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Biomass and Waste Conversion and Valorization to Chemicals, Energy and Fuels

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A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Green Chemistry".

Deadline for manuscript submissions: 15 June 2024 | Viewed by 7998

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Prof. Dr. José A.P. Coelho

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Instituto Superior de Engenharia de Lisboa, Lisbon, Portugal
Interests: green technologies; supercritical fluid extraction; biomass; bioactive compounds; lipids; fatty acids; modelling

Prof. Dr. Roumiana P. Stateva

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Institute of Chemical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
Interests: chemical engineering; thermodynamics; green processes; thermophysical properties prediction; process system simulation and design
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Dear Colleagues,

Plants, algal as well as residual biomass, and wastes are, to a large extent, renewable resources that can be transformed into high-value-added products such as chemicals, biofuels, and advanced materials. Moreover, the introduction of innovative conversion pathways can play a significant role in promoting sustainability, reducing waste, and mitigating the negative environmental impacts associated with conventional resource valorization and waste disposal.

In the last few decades, an increasing number of biomass species, varieties of waste, and clean green as well as sustainable chemical processes have been introduced and promoted to line up with the concept of biorefinery. Without being exhaustive, we provide two examples: Biomass chemical processing, through various methods for energy production, can reduce our dependence on non-renewable fossil fuels such as coal, oil, and natural gas. The production of advanced and innovative materials, such as food additives, nutraceuticals, bioplastics, biocomposites, bio-based fibers, etc., from biomass and biowaste as feedstocks.

This Special Issue aims to cover recent and emerging new-generation strategies for the development of sustainable biomass/waste conversion processes, as well as discussions of aspects that drive present and future research. Review articles by experts in the field are also strongly encouraged. We look forward to receiving your contributions.

Prof. Dr. José A.P. Coelho
Prof. Dr. Roumiana P. Stateva
Guest Editors

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Keywords

plants and microalgal biomass
green chemistry
waste valorisation
compressed solvents
biofuels
biorefinery

Published Papers (9 papers)

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Research

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15 pages, 4647 KiB

Open AccessArticle

Biological Valorization of Lignin-Derived Aromatics in Hydrolysate to Protocatechuic Acid by Engineered Pseudomonas putida KT2440

by Xinzhu Jin, Xiaoxia Li, Lihua Zou, Zhaojuan Zheng and Jia Ouyang

Molecules 2024, 29(7), 1555; https://doi.org/10.3390/molecules29071555 - 30 Mar 2024

Viewed by 629

Abstract

Alongside fermentable sugars, weak acids, and furan derivatives, lignocellulosic hydrolysates contain non-negligible amounts of lignin-derived aromatic compounds. The biological funnel of lignin offers a new strategy for the “natural” production of protocatechuic acid (PCA). Herein, Pseudomonas putida KT2440 was engineered to produce PCA from lignin-derived monomers in hydrolysates by knocking out protocatechuate 3,4-dioxygenase and overexpressing vanillate-O-demethylase endogenously, while acetic acid was used for cell growth. The sugar catabolism was further blocked to prevent the loss of fermentable sugar. Using the engineered strain, a total of 253.88 mg/L of PCA was obtained with a yield of 70.85% from corncob hydrolysate 1. The highest titer of 433.72 mg/L of PCA was achieved using corncob hydrolysate 2 without any additional nutrients. This study highlights the potential ability of engineered strains to address the challenges of PCA production from lignocellulosic hydrolysate, providing novel insights into the utilization of hydrolysates. Full article

(This article belongs to the Special Issue Biomass and Waste Conversion and Valorization to Chemicals, Energy and Fuels)

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21 pages, 3863 KiB

Open AccessArticle

The Neglected Role of Asphaltene in the Synthesis of Mesophase Pitch

by Mingzhi Wang, Yulin Li, Haoyu Wang, Junjie Tao, Mingzhe Li, Yuzhu Shi and Xiaolong Zhou

Molecules 2024, 29(7), 1500; https://doi.org/10.3390/molecules29071500 - 27 Mar 2024

