Now showing items 7039-7058 of 49888

    • B Corps’ Social Media Communications during the COVID-19 Pandemic: Through the Lens of the Triple Bottom Line

      Manveer Mann; Sang-Eun Byun; Whitney Ginder (MDPI AG, 2021-08-01)
      The COVID-19 pandemic and rising demand for transparency has heightened the importance of sustainability communications on social media to generate deeper stakeholder engagement. Although B Corporations (B Corps), businesses committed to the triple bottom line (TBL), could serve as a catalyst for sustainable development, little is known about how they communicate on social media during a crisis. Therefore, we examined social media communications of B Corps to (1) identify salient topics and themes, (2) analyze how these themes align with the TBL, and (3) evaluate social media performance against industry benchmarks. We focused on the apparel, footwear, and accessories (AFA) sectors in the U.S. and chose Twitter, a platform known for crisis communication. Using a qualitative method, we found four topics and 21 underlying themes. Topics related to social/environmental issues and COVID-19 were most dominant, followed by product/brand promotions. Further classification of specific themes and cases from a TBL perspective demonstrated that, overall, B Corps in the AFA sectors leveraged various approaches to promote balance between each TBL dimension. Lastly, although collectively B Corps exceeded some of the Twitter industry benchmarks, at an individual level, most brands had room for improvement to build a stronger community and promote synergy among the three pillars of the TBL.
    • B Impact Assessment as a Sustainable Tool: Analysis of the Certification Model

      Vítor Silva; Vanda Lima; José Carlos Sá; Luís Fonseca; Gilberto Santos (MDPI AG, 2022-05-01)
      Currently, certification is an essential tool for a company’s sustainability and a seal of trust for the stakeholders. The B Corporation (B Corp) certification system is in line with the leading indicators of sustainable development and social responsibility published by the general assembly of the United Nations, namely: environment, community, workers, customers, and governance. Nevertheless, it is essential that academic research should empirically assess the B Corp model’s reliability for its validation and legitimization. In this study, we address the results of the B Impact Assessment of 2262 companies certified by B Corp from the beginning of 2017 to March 2021. The main objective is to analyze the B Impact Assessment, verifying the robustness and consistency of the model to measure and improve the economic, social, and environmental impact of companies. We analyzed the construct’s validity through a confirmatory factorial analysis using AMOS statistical software. The results allowed us to identify some weaknesses and limitations of the B Impact Assessment. This certification system reflects an unadjusted model where the main assessment indicators have problems with regard to the measurement scale. The governance and customer indicators are the most vulnerable. The findings also allow us to state that there are apparently no minimum values established for each of the parameters evaluated, which may cause imbalances in the sustainable development process of B Corp companies. This research contributes to enhancing B Impact Assessment as a sustainability tool, highlighting areas for improvement concerning the indicators’ measurement scales and the assessment process, including the monitoring of evaluators.
    • B-Learning and Technology: Enablers for University Education Resilience. An Experience Case under COVID-19 in Spain

      Luis M. Sánchez Ruiz; Santiago Moll-López; Jose Antonio Moraño-Fernández; Nuria Llobregat-Gómez (MDPI AG, 2021-03-01)
      Innovative teaching methodologies begat blended learning, which seems to facilitate engineering students’ achievement of competencies required for the 21st century and has proven to be essential to keep quality standards as university education has suffered the COVID-19 pandemic. In this paper, we approach the use of b-learning and digital technologies before the pandemic started, and how it worked like a vaccine, enabling university education resilience and facilitating the sustainability of the students learning process. A questionnaire-based study is presented, in which the data came from Aerospace Engineering students following a Mathematics subject in a Technological University in Spain. ANOVA and ANCOVA analysis provided a significant difference in the appreciation of the adaptation based on the prior application of b-learning methodologies or more traditional methodologies. Results obtained indicated that the use of digital resources and educational platforms caused a noticeable change in the students’ way of learning, improving habits and digital skills.
    • Back and Forth on Sustainable Development: A Focus on Healthcare Organisations

