Resources

32 pages, 1918 KB

Open AccessReview

Biocatalytic Recycling of Polyethylene Terephthalate: From Conventional to Innovative Routes for Transforming Plastic and Textile Waste into Renewable Resources

by Damayanti Damayanti, David Septian Sumanto Marpaung, Abdul Rozak Kodarif, Andri Sanjaya, Desi Riana Saputri, Yunita Fahni, Lutfia Rahmiyati, Putri Zulva Silvia, Dewi Qurrota A’yuni, Calaelma Logys Imalia, Dikri Uzlifah Janah and Ho Shing Wu

Resources 2025, 14(11), 176; https://doi.org/10.3390/resources14110176 - 20 Nov 2025

Viewed by 1178

Abstract

The rapid accumulation of plastic and textile waste, particularly polyethylene terephthalate (PET), has emerged as a global challenge for sustainable resource management. Conventional recycling methods, including mechanical and chemical routes, recover limited value and often degrade material quality while consuming substantial energy. Biocatalytic [...] Read more.

The rapid accumulation of plastic and textile waste, particularly polyethylene terephthalate (PET), has emerged as a global challenge for sustainable resource management. Conventional recycling methods, including mechanical and chemical routes, recover limited value and often degrade material quality while consuming substantial energy. Biocatalytic recycling, by contrast, offers a resource-efficient alternative that transforms post-consumer PET into high-purity monomers under mild and environmentally benign conditions. This review examines advances in enzymatic PET depolymerization, focusing on hydrolases such as cutinases, PETases, MHETases, and lipases. The discussion highlights enzyme engineering, reactor design, and process integration that improve kinetics, thermostability, and yield. From a resource perspective, biocatalytic recycling redefines PET waste as a renewable carbon feedstock capable of re-entering industrial cycles, thereby reducing reliance on virgin petrochemicals and mitigating greenhouse gas emissions. Ultimately, this review positions biocatalytic PET recycling as a cornerstone technology for achieving circularity and advancing global resource sustainability. Full article

► Show Figures

Figure 1

21 pages, 1453 KB

Open AccessArticle

Circular Economy Framework for Plastic Waste Management: A Case Study from Coastal Hotels in Zanzibar

by Aziza Abdulkadir, Biubwa Ally, Arne Remmen, Stig Hirsbak and Fredrick Salukele

Resources 2025, 14(11), 175; https://doi.org/10.3390/resources14110175 - 18 Nov 2025

Viewed by 1086

Abstract

Tourism-driven growth in Zanzibar has intensified solid waste generation, creating critical environmental and resource management challenges for the hotel sector. This study provides the first comprehensive assessment of the volume, composition, and management of solid waste in Zanzibar’s hotels, establishing a quantitative basis [...] Read more.

Tourism-driven growth in Zanzibar has intensified solid waste generation, creating critical environmental and resource management challenges for the hotel sector. This study provides the first comprehensive assessment of the volume, composition, and management of solid waste in Zanzibar’s hotels, establishing a quantitative basis for evidence-based sustainable practices beyond prior research on food waste. Ten hotels were examined through direct waste sampling, structured interviews, and field observations. Results show that hotels generate high levels of unsorted waste (2.45 kg/guest/day), with plastics posing major challenges under the prevailing linear disposal system. Findings reveal that waste patterns depend primarily on management, service, and collection practices, with no significant differences across hotel types or sizes. While the assessment covered the entire waste stream, a tailored circular economy framework is proposed for plastic waste, given its significant contribution to environmental pollution and ecological impact, providing a practical, structured guide for sustainable interventions across hotel operations. Achieving these outcomes requires collaboration, institutional support, and capacity building. By embedding waste audits, reduction strategies, and circular innovations into hotel operations, this framework charts a forward-looking pathway for coastal destinations to transform waste challenges into opportunities, promoting sustainable tourism, resource-use efficiency, and the transition toward a circular economy. Full article