Viewed by 493

Abstract

This study investigates the synthesis of mesophase pitch using low-cost fluid catalytic cracking (FCC) slurry and waste fluid asphaltene (WFA) as raw materials through the co-carbonization method. The resulting mesophase pitch product and its formation mechanism were thoroughly analyzed. Various characterization techniques, including polarizing microscopy, softening point measurement, Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA), were employed to characterize and analyze the properties and structure of the mesophase pitch. The experimental results demonstrate that the optimal optical texture of the mesophase product is achieved under specific reaction conditions, including a temperature of 420 °C, pressure of 1 MPa, reaction time of 6 h, and the addition of 2% asphaltene. It was observed that a small amount of asphaltene contributes to the formation of mesophase pitch spheres, facilitating the development of the mesophase. However, excessive content of asphaltene may cover the surface of the mesophase spheres, impeding the contact between them and consequently compromising the optical texture of the mesophase pitch product. Furthermore, the inclusion of asphaltene promotes polymerization reactions in the system, leading to an increase in the average molecular weight of the mesophase pitch. Notably, when the amount of asphaltene added is 2%, the mesophase pitch demonstrates the lowest I_D/I_G value, indicating superior molecular orientation and larger graphite-like microcrystals. Additionally, researchers found that at this asphaltene concentration, the mesophase pitch exhibits the highest degree of order, as evidenced by the maximum diffraction angle (2θ) and stacking height (Lc) values, and the minimum d₀₀₂ value. Moreover, the addition of asphaltene enhances the yield and aromaticity of the mesophase pitch and significantly improves the thermal stability of the resulting product. Full article

(This article belongs to the Special Issue Biomass and Waste Conversion and Valorization to Chemicals, Energy and Fuels)

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18 pages, 3973 KiB

Open AccessArticle

A Network of Processes for Biorefining Burdock Seeds and Roots

by Luigi di Bitonto, Enrico Scelsi, Massimiliano Errico, Hilda Elizabeth Reynel-Ávila, Didilia Ileana Mendoza-Castillo, Adrián Bonilla-Petriciolet, Marcos Lucio Corazza, Luis Ricardo Shigueyuki Kanda, Martin Hájek, Roumiana P. Stateva and Carlo Pastore

Molecules 2024, 29(5), 937; https://doi.org/10.3390/molecules29050937 - 21 Feb 2024

Cited by 1 | Viewed by 744

Abstract

In this work, a novel sustainable approach was proposed for the integral valorisation of Arctium lappa (burdock) seeds and roots. Firstly, a preliminary recovery of bioactive compounds, including unsaturated fatty acids, was performed. Then, simple sugars (i.e., fructose and sucrose) and phenolic compounds were extracted by using compressed fluids (supercritical CO₂ and propane). Consequently, a complete characterisation of raw biomass and extraction residues was carried out to determine the starting chemical composition in terms of residual lipids, proteins, hemicellulose, cellulose, lignin, and ash content. Subsequently, three alternative ways to utilise extraction residues were proposed and successfully tested: (i) enzymatic hydrolysis operated by Cellulases (Thricoderma resei) of raw and residual biomass to glucose, (ii) direct ethanolysis to produce ethyl levulinate; and (iii) pyrolysis to obtain biochar to be used as supports for the synthesis of sulfonated magnetic iron-carbon catalysts (Fe-SMCC) to be applied in the dehydration of fructose for the synthesis of 5-hydroxymethylfurfural (5-HMF). The development of these advanced approaches enabled the full utilisation of this resource through the production of fine chemicals and value-added compounds in line with the principles of the circular economy. Full article

(This article belongs to the Special Issue Biomass and Waste Conversion and Valorization to Chemicals, Energy and Fuels)

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15 pages, 1230 KiB

Open AccessArticle

Extraction of High Value Products from Zingiber officinale Roscoe (Ginger) and Utilization of Residual Biomass

by Alexandra Spyrou, Marcelle G. F. Batista, Marcos L. Corazza, Maria Papadaki and Maria Antonopoulou

Molecules 2024, 29(4), 871; https://doi.org/10.3390/molecules29040871 - 16 Feb 2024