      Caterina Cavicchi; Chiara Oppi; Emidia Vagnoni (MDPI AG, 2022-04-01)
      The sustainability of healthcare systems represents a relevant target of the 2030 Sustainable Development Goals Agenda. Nevertheless, academic research has neglected to study healthcare systems when focusing on the transition toward sustainable healthcare. This study addresses this gap by investigating the implementation of the sustainable development (SD) principle in the Italian healthcare system, in light of international and national institutional discourses on SD. A questionnaire-based survey has been directed to the General Directors (GDs) of government-funded healthcare orgsanisations to investigate their perceptions about the SD principle applied to healthcare, their strategic planning for SD, their implemented projects for sustainability and the intellectual capital factors that influence the latter’s implementation. The study was conducted in two waves: a first survey was administered in 2016, with a second one in 2021. We used content analysis to identify the potential differences emerging over time in GDs’ perceptions in light of the changes in the institutional discourse; we then assessed the differences over time in the perceived contribution of intellectual capital factors to the implementation of sustainability actions. Results show a substantial decrease in strategic planning for sustainability, as well as in the volume of sustainability projects implemented, as organisations were found to be less involved in implementing SD strategies and projects in 2021 than in 2016. Policies at the country level have mainly focused on balancing cost containment with quality targets, leaving the environmental dimension of sustainability and its connection with healthcare with limited guidelines. Regarding intellectual capital factors, organisational culture and technologies are increasingly perceived as enablers of SD; nevertheless, further studies are needed to deepen their effective contribution to sustainable healthcare.
    • Back Contact Engineering to Improve CZTSSe Solar Cell Performance by Inserting MoO3 Sacrificial Nanolayers

      Cheng-Ying Chen; Septia Kholimatussadiah; Wei-Chao Chen; Yi-Rung Lin; Jia-Wei Lin; Po-Tuan Chen; Ruei-San Chen; Kuei-Hsien Chen; Li-Chyong Chen (MDPI AG, 2022-08-01)
      Earth-abundant Cu2ZnSn(S,Se)4 (CZTSSe) is a promising nontoxic alternative compound for commercially available Cu(In,Ga)(S,Se)2 thin-film solar cells. In this study, a MoO3 nanolayer was applied as a sacrificial layer to optimize the quality of the interface between the CZTSSe and Mo back contact. MoO3 nanolayers can greatly improve CZTSSe grain growth and suppress the formation of some harmful secondary phases, especially the undesirable MoS(e)2. In terms of device performance, the series resistance was reduced from 1.83 to 1.54 Ω·cm2, and the fill factor was significantly enhanced from 42.67% to 52.12%. Additionally, MoO3 nanolayers improved CZTSSe absorber quality by lowering the defect energy levels from 228 to 148 meV. Furthermore, first-principles calculations demonstrate that the partial sulfoselenized MoO3 nanolayers may function as the (p-type) hole-selective contacts at Mo/CZTSSe interfaces, leading to an overall improvement in device performance. Lastly, a CZTSSe solar cell with about 26% improvement (compared with reference cells) in power conversion efficiency was achieved by inserting 5 nm MoO3 sacrificial layers.
    • Back Pain and Knowledge of Back Care Related to Physical Activity in 12 to 17 Year Old Adolescents from the Region of Murcia (Spain): ISQUIOS Programme

      Alba Aparicio-Sarmiento; Olga Rodríguez-Ferrán; María Teresa Martínez-Romero; Antonio Cejudo; Fernando Santonja; Pilar Sainz de Baranda (MDPI AG, 2019-09-01)
      Knowledge on back care is important to prevent back problems. The purpose of this study was to a) describe back pain and knowledge on back care related to physical activity in adolescents and b) determine the association between these two factors. This was a cross-sectional study. A total of 276 students (aged from 12 to 17 years old), from three Spanish public secondary schools, had to complete a survey about back pain and another one about their knowledge on back care related to physical activity. The results showed a mean score of 2.54 ± 1.85 (out of 10), and 90.58% of students failed the knowledge test. Those who suffered from back pain in the week before scored higher (2.91 ± 1.66) than non-sufferers (2.42 ± 1.90), with statistically significant differences (Z = −2.109; <i>p</i> = 0.035; r = 0.127), although with no academically relevant differences. Finally, despite the relationship between a higher mean score in the knowledge test and back pain within the previous week, it has been found that there was not a significant association because most of the students got very low scores in the knowledge test. It also shows an important lack of knowledge about physical activity for back care in adolescents.
    • Back to the Future: The Potential of Intergenerational Justice for the Achievement of the Sustainable Development Goals

