill in Colombia and the reduced BMP of EW despite a relatively short period after disposal under conventional landfill operation conditions.

Temperature-dependent formulation of a hydrogel based on Hyaluronic acid-polydimethylsiloxane for biomedical applications

Hyaluronic acid (HA), as a safe biomaterial with minimal immunogenicity, is being employed in a broad range of medical applications. Since unmodified HA has a high potential for biodegradation in the physiological condition, herein, an HA-based cross-linked hydrogel was formulated using polydimethylsiloxane-diglycidyl ether terminated (PDMS-DG) via epoxide-OH reaction. The formation of HA-PDMS hydrogel was confirmed using FTIR, NMR, and FESEM. Temperature demonstrated a critical role in the physicochemical properties of the final products. Gel-37, which formed at 37 °C, had a higher modification degree (MD) and more stability against hyaluronidase and oxidative stress than the hydrogel formulated at 25 °C (Gel-25). In addition, the swelling ratio, roughness, and porous network topology of Gel-25 and Gel-37 were different. The rheology measurement indicated that HA-PDMS hydrogel had a stable viscoelastic character. The hydrogel was also biocompatible, non-cytotoxic, and considerably stable during 7-months storage. Overall, various determined parameters confirmed that HA-PDMS hydrogel is worth using in different medical applications. Keywords: Hyaluronic acid; Polydimethylsiloxane-diglycidyl ether terminated; Hydrogels; Long-term stability; Viscoelastic behavior; Biocompatibility.

Plastics: physical-and-mechanical properties and biodegradable potential

Introduction. Processing agricultural waste into plant biodegradable plastics is a promising way for its recycling. This work featured the main physical-and-mechanical properties of plant plastics without adhesive substances obtained from millet husk and wheat husk and wood plastic obtained from sawdust, as well as their biodegradation potential.
 Study objects and methods. Objects of the study were plastics without adhesives based on wood sawdust, millet husk, and wheat husk.
 Results and discussion. We analyzed of the physical-and-mechanical parameters of the plant plastic based on millet husk, wheat husk, as well as wood plastic based on sawdust. The analysis showed that, in general, the strength characteristics of the wood plastics were higher than those of the plastics based on millet husk, especially flexural strength. Thus, the average value of the density of the wood plastic exceeded that of the plant plastic from millet husk by 10%, hardness by 40%, compression elasticity modulus by 50%, and flexural modulus by 3.9 times. It was found that wood and plant plastics obtained from sawdust, millet husk, and wheat husk without adhesives had a high biodegradation potential.
 Conclusion. The plastics obtained can be used as an insulating, building, and decorative material in the steppe regions experiencing a shortage of wood and wood powder.

Electrospun poly(3-hydroxybutyrate-co-4-hydroxybutyrate) /Octacalcium phosphate Nanofibrous membranes for effective guided bone regeneration.

Membranes used in guided bone regeneration (GBR) are required to exhibit high mechanical strength, biocompatibility, biodegradation, osteogenic and osteoinductive potential. In our study, poly(3-hydroxybutyrate-co-4-hydroxybutyrate)(P(3HB-co-4HB))/octacalcium phosphate (OCP) (P(3HB-co-4HB)/OCP) nanofibrous membranes were fabricated by electrospinning with two different P(3HB-co-4HB) to OCP ratios (P(3HB-co-4HB):OCP=95:5wt% and 90:10wt%, termed P(3HB-co-4HB)/OCP(5)and P(3HB-co-4HB)/OCP (10), respectively) for GBR. The developed P(3HB-co-4HB)/OCP nanofibrous membranes were analysed for their osteogenic and osteoinductive properties using mesenchymal stem cells (MSCs) in vitro and in a calvarial bone defect rat model. The composite P(3HB-co-4HB)/OCP nanofibrous membranes showed decreased fibre size and enhanced tensile strength compared with those of P(3HB-co-4HB) nanofibrous membranes. In the in vitro studies, the P(3HB-co-4HB)/OCP membranes facilitated cell growth and osteoblastic differentiation of MSCs and were superior to P(3HB-co-4HB) membranes. After covered on the calvarial bone defects, P(3HB-co-4HB)/OCP membranes facilitated greater neobone formation than P(3HB-co-4HB) membranes did, as the result of histological evaluation and micro-CT analysis with higher bone volume/total volume (BV/TV) ratio and bone mineral density (BMD). P(3HB-co-4HB)/OCP(10) membranes with higher OCP content showed greater stiffness and osteoinductivity than P(3HB-co-4HB)/OCP (5)membranes, demonstrating the role of OCP in the composite membranes. These results indicated that electrospun P(3HB-co-4HB)/OCP nanofibrous membranes hold promise for the clinical application of GBR.

