Recycling

Research

14 pages, 1902 KiB

Open AccessArticle

Valuable Ca/P Sources Obtained from Tuna Species’ By-Products Derived from Industrial Processing: Physicochemical and Features of Skeleton Fractions

by Miriam López-Álvarez, Paula Souto-Montero, Salvador Durán, Sara Pérez-Davila, José Antonio Vázquez, Pío González and Julia Serra

Recycling 2024, 9(6), 109; https://doi.org/10.3390/recycling9060109 - 8 Nov 2024

Viewed by 782

Abstract

The global tuna canning industry generates substantial volumes of by-products, comprising 50% to 70% of the total processed material. Traditionally, these by-products have been utilized in low-value products such as fish oils and fishmeal. However, there is significant potential to extract high-value compounds [...] Read more.

The global tuna canning industry generates substantial volumes of by-products, comprising 50% to 70% of the total processed material. Traditionally, these by-products have been utilized in low-value products such as fish oils and fishmeal. However, there is significant potential to extract high-value compounds from these by-products, such as calcium phosphates (CaP), which can have pharmaceutical, agricultural and biotechnological applications. This work explores the potential of tuna canning by-products, particularly mineral-rich fractions (central skeleton, head and fish bones) as sources of calcium phosphates (CaP), offering a sustainable alternative to conventional synthetic derivatives within a circular bioeconomy framework. By-products from two of the most exploited species (yellowfin and skipjack) were subjected to enzymatic hydrolysis and chemical extraction, followed by controlled calcination to obtain CaP. The content of organic matter, nitrogen, total proteins, lipids and amino acids in the cleaned bones, as well as the main chemical bonds, structure and elemental composition (FT-Raman, XRD, XRF) were evaluated. Results indicated that the highest recovery yield of wet bones was achieved using the chemical method, particularly from the dorsal and caudal fins of yellowfin tuna. The proximal composition, with ash content ranging from 52% to 66% and protein content varying between 30% and 53%, highlights the potential of tuna skeleton substrates for plant growth formulations. Furthermore, variations in crystalline structures of the substrates revealed significant differences depending on the by-product source and species. XRD and Raman results confirmed a monophase calcium phosphate composition in most samples from both species, primarily based on hydroxyapatite (central skeleton, caudal and dorsal fin) or whitlockite/β-tricalcium phosphate (viscera), whereas the heads exhibited a biphasic composition. Comparing the species, yellowfin tuna (YF) exhibited a hydroxyapatite structure in the branchial arch and scales, while skipjack (SKJ) had a biphasic composition in these same regions. Full article

(This article belongs to the Special Issue Resource Recovery from Waste Biomass)

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15 pages, 3566 KiB

Open AccessArticle

Pressmud Compost for Improved Nitrogen and Phosphorus Content Employing Bacillus Strains

by Uzma Sajid, Sumaira Aslam, Ali Hussain, Tamseela Mumtaz and Safina Kousar

Recycling 2024, 9(6), 104; https://doi.org/10.3390/recycling9060104 - 1 Nov 2024

Viewed by 953

Abstract

Pressmud, a by-product of sugarcane processing, is typically disposed of through incineration or landfilling, though it has considerable potential in organic agriculture. This study explored the composting of pressmud through bioaugmentation using specific bacterial strains. Two experimental setups were created: E2 with a [...] Read more.

Pressmud, a by-product of sugarcane processing, is typically disposed of through incineration or landfilling, though it has considerable potential in organic agriculture. This study explored the composting of pressmud through bioaugmentation using specific bacterial strains. Two experimental setups were created: E2 with a cellulolytic and phosphorus-solubilizing strain, Bacillus amyloliquefaciens-ASK11, and E3 with a nitrogen-fixing strain, Bacillus megaterium-ASNF3. A control setup (E1) was also maintained without bacterial augmentation. Results indicated that the Bacillus-enhanced composts in E2 and E3 showed significant increases of 129% and 83% in nitrogen and of 49% and 91% in phosphorus contents, respectively, after 60 days. Additionally, organic matter decomposition improved by 49–50% in the bioaugmented setups after 60 days. FTIR analysis revealed organic phosphate peaks and P-O-C stretching bands at 1025 cm⁻¹ in the E2 compost, while a nitrogen vibration band at 3849 cm⁻¹ in E3 indicated significantly higher nitrogen content compared to the control. The Bacillus-enriched pressmud compost not only accelerated the composting process but also enhanced nutrient levels, positioning it as a promising biofertilizer for rehabilitating barren lands. Full article