(This article belongs to the Collection Management, Environment, Energy and Sustainability under a Circular Economy)

► Show Figures

Figure 1

23 pages, 2806 KB

Open AccessArticle

Sustainable Stabilisation of Expansive Clay with Shredded PET Fibers: Multi-Scale Performance and Microstructural Analysis

by Thatikonda Naresh, Sandeep Bandipally, Nannuta Satya Shiva Prasad, Krzysztof Skrzypkowski, Krzysztof Zagórski and Anna Zagórska

Resources 2025, 14(11), 174; https://doi.org/10.3390/resources14110174 - 11 Nov 2025

Viewed by 632

Abstract

Expansive clay soils present major challenges for infrastructure due to their high swelling potential and low bearing capacity. While conventional stabilisers, such as lime and Ordinary Portland Cement (OPC), are effective, they are environmentally unsustainable due to their high carbon footprint. This study [...] Read more.

Expansive clay soils present major challenges for infrastructure due to their high swelling potential and low bearing capacity. While conventional stabilisers, such as lime and Ordinary Portland Cement (OPC), are effective, they are environmentally unsustainable due to their high carbon footprint. This study examines the potential of shredded recycled polyethene terephthalate (PET) fibres as a low-carbon alternative for stabilising high-plasticity clays. PET fibres were incorporated at dosages ranging from 0% to 1.2% by dry weight, and their influence on compaction characteristics, unconfined compressive strength (UCS), California Bearing Ratio (CBR), swelling behaviour, and microstructure was evaluated through laboratory testing and Scanning Electron Microscopy (SEM). Among the tested mixes, the 1.0% PET content exhibited the highest measured performance, resulting in a 37% increase in UCS, a 125% enhancement in unsoaked CBR, more than a two-fold increase in soaked CBR, and a 15% reduction in the Differential Free Swell Index (DFSI). SEM analysis indicated the formation of a three-dimensional fibre matrix, which improved particle interlock and reduced microcrack propagation. However, higher fibre dosages caused agglomeration and macrovoid formation, which adversely affected performance. Overall, the findings suggest that the inclusion of PET fibres can enhance both geotechnical and environmental performance, providing a sustainable stabilisation strategy that utilises plastic waste while reducing reliance on OPC. Full article

► Show Figures

Figure 1

18 pages, 1195 KB

Open AccessArticle

Learnings from Food Waste Dynamics During the COVID-19 Pandemic: An Evaluation of Representative Diary Studies in German Households

by Lara Witte, Ronja Herzberg, Philip Christoph Richartz, Felicitas Schneider and Mario Hasler

Resources 2025, 14(11), 173; https://doi.org/10.3390/resources14110173 - 4 Nov 2025

Viewed by 958

Abstract

The COVID-19 pandemic had a major impact on the reliability of global supply chains, the availability of selected products including food, food prices, food purchase and consumption behaviour. The aim of this study is to identify potential differences in food waste levels and [...] Read more.

The COVID-19 pandemic had a major impact on the reliability of global supply chains, the availability of selected products including food, food prices, food purchase and consumption behaviour. The aim of this study is to identify potential differences in food waste levels and behaviours in Germany during the pandemic compared to pre-pandemic periods. The data are based on two highly representative household diary studies on food waste with sample sizes of over 6500 participants each. This study uses descriptive statistics as well as a mixed model approach to examine food waste amounts per product group, disposal reason and life cycle category and compare the survey year 2020 with the years 2016/17. A linear mixed model is applied to examine the effects of the pandemic and lockdown phases on the development of food waste amounts in 2020. The results show that total and unavoidable food waste increased significantly in the 2020 pandemic period compared to the same period in the 2016/17 survey, while avoidable food waste decreased. This suggests an improvement of food management skills while, at the same time, food consumption, and therefore also food waste, shifted from outside to inside the home. Also, the composition of product groups was affected by altered consumption patterns during the pandemic. The results are relevant to the post-pandemic period, as they raise the question of whether a deceleration in everyday life is a prerequisite for adopting more sustainable food behaviours and developing appropriate planning, storage and handling. Policies should therefore focus on encouraging citizens to engage with the issue, prioritise it and develop an interest in food management. Future research should focus on the ways in which behaviours that reduce food waste can be encouraged, as well as on the long-term effects of food supply chain disruptions and events altering everyday life in households in relation to food waste. Full article