Effects of different simulated seasonal temperatures on the fermentation characteristics and microbial community diversities of the maize straw and cabbage waste co-ensiling system

Ensiling is considered as a suitable method to preserve seasonal agricultural residues to enable long-term supply for wastes valorization. In this study, the effects of simulated seasonal temperatures (−3, 18 and 34 °C) on the organic compositions, ensiling fermentation characteristics, and microbial community evolution during 120 days co-ensiling of maize straw and cabbage wastes were investigated. Successful storage performance was obtained at all these three temperatures. Comparatively, silages at 18 and 34 °C showed lower ammonia nitrogen, lower pH and more intensive lactic acid bacteria fermentation than that at −3 °C. Both silages at −3 and18 °C were well-preserved for 120 days with higher biodegradation potential (BDP), accompanied by lower content of acid detergent lignin (ADL). However, the silages at 34 °C could only preserved for 90 days due to low carbohydrate, low BDP and higher ADL content than that at −3 or18 °C. The storage temperature is a critical parameter that significantly affected the silage quality by influencing the microbial community diversity in silages. Proteobacteria and Firmicutes were dominant bacteria at phylum level for all silages while the dominant lactic acid bacteria at genus level were Lactobacillus and Leuconostoc, which restrained the undesirable microbes such as Enterobacteriaceae, Pseudomonas, Flavobacterium, and Pantoea during co-ensiling. Co-ensiling of maize straw with vegetable wastes may provide a promising strategy for long-term preservation of air-dried crop straw while using vegetable wastes as regulatable supplement to achieve silages of desired quality. This study could provide valuable information for conservation and management of agricultural wastes.

Three chlorotoluene-degrading bacterial strains: Differences in biodegradation potential and cell surface properties

Pollution of the environment with chlorinated aromatic compounds is a problem of increasing importance, which has stimulated the search for efficient methods for the remediation of contaminated soil and water. Additionally, for better understanding of the significance of bioavailability to biodegradation, investigation of the cell surface properties is necessary. Hence, this study concerns the properties and possible application, in chlorotoluene removal, of three newly isolated environmental bacterial strains from the genera Pseudomonas, Raoultella and Rahnella. The results show the differences in the biochemical profiles of the isolated strains, their cellular fatty acid composition and their hemolytic properties. However, all three strains exhibit high biodegradation potential, degrading not less than 60% of each monochlorotoluene isomer in 21-day experiments. What is more, observations of changes in the cell surface properties indicate the possible adaptation mechanisms of the strains that enable efficient biodegradation of hydrophobic pollutants such as monochlorotoluenes.

Thermomechanical Properties of Corn Starch Based Film Reinforced with Coffee Ground Waste as Renewable Resource

Abstract Starches polymeric films offer several advantages for the replacement of synthetic polymers due to their biodegradability, non-toxicity, availability and low cost. However, the high biodegradation potential can cause fragility, considering some fundamental mechanical properties. Therefore, starch based polymeric films were reinforced incorporating lignocellulosic waste from coffee grounds post-consume. The effect of incorporation of coffee ground in cornstarch matrix and polymer interaction on morphology, thermal and mechanical properties were investigated. The characterization analyzes were based on Dynamic Mechanical Thermal Analysis (DMTA), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA) and Scanning Eletronic Microscopy (SEM). The coffee ground behaved as reinforcement agent according tensile values. Thermochemical conversion showed that polymeric films molding did not change his thermal stability. In temperature range was possible to observe the devolatilization, organic and inorganic compounds decomposition. SEM images showed the coffee ground adhesion in the polymer matrix promoting a better mechanical tensile strength.

Carbon dioxide capture by solvent absorption using amino acids: A review

Abstract The emission of large amounts of carbon dioxide is of major concern with regard to increasing the risk of climate change. Carbon capture, utilisation and storage (CCUS) has been proposed as an important pathway for slowing the rate of these emissions. Solvent absorption of CO2 using amino acid solvents has drawn much attention over the last few years due to advantages including their ionic nature, low evaporation rate, low toxicity, high absorption rate and high biodegradation potential, compared to traditional amine solvents. In this review, recent progress on the absorption kinetics of amino acids is summarised, and the engineering potential of using amino acids as carbon capture solvents is discussed. The reaction orders between amino acids and carbon dioxide are typically between 1 and 2. Glycine exhibits a reaction order of 1, whilst, by comparison, lysine, proline and sarcosine have the largest reaction constants with carbon dioxide which is much larger than that of the benchmark solvent monoethanolamine (MEA). Ionic strength, pH and cations such as sodium and potassium have been shown to be important factors influencing the reactivity of amino acids. Corrosivity and reactivity with impurities such as SOx and NOx are not considered to be significant problems for amino acids solvents. The precipitation of CO2 loaded amino acid salts is thought to be a good pathway for increasing CO2 loading capacity and cutting desorption energy costs if well-controlled. It is recommended that more detailed research on amino acid degradation and overall process energy costs is conducted. Overall, amino acid solvents are recognised as promising potential solvents for carbon dioxide capture.