Bio-based Approaches Research Articles

Green synthesis of chitosan nanoparticles using Cassia fistula leaf extract: evaluation of antimicrobial, antioxidant, antibiofilm, and cytotoxic activities.

The emerging field of green synthesis within nanobiotechnology presents significant environmental and economic advantages compared to conventional methodologies. This study investigates the synthesis and application of chitosan nanoparticles (ChNPs) using Cassia fistula (CF) leaf extract as a sustainable, and bio-based approach. Characterization of CF-ChNPs confirmed effective bioconversion and also demonstrated significant antimicrobial activity. Notably, CF-ChNPs demonstrated a remarkable antimicrobial effect against Pseudomonas aeruginosa, with a zone of inhibition of 17 ± 0.2mm surpassing the impact on other organisms tested. The CF-ChNPs exhibited an initial burst release of 28 ± 0.28% after 2h, gradually achieving a controlled release of 76.3 ± 0.43% within 24h. In addition, CF-ChNPs exhibited an antioxidant activity of 43.1 ± 0.48% and showed excellent antibiofilm activity against Staphylococcus aureus in comparison to other organisms. The cell viability assay results have confirmed that CF-ChNPs do not have any negative impact on the viability of L929 fibroblasts, further highlighting their potential as versatile nanomaterials for treating microbial infections and other therapeutic applications.

Green synthesis and anti‐biofilm effect on Drosophila melanogaster of selenium nanoparticles from Vitis vinifera for photocatalytic degradation and different biological applications

AbstractThis study aims to combine Vitis vinifera extract with sodium selenite (Na2SeO3) solution to develop a biobased approach for producing green selenium nanoparticles. V. vinifera fruit extract is potent in secondary metabolites such as phenols (1.19 mg gallic acid equivalents/g), flavonoids (0.42 mg catechin equivalents/g), and tannins (2.84 mg tannic acid equivalents/g), it was discovered to be particularly appropriate for the production of nanoparticles. SeNPs were characterized using UV–vis, SEM, zeta potential, EDS, DLS, FTIR, and XRD AFM. SeNPs were assessed for anti‐microbial, anti‐biofilm, and antioxidant assay. Biosynthesized‐produced SeNPs were discovered to possess significant antioxidant activity and high antibacterial action. Selenium nanoparticles had the potential to modulate the impact of Pseudomonas aeruginosa on Drosophila melanogaster. Molecular analyses were performed, and survival analysis curves were plotted to study the impact of SeNPs. When SeNPs are exposed to UV light, they efficiently break down crystal violet dye. To comprehend the impact of three variables—pH, time, and SeNP concentration—on the dye degradation, a full factorial design was employed. This study showed that SeNPs can be used as a potential anti‐biofilm agent and are also effective in the textile, dye, and pharmaceutical industries.

The landscape of clinical trials in corneal regeneration: A systematic review of tissue engineering approaches in corneal disease.

The limited availability of a healthy donor cornea and the incidence of allograft failure led researchers to seek other corneal substitutes via tissue engineering. Exploring the trend of clinical trials of the cornea with the vision of tissue engineering provides an opportunity to reveal future potential corneal substitutes. The results of this clinical trial are beneficial for future study designs to overcome the limitations of current therapeutic approaches. In this study, registered clinical trials of bio-based approaches were reviewed for corneal regeneration on March 22, 2024. Among the 3955 registered trials for the cornea, 392 trials were included in this study, which categorized in three main bio-based scaffolds, stem cells, and bioactive macromolecules. In addition to the acellular cornea and human amniotic membrane, several bio-based materials have been introduced as corneal substrates such as collagen, fibrin, and agarose. However, some synthetic materials have been introduced in recent studies to improve the desired properties of bio-based scaffolds for corneal substitutes. Nevertheless, new insights into corneal regenerative medicine have recently emerged from cell sheets with autologous and allogeneic cell sources. In addition, the future perspective of corneal regeneration is described through a literature review of recent experimental models.