► Show Figures

Figure 1

20 pages, 1621 KB

Open AccessArticle

Assessment of Organizational Carbon Footprints in a Rubber Plantation Company: A Systematic Approach to Direct and Indirect Emissions

by Chethiya Prasanga, Enoka Munasinghe, Pasan Dunuwila, V. H. L. Rodrigo, Ichiro Daigo and Naohiro Goto

Resources 2025, 14(11), 172; https://doi.org/10.3390/resources14110172 - 3 Nov 2025

Viewed by 1031

Abstract

This study presents a comprehensive organizational carbon footprint assessment that integrates Scope 1, 2, and 3 emissions for a rubber plantation company, including often-overlooked non-energy sources such as fertilizer application, employee commuting, company-owned vehicle operations, and wastewater discharge. Using the Greenhouse Gas Protocol [...] Read more.

This study presents a comprehensive organizational carbon footprint assessment that integrates Scope 1, 2, and 3 emissions for a rubber plantation company, including often-overlooked non-energy sources such as fertilizer application, employee commuting, company-owned vehicle operations, and wastewater discharge. Using the Greenhouse Gas Protocol standard, IPCC 2006 guidelines, and locally adapted emission factors, the assessment quantified the company’s total organizational carbon footprint at 3125 tCO₂e—revealing a previously undocumented emission profile where methane from wastewater discharge, nitrous oxide from fertilizer application, and carbon dioxide from purchased electricity collectively account for over 75% of total emissions. This finding challenges conventional rubber industry practice, which has historically focused on energy-related emissions alone. Three targeted mitigation scenarios were evaluated: (1) optimized nutrient management to reduce fertilizer usage, (2) solar photovoltaic installation to offset grid electricity consumption, and (3) advanced wastewater treatment using Fenton’s reagent combined with activated carbon. Results demonstrate that substantial emission reductions are achievable while maintaining or enhancing productivity and profitability. By establishing a replicable methodological framework grounded in comprehensive emission accounting, this study advances environmental management practices in the rubber sector and provides actionable strategies for plantation-based industries to meet national sustainability agendas and international climate commitments. Full article

► Show Figures

Figure 1

5 pages, 174 KB

Open AccessEditorial

Alternative Use of Biological Resources

by Anita Boros and Zoltán Lakner

Resources 2025, 14(11), 171; https://doi.org/10.3390/resources14110171 - 31 Oct 2025

Viewed by 538

Abstract

Over the last few decades, the use of materials of biological origin has garnered significant attention due to their favorable substitutional or complementary benefits [...] Full article

(This article belongs to the Special Issue Alternative Use of Biological Resources)

26 pages, 4029 KB

Open AccessArticle

Comparison of Semi-Empirical Models in Estimating Global Horizontal Irradiance for South Korea and Indonesia

by Pranda M. P. Garniwa, Rifdah Octavi Azzahra, Hyunjin Lee, Indra Ardhanayudha Aditya, Ratih Dewanti Dimyati, Inuwa Sani Sani, Ramlah Ramlah, Iwa Garniwa, Josaphat Tetuko Sri Sumantyo and Muhammad Dimyati

Resources 2025, 14(11), 170; https://doi.org/10.3390/resources14110170 - 28 Oct 2025

Viewed by 1050

Abstract

Accurate estimation of global horizontal irradiance (GHI) is essential for optimizing photovoltaic (PV) systems, particularly in regions with distinct climatic characteristics. Geostationary satellites, such as GK2A and COMS, provide consistent and spatially extensive data, offering a practical alternative to ground-based measurements. However, the [...] Read more.