      Rita Vasconcellos Oliveira (MDPI AG, 2018-02-01)
      The establishment of the UN Sustainable Development Goals (SDGs) bolstered momentum to achieve a sustainable future. Undeniably, the welfare of future generations is a fundamental value of sustainable development since the publication of the Brundtland report. Nevertheless, SDGs and their targets are meagre on intergenerational justice concerns. The 15-year target horizon of the SDGs might be beneficial for implementation reasons. However, such a short-term perspective is far from innocuous in justice terms. It jeopardises the establishment of long-term goals, which protect both present and future people. This article advocates for clearer stances on intergenerational justice. What type of distributive principles could and should dictate the present socio-economic development? Looking at intragenerational justice principles contained in SDGs does not provide a full answer since they express conflicting visions of what constitutes a fair development. Furthermore, a fair distribution of the development benefits and burdens among present and near future people does not necessarily guarantee the wellbeing of more distant generations. I propose an intergenerational sufficientarian perspective as a way of extending the beneficial impacts of SDGs to both close and distant future generations. Hopefully, it facilitates the translation of the SDGs into policies that promote fairer implementation strategies.
    • Back-Calculation of Fish Size in Diet Analysis of Piscivorous Predators: A New Index for the Alien <i>Silurus glanis</i>

      Renato Bacchetta; Andrea Marotta; Alessandro Nessi; Paolo Tremolada (MDPI AG, 2021-04-01)
      The wels catfish <i>Silurus glanis</i> has been constantly spreading in many European basins, outside its native range. Being a voracious predator, it is considered to have a severe impact on local fish communities. In the Ticino River (Northern Italy), bones of <i>S. glanis</i> were found in feces from the top predator <i>Lutra lutra</i>. To estimate the control capability of <i>L. lutra</i> for this species and to back-calculate <i>S. glanis</i>’ size from its bone remains, whole skeletons from 27 differently sized <i>S. glanis</i> specimens were analyzed. A double pharyngeal element and all caudal vertebrae emerged as significant items for species identification. The mean length of the pharyngeal element was directly related to fish mass, while for vertebrae, a K-index was proposed to identify the position of each vertebra along the spine and, from this, to calculate the original fish mass. This methodology allowed us to establish that the length of the preyed <i>S. glanis</i> was 85–435 mm, and the ages were between 0+ and 2+ years. The proposed methodology opens new perspectives for more detailed studies on the efficiency of predation by piscivorous species on allochthonous ones.
    • Backcasting for Sustainable Employment: A Hungarian Experience

      Bálint Balázs; Gábor Király; György Pataki; Alexandra Köves (MDPI AG, 2013-07-01)
      Sustainability and employment are terms seldom used together. Especially when defining sustainability in the stricter sense of the word, delineating a world where strong sustainability is the norm, it is problematic to deduct which elements may compose sustainable employment. In the relevant discourse, two distinct directions can be identified. Ecological modernization promises “quick fixes” to employment problems while reducing environmentally harmful economic activities without initiating major changes either in our ways of thinking or in our way of living. At the same time, the radical change paradigm disposes of the concepts of the free market society and believes that new “great transformations” are unavoidable, whereby values must change just as much as institutions. Yet, how far have these normative theoretical approaches penetrated our everyday thinking? The paper builds upon the experience of a backcasting project on sustainable employment conducted in Hungary in 2012 and early 2013 and suggests that when people are given the chance to leave the path dependencies of today behind and imagine a sustainable future, their normative visions provide us with invaluable insight as to what may constitute sustainable employment. It also contributes towards our understanding of which policy tools lead us towards a more sustainable world of work in particular and a more sustainable society in general.
    • Background on the Sustainability of Knowledge