(This article belongs to the Special Issue Resource Recovery from Waste Biomass)

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11 pages, 22701 KiB

Open AccessArticle

Biodegradation Studies of Biobased Mulch Films Reinforced with Cellulose from Waste Mango

by Miguel Angel Lorenzo Santiago, J. Rodolfo Rendón Villalobos, Silvia Maribel Contreras Ramos, Glenda Pacheco Vargas and Edgar García Hernández

Recycling 2024, 9(5), 96; https://doi.org/10.3390/recycling9050096 - 10 Oct 2024

Viewed by 952

Abstract

Excessive use of plastic mulches has triggered a series of environmental problems, primarily due to the large volumes generated and their low or non-existent degradability. For this reason, materials with similar characteristics to synthetic mulches but with a biodegradable character were sought. In [...] Read more.

Excessive use of plastic mulches has triggered a series of environmental problems, primarily due to the large volumes generated and their low or non-existent degradability. For this reason, materials with similar characteristics to synthetic mulches but with a biodegradable character were sought. In this work, mulch films were produced from gelatin/glycerol/cellulose (GelC) and chitosan/glycerol/cellulose (ChiC). Their biodegradation time in soil and photographic analysis using scanning electron microscopy (SEM) were determined. The GelC sample presented a weight loss of 80% at 25 days, compared to 58% for the ChiC sample in the same exposure time. However, the latter was the only sample that could be evaluated up to 70 days, during which it presented its greatest weight loss (97%). The SEM results for both mulch films showed some color changes after 30 days; complete fracturing, growth of mycelium on the surface, and the presence of pores were observed. FTIR spectra revealed a decrease in hydroxyl groups, amides, and carbonyl bands as the number of degradation days increased. Obtaining polymers from waste materials, such as mango, represents an important task to obtain cellulose that can both reinforce and provide biodegradable properties to biobased materials, which can be degraded by microorganisms present in the soil. Full article

(This article belongs to the Special Issue Resource Recovery from Waste Biomass)

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11 pages, 936 KiB

Open AccessArticle

Production of Volatile Fatty Acids from Cheese Whey and Their Recovery Using Gas-Permeable Membranes

by Beatriz Molinuevo-Salces, Viviane da Silva-Lacerda, María Cruz García-González and Berta Riaño

Recycling 2024, 9(4), 65; https://doi.org/10.3390/recycling9040065 - 5 Aug 2024

Viewed by 1131

Abstract

The use of anaerobic fermentation to produce volatile fatty acids (VFAs) is an environmentally sustainable alternative for cheese whey (CW) valorization. This study evaluates the effect of pH control on the conversion of organic matter to VFAs from CW and assesses VFA recovery [...] Read more.

The use of anaerobic fermentation to produce volatile fatty acids (VFAs) is an environmentally sustainable alternative for cheese whey (CW) valorization. This study evaluates the effect of pH control on the conversion of organic matter to VFAs from CW and assesses VFA recovery using a novel approach based on gas-permeable membranes. VFA bioconversion and composition were studied with initial and sequential control of pH, both in acidic and alkaline conditions. Bioconversion efficiencies for assays with initial pH control were 36% and 45% for acidic and alkaline conditions, respectively. Sequential control of pH resulted in an increase in bioconversion to 54% under acidic conditions. Under acidic conditions, a variety of VFA was produced (mainly butyric, acetic, and propionic acids), while under alkaline conditions the majority was acetic acid. VFA recovery using a novel system of tubular gas-permeable membranes accounted for 15% and 100% of the total VFA from effluent 1 (butyric, acetic, and propionic acids) and effluent 2 (mainly acetic acid), respectively. Full article