Viewed by 708

Abstract

Zingiber officinale Roscoe (ginger) is a plant from the Zingiberaceae family, and its extracts have been found to contain several compounds with beneficial bioactivities. Nowadays, the use of environmentally friendly and sustainable extraction methods has attracted considerable interest. The main objective of this study was to evaluate subcritical propane (scPropane), supercritical CO₂ (scCO₂), and supercritical CO₂ with ethanol (scCO₂ + EtOH) as co-solvent methods for the extraction of high value products from ginger. In addition, the reuse/recycling of the secondary biomass in a second extraction as a part of the circular economy was evaluated. Both the primary and the secondary biomass led to high yield percentages, ranging from 1.23% to 6.42%. The highest yield was observed in the scCO₂ + EtOH, with biomass prior used to scCO₂ extraction. All extracts presented with high similarities as far as their total phenolic contents, antioxidant capacity, and chemical composition. The most abundant compounds, identified by the two different gas chromatography-mass spectrometry (GC-MS) systems present, were a-zingiberene, β- sesquiphellandrene, a-farnesene, β-bisabolene, zingerone, gingerol, a-curcumene, and γ-muurolene. Interestingly, the reuse/recycling of the secondary biomass was found to be promising, as the extracts showed high antioxidant capacity and consisted of significant amounts of compounds with beneficial properties. Full article

(This article belongs to the Special Issue Biomass and Waste Conversion and Valorization to Chemicals, Energy and Fuels)

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19 pages, 1564 KiB

Open AccessArticle

Sustainable Transformation of Two Algal Species of Different Genera to High-Value Chemicals and Bioproducts

by Flora V. Tsvetanova, Stanislava S. Boyadzhieva, Jose A. Paixão Coelho, Dragomir S. Yankov and Roumiana P. Stateva

Molecules 2024, 29(1), 156; https://doi.org/10.3390/molecules29010156 - 27 Dec 2023

Cited by 1 | Viewed by 1023

Abstract

This study investigates the potential of two algae species from different genera, namely the recently isolated Scenedesmus obliquus BGP and Porphyridium cruentum, from the perspective of their integral sustainable transformation to valuable substances. Conventional Soxhlet and environmentally friendly supercritical fluid extraction were applied to recover oils from the species. The extracts were characterized through analytical techniques, such as GC-Fid and LC-MS/MS, which allowed their qualitative and quantitative differentiation. Thus, P. cruentum oils contained up to 43% C20:4 and C20:5 fatty acids, while those of S. obliquus BGP had only residual amounts. The LC-MS/MS analysis of phenolic compounds in the S. obliquus BGP and P. cruentum extracts showed higher content of 3-OH-4-methoxybenzoic acid and kaempferol 3-O-glycoside in the former and higher amounts of ferulic acid in the latter. Total phenolic content and antioxidant activity of the oils were also determined and compared. The compositional analysis of the oil extracts revealed significant differences and varying potentialities based on their genera and method of extraction. To the best of our knowledge our work is unique in providing such detailed information about the transformation prospects of the two algae species to high-value chemicals and bioproducts. Full article

(This article belongs to the Special Issue Biomass and Waste Conversion and Valorization to Chemicals, Energy and Fuels)

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17 pages, 5148 KiB

Open AccessArticle

Sustainable Coating Based on Zwitterionic Functionalized Polyurushiol with Antifouling and Antibacterial Properties

by Kaiyue Xu, Huimin Xie, Chenyi Sun, Wenyan Lin, Zixuan You, Guocai Zheng, Xiaoxiao Zheng, Yanlian Xu, Jipeng Chen and Fengcai Lin

Molecules 2023, 28(24), 8040; https://doi.org/10.3390/molecules28248040 - 11 Dec 2023

