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Upcycling Biowaste into Biobased Products

A special issue of Sustainability (ISSN 2071-1050). This special issue belongs to the section "Waste and Recycling".

Deadline for manuscript submissions: 10 October 2024 | Viewed by 8255

Special Issue Editors


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Guest Editor
Unit of Environmental Science & Technology, School of Chemical Engineering, Zographou Campus, National Technical University of Athens, 15780 Athens, Greece
Interests: waste and wastewater treatment; agro-industrial waste; anaerobic digestion; composting and other waste treatment technologies; circular economy; waste-to-energy; recycling

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Guest Editor
Unit of Environmental Science & Technology, School of Chemical Engineering, Zographou Campus, National Technical University of Athens, 15780 Athens, Greece
Interests: municipal and industrial waste management technologies; the recovery of useful, commercial products (biofuels, chemical blocks) from waste recovery; integrated waste management lines

Special Issue Information

Dear Colleagues,

In order to successfully transition to a sustainable, biobased society and circular economy, the implementation of processes able to recover biofuels as well as bioproducts from renewable raw materials is of vital importance. Novel and emerging processing technologies can enable the recycling and valorisation of biowaste into higher-value biobased products (e.g., biobased chemicals and plastics, nutrients, human food or animal feed ingredients and proteins), thereby generating significant economic, social and environmental benefits.

Thus, this Special Issue aims to focus on upcycling biowaste into biobased products to communicate up-to-date knowledge to experts working in the field, as well as interested readers. The goal of this Special Issue is to outline the optimal use of biowaste for the production of a wide array of biobased products by demonstrating innovative technologies. Types of biowaste considered can include, but are not limited to, food and kitchen waste, sludge from the treatment of wastewater, residues from gardens and parks and organic industrial biowaste. The ultimate goal is to showcase possible pathways with the potential to boost the integration of a zero-waste circular economy, reduce resource depletion and as create job opportunities. We also hope to bring to light the main regulatory barriers and technical and financial hurdles faced during the development of such schemes.

Dr. Elli Maria Barampouti
Dr. Sofia Th. Mai
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Sustainability is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • animal feed biobased products
  • biofuels
  • biopolymers
  • biorefinery
  • biowaste valorisation

Published Papers (6 papers)