(This article belongs to the Special Issue Resource Recovery from Waste Biomass)

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15 pages, 1221 KiB

Open AccessArticle

Environmental and Economic Forecast of the Widespread Use of Anaerobic Digestion Techniques

by Andrey Kiselev, Elena Magaril and Ramona Giurea

Recycling 2024, 9(4), 62; https://doi.org/10.3390/recycling9040062 - 26 Jul 2024

Viewed by 1114

Abstract

The concept of the circular economy represents the most relevant mainstream approach to reducing the negative environmental impact of waste. Anaerobic digestion has proved to be one of the leading and widely adopted techniques for sewage sludge treatment under the principles of the [...] Read more.

The concept of the circular economy represents the most relevant mainstream approach to reducing the negative environmental impact of waste. Anaerobic digestion has proved to be one of the leading and widely adopted techniques for sewage sludge treatment under the principles of the circular economy. The purpose of this study is to forecast environmental and economic indicators through modeling the extensive utilization of biogas technologies with a case study of an administrative territorial unit. The proposed methodological framework involves the use of averaged specific indicators and is based on the relationship between inhabitants, waste generation rates, biogas yield, greenhouse gas emission mitigation and biogas energy potential. The widespread use of anaerobic digestion techniques according to the proposed methodology in the instant scenario will ensure the biogas yield of 10 million Nm³ within the considered administrative territory unit with a population of 4.2 million P.E., which ultimately can be expressed in electricity and thermal generation potential of 20.8 and 24.8 million kWh*y, respectively, annual greenhouse gas elimination of 119.6 thousand tons of CO₂ equivalent and capital investment attraction of EUR 65.18 million. Furthermore, all sewage sludge will be subjected to disinfection and stabilization procedures to ensure its safe utilization. The findings of this study offer an opportunity for a wide range of stakeholders to assess the environmental and economic benefits of the widespread adoption of biogas technologies. The developed methodology can be utilized to inform management decisions through the use of the instant and scenario forecasts. Full article

(This article belongs to the Special Issue Resource Recovery from Waste Biomass)

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11 pages, 1227 KiB

Open AccessArticle

A New Recycling Method through Mushroom Cultivation Using Food Waste: Optimization of Mushroom Bed Medium Using Food Waste and Agricultural Use of Spent Mushroom Substrates

by Babla Shingha Barua, Ami Nigaki and Ryota Kataoka

Recycling 2024, 9(4), 58; https://doi.org/10.3390/recycling9040058 - 15 Jul 2024

Cited by 1 | Viewed by 1935

Abstract

Food waste is generated in large amounts locally and globally, and requires expenditure for disposal. However, it has high nutritional value and almost no toxic components. Therefore, it can be returned to mushroom mediums for further use, leading to food waste circulation. Though [...] Read more.

Food waste is generated in large amounts locally and globally, and requires expenditure for disposal. However, it has high nutritional value and almost no toxic components. Therefore, it can be returned to mushroom mediums for further use, leading to food waste circulation. Though disposing of spent mushroom substrate (SMS) after harvesting is an additional problem, there have been increased efforts to compost it and apply it to the soil for growing vegetables. This study, therefore, aimed to optimize (1) mushroom spawn production with rice hull, (2) mushroom substrates using food waste to accelerate food waste recycling, and (3) the utilization of SMS as an organic fertilizer. An optimal substrate composition and high yield were obtained at 120–140 g of food waste per bag among substrates from Pleorutus ostreatus and Pleorutus citrinopileatus; therefore, using a high ratio of food waste in the mushroom mediums was achieved. On the other hand, the SMS of P. citrinopileatus demonstrated higher plant biomass growth, at 36 g, than that of P. ostreatus, at 21.2 g, in a treatment using SMS + okara. The present discovery is that people may be encouraged to be mindful of food loss by the delivery of mushrooms and plants grown from agro/food waste to the dining table, and this circular system may therefore be used as a key resource in mushroom and plant cultivation and to achieve a zero-emission cycle. Full article