Microaeration promotes volatile siloxanes conversion to methane and simpler monomeric products

The ubiquitous use of volatile siloxanes in a myriad of product formulations has led to a widespread distribution of these persistent contaminants in both natural ecosystems and wastewater treatment plants. Microbial degradation under microaerobic conditions is a promising approach to mitigate D4 and D5 siloxanes while recovering energy in wastewater treatment plants. This study examined D4/D5 siloxanes biodegradation under both anaerobic and microaerobic conditions (PO2 = 0, 1, 3 %) using wastewater sludge. Results show that the use of microaeration in an otherwise strictly anaerobic environment significantly enhances siloxane conversion to methane. 16S rRNA gene sequencing identified potential degraders, including Clostridium lituseburense, Clostridium bifermentans and Synergistales species. Furthermore, chemical analysis suggested a stepwise siloxane conversion preceding methanogenesis under microaerobic conditions. This study demonstrates the feasibility of microaerobic siloxane biodegradation, laying groundwork for scalable removal technologies in wastewater treatment plants, ultimately highlighting the importance of using bio-based approaches in tackling persistent pollutants.

A novel front in sustainable microbial management: computational analysis of curcumin and mangiferin's synergistic action against Bacillus anthracis.

Microorganisms are crucial in our ecosystem, offering diverse functions and adaptability. The UNGA Science Summit has underscored the importance of understanding microbes in alignment with the UN Sustainable Development Goals. Bacillus anthracis poses significant challenges among various microorganisms due to its harmful effects on both soil and public health. Our study employed computational techniques to investigate the inhibitory effects of curcumin and mangiferin on Bacillus anthracis, with the aim of presenting a novel bio-based approach to microbial management. Employing high-throughput screening, we identified potential binding sites on B. anthracis. Molecular docking revealed that curcumin and mangiferin, when synergistically combined, exhibited strong binding affinities at different sites on the bacterium. Our findings demonstrated a significant drop in binding free energy, indicating a stronger interaction when these compounds were used together. Results of Molecular docking indicated binding energies of -8.45 kcal/mol for mangiferin, -7.68 kcal/mol for curcumin, and a notably higher binding energy of -19.47 kcal/mol for the combination of mangiferin and curcumin with CapD protein. Molecular dynamics simulations further validated these interactions, demonstrating increased stability and structural changes in the bacterium. This study highlights the effectiveness of natural compounds like curcumin and mangiferin in microbial management, especially against challenging pathogens like B. anthracis. It emphasizes the potential of sustainable, nature-based solutions and calls for further empirical research to expand upon these findings.

Synthesis of 1, 8-dioxodecahydroacridines via Hantzsch condensation using theophylline in an aqueous medium: an eco-friendly and bio-based approach

Synthesis of 1, 8-dioxodecahydroacridines via Hantzsch condensation using theophylline in an aqueous medium: an eco-friendly and bio-based approach

An overview of the biosensing potential of organometallic compounds

Sensing technology is receiving increasing attention and improvements every day, making it a suggested component of personalized healthcare management. This is due to the capabilities of organometallic compounds supported by bioengineering. Organometallic compounds have abundant biological activity and many industrial and material science applications. Due to their unique biological targetability, they possess potential applications in drug development, diagnosis, and treatment. Organometallic compounds are emerging as promising candidates for the advancement in sensor technology as they are engineered to address some of the limitations encountered by their traditional counterparts. These compounds have distinctive characteristics that render them exceptionally responsive to alterations in their surroundings, hence enabling their use as sensors for the detection of diverse chemicals or circumstances. In addition, the adaptability of organometallic compounds allows for their incorporation into various sensor platforms, rendering them appropriate for a diverse array of applications such as environmental surveillance, medical analysis, and industrial assurance of quality. This review presents an overview of the recent progress made in the field of organometallic compounds’ design and production, specifically focusing on their potential uses as sensors. In addition, the structural modifications, functionalization procedures, integration of microfluidics, and the consequent effects on the sensing capacities of the materials are recalled. These bio-based approaches will align with sustainability objectives and make sensing more affordable, applicable, and successful.