      Andrea BENCSIK (MDPI AG, 2022-08-01)
      For years, sustainability has been on the minds of professionals, organisational leaders and everyone involved in everyday life. There has been a lot of research on different areas and processes of corporate operations, and more and more initiatives are emerging to address nature conservation, environmental protection and climate change issues. However, little research addresses the potential for sustainability of organisational knowledge, a factor that fundamentally influences the functioning of organisations. Beyond the steps of the knowledge management process, organisational culture, working conditions, the organisational environment and the organisational leadership that manages them are also at the forefront. The aim of this study is to highlight the supporting role of sustainable management for the sustainability of knowledge and to show the context of further supporting conditions. Previous research has identified sustainable management as an alternative management style that can significantly change organisations and society by deepening understanding of natural and economic systems and their interdependencies. Accordingly, it ensures market performance in a holistic approach based on the concept of sustainable knowledge and with a view to the efficient use of the company’s internal resources. The cornerstones of these interrelationships and the conditions of the relationships are presented here in a theoretical approach.
    • Backyard Agricultural and Farm Activity as an Option of Socioeconomic and Food Improvement in the Rural Towns of the Municipality of Guasave, Sinaloa

      Griselda Karina González-Félix; Víctor Manuel-Peinado Guevara; Héctor José Peinado-Guevara; Aldo Alán Cuadras-Berrelleza; Jaime Herrera-Barrientos; José de Jesús López-López; Zúñiga-Espinoza Nicolás Guadalupe (MDPI AG, 2021-03-01)
      The analysis of the economic problems of the population in Latin America in the face of unemployment and inflation, which have become permanent in these economies, gives rise to the generation of proposals for the solution of social deficiencies, as well as sustainable factors that govern the behavior and culture of production today. The objective was to establish the importance and contribution that backyard activities can have to reach positive socioeconomic and nutritional levels in the rural area of the municipality of Guasave, Sinaloa, Mexico. An exploratory analysis was carried out, to diagnose the problem, applying interviews to describe the socioeconomic and backyard perspectives, finding that more than 70% of those consulted carry out this activity in relation to livestock and/or agricultural dynamics. Two variables with positive economic effects stand out: self-consumption and commercialization, which are relevant socioeconomic aspects in the relationship between production and family economy, as well as the promotion of self-employment and preservation of family traditions in rural communities.
    • Backyard Agricultural Production as a Strategy for Strengthening Local Economy: The Case of Chontla and Tempoal, Mexico

      Fabiola Sánchez-Galván; Horacio Bautista-Santos; José Luis Martínez-Flores; Diana Sánchez-Partida; Arely del Rocio Ireta-Paredes; Gregorio Fernández-Lambert (MDPI AG, 2019-09-01)
      In order to define chain strategies for a backyard agricultural production system, this study identified agricultural products produced by high development priority communities with indigenous presence located in the Chontla and Tempoal municipalities in Veracruz, Mexico. The production system was integrated into a generic model decomposing the supply chain into hierarchical components. Data were collected through a face-to-face semistructured questionnaire based on statistical sampling of rural households, backyard producers, intermediaries, retailers, and wholesalers, as well as municipal authorities. The research was carried out from January 2017 to June 2018 and a computational program was designed to analyze the data. As a result, products were identified and their production destinations were quantified. Moreover, it revealed a backyard agricultural supply chain of five echelons with opportunities for improvement in areas such as unstructured agricultural processes and practices, inappropriate product storage and handling, and the lack of production records, and up to three intermediaries that sequentially drove up product cost in regional consumption centers. In this study, 20.9% of total production was destined for sale, 34.8% for self-consumption, and 44.2% was noncommercialized. Nopal, creole pumpkin, coriander, plum, passion fruit, and jobo were products with greater economic value for noncommercialized production. An improvement strategy would be to build inclusive agro-food chains through consolidated centers of backyard agricultural products.
    • Bacteria Isolated from Wastewater Irrigated Agricultural Soils Adapt to Heavy Metal Toxicity While Maintaining Their Plant Growth Promoting Traits