(This article belongs to the Special Issue Resource Recovery from Waste Biomass)

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14 pages, 957 KiB

Open AccessArticle

Optimization Production of an Endo-β-1,4-Xylanase from Streptomyces thermocarboxydus Using Wheat Bran as Sole Carbon Source

by Thi Ngoc Tran, Chien Thang Doan, Thi Kieu Loan Dinh, Thi Hai Ninh Duong, Thi Thuc Uyen Phan, Thi Thuy Loan Le, Trung Dung Tran, Pham Hung Quang Hoang, Anh Dzung Nguyen and San-Lang Wang

Recycling 2024, 9(3), 50; https://doi.org/10.3390/recycling9030050 - 9 Jun 2024

Cited by 1 | Viewed by 1796

Abstract

Xylanases, key enzymes for hydrolyzing xylan, have diverse industrial applications. The bioprocessing of agricultural byproducts to produce xylanase through fermentation approaches is gaining importance due to its significant potential to reduce enzyme production costs. In this work, the productivity of Streptomyces thermocarboxydus TKU045 [...] Read more.

Xylanases, key enzymes for hydrolyzing xylan, have diverse industrial applications. The bioprocessing of agricultural byproducts to produce xylanase through fermentation approaches is gaining importance due to its significant potential to reduce enzyme production costs. In this work, the productivity of Streptomyces thermocarboxydus TKU045 xylanase was enhanced through liquid fermentation employing wheat bran as the sole carbon source. The maximum xylanase activity (25.314 ± 1.635 U/mL) was obtained using the following optima factors: 2% (w/v) wheat bran, 1.4% (w/v) KNO₃, an initial pH of 9.8, an incubation temperature of 37.3 °C, and an incubation time of 2.2 days. Xylanase (Xyn_TKU045) of 43 kDa molecular weight was isolated from the culture supernatant and was biochemically characterized. Analysis through liquid chromatography with tandem mass spectrometry revealed a maximum amino acid identity of 19% with an endo-1,4-β-xylanase produced by Streptomyces lividans. Xyn_TKU045 exhibited optimal activity at pH 6, with remarkable stability within the pH range of 6.0 to 8.0. The enzyme demonstrated maximum efficiency at 60 °C and considerable stability at ≤70 °C. Mg²⁺, Mn²⁺, Ba²⁺, Ca²⁺, 2-mercaptoethanol, Tween 20, Tween 40, and Triton X-100 positively influenced Xyn_TKU045, while Zn²⁺, Fe²⁺, Fe³⁺, Cu²⁺, and sodium dodecyl sulfate exhibited adverse impact. The kinetic properties of Xyn_TKU045 were a K_m of 0.628 mg/mL, a k_cat of 75.075 s⁻¹ and a k_cat/K_m of 119.617 mL mg⁻¹s⁻¹. Finally, Xyn_TKU045 could effectively catalyze birchwood xylan into xylotriose and xylobiose as the major products. Full article

(This article belongs to the Special Issue Resource Recovery from Waste Biomass)

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12 pages, 2873 KiB

Open AccessArticle

Development and Properties of Recycled Biomass Fly Ashes Modified Mortars

by Julien Hubert, Sophie Grigoletto, Frédéric Michel, Zengfeng Zhao and Luc Courard

Recycling 2024, 9(3), 46; https://doi.org/10.3390/recycling9030046 - 24 May 2024

Cited by 2 | Viewed by 1579

Abstract

The production of biomass fly ash has been increasing every year in Europe, reaching 5.5 million tons in 2020. Fly ash produced by burning biomass is not yet accepted in the standards as a substitute material for cement in mortar and concrete. In [...] Read more.

