Resources, Volume 9, Issue 7 (July 2020) – 11 articles

The bio-based plastic market is forecast to grow in the next years. With a growing market share and product range, the implementation of circular thinking is becoming more and more important also for bio-based plastics to enable a sound circular economy for these group of plastics. Therefore, it is important to assess the environmental performance for different end-of-life options of bio-based plastics from an early stage on. This review presents a comprehensive overview on the current status quo of different end-of-life options for bio-based plastics from an environmental perspective. Based on the status quo and the corresponding impact assessment results, the global plastic demand as well as the technical substitution potential of bio-based plastics, the environmental saving potential in case of the different end-of-life options was calculated. The review shows that there is a focus on polylactic acid (PLA) regarding end-of-life assessment, with studies covering all end-of-life options. The focus of the impact assessment has been set on global warming potential (GWP). With respect to GWP, the analysis of a future global potential of PLA showed, for mechanical recycling, the highest saving potential with 94.1 Mio. t CO₂-eq. per year in comparison to virgin material. Full article

Biotechnological production of lactic acid (LA) is based on the so-called first generation feedstocks, meaning sugars derived from food and feed crops such as corn, sugarcane and cassava. The aim of this study was to exploit the potential of a second generation resource: Common reed (Phragmites australis) is a powerfully reproducing sweet grass which grows in wetlands and creates vast monocultural populations. This lignocellulose biomass bears the possibility to be refined to value-added products, without competing with agro industrial land. Besides utilizing reed as a renewable and inexpensive substrate, low-cost nutritional supplementation was analyzed for the fermentation of thermophilic Bacillus coagulans. Various nutritional sources such as baker’s and brewer’s yeast, lucerne green juice and tryptone were investigated for the replacement of yeast extract. The structure of the lignocellulosic material was tackled by chemical treatment (1% NaOH) and enzymatic hydrolysis (Cellic^® CTec2). B. coagulans DSM ID 14-300 was employed for the homofermentative conversion of the released hexose and pentose sugars to polymerizable L-(+)-LA of over 99.5% optical purity. The addition of autolyzed baker’s yeast led to the best results of fermentation, enabling an LA titer of 28.3 g L⁻¹ and a yield of 91.6%. Full article

Domestic wastewater treatment by purple phototrophic bacteria (PPB) is based on the assimilative uptake of organics and nutrients into the bacterial biomass. Thereby, it strongly depends on the carbon/nutrients ratio of the wastewater. The physiological COD/N/P ratio for PPB growth in domestic wastewater makes the addition of an external organic carbon source necessary in order to allow for an efficient process. However, PPB need a source of alkalinity (as CO₂) to grow on reduced organics that serves as an electron acceptor since biohydrogen production (an alternative electron sink) is inhibited by ammonium. A preliminary experiment showed that high nutrients-loading wastewater was limited by CO₂ imbalance, leading to poor removal efficiencies. Subsequently, the effect of the oxidation state of the organics added as external organic carbon sources to PPB reactors treating low nutrients-loading domestic wastewater has been analyzed. Three organics were used as additives to PPB development in four consecutive batches: acetate (more oxidized), ethanol and butyrate (more reduced). The PPB population was settled and the general performance under the three situations, in terms of organics, N and P assimilation, and growth kinetics was not significantly different irrespective of the external organic carbon source. The reactors were dominated by PPB, though reduced organics allowed for dominance of Rhodopseudomonas palustris, whereas oxidized organics caused co-dominance of R. palustris and Rhodobacter capsulatus. Thereby, alkalinity (as bicarbonate), and not the oxidation state of the organics, is the key parameter for the efficient treatment of domestic wastewater by PPB. Full article