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Research

15 pages, 1709 KiB  
Article
Piloting Bioethanol Production from Source-Separated Food Waste Boosts Technology Readiness
by Fotis Chatzimaliakas, Diogenis Christianides, Dimitris Malamis, Sofia Mai and Elli Maria Barampouti
Sustainability 2023, 15(23), 16349; https://doi.org/10.3390/su152316349 - 27 Nov 2023
Viewed by 796
Abstract
By the end of 2023, biowaste must be completely separated or recycled at source, based on EU legislation. Separate biowaste collection and valorisation for biofuels could play an essential role in the biobased circular economy. In this context, the principal goal of this [...] Read more.
By the end of 2023, biowaste must be completely separated or recycled at source, based on EU legislation. Separate biowaste collection and valorisation for biofuels could play an essential role in the biobased circular economy. In this context, the principal goal of this paper was to demonstrate on a pilot scale the technological solution of bioethanol production via the utilisation of urban source-separated biowaste within the city context of Athens, Greece. More specifically, the main aim was the demonstration of a pilot system for more than 10 consecutive operating cycles with real feedstock—wet; separately collected biowaste. From the 11 pilot trials performed with wet feedstock, the mean starch and cellulose degradation of the pilot trials amounted to 80.69 ± 16.27% and 79.41 ± 10.37%, respectively, while the bioethanol yield was 74.05 ± 6.82%. The latter was comparable to that of more intensive pretreatment methods. Homogenization and shredding, which were applied in this study, stand as promising pretreatment methods for bioethanol production from wet feedstock. Further research is needed to optimize conditions and evaluate scalability. Nevertheless, pilot-scale testing is a crucial step in the deployment of this technology since it serves as a bridge between laboratory research and full-scale implementation, offering a practical and controlled environment to validate and optimize the technology while minimizing risks and uncertainties. Conclusively, this study could stand as a flagship case study for the implementation of circular and sustainable approaches in the management of organic fractions of source-separated municipal waste, showcasing the technical feasibility of the whole value chain from waste collection to final bioethanol product recovery. Full article
(This article belongs to the Special Issue Upcycling Biowaste into Biobased Products)
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16 pages, 3853 KiB  
Article
Enhanced Recovery of Alginate-like Extracellular Polymers (ALE) from Waste-Activated Sludge Using Sodium Percarbonate: Performance and Characteristics
by Xiaoping Liu, Wanying Ren, Yunbo Zhai, Yu Xie, Fashen Liang and Zhixiang Xu
Sustainability 2023, 15(19), 14573; https://doi.org/10.3390/su151914573 - 08 Oct 2023
Viewed by 742
Abstract
Resource recovery from waste-activated sludge is of great practical significance to achieve sustainable wastewater treatment. Alginate-like extracellular polymers (ALE), a typical class of extracellular polymer substances, are valuable bio-based products with broad application prospects. However, due to the low extraction efficiency of the [...] Read more.
Resource recovery from waste-activated sludge is of great practical significance to achieve sustainable wastewater treatment. Alginate-like extracellular polymers (ALE), a typical class of extracellular polymer substances, are valuable bio-based products with broad application prospects. However, due to the low extraction efficiency of the current method, its practical applications are severely limited. In this study, sodium percarbonate (SPC) was first applied to enhance ALE extraction from conventional activated sludge to replace the sodium carbonate (SC) in the heating-SC method. The results showed that the ALE extracted by the heating-SPC method increased by 30.11% compared to the heating-SC method, and the alginate equivalent was slightly improved. Monosaccharide composition analysis showed that the ALE primarily comprised galactose and glucose, indicating the potential for biomedical applications. The particle size distribution and extracellular polymeric substances (EPS) composition of the sludge indicated that SPC could improve the cracking of the sludge flocs and the organic release. In addition, due to SPC’s ability to oxidize, the molecular composition of the ALE extract changed. In conclusion, SPC used as a substitute for SC in the heating-SC method could be effectively employed to recover ALE from waste-activated sludge. In future studies, further optimization of the operational conditions needs to be considered. Full article
(This article belongs to the Special Issue Upcycling Biowaste into Biobased Products)
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13 pages, 321 KiB  
Article
Evaluation of Valorisation Strategies to Improve Grape Stems’ Nutritional Value as an Ingredient for Ruminants’ Diets
by David San Martin, Jone Ibarruri, Nagore Luengo, Jorge Ferrer, Aser García-Rodríguez, Idoia Goiri, Raquel Atxaerandio, Jaime Zufía, Estíbaliz Sáez de Cámara and Bruno Iñarra
Sustainability 2023, 15(15), 11951; https://doi.org/10.3390/su151511951 - 03 Aug 2023
Viewed by 861
Abstract
Grape stems are a by-product of wine production which is managed as a waste. Animal feeding arises as a potential alternative. However, its practical use may be compromised by its high lignin content. In this sense, hydrolysis emerges as a strategy to increase [...] Read more.
Grape stems are a by-product of wine production which is managed as a waste. Animal feeding arises as a potential alternative. However, its practical use may be compromised by its high lignin content. In this sense, hydrolysis emerges as a strategy to increase fibre digestibility. In addition, due to its high and variable moisture content, it should be dried to prevent microbial deterioration and a washing pre-treatment to reduce sugar content becomes necessary to minimize drying problems due to sugar melting at high temperatures. Within this framework, this study assessed the effect of washing and three different hydrolysis on the nutritive value of grape stems. A factorial design was carried out, with washing (with or without) and hydrolysis (without, enzymatic, alkali, and alkali-enzymatic) as factors. When the washing pre-treatment was not applied, only the alkali hydrolysis process maintained in vitro digestibility, but at the expense of a lower fermentation efficiency. When the washing pre-treatment was applied, fibre contents were similar among hydrolysis processes, but the alkali hydrolysis improved in vitro digestibility with similar fermentation efficiency. In conclusion, the alkali hydrolysis maintained or improved the grape stem nutritive value depending on whether the washing pre-treatment was applied or not. Full article
(This article belongs to the Special Issue Upcycling Biowaste into Biobased Products)