The production of biomass fly ash has been increasing every year in Europe, reaching 5.5 million tons in 2020. Fly ash produced by burning biomass is not yet accepted in the standards as a substitute material for cement in mortar and concrete. In a first approach, the substitution limit of biomass ash is determined by comparing the mechanical strengths (among others, compressive strength), fresh state properties and hardened properties of mortars produced with fly ash with those of mortars produced with coal fly ash (EN 450-1 and ASTM C618). Masonry and rendering mortars have been designed with different substitution rates of fly ashes from wood combustion in thermal power plants. Although there is an overall decrease in performance, mortars made with biomass ash retain properties that make them suitable for use in masonry (loss of 13% compressive strength for masonry mortars with 10% substitution rate after 90 days) or rendering (loss of 20% compressive strength for rendering mortars with 10% substitution rate after 90 days). Water absorption and porosity (24.1 and 23.7% for masonry and rendering mortars, respectively) are, however, not significantly modified, which potentially contributes to good durability properties. Full article

(This article belongs to the Special Issue Resource Recovery from Waste Biomass)

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12 pages, 3112 KiB

Open AccessArticle

Rapid Waste Motor Oil Conversion into Diesel-Range Hydrocarbons Using Hydrochar as Catalyst: Kinetic Study and Product Characterization

by Herman A. Murillo, Evelyn Juiña, Karla Vizuete, Alexis Debut, Daniel Echeverría, Sebastian Taco-Vasquez and Sebastian Ponce

Recycling 2024, 9(3), 39; https://doi.org/10.3390/recycling9030039 - 17 May 2024

Viewed by 1676

Abstract

Herein, raw and alkali-treated hydrochars from biomass waste are prepared as a highly active catalyst for the conversion of waste motor oil into diesel-like fuels. Among all materials, hydrochar obtained at 250 °C and subsequent alkali activation with KOH showed a 600% improvement [...] Read more.

Herein, raw and alkali-treated hydrochars from biomass waste are prepared as a highly active catalyst for the conversion of waste motor oil into diesel-like fuels. Among all materials, hydrochar obtained at 250 °C and subsequent alkali activation with KOH showed a 600% improvement of the kinetic constant from 0.0088 to 0.0614 m⁻¹. Conversion values at the same conditions were also improved from 66 to 80% regarding thermal and catalytic cracking, respectively. Moreover, the activation energy was also reduced from 293 to 246 kJ mol⁻¹ for thermal and catalytic cracking, respectively. After characterization, the enhanced catalytic activity was correlated to an increased surface area and functionalization due to the alkali activation. Finally, the liquid product characterization demonstrated that catalytic cracking is more effective than thermal cracking for producing hydrocarbons in the diesel range. In particular, hydrochar-based catalysts are suggested to promote the formation of specific hydrocarbons so that the carbon distribution can be tailored by modifying the hydrothermal treatment temperature. Full article

(This article belongs to the Special Issue Resource Recovery from Waste Biomass)

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14 pages, 5171 KiB

Open AccessArticle

Using Cassava Starch Processing By-Product for Bioproduction of 1-Hydroxyphenazine: A Novel Fungicide against Fusarium oxysporum

by Tu Quy Phan, San-Lang Wang, Thi Hanh Nguyen, Thi Huyen Nguyen, Thi Huyen Thoa Pham, Manh Dung Doan, Thi Ha Trang Tran, Van Anh Ngo, Anh Dzung Nguyen and Van Bon Nguyen

Recycling 2024, 9(1), 12; https://doi.org/10.3390/recycling9010012 - 2 Feb 2024

Cited by 1 | Viewed by 2250

Abstract

This study aimed to develop the eco-friendly production of bioactive 1-hydroxyphenazine (HP) through fermentation using an industrial processing by-product of cassava as the main carbon/nitrogen source. Cassava starch processing by-product (CSPB) was screened as a suitable substrate for fermentation to produce HP [...] Read more.