The approaching prospect of obligatory implementation and pursuit of Water Safety Plans forces water companies to reflect on supplies in crisis situations that, for example, relate to the closure of a basic intake, or scarcity of water due to climates changes (droughts). Where supplies are diversified, there can be greater certainty as to the continuity of good quality supply, even in an emergency. As one of each country’s systems of critical infrastructure, the collective water supply system (CWSS) should be protected, with the diversification of supply treated as a basic tool to raise levels of security among consumers. This article, therefore, presents a method from the authors’ by which diversification may be assessed, including by reference to basic and key elements of the CWSS capable of affecting the continuity of water supply. Sample calculations using the proposed method are also presented here for selected Polish cities. In the event, as only one Polish CWSS can be assigned to the category representing excellent diversification, the suggestion is clearly that Poland’s systems must still progress with the diversification of water supply, in order to further reduce the risk of water shortages. Full article

The objective of this study was the development and verification of a model of soil moisture decrease during dry spells—SMDS. The analyses were based on diurnal information of the occurrence of atmospheric precipitation and diurnal values of soil moisture under a bare soil surface, covering the period of 2003–2019, from May until October. A decreasing exponential trend was used for the description of the rate of moisture decrease in six layers of the soil profile during dry spells. The least squares method was used to determine, for each dry spell and soil depth, the value of exponent $\alpha$ , which described the rate of soil moisture decrease. Data from the years 2003–2015 were used for the identification of parameter $\alpha$ of the model for each of the layers separately, while data from 2016–2019 were used for model verification. The mean relative error between moisture values measured in 2016–2019 and the calculated values was 3.8%, and accepted as sufficiently accurate. It was found that the error of model fitting decreased with soil layer depth, from 8.1% for the surface layer to 1.0% for the deepest layer, while increasing with the duration of the dry spell at the rate of 0.5%/day. The universality of the model was also confirmed by verification made with the use of the results of soil moisture measurements conducted in the years 2009–2019 at two other independent locations. However, it should be emphasized that in the case of the surface horizon of soil, for which the process of soil drying is a function of factors occurring in the atmosphere, the developed model may have limited application and the obtained results may be affected by greater errors. The adoption of calculated values of coefficient $\alpha$ as characteristic for the individual measurement depths allowed calculation of the predicted values of moisture as a function of the duration of a dry spell, relative to the initial moisture level adopted as 100%. The exponential form of the trend of soil moisture changes in time adopted for the analysis also allowed calculation of the duration of a hypothetical dry spell t, after which soil moisture at a given depth drops from the known initial moisture θ₀ to the predicted moisture θ. This is an important finding from the perspective of land use. Full article

The article deals with the meaning and the management of land-based resources by indigenous peoples, which are analyzed through an assessment of the lived spaces of the Guarani–Kaiowa indigenous people in the Brazilian state of Mato Grosso do Sul. The discussion follows an analytical framework that is focused on land, labor and ethnicity. These interconnected politico-economic categories provide the basis for understanding the violence and exploitation perpetrated against indigenous groups, as well as their capacity to reclaim ancestral territories lost to extractivism and agribusiness development. Empirical results indicate that ethnicity is integral to labor and land management processes. In the case of the Guarani–Kaiowa, not only have they become refugees in their own lands due to racist discrimination, but also their labor has been incorporated in the regional economy through interrelated peasantification and proleterianization tendencies. The result is a complex situation that combines major socio-spatial asymmetries with the strategic, exploitative use of land and labor and the growing political contestation by the indigenous groups. Full article

Many countries in Africa provide ethnobiological resources (more especially ethnomedicinal plants), which are converted by companies and users from developed countries into biopharmaceutical products without any monetary benefits to the countries of origin. To mitigate the lack of benefits, African countries are beginning to enact access and benefit-sharing (ABS) legislation, though their wheels turn very slowly. Since many African ABS laws have not been appraised for their feasibility, this paper presents a contextual analysis of Namibia’s new ABS law: The Access to Biological and Genetic Resources and Associated Traditional Knowledge Act No. 2 of 27 June 2017. Even if several international conventions on ABS and local institutional structures guided the evolution of the 2017 Act, the main drivers for the enactment of the ABS legislation in Namibia are: Inequitable sharing of monetary benefits from the green economy, putative, but unproven cases of biopiracy, and political power contestations over ethnobiological resources. A critical analysis of important challenges faced by Namibia’s new ABS law include: Lack of adequate participatory consultations and technical capacity at the local level, discount of the non-commodity cultural value of TK, ambiguous and narrow definition of the term ‘community’, lack of a clause on confidentiality, and assertions that the new ABS law negatively impacts research in Namibian universities and botanic gardens. In contrast to South Africa’s ABS law, Namibia’s law is more onerous because it does not differentiate between commercial and non-commercial research. Full article