16 pages, 660 KiB  
Article
Characterization and Risk Assessment of Different-Origin Biochars Applied in Agricultural Experiments
by Maria A. Lilli, Nikolaos V. Paranychianakis, Konstantinos Lionoudakis, Maria L. Saru, Styliani Voutsadaki, Anna Kritikaki, Konstantinos Komnitsas and Nikolaos P. Nikolaidis
Sustainability 2023, 15(11), 9036; https://doi.org/10.3390/su15119036 - 02 Jun 2023
Cited by 1 | Viewed by 947
Abstract
This study aimed to assess the impacts of biochar amendments derived from different feedstocks (sewage sludge (SS), olive-mill waste (OMW), compost, and sawdust) in land applications. Tomatoes were used as a test crop in four experiments both under greenhouse and field conditions. SS, [...] Read more.
This study aimed to assess the impacts of biochar amendments derived from different feedstocks (sewage sludge (SS), olive-mill waste (OMW), compost, and sawdust) in land applications. Tomatoes were used as a test crop in four experiments both under greenhouse and field conditions. SS, OMW, and compost biochar treatments presented 17% to 178.5% higher tomato productivity than control, verifying that biochar behaves as a plant-growth bio-stimulant. This impact is related to the raw material since sawdust biochar did not present results as positive as the other types of biochars. The physicochemical characterization of biochars and their comparison with international and European standards confirmed the safety of their use. A risk-assessment analysis of tomato consumption was conducted in order to explore unfavorable effects on human health. The estimation of cumulative non-carcinogenic risk, found to be between 8.25 × 10−3 and 4.23 × 10−2, and cancer risk for Cr(VI), found to be between 6.56 × 10−6 and 5.2 × 10−5, suggested no risk of potential chronic exposure due to tomato consumption cultivated in biochar-amended soils. This study may be used as a recommendation for farmers and agriculturists for maximizing the yield of agricultural crops in the Mediterranean region, improving soil health, and contributing to the sustainable management of agroecosystems. Full article
(This article belongs to the Special Issue Upcycling Biowaste into Biobased Products)
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22 pages, 1382 KiB  
Article
Investigating the Environmental Benefits of Novel Films for the Packaging of Fresh Tomatoes Enriched with Antimicrobial and Antioxidant Compounds through Life Cycle Assessment
by Christina Tsouti, Christina Papadaskalopoulou, Angeliki Konsta, Panagiotis Andrikopoulos, Margarita Panagiotopoulou, Sofia Papadaki, Christos Boukouvalas, Magdalini Krokida and Katerina Valta
Sustainability 2023, 15(10), 7838; https://doi.org/10.3390/su15107838 - 10 May 2023
Cited by 2 | Viewed by 2470
Abstract
Food systems account for 21–37% of total net anthropogenic greenhouse gas emissions. At the same time, in the European Union, the retail and consumption stages account for half of the total food waste produced across the entire food supply chain. For this, there [...] Read more.
Food systems account for 21–37% of total net anthropogenic greenhouse gas emissions. At the same time, in the European Union, the retail and consumption stages account for half of the total food waste produced across the entire food supply chain. For this, there is a continuous development of novel packaging materials to extend the shelf life of fresh products and thus reduce food waste produced at these stages. The aim of the present research is to examine the environmental performance of such materials enriched with antioxidant and antimicrobial compounds by considering their effect on the shelf-life extension of packed fresh tomatoes. In particular, two novel packaging films, a film with incorporated tomato leaf-stem extract and Flavomix through extrusion and a film coated with zein nanofibers containing the aforementioned bio-active compounds through electrospinning were studied for the packaging of fresh tomatoes and compared to conventional polypropylene packaging film. An antioxidant effect was recorded for both films achieving a shelf life prolongation of three days. Moreover, both films exhibited in vitro antibacterial activity against Staphylococcus aureus and Escherichia coli. In addition, antimicrobial activity was observed against yeast and molds and the total viable bacterial count in packed fresh tomatoes. The environmental benefits were evaluated using a life cycle assessment. The results indicated a decrease in the environmental impacts by 14% considering the entire food supply chain for both novel films. The environmental performance of novel film production by extrusion shows an increased impact of 31% compared to conventional film, while nanocoating shows an increased impact of 18%. Full article
(This article belongs to the Special Issue Upcycling Biowaste into Biobased Products)
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15 pages, 3195 KiB  
Article
The Impact of Sewage-Sludge- and Olive-Mill-Waste-Derived Biochar Amendments to Tomato Cultivation
by Maria A. Lilli, Nikolaos V. Paranychianakis, Konstantinos Lionoudakis, Anna Kritikaki, Styliani Voutsadaki, Maria L. Saru, Konstantinos Komnitsas and Nikolaos P. Nikolaidis
Sustainability 2023, 15(5), 3879; https://doi.org/10.3390/su15053879 - 21 Feb 2023
Cited by 2 | Viewed by 1694
Abstract
This study elucidated the impact of sewage-sludge (SS) and olive-mill-waste (OMW) biochar amendments to soil using tomatoes as a test crop. Four treatments were evaluated: the “control” with no biochar amendment, two SS biochar treatments with the addition of 10 t/ha and 25 [...] Read more.
This study elucidated the impact of sewage-sludge (SS) and olive-mill-waste (OMW) biochar amendments to soil using tomatoes as a test crop. Four treatments were evaluated: the “control” with no biochar amendment, two SS biochar treatments with the addition of 10 t/ha and 25 t/ha, respectively, and an OMW biochar treatment with the addition of 25 t/ha. Higher yields were observed in both SS biochar treatments, providing evidence that biochar acts as a plant bio-stimulant. Biochar application had positive impacts on carbon sequestration and soil structure. The uptake of heavy metals by all plant parts was very low, indicating that biochar is an appropriate product for land application. Biochar dose and type induced changes in the composition due to the different unique species and biodiversity of microbial communities. Venn diagrams revealed that the majority of the identified taxa were shared among the treatments, and only a small proportion of them were unique in bulk soil between treatments. In the rhizosphere, the OMW-biochar-treated plants showed a higher number of unique taxa. Microbiota structure plays a major role in the stimulation of plant growth; however, further research is needed to understand the impact of these shifts in the functioning of agroecosystems. Full article
(This article belongs to the Special Issue Upcycling Biowaste into Biobased Products)
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