      Abdul Wahab Ajmal; Saleha Saroosh; Shah Mulk; Muhammad Nadeem Hassan; Humaira Yasmin; Zahra Jabeen; Asia Nosheen; Syed Muhammad Usman Shah; Rabia Naz; Zuhair Hasnain (MDPI AG, 2021-07-01)
      The present study explored the plant growth promotion and bioremediation potential of bacteria inhabiting wastewater irrigated agricultural soils. Thirty out of 75 bacterial isolates (40%), 29/75 (39%) and 28/75 (37%) solubilized Zn, K and PO<sub>4</sub> during plate essays respectively. Fifty-six percent of the isolates produced siderophores, while 30% released protease in vitro. Seventy-four percent of bacteria resisted Pb, Ni and Cd at various concentrations added to the culture media plates. Sixteen out of 75 (26%) isolates were able to fix N in Nbf medium. Among these 16 N fixers, N fixing <i>nifH, nifD</i> and <i>nifK</i> genes was detected through PCR in 8, 7 and 1 strain respectively using gene specific primers designed in the study with <i>Enterobacter</i> sp. having all three (<i>nifHKD)</i> genes. Isolated bacteria showed resemblance to diverse genera such as <i>Bacillus, Pseudomonas, Enterobacter, Citrobacter, Acinetobacter, Serratia, Klebsiella</i> and <i>Enterococcus</i> based on 16S rRNA gene sequence analysis. In addition to showing the best mineral solubilization and metal resistance potential, <i>Citrobacter</i> sp. and <i>Enterobacter</i> sp. also removed 87%, 79% and 43% and 86%, 78% and 51% of Ni, Cd and Pb, respectively, from aqueous solution. These potent bacteria may be exploited both for bioremediation and biofertilization of wastewater irrigated soils leading to sustainable agriculture.
    • Bacterial and Fungal Community Dynamics and Shaping Factors During Agricultural Waste Composting with Zeolite and Biochar Addition

      Xin Wu; Liheng Ren; Lin Luo; Jiachao Zhang; Lihua Zhang; Hongli Huang (MDPI AG, 2020-08-01)
      Bacterial and fungal communities play significant roles in waste biodegradation and nutrient reservation during composting. Biochar and zeolite were widely reported to directly or indirectly promote microbial growth. Therefore, the effects of zeolite and biochar on the abundance and structure of bacterial and fungal communities and their shaping factors during the composting of agricultural waste were studied. Four treatments were carried out as follows: Run A as the control without any addition, Run B with zeolite (5%), Run C with biochar (5%), and Run D with zeolite (5%) and biochar (5%), respectively. The bacterial and fungal community structures were detected by high-throughput sequencing. Redundancy analysis was used for determining the relationship between community structure and physico-chemical parameters. The results indicated that the addition of biochar and zeolite changed the physico-chemical parameters (e.g., pile temperature, pH, total organic matter, ammonium, nitrate, and water-soluble carbon) during the composting process. Zeolite and biochar significantly changed the structure and diversity of bacterial and fungal populations. Moreover, the bacterial community rather than the fungal community was sensitive to the biochar and zeolite addition during the composting process. Community phylogenetic characteristics showed that Nocardiopsaceae, Bacillaceae, Leuconostocaceae, Phyllobacteriaceae, and Xanthomonadaceae were the predominant bacterial species at the family-level. Chaetomiaceae and Trichocomaceae were the two most dominant fungal species. The pH, total organic matter, and nitrate were the most important factors affecting the bacterial and fungal population changes during the composting process.
    • Bacterial Augmented Floating Treatment Wetlands for Efficient Treatment of Synthetic Textile Dye Wastewater