This study aimed to develop the eco-friendly production of bioactive 1-hydroxyphenazine (HP) through fermentation using an industrial processing by-product of cassava as the main carbon/nitrogen source. Cassava starch processing by-product (CSPB) was screened as a suitable substrate for fermentation to produce HP with a high yield. Mixing CSPB with a minor amount of tryptic soy broth (TSB) at a ratio of 8/2 and with 0.05% K₂HPO₄ and 0.05% FeSO₄ was effective in HP production by Pseudomonas aeruginosa TUN03. HP was also further scaled up through production on a bioreactor system, which achieved a higher level yield (36.5 µg/mL) in a shorter fermentation time (10 h) compared to its production in the flask (20.23 µg/mL after 3 days). In anti-fungal activity tests against various Fusarium phytopathogens, HP exhibited the most significant effect on Fusarium oxysporum F10. It could inhibit the mycelial growth of this fungus, with an inhibition rate of 68.7% and anti-spore germination activity of up to 98.4%. The results of the docking study indicate that HP effectively interacted with the protein 1TRY targeting anti-F. oxysporum, with all obtained docking parameters in the accepted range. This study supports the novel use of CSPB as the carbon/nitrogen source for P. aeruginosa fermentation to produce HP, a F. oxysporum anti-fungal agent reported here for the first time. Full article

(This article belongs to the Special Issue Resource Recovery from Waste Biomass)

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16 pages, 11536 KiB

Open AccessArticle

Application of TIMES for Bioresource Flow Optimization—Case Study of Animal Husbandry in Latvia, Europe

by Ketija Bumbiere, Maksims Feofilovs, Pauls Asaris and Dagnija Blumberga

Recycling 2023, 8(5), 70; https://doi.org/10.3390/recycling8050070 - 12 Sep 2023

Viewed by 2395

Abstract

As an integral part of the EU’s Green Deal, the purpose of the bioeconomy is to ensure an effective transition to meet people’s needs based on renewable resources while maintaining economic growth. This study undertakes the modeling of bioresource value scenarios in the [...] Read more.

As an integral part of the EU’s Green Deal, the purpose of the bioeconomy is to ensure an effective transition to meet people’s needs based on renewable resources while maintaining economic growth. This study undertakes the modeling of bioresource value scenarios in the agricultural sector and proposes a methodology to evaluate the possibilities of reaching a higher added value of bioresource products. The main objective of the study is the adaptation of the market allocation–energy flow optimization model system (TIMES) for analysis of high-value-added product production capacities in the livestock sector to reach an increase in added value for 2030 with the introduction of new technologies. The developed model is tested in a case study of the animal husbandry sector in Latvia. The results show which pathways are economically feasible to achieve value-added targets set for 2030. Although not all of the available resources are used due to local market limitations, there is significant potential for the use of animal husbandry resource waste, and it is possible to achieve about 62% higher cumulative added value from 2023 to 2030 with the production of new products (protein powder, wool pellets, and gelatin) in comparison with the base scenario. Full article

(This article belongs to the Special Issue Resource Recovery from Waste Biomass)

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Review

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19 pages, 1706 KiB

Open AccessReview

Drivers and Barriers in the Production and Utilization of Second-Generation Bioethanol in India

by Falguni Pattnaik, Biswa R. Patra, Sonil Nanda, Mahendra K. Mohanty, Ajay K. Dalai and Jaya Rawat

Recycling 2024, 9(1), 19; https://doi.org/10.3390/recycling9010019 - 9 Feb 2024

Cited by 6 | Viewed by 3082

Abstract

Second-generation biorefinery refers to the production of different types of biofuels, biomaterials, and biochemicals by using agri-based and other lignocellulosic biomasses as substrates, which do not compete with arable lands, water for irrigation, and food supply. From the perspective of transportation fuels, second-generation [...] Read more.

Second-generation biorefinery refers to the production of different types of biofuels, biomaterials, and biochemicals by using agri-based and other lignocellulosic biomasses as substrates, which do not compete with arable lands, water for irrigation, and food supply. From the perspective of transportation fuels, second-generation bioethanol plays a crucial role in minimizing the dependency on fossil-based fuels, especially gasoline. Significant efforts have been invested in the research and development of second-generation bioethanol for commercialization in both developing and developed countries. However, in different developing countries like India, commercialization of second-generation bioethanol has been obstructed despite the abundance and variety of agricultural feedstocks. This commercial obstruction was majorly attributed to the recalcitrance of the feedstock, by-product management, and marginal subsidies compared to other nations. This article reviews the major roadblocks to the viability and commercialization of second-generation biofuels, especially bioethanol in India and a few other leading developed and developing nations. This article also reviews the biomass availability, technological advancements, investments, policies, and scale-up potential for biorefineries. A thorough discussion is made on the prospects and barriers to research, development, and demonstration as well as strengths, weaknesses, opportunities, and threats for the commercialization of second-generation bioethanol. Full article