Cited by 2 | Viewed by 971

Abstract

Zwitterionic polymer coatings facilitate the formation of hydration layers via electrostatic interactions on their surfaces and have demonstrated efficacy in preventing biofouling. They have emerged as a promising class of marine antifouling materials. However, designing multifunctional, environmentally friendly, and natural products-derived zwitterionic polymer coatings that simultaneously resist biofouling, inhibit protein adhesion, exhibit strong antibacterial properties, and reduce algal adhesion is a significant challenge. This study employed two diisocyanates as crosslinkers and natural urushiol and ethanolamine as raw materials. The coupling reaction of diisocyanates with hydroxyl groups was employed to synthesize urushiol-based precursors. Subsequently, sulfobetaine moieties were introduced into the urushiol-based precursors, developing two environmentally friendly and high-performance zwitterionic-functionalized polyurushiol antifouling coatings, denoted as HUDM-SB and IPUDM-SB. The sulfobetaine-functionalized polyurushiol coating exhibited significantly enhanced hydrophilicity, with the static water contact angle reduced to less than 60°, and demonstrated excellent resistance to protein adhesion. IPUDM-SB exhibited antibacterial efficacy up to 99.9% against common Gram-negative bacteria (E. coli and V. alginolyticus) and Gram-positive bacteria (S. aureus and Bacillus. sp.). HUDM-SB achieved antibacterial efficacy exceeding 95.0% against four bacterial species. Furthermore, the sulfobetaine moieties on the surfaces of the IPUDM-SB and HUDM-SB coatings effectively inhibited the growth and reproduction of algal cells by preventing microalgae adhesion. This zwitterionic-functionalized polyurushiol coating does not contain antifouling agents, making it a green, environmentally friendly, and high-performance biomaterial-based solution for marine antifouling. Full article

(This article belongs to the Special Issue Biomass and Waste Conversion and Valorization to Chemicals, Energy and Fuels)

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25 pages, 7205 KiB

Open AccessArticle

Functionalized Biochar from the Amazonian Residual Biomass Murici Seed: An Effective and Low-Cost Basic Heterogeneous Catalyst for Biodiesel Synthesis

by Thaissa Saraiva Ribeiro, Matheus Arrais Gonçalves, Geraldo Narciso da Rocha Filho and Leyvison Rafael Vieira da Conceição

Molecules 2023, 28(24), 7980; https://doi.org/10.3390/molecules28247980 - 07 Dec 2023

Viewed by 745

Abstract

This study presents the synthesis of a basic heterogeneous catalyst based on sodium functionalized biochar. The murici biochar (BCAM) support used in the process was obtained through the pyrolysis of the murici seed (Byrsonimia crassifolia), followed by impregnation of the active phase in amounts that made it possible to obtain concentrations of 6, 9, 12, 15 and 18% of sodium in the final composition of the catalyst. The best-performing 15Na/BCAM catalyst was characterized by Elemental Composition (CHNS), Thermogravimetric Analysis (TG/DTG), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), and Energy Dispersion X-ray Spectroscopy (EDS). The catalyst 15Na/BCAM was applied under optimal reaction conditions: temperature of 75 °C, reaction time of 1.5 h, catalyst concentration of 5% (w/w) and MeOH:oil molar ratio of 20:1, resulting in a biodiesel with ester content of 97.20% ± 0.31 in the first reaction cycle, and maintenance of catalytic activity for five reaction cycles with ester content above 65%. Furthermore, the study demonstrated an effective catalyst regeneration process, with the synthesized biodiesels maintaining ester content above 75% for another five reaction cycles. Thus, the data indicate a promising alternative to low-cost residual raw materials for the synthesis of basic heterogeneous catalysts. Full article

(This article belongs to the Special Issue Biomass and Waste Conversion and Valorization to Chemicals, Energy and Fuels)

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12 pages, 2907 KiB

Open AccessArticle

Fractionation of Arctic Brown Algae (Fucus vesiculosus) Biomass Using 1-Butyl-3-methylimidazolium-Based Ionic Liquids

by Artyom V. Belesov, Daria A. Lvova, Danil I. Falev, Ilya I. Pikovskoi, Anna V. Faleva, Nikolay V. Ul’yanovskii, Anton V. Ladesov and Dmitry S. Kosyakov

Molecules 2023, 28(22), 7596; https://doi.org/10.3390/molecules28227596 - 14 Nov 2023

Viewed by 933

Abstract

Arctic brown algae are considered a promising industrial-scale source of bioactive sub-stances as polysaccharides, polyphenols, and low-molecular secondary metabolites. Conventional technologies for their processing are focused mainly on the isolation of polysaccharides and involve the use of hazardous solvents. In the present study a “green” approach to the fractionation of brown algae biomass based on the dissolution in ionic liquids (ILs) with 1-butil-3-methylimidazolium (bmim) cation with further sequential precipitation of polysaccharides and polyphenols with acetone and water, respectively, is proposed. The effects of IL cation nature, temperature, and treatment duration on the dissolution of bladderwrack (Fucus vesiculosus), yields of the fractions, and their chemical composition were studied involving FTIR and NMR spectroscopy, as well as size-exclusion chromatography and monosaccharide analysis. It was shown that the use of bmim acetate ensures almost complete dissolution of plant material after 24 h treatment at 150 °C and separate isolation of the polysaccharide mixture (alginates, cellulose, and fucoidan) and polyphenols (phlorotannins) with the yields of ~40 and ~10%, respectively. The near-quantitative extraction of polyphenolic fraction with the weight-average molecular mass of 10–20 kDa can be achieved even under mild conditions (80–100 °C). Efficient isolation of polysaccharides requires harsh conditions. Higher temperatures contribute to an increase in fucoidan content in the polysaccharide fraction. Full article