Technology Focus: Decarbonization (July 2023)

With several applications under its belt, carbon capture and sequestration (CCS) is a proven technology. Costs are a concern, however, when it is not accompanied with CO2 enhanced oil recovery. Naturally, the effort is now to bring down costs by understanding various aspects of the process. This is reflected amply in the overwhelming majority of the approximately 300 papers on emissions reduction produced since late 2021 at various SPE conferences. These cover a range of CCS-related topics, such as onshore to offshore applications, drilling operations, well metallurgy, well-flow modeling, repurposing wells, storage capacity, and reservoir suitability. Because the basics of CCS and carbon capture, use, and storage (CCUS) are mostly familiar to a large part of the readership, I am choosing to bring to your attention the summary of those articles that are devoted to approaches other than or beyond CCS, even if they have to climb further on the development ladder. These include bio-based approaches, geothermal, and use of hydrogen as a substitute fuel. The first of these papers discusses the generation of biomethane and hydrogen from palm oil mill effluent and using hyperthermophile bacteria. The second deals with making use of seaweeds such as Macrocystis pyrifera, commonly found in desertic or semidesertic climates though thermal conversion to hydrogen. The third deals with mangrove restoration for biomass growth and carbon fixation. For further reading and interest I have two topics to suggest: geothermal and hydrogen. Geothermal is not a new technology, but selecting and targeting the right reservoir can make a huge difference to its commercial viability. In this respect, the readers will find the included paper to be a good atlas. While I have been skeptical about hydrogen’s capacity to play an immediate role in decarbonization, the recommended paper focused on hydrogen challenges my preconceptions to an extent, and I think is therefore worthy of mention. In a 2019 International Energy Agency report, the cost of blue hydrogen from natural gas was mentioned to be approximately $1.50/kg in a few favorable jurisdictions, including the US. Can the cost of producing clean hydrogen from noncommercial gas pools be in the same range? The recommended-reading paper on this subject estimates the calculation-based cost of green hydrogen to be even 5–10 times more favorable. Although it may be premature to celebrate, given that this is still based on paper estimates and that other challenges in hydrogen storage and transport exist, it still bodes well for the commerce of clean hydrogen. While it causes optimism, caution is warranted, given significant challenges (not dwelled upon in the paper) in purification and sustainability of a subsurface hydrogen-production process. I am confident you will find these papers to be interesting and stimulating reads. Recommended additional reading at OnePetro: www.onepetro.org. OTC 32035 A Fully Integrated and Updated Geothermal Gradient Atlas of the World by Susan Smith Nash, American Association of Petroleum Geologists, et al. SPE 209558 Subsurface Hydrogen Generation: Low-Cost and Low-Footprint Method of Hydrogen Production by Roman Berenblyum, Hydrogen Source, et al.

Towards Sustainable Recycling of Epoxy-Based Polymers: Approaches and Challenges of Epoxy Biodegradation.

Epoxy resins are highly valued for their remarkable mechanical and chemical properties and are extensively used in various applications such as coatings, adhesives, and fiber-reinforced composites in lightweight construction. Composites are especially important for the development and implementation of sustainable technologies such as wind power, energy-efficient aircrafts, and electric cars. Despite their advantages, their non-biodegradability raises challenges for the recycling of polymer and composites in particular. Conventional methods employed for epoxy recycling are characterized by their high energy consumption and the utilization of toxic chemicals, rendering them rather unsustainable. Recent progress has been made in the field of plastic biodegradation, which is considered more sustainable than energy-intensive mechanical or thermal recycling methods. However, the current successful approaches in plastic biodegradation are predominantly focused on polyester-based polymers, leaving more recalcitrant plastics underrepresented in this area of research. Epoxy polymers, characterized by their strong cross-linking and predominantly ether-based backbone, exhibit a highly rigid and durable structure, placing them within this category. Therefore, the objective of this review paper is to examine the various approaches that have been employed for the biodegradation of epoxy so far. Additionally, the paper sheds light on the analytical techniques utilized in the development of these recycling methods. Moreover, the review addresses the challenges and opportunities entailed in epoxy recycling through bio-based approaches.