      Neeha Nawaz; Shafaqat Ali; Ghulam Shabir; Muhammad Rizwan; Muhammad Bilal Shakoor; Munazzam Jawad Shahid; Muhammad Afzal; Muhammad Arslan; Abeer Hashem; Elsayed Fathi Abd_Allah (MDPI AG, 2020-05-01)
      Floating treatment wetland (FTW) is an innovative, cost effective and environmentally friendly option for wastewater treatment. The dyes in textile wastewater degrade water quality and pose harmful effects to living organisms. In this study, FTWs, vegetated with <i>Phragmites australis</i> and augmented with specific bacteria, were used to treat dye-enriched synthetic effluent. Three different types of textile wastewater were synthesized by adding three different dyes in tap water separately. The FTWs were augmented with three pollutants degrading and plant growth promoting bacterial strains (i.e., <i>Acinetobacter junii</i> strain NT-15, <i>Rhodococcus</i> <i>sp</i>. strain NT-39, and <i>Pseudomonas indoloxydans </i>strain NT-38). The water samples were analyzed for pH, electrical conductivity (EC), total dissolved solid (TDS), total suspended solids (TSS), chemical oxygen demand (COD), biological oxygen demand (BOD), color, bacterial survival and heavy metals (Cr, Ni, Mn, Zn, Pb and Fe). The results indicated that the FTWs removed pollutants and color from the treated water; however, the inoculated bacteria in combination with plants further enhanced the remediation potential of floating wetlands. In FTWs with <i>P. australis</i> and augmented with bacterial inoculum, pH, EC, TDS, TSS, COD, BOD and color of dyes were significantly reduced as compared to only vegetated and non-vegetated floating treatment wetlands without bacterial inoculation. . Similarly, the FTWs application successfully removed the heavy metal from the treated dye-enriched wastewater, predominately by FTWs inoculated with bacterial strains. The bacterial augmented vegetated FTWs, in the case of dye 1, reduced the concentration of Cu, Ni, Zn, Fe, Mn and Pb by 75%, 73.3%, 86.9%, 75%, 70% and 76.7%, respectively. Similarly, the bacterial inoculation to plants in the case of dye 2 achieved 77.5% (Cu), 73.3% (Ni), 83.3% (Zn), 77.5% (Fe), 66.7% (Mn) and 73.3% (Pb) removal rates. Likewise in the case of dye 3, which was treated with plants and inoculated bacteria, the metals removal rates were 77.5%, 73.3%, 89.7%, 81.0%, 70% and 65.5% for Cu, Ni, Zn, Fe, Mn and Pb, respectively. The inoculated bacteria showed persistence in water, in roots and in shoots of the inoculated plants. The bacteria also reduced the dye-induced toxicity and promoted plant growth for all three dyes. The overall results suggested that FTW could be a promising technology for the treatment of dye-enriched textile effluent. Further research is needed in this regard before making it commercially applicable.
    • Bacterial Community Structure and Predicted Metabolic Function of Landfilled Municipal Solid Waste in China

      Han Ke; Jinghang Li; Xuanqi Zhang; Jie Hu (MDPI AG, 2022-03-01)
      The biodegradation behavior of municipal solid waste (MSW) depends on the diversity and metabolic function of bacterial communities, which are affected by environmental factors. However, the diversity of the bacterial communities and metabolic functions in MSW, as well as their influencing factors, remain unclear. In deep-aged MSW, the abovementioned deficiencies are more significant, and will effectively hamper landfill disposal. In this study, high-throughput sequencing was performed to examine the bacterial community structure and metabolic function from depths of 10 m to 40 m, of two large MSW landfills on the southeast coast of China. Thermotogota (1.6–32.0%), Firmicutes (44.2–77.1%), and Bacteroidota (4.0–34.3%) were the three dominant phyla among the 39 bacterial phyla identified in aged MSW samples. Bacterial genera associated with the degradation of many macromolecules, e.g., Defluviitoga, Hydrogenispora, and Lentimicrobium were abundantly detected in MSW samples, even in aged MSW. Redundancy analysis (RDA) showed that bacterial diversity in the landfills was most strongly correlated with electrical conductivity, age, and moisture content of the MSW. Tax4fun2 analysis predicted that there were abundant metabolism functions in aged MSW, especially functional enzymes (e.g., glycine dehydrogenase and cellulase) related to amino acids and cellulose degradation. This study increases our understanding of the bacterial diversity and functional characteristics in landfilled MSW.
    • Bacterial Concrete as a Sustainable Building Material?

      Elżbieta Stanaszek-Tomal (MDPI AG, 2020-01-01)
      The right selection of building materials plays an important role when designing a building to fall within the definition of sustainable development. One of the most commonly used construction materials is concrete. Its production causes a high energy burden on the environment. Concrete is susceptible to external factors. As a result, cracks occur in the material. Achieving its durability along with the assumptions of sustainable construction means there is a need to use an environmentally friendly and effective technique of alternative crack removal in the damaged material. Bacterial self-healing concrete reduces costs in terms of detection of damage and maintenance of concrete structures, thus ensuring a safe lifetime of the structure. Bacterial concrete can improve its durability. However, it is not currently used on an industrial scale. The high cost of the substrates used means that they are not used on an industrial scale. Many research units try to reduce production costs through various methods; however, bacterial concrete can be an effective response to sustainability.
    • Bacterial Flagellum versus Carbon Nanotube: A Review Article on the Potential of Bacterial Flagellum as a Sustainable and Green Substance for the Synthesis of Nanotubes