Waste management under emergency conditions requires proper handling. The sudden closure of a strategic final disposal site can result in serious environmental and health hazards which need to be addressed. Furthermore, this situation requires the identification of new sites to be used for waste disposal. This study analysed the case-study of Genoa, Northern Italy, following the closure of the Scarpino landfill previously dedicated to the disposal of waste generated in this municipality. A multi-objective tool was developed and applied from long-term planning to day-to-day scheduling. A sensitivity analysis was performed on the basis of collected waste volumes, in order to study the utilization and actual rate of fulfilling of the plants according to the leading objective function. Considering all of the objective functions, the emissions optimization shows better behaviour in terms of simultaneous global accomplishment of each function. In this context, the introduction of a decision support system for waste management shows its usefulness in setting and effectively pursuing long-term targets in term of total costs, emissions generated by waste transport, and exploitation of single plants from a sustainability perspective. Full article

Lovage (Levisticum officinale W.D.J. Koch) is an aromatic plant from the Apiaceae (Umbelliferae) family used as a condiment in several regions of Europe and also described to have medicinal properties. While the aerial parts are used as foods, the roots are generally discarded. In the past, lovage roots were used in folk medicine for their diuretic, carminative, and spasmolytic properties. Therefore, the exploitation of this undervalued part of the plant can be a source of valuable bioactive compounds for food and/or pharmaceutical industries. Thus, in this study, extracts of different polarity were prepared and studied regarding their chemical composition and bioactive properties. To the best of our knowledge, the composition in phenolic compounds and the volatile profile of the n-hexane extract are reported for the first time. A total of 24 compounds were identified by GC-MS in the n-hexane extract, evidencing a high relative abundance of phthalides. A total of eight phenolic compounds were identified in lovage root extracts (decoction and hydroethanolic extract), with vanillic acid being the major compound. Regarding antioxidant activity, also reported for the first time, decoction and hydroethanolic extract exhibited a high antioxidant capacity in thiobarbituric acid reactive substances (TBARS) (179 ± 11 μg/mL) and in oxidative hemolysis (OxHLIA) assays (510 ± 6 μg/mL), respectively. n-Hexane extract showed relevant anti-proliferative activity against all tumor cell lines tested (GI₅₀, 48–69 μg/mL), despite inhibiting also the growth of a non-tumoral hepatocyte cell line, however, presenting a significantly higher GI₅₀ value (147 μg/mL). This study revealed that lovage root, an agri-food residue, can be a source of valuable bioactive compounds also presenting biological properties that deserve being explored, which could lead to a circular economy for food and/or the pharmaceutical industry. Full article

This Special Issue wants to outline the role of Geoheritage and Geotourism as potential touristic resources of a region. The term “Geoheritage” refers to a peculiar type of natural resources represented by sites of special geological significance, rarity or beauty that are representative of a region and of its geological history, events and processes. These sites are also known as “geosites” and, as well as archaeological, architectonic and historical ones, they can be considered as part of the cultural estate of a country. “Geotourism” is an emerging type of sustainable tourism, which concentrates on geosites, furnishing to visitors knowledge, environmental education and amusement. In this meaning, Geotourism may be very useful for geological Sciences divulgation and may furnish additional opportunities for the development of rural areas, generally not included among the main touristic attractions. The collected papers focused on these main topics with different methods and approaches and can be grouped as follows: (i) papers dealing with geosites promotion and valorisation in protected areas; (ii) papers dealing with geosites promotion and valorisation in non-protected areas; (iii) papers dealing with geosites promotion by exhibition, remote sensing analysis and apps; (iv) papers investigating geotourism and geoheritage from the tourists’ perspective. Full article