Realizing the Continuous Chemoenzymatic Synthesis of Anilines Using an Immobilized Nitroreductase.

The use of biocatalysis for classically synthetic transformations has seen an increase in recent years, driven by the sustainability credentials bio-based approaches can offer the chemical industry. Despite this, the biocatalytic reduction of aromatic nitro compounds using nitroreductase biocatalysts has not received significant attention in the context of synthetic chemistry. Herein, a nitroreductase (NR-55) is demonstrated to complete aromatic nitro reduction in a continuous packed-bed reactor for the first time. Immobilization on an amino-functionalized resin with a glucose dehydrogenase (GDH-101) permits extended reuse of the immobilized system, all operating at room temperature and pressure in aqueous buffer. By transferring into flow, a continuous extraction module is incorporated, allowing the reaction and workup to be continuously undertaken in a single operation. This is extended to showcase a closed-loop aqueous phase, permitting reuse of the contained cofactors, with a productivity of >10 gproduct gNR-55-1 and milligram isolated yields >50% for the product anilines. This facile method removes the need for high-pressure hydrogen gas and precious-metal catalysts and proceeds with high chemoselectivity in the presence of hydrogenation-labile halides. Application of this continuous biocatalytic methodology to panels of aryl nitro compounds could offer a sustainable approach to its energy and resource-intensive precious-metal-catalyzed counterpart.

Toward a Resilient Future: The Promise of Microbial Bioeconomy

Naturally occurring resources, such as water, energy, minerals, and rare earth elements, are limited in availability, yet they are essential components for the survival and development of all life. The pressure on these finite resources is anthropogenic, arising from misuse, overuse, and overdependence, which causes a loss of biodiversity and climate change and poses great challenges to sustainable development. The focal points and principles of the bioeconomy border around ensuring the constant availability of these natural resources for both present and future generations. The rapid growth of the microbial bioeconomy is promising for the purpose of fostering a resilient and sustainable future. This highlights the economic opportunity of using microbial-based resources to substitute fossil fuels in novel products, processes, and services. The subsequent discussion delves into the essential principles required for implementing the microbial bioeconomy. There is a further exploration into the latest developments and innovations in this sub-field. The multi-sectoral applications include use in bio-based food and feed products, energy recovery, waste management, recycling, and cascading. In multi-output production chains, enhanced microbes can simultaneously produce multiple valuable and sustainable products. The review also examines the barriers and facilitators of bio-based approaches for a sustainable economy. Despite limited resources, microbial-based strategies demonstrate human ingenuity for sustaining the planet and economy. This review highlights the existing research and knowledge and paves the way for a further exploration of advancements in microbial knowledge and its potential applications in manufacturing, energy production, reduction in waste, hastened degradation of waste, and environmental conservation.

Engineering Bacillus subtilis for production of 3-hydroxypropanoic acid.

3-Hydroxypropionic acid (3-HP) is a valuable platform chemical that is used as a precursor for several higher value-added chemical products. There is an increased interest in development of cell factories as a means for the synthesis of 3-HP and various other platform chemicals. For more than a decade, concentrated effort has been invested by the scientific community towards developing bio-based approaches for the production of 3-HP using primarily Escherichia coli and Klebsiella pneumoniae as production hosts. These hosts however might not be optimal for applications in e.g., food industry due primarily to endotoxin production and the pathogenic origin of particularly the K. pneumoniae. We have previously demonstrated that the generally recognized as safe organism Bacillus subtilis can be engineered to produce 3-HP using glycerol, an abundant by-product of the biodiesel industry, as substrate. For commercial exploitation, there is a need to substantially increase the titer. In the present study, we optimized the bioprocess conditions and further engineered the B. subtilis 3-HP production strain. Thereby, using glycerol as substrate, we were able to improve 3-HP production in a 1-L bioreactor to a final titer of 22.9g/L 3-HP.