      Charles Ng Wai Chun; Husnul Azan Tajarudin; Norli Ismail; Baharin Azahari; Muaz Mohd Zaini Makhtar; Leong Kah Yan (MDPI AG, 2021-12-01)
      Bacterial flagella are complex multicomponent structures that help in cell locomotion. It is composed of three major structural components: the hook, the filament and basal body. The special mechanical properties of flagellar components make them useful for the applications in nanotechnology especially in nanotube formation. Carbon nanotubes (CNTs) are nanometer scale tube-shaped material and it is very useful in many applications. However, the production of CNTs is costly and detrimental to the environment as it pollutes the environment. Therefore, bacterial flagella have become a highly interesting research area especially in producing bacterial nanotubes that could replace CNTs. In this review article, we will discuss about bacterial flagellum and carbon nanotubes in the context of their types and applications. Then, we will focus and review on the characteristics of bacterial flagellum in comparison to carbon nanotubes and subsequently, the advantages of bacterial flagellum as nanotubes in comparison with carbon nanotubes.
    • Bacterial Isolates from Greek Sites and Their Efficacy in Degrading Petroleum

      Georgia C. Ntroumpogianni; Eleni Giannoutsou; Amalia D. Karagouni; Alexandros L. Savvides (MDPI AG, 2022-08-01)
      Polycyclic aromatic hydrocarbons (PAHs) are a major organic pollutant, not only because they do not self-degenerate but also because they accumulate in the food chain and give rise to serious repercussions in terms of biodiversity sustainability. Petroleum-degrading bacteria have long been used as a promising solution in the effort to biodegrade crude oil. In this study, new isolates from specific Greek environments displaying various levels of crude oil contamination, as well as isolates belonging to the ATHUBA collection, were thoroughly investigated for their capacity to degrade crude oil. Furthermore, the presence of nahH and alkJ genes in the above bacterial isolates, as well as their ability to form agglomerates or release surfactants, was investigated. Two consortia were formed, and their ability to degrade crude oil was tested, achieving similar degrading capacities as those observed with the individual strains. A Pseudomonas plecoglossicida isolate demonstrated the highest percentage (76.7%) ability to degrade crude oil. The biodegradation rate of this isolate was further evaluated by measuring the alkanes/hopanes ratio over a period of ten days, exhibiting a higher degradation rate in short-chain (C11–C21) alkanes, whereas a decrease in the ratio was observed when the number of carbons in petroleum increased. This is the first detailed report on bacterial communities in oil-polluted areas of Greece that contain a variety of bacteria with the ability to degrade PAHs in contaminated sites and may provide a novel alternative to various bioremediation processes or be used as inocula in autochthonous bioaugmentation procedures for crude oil biodegradation.
    • Bacterial Movement in Subsurface Soil during Winter Irrigation of Reclaimed Wastewater

      Guannan Ding; Karen Mancl; Jiyoung Lee; Olli H. Tuovinen (MDPI AG, 2021-08-01)
      Processes to remove and inactivate <i>Escherichia coli</i> from wastewater effluents and drainage are complex and interrelated. The objective of this study was to determine if irrigation of undisinfected wastewater effluents in the winter moves bacteria to surface water through subsurface drainage, posing a public health risk. The central Ohio study site, an open meadow constructed in the 1970s, is irrigated with lagoon effluents each summer. The irrigated area has subsurface drainage that collects for discharge in one spot. Undisinfected wastewater from a stabilization pond was irrigated for the first time in the winter of 2013/2014. <i>E. coli</i> was measured in the subsurface discharge during the irrigated winter season and compared to the non-irrigated previous winter season. Soil temperature and moisture were also monitored. <i>E. coli</i> moved to subsurface drains when the water table was above the drain. <i>E. coli</i> also moved to subsurface drains when the shallow soil temperature dropped to near freezing. With less winter sunlight and minimal evapotranspiration, the soil stayed moist near field capacity. Temperature appears to be the most important factor in limiting natural inactivation in subsurface soil and allowing the movement of <i>E. coli</i> in undisinfected wastewater effluents to the subsurface drainage systems. The results show that winter reuse of undisinfected wastewater does pose a public health risk to surface water through subsurface drainage. Therefore, disinfection of wastewater effluents used for irrigation is strongly recommended.