(This article belongs to the Special Issue Resource Recovery from Waste Biomass)

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23 pages, 3636 KiB

Open AccessReview

Avocado Waste Biorefinery: Towards Sustainable Development

by Teresa Sandoval-Contreras, Fernando González Chávez, Amrita Poonia, Maricarmen Iñiguez-Moreno and Lizet Aguirre-Güitrón

Recycling 2023, 8(5), 81; https://doi.org/10.3390/recycling8050081 - 20 Oct 2023

Cited by 8 | Viewed by 11158

Abstract

The increasing demand for avocado consumption has led to a vast generation of waste products. Despite the high nutritional value of avocados, the waste generated from their processing poses a significant environmental challenge. Therefore, the development of a sustainable approach to avocado waste [...] Read more.

The increasing demand for avocado consumption has led to a vast generation of waste products. Despite the high nutritional value of avocados, the waste generated from their processing poses a significant environmental challenge. Therefore, the development of a sustainable approach to avocado waste management is a major concern. Biorefinery presents a promising approach to the valorization of avocado waste components, including the seed, peel, and pulp residues. This paper explores the potential of avocado waste biorefinery as a sustainable solution to produce bio-based products. Several approaches, including extraction, hydrolysis, fermentation, and biodegradation, to obtain valuable products such as starch, oil, fiber, and bioactive compounds for food or feed goods have been proposed. The review also highlights the approaches towards addressing challenges of energy security and climate change by utilizing avocado waste as a source to produce biofuels such as biogas, biodiesel, and bioethanol. In conclusion, the development of avocado waste biorefinery presents a promising avenue for sustainable development. This process can efficiently convert the avocado waste components into valuable bio-based products and clean energy sources, contributing to the attainment of a circular economy and a more sustainable future. Full article

(This article belongs to the Special Issue Resource Recovery from Waste Biomass)

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Other

Jump to: Research, Review

24 pages, 1785 KiB

Open AccessSystematic Review

Valorizing Fruit and Vegetable Waste: The Untapped Potential for Entrepreneurship in Sub-Saharan Africa—A Systematic Review

by Grace Okuthe

Recycling 2024, 9(3), 40; https://doi.org/10.3390/recycling9030040 - 17 May 2024

Cited by 3 | Viewed by 2693

Abstract

Valorizing food waste (FW) in sub-Saharan Africa (SSA) can enhance the efficiency of limited resources, make healthy diets more affordable, and foster the creation of innovative enterprises. The vast quantities of FW from the agri-food chain significantly threaten food security. To address this [...] Read more.

Valorizing food waste (FW) in sub-Saharan Africa (SSA) can enhance the efficiency of limited resources, make healthy diets more affordable, and foster the creation of innovative enterprises. The vast quantities of FW from the agri-food chain significantly threaten food security. To address this issue and maximize potential environmental and socio-economic benefits, valorizing waste, a value-adding process for waste materials, has emerged as a sustainable and efficient strategy. Valorizing FW reduces greenhouse gas emissions, mitigates climate change, enhances resource efficiency, and improves planetary health. As a pivotal player in the transition toward the circular economy, this study investigates the potential of converting FW into value-added products, offering entrepreneurial opportunities for SSA’s unemployed youth. A systematic literature review is conducted to identify and filter relevant articles over five years by applying inclusion and exclusion criteria. A total of 33 articles were included for in-depth analysis to address the study’s aim. The findings highlight a range of value-added products derived from FW, including renewable energy sources, nutraceuticals, and heavy metal adsorbents. These products present promising entrepreneurial prospects within SSA. Nonetheless, overcoming barriers to FW valorization adoption is crucial for fully realizing its potential as a profitable business avenue. Full article

(This article belongs to the Special Issue Resource Recovery from Waste Biomass)

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