Growth enhancement and extenuation of drought stress in maize inoculated with multifaceted ACC deaminase producing rhizobacteria

IntroductionMaize is a major staple cereal crop grown and consumed globally. However, due to climate change, extreme heat and drought stresses are greatly affecting its production especially in sub-Saharan Africa. The use of a bio-based approach to mitigate drought stress is therefore suggested using plant growth-promoting rhizobacteria (PGPR).MethodsThis study investigated the abilities of 1-aminocyclopropane-1-carboxylate (ACC) deaminase producing PGPR Pseudomonas sp. MRBP4, Pseudomonas sp. MRBP13 and Bacillus sp. MRBP10 isolated from maize rhizosphere soil, to ameliorate the effect of drought stress in maize genotypes MR44 and S0/8/W/I137TNW//CML550 under two water regimes; mild drought stress (50% FC) and well-watered conditions (100% FC). The rhizobacterial strains were identified by 16S rRNA sequencing and biochemical tests, and evaluated for plant growth-promoting and abiotic stress tolerance traits.Results and discussionThe synergistic effect of the bacterial strains had a highly significant (p < 0.001) effect on the total soluble sugar, soil moisture content and relative water content, which were enhanced under water-stress in the inoculated plants. Relative water content was significantly highest (p < 0.001) in maize plants co-inoculated with Pseudomonas sp. MRBP4 + Bacillus sp. MRBP10 (60.55%). Total chlorophyll content was significantly enhanced in maize seedlings sole inoculated with Pseudomonas sp. MRBP4, Pseudomonas sp. MRBP13, and co-inoculated with Pseudomonas sp. MRBP13 + Bacillus sp. MRBP10 by 15.91%, 14.99% and 15.75% respectively, over the un-inoculated control. Soil moisture content increased by 28.67% and 30.71% compared to the un-inoculated control when plants were inoculated with Pseudomonas sp. MRBP4 + Bacillus sp. MRBP10 and Pseudomonas sp. MRBP4 + Bacillus sp. MRBP10 respectively. The interactive effect of genotype × bacteria significantly enhanced biomass production. Leaf area was highest in maize plants co-inoculated with Pseudomonas sp. MRBP4 + Pseudomonas sp. MRBP13 (212.45 ± 0.87 cm2) under drought stress. Treatment of maize seeds with Pseudomonas sp. MRBP 4 + Pseudomonas sp. MRBP13 + Bacillus sp. MRBP10 significantly increased the root length (10.32 ± 0.48 cm) which enhanced survival of the maize seedlings. Bioinoculation of maize seeds with these strains could boost maize production cultivated in arid regions.

Greener approach to the comprehensive utilization of algal biomass and oil using novel Clostridial fusants and bio-based solvents

A greener method has been tested to utilize algal biomass as a feedstock to produce bio-oil in addition to acetone, butanol, and ethanol (ABE) products. Various hydrolysis treatments were used prior to fermentation including combination of thermal, chemical, and enzymatic, which resulted in maximum sugar release of 27.78 g/L. Bio-based terpenes was used instead of common toxic chemicals together with Clostridial fustants to produce bio-alcoholic fuels. Protoplast fusion technique were used to produce the novel Clostridia fusants (C. beijernickii + C. thermocellum and C. acetobutylicum + C. thermocellocum). Fused strains were then subjected to UV radiation for strain enhancement. Final fusansts showed clear improvement in thermal stability and resistance to biobutanol toxicity. Fermentation experiments showed maximum biobutanol final production of 7.98 g/L using CbCt versus 7.39 g/L using CaCt. Oil extraction from virgin algae was tested using a green, bio-based approach using terpenes with ultrasonication and green Bligh and Dyer method, separately. In preliminary study on algal biomass, the combinations of ultrasonication followed by the green Bligh and Dyer have resulted in oil yield of 46.27% (d-limonene) and 39.85% (p-cymene). Oil extraction from an algae sample following fermentation using the combined extraction method resulted in significantly higher oil yield of 65.04%.