Accurate estimation of global horizontal irradiance (GHI) is essential for optimizing photovoltaic (PV) systems, particularly in regions with distinct climatic characteristics. Geostationary satellites, such as GK2A and COMS, provide consistent and spatially extensive data, offering a practical alternative to ground-based measurements. However, the performance of semi-empirical GHI models has been sparsely evaluated across diverse geographic zones. This study aimed to conduct a comparative analysis of four semi-empirical models—Beyer, Rigollier, Hammer, and Perez—applied to two contrasting locations: Seoul, South Korea (temperate) and Jakarta, Indonesia (tropical). Using satellite-derived cloud indices and ground-based pyranometer data, model performance was evaluated via RMSE, MBE, and their relative metrics. Results indicate that the Hammer model achieves the best performance in Seoul (RMSE: 103.92 W/m²; MBE: 0.09 W/m²), while the Perez model outperforms others in Jakarta with the lowest relative RMSE of 58.69%. The analysis outlines the limitations of transferring models calibrated in temperate climates to tropical settings without regional adaptation. This study provides critical insights for improving satellite-based GHI estimation and supports the development of region-specific forecasting tools essential for expanding solar infrastructure in Southeast Asia. Full article

► Show Figures

Figure 1

35 pages, 28478 KB

Open AccessArticle

The Influence of the Rainfall Extremes and Land Cover Changes on the Major Flood Events at Bekasi, West Jawa, and Its Surrounding Regions

by Fanny Meliani, Reni Sulistyowati, Elenora Gita Alamanda Sapan, Lena Sumargana, Sopia Lestari, Jaka Suryanta, Aninda Wisaksanti Rudiastuti, Ilvi Fauziyah Cahyaningtiyas, Teguh Arif Pianto, Harun Idham Akbar, Yulianingsani, Winarno, Hari Priyadi, Darmawan Listya Cahya, Bambang Winarno and Bayu Sutejo

Resources 2025, 14(11), 169; https://doi.org/10.3390/resources14110169 - 27 Oct 2025

Viewed by 2003

Abstract

The Bekasi River Basin is highly vulnerable to severe and recurrent flooding, as evidenced by significant infrastructure and environmental damage during major events. This study investigates the catastrophic floods of 2016, 2020, 2022, and 2025 by implementing the Rainfall-Runoff-Inundation (RRI) model to simulate [...] Read more.

The Bekasi River Basin is highly vulnerable to severe and recurrent flooding, as evidenced by significant infrastructure and environmental damage during major events. This study investigates the catastrophic floods of 2016, 2020, 2022, and 2025 by implementing the Rainfall-Runoff-Inundation (RRI) model to simulate key hydrological processes. After validation using historical water level data, the model performed effectively, achieving the highest coefficient of determination (R² = 0.75) and lowest root mean square error (RMSE = 0.66) at Cileungsi Station. In contrast, the lowest R² = 0.02, and the highest RMSE = 3.74 at Pondok Gede Permai (PGP) Station. The results reveal a concerning trend of worsening 5-year flood events, with the 2025 flood reaching a peak inundation depth exceeding 3 m and affecting an area of 2.97 km², caused by a rainfall threshold of more than 180 mm/day. Furthermore, the model shows a rapid hydrological response, with a time lag of approximately 7 h or less between peak rainfall and flood onset across three monitoring stations. Analysis indicates these severe floods were primarily triggered by heavy rainfall combined with significant land cover changes. The findings provide valuable insights for flood prediction and mitigation strategies in this vulnerable region. Full article

► Show Figures

Figure 1

16 pages, 1223 KB

Open AccessArticle

Assessing the Factors of Natural Afforestation on Postagrogenic Lands in the Forest-Steppe over the Last Decades

by Edgar A. Terekhin and Fedor N. Lisetskii

Resources 2025, 14(11), 168; https://doi.org/10.3390/resources14110168 - 27 Oct 2025

Viewed by 735

Abstract

Analysis of tree vegetation recovery on abandoned agricultural lands is one of the key tasks in landscape research. This study considered the factors of forest cover of postagrogenic lands typical of the Central Russian forest-steppe. We applied a combination of geoinformation and statistical [...] Read more.