(This article belongs to the Special Issue Biomass and Waste Conversion and Valorization to Chemicals, Energy and Fuels)

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Review

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31 pages, 4218 KiB

Open AccessReview

Challenges and Opportunities in the Catalytic Synthesis of Diphenolic Acid and Evaluation of Its Application Potential

by Sara Fulignati, Nicola Di Fidio, Claudia Antonetti, Anna Maria Raspolli Galletti and Domenico Licursi

Molecules 2024, 29(1), 126; https://doi.org/10.3390/molecules29010126 - 24 Dec 2023

Viewed by 1047

Abstract

Diphenolic acid, or 4,4-bis(4-hydroxyphenyl)pentanoic acid, represents one of the potentially most interesting bio-products obtainable from the levulinic acid supply-chain. It represents a valuable candidate for the replacement of bisphenol A, which is strongly questioned for its toxicological issues. Diphenolic acid synthesis involves the condensation reaction between phenol and levulinic acid and requires the presence of a Brønsted acid as a catalyst. In this review, the state of the art related to the catalytic issues of its synthesis have been critically discussed, with particular attention to the heterogeneous systems, the reference benchmark being represented by the homogeneous acids. The main opportunities in the field of heterogeneous catalysis are deeply discussed, as well as the bottlenecks to be overcome to facilitate diphenolic acid production on an industrial scale. The regioselectivity of the reaction is a critical point because only the p,p′-isomer is of industrial interest; thus, several strategies aiming at the improvement of the selectivity towards this isomer are considered. The future potential of adopting alkyl levulinates, instead of levulinic acid, as starting materials for the synthesis of new classes of biopolymers, such as new epoxy and phenolic resins and polycarbonates, is also briefly considered. Full article

(This article belongs to the Special Issue Biomass and Waste Conversion and Valorization to Chemicals, Energy and Fuels)

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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Title: Utilization of oak tree (Quercus robur) and mugwort (Artemisia vulgaris) biomass for the production of bioactive extracts
Authors: David Villanueva-Bermejo; Diego Martín Hernández; Elvis Judith Hernández; Susana Santoyo; Tiziana Fornari
Affiliation: Institute of Food Science Research (CIAL CSIC-UAM), 28049 Madrid, Spain
Abstract: Quercus robur bark and Artemisia vulgaris are renewable resources that can be transformed into high value-added chemicals. The aim of this study was to investigate the Pressurized Liquid Extraction (PLE) and Supercritical Fluid Extraction (SFE) of this biomass to produce bioactive extracts. PLE of Q. robur and A. vulgaris were carried out at different temperatures with water, ethanol and several hydroalcoholic mixtures. SFE of A. vulgaris was performed at different pressures (15 and 30 MPa) and ethanol concentrations (0% and 10% w/w). The anti-inflammatory activity of Q. robur extracts, the antibacterial activity of A. vulgaris extracts and the antioxidant activity of the extracts from both materials was determined. The highest TPC content and antioxidant activity of Q. robur extracts were achieved with water at 100 °C (487.97 mg GAE/g and 3741 µg trolox/g). The highest values for A. vulgaris extracts were obtained with ethanol at 200 °C (149.16 mg/g and 437.13 µmol/g). The ethanolic extract at 150 °C from A. vulgaris had a noticeable anti-inflammatory activity (inhibition of TNF-α and IL-6 secretion near to basal values and inhibition of IL-1β higher than 80% at 20 µg/mL). A. vulgaris extracts obtained by SFE exerted antibacterial activity against E. coli (IC50 of 1388 with neat SCCO2 at 15 MPa) and S. aureus (1406 µg/mL using SCCO2 with 10% ethanol).

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