Green approaches for extraction, chemical modification and processing of marine polysaccharides for biomedical applications.

Over the past few decades, natural-origin polysaccharides have received increasing attention across different fields of application, including biomedicine and biotechnology, because of their specific physicochemical and biological properties that have afforded the fabrication of a plethora of multifunctional devices for healthcare applications. More recently, marine raw materials from fisheries and aquaculture have emerged as a highly sustainable approach to convert marine biomass into added-value polysaccharides for human benefit. Nowadays, significant efforts have been made to combine such circular bio-based approach with cost-effective and environmentally-friendly technologies that enable the isolation of marine-origin polysaccharides up to the final construction of a biomedical device, thus developing an entirely sustainable pipeline. In this regard, the present review intends to provide an up-to-date outlook on the current green extraction methodologies of marine-origin polysaccharides and their molecular engineering toolbox for designing a multitude of biomaterial platforms for healthcare. Furthermore, we discuss how to foster circular bio-based approaches to pursue the further development of added-value biomedical devices, while preserving the marine ecosystem.

Sustainable, bio-based conductive materials from peanut waste for flexible electronics and tunable piezoresistive strain sensors

Sustainable engineering applications are of great significance in materials science because of limited natural resources. This study presents a sustainable, bio-based approach for the fabrication of flexible electronics and sensors by using peanut shell and skin as the precursors for conductive carbon-based fillers. Carbonized samples showed differences in terms of morphological, structural, and electrical properties. While peanut shell-based carbon showed higher crystallinity and morphology with multiple channels; peanut skin-based carbon showed stacked, layered morphology with smaller particle size. Elastic modulus of the samples increased, tensile strength, and tensile strain values were decreased for both composite sets. The electrical conductivity of the samples prepared by carbon from peanut shell showed lower percolation concentration. Both composites showed piezoresistive response under cycling loading/unloading and tunable piezoresistive sensors were shown to be sensitive to human motions including horizontal and vertical elbow movement and back and forth knee bending and squatting.

A bio-based approach to simultaneously improve flame retardancy, thermal stability and mechanical properties of nano-silica filled jute/thermoplastic starch composite

This novel work discusses the simultaneous improvement in flame retardancy, thermal stability and mechanical performance of jute/thermoplastic starch (TPS) composite through the incorporation of nano-silica particles (1–4 wt% of starch) as a bio-based flame retardant. The enhancement in mechanical properties of the composite has been achieved due to hydrogen bonding and the formation of a strong Si–O–Si covalent bond between silica and jute/TPS which has been verified through Fourier transform infrared spectroscopy (FTIR). Tensile, flexural and impact strengths of the jute/TPS composites were observed to increase respectively by 23%, 97% and 70% after incorporation of nano-silica. The improvement in interfacial bonding was verified using scanning electron microscopy (SEM). Cone calorimetry and UL-94 burning tests revealed that the composites have excellent sustainability towards flame supported by a 128% reduction in burning time, 12% decrease in total heat released and 14% decrease in peak heat release rate. Thermogravimetric analysis (TGA) showed thermal stability through increase in decomposition temperature due to a 37% increase in residual char. Furthermore, biodegradation of the developed composites was proven through a soil burial test. Hence, the research provides the design of novel biodegradable material with simultaneous enhancement of mechanical properties, thermal stability and flame-retardancy, which expands the applications of thermoplastic composites in automobile, aerospace and structural applications.

Identification and profiling of silicate-solubilizing bacteria for plant growth-promoting traits and rhizosphere competence

Excessive use of synthetic fertilizers may negatively affect overall soil health and the environment. There is a need to come up with alternative strategies to ensure competitive yields of crops and at the same time maintain soil ecological balance. The use of soil microorganisms as microbial inoculants in agriculture is considered an alternative approach to enhance crop growth. Soil is a good source of microorganisms that are capable of producing different beneficial enzymes such as silicase, phosphatase and other growth-promoting enzymes which are important in crop growth. Soil beneficial microorganisms such as silicate-solubilizing bacteria play an important role in solubilizing insoluble forms of silicates that are important in crop growth. This study was conducted to identify and profile silicate-solubilizing bacteria (SSB) in Louisiana soils and to document the colonization potential of SSB in rice (Oryza sativa) plants. Bacterial isolates were spot-inoculated on silica agar medium and incubated at 37 °C for 48 h. The clearing zone around colonies was measured and used to compute for solubilization index (SI), i.e., halo diameter (mm)/colony diameter (mm). Despite of the abundance of microorganisms found in these soils only 20 bacterial isolates are capable of solubilizing silicates; 16 were with low (SI < 2.0) and 4 with intermediate (2.00 < SI < 4.00) solubilization capacities. Further analysis also revealed that three of the isolates with intermediate silicate solubilization capacities also produced plant growth-promoting enzymes: phosphatase, 1-aminocyclopropane-1-carboxylic acid deaminase and indole-3-acetic acid enzyme. Based on the sequencing information and the phylogenetic tree, the putative SSB were identified into four genera: Aeromonas, Bacillus, Enterobacter and Pseudomonas. The fluorescent microscopy analysis revealed that the GFP-tagged SSB can colonize roots of young rice seedlings, a good indicator of SSB potential as seed treatment for scaling up its application in production field. Furthermore, information on the survival of SSB inoculates in different soil-plant systems in Louisiana and impact of management practices on SSB activity and population are needed to fully develop this bio-based approach to improve Si nutrition in soil and plants.

Capital Structure Determinants of Forest Enterprises: Empirical Study Based on Panel Data Analysis from the Czech Republic, Slovakia, and Bulgaria

At present, forest enterprises face many challenges in adopting innovative bio-based approaches considering global changes. Due to the specifics of forestry, the choice of financing sources is a complex issue. The aim of this study is to estimate the capital structure determinants of forest enterprises in the Czech Republic, Slovakia, and Bulgaria in the context of the relationship between leverage and the factors of its appearance. The evaluation of capital structure determinants was carried out using selected indicators for 18 forest enterprises, with 6 enterprises per country. Data were processed for the period of 2015–2019. The study methodology was based on a Panel Data Analysis with Fixed Effects and Random Effect models and Ordinary Least Squares estimation. The following specific variables were included: liquidity, leverage, return on assets, size of the enterprises, and gross domestic product. The results revealed that the forest enterprises in these three countries can be differentiated by size and form individual functional relationships with the positive influence of enterprise size on liability share. The next significant determinant was found to be liquidity, which has a negative relationship with enterprise leverage. These results will be useful for managers of forest enterprises in decision-making processes to determine the amount of debt and planning investment programme strategies.

Microbial Involvement in the Bioremediation of Total Petroleum Hydrocarbon Polluted Soils: Challenges and Perspectives

Nowadays, soil contamination by total petroleum hydrocarbons is still one of the most widespread forms of contamination. Intervention technologies are consolidated; however, full-scale interventions turn out to be not sustainable. Sustainability is essential not only in terms of costs, but also in terms of restoration of the soil resilience. Bioremediation has the possibility to fill the gap of sustainability with proper knowledge. Bioremediation should be optimized by the exploitation of the recent “omic” approaches to the study of hydrocarburoclastic microbiomes. To reach the goal, an extensive and deep knowledge in the study of bacterial and fungal degradative pathways, their interactions within microbiomes and of microbiomes with the soil matrix has to be gained. “Omic” approaches permits to study both the culturable and the unculturable soil microbial communities active in degradation processes, offering the instruments to identify the key organisms responsible for soil contaminant depletion and restoration of soil resilience. Tools for the investigation of both microbial communities, their degradation pathways and their interaction, will be discussed, describing the dedicated genomic and metagenomic approaches, as well as the interpretative tools of the deriving data, that are exploitable for both optimizing bio-based approaches for the treatment of total petroleum hydrocarbon contaminated soils and for the correct scaling up of the technologies at the industrial scale.