Analysis of tree vegetation recovery on abandoned agricultural lands is one of the key tasks in landscape research. This study considered the factors of forest cover of postagrogenic lands typical of the Central Russian forest-steppe. We applied a combination of geoinformation and statistical methods to analyze the relationship between climatic, geomorphological, and soil factors and the forest cover of abandoned agricultural lands. The results of this study showed varying strengths of the relationship between the climatic factors of the warm and cold seasons and the afforestation rate of postagrogenic lands. In the flat terrain region, warm-season climatic variables have a major effect on forest cover. Among the climatic factors, the precipitation of the warmest quarter and the hydrothermal coefficient show the strongest direct correlation with the forest cover of the abandoned agricultural lands. The accumulated temperature over the period with values above 10 °C and the average temperature of the warmest quarter show the strongest inverse correlation with forest cover. It has been established that soil type has a significant impact on the rate of abandoned lands afforestation. Forest cover on even-aged abandoned agricultural lands on gray forest soils (Haplic Phaeozems) is, on average, twice that of chernozem soils. The variation in forest cover is higher on abandoned croplands located on Chernozem. We analyzed forest cover as a variable dependent on various environmental conditions and proposed a number of multivariate regression models that estimate forest cover as a response to a combination of climatic, geomorphological, and soil conditions. As a result, the influence of various factors on the afforestation rate of postagrogenic lands was quantitatively shown. Full article

► Show Figures

Figure 1

19 pages, 1540 KB

Open AccessFeature PaperArticle

Polymer-Driven Fuel Conditioning: A Novel Approach to Improving the Stability and Environmental Performance of Marine Fuels

by George Tzilantonis, Eleni Zafeiriou, Adam Stimoniaris, Athanasios Kanapitsas and Constantinos Tsanaktsidis

Resources 2025, 14(11), 167; https://doi.org/10.3390/resources14110167 - 24 Oct 2025

Viewed by 761

Abstract

The precise regulation of water content plays a pivotal role in determining several the critical properties of marine fuels, including combustion stability, corrosion resistance, and the mitigation of pollutant emissions. The present study introduces an innovative, additive-free technique for moisture extraction from Marine [...] Read more.

The precise regulation of water content plays a pivotal role in determining several the critical properties of marine fuels, including combustion stability, corrosion resistance, and the mitigation of pollutant emissions. The present study introduces an innovative, additive-free technique for moisture extraction from Marine Gasoil (MGO) utilizing the hydrophilic polymer polyacrylamide, which leverages its polar amino groups to attract water molecules. This process facilitates the physical extraction of moisture without modifying the fuel’s composition, in contrast to traditional drying techniques or chemical additions. Experimental findings indicate a 34.6% decrease in water content in MGO (from 29.3 mg/kg to 19.15 mg/kg) and a 36.5% reduction in MGO–biodiesel blends (from 32.04 mg/kg to 20.34 mg/kg), accomplished within one hour of treatment. The scientific significance of this work lies in its discovery of polyacrylamide’s ability to retain moisture within a nonpolar fuel matrix—a phenomenon not previously investigated in maritime fuel applications. The findings highlight the potential for further research into polymer–fuel interactions and non-chemical strategies for fuel enhancement. Economically, the proposed technology reduces dependence on costly chemical additives and energy-intensive drying processes, while environmentally, it improves combustion efficiency and lowers emissions of hydrocarbons (HC), carbon monoxide (CO), and smoke. Overall, the results introduce a novel, sustainable, and practical process for improving maritime fuel quality, while supporting compliance with increasingly stringent regional and global environmental regulations. Full article

► Show Figures

Figure 1

Journal Menu

Journal Browser

Resources, Volume 14, Issue 11 (November 2025) – 10 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI