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Special Issue "Advances in Conversion of Biomass and Waste to Chemicals and Fuels"

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

Deadline for manuscript submissions: 30 November 2020.

Special Issue Editors

Prof. Luís Adriano Santos Do Nascimento
Website SciProfiles
Guest Editor
Institute of Biological Sciences, Federal University of Pará, Belém, Brazil
Interests: biomass/waste valorisation; oil chemistry; heterogeneous catalysts; biofuels

Special Issue Information

Dear Colleagues,

Residual biomass and wastes are ideal and sustainable substitutes for products derived from petroleum. The development of processes for decreasing the use of non-renewable products is recent, but significant. Several new technologies are focusing processes for the production of biofuels and chemicals from different types of residual biomass or wastes. However, research on these themes is advancing extremely fast; therefore, a compilation of the latest advances in the field would be useful to connect interested authors and readers. This Special Issue aims to cover recent and emerging strategies for the development of sustainable biomass/waste conversion processes, focusing on the aspects that drive present and future research, from chemical catalysis to biocatalysis and bioprocessing. For authors, this issue will be a good opportunity to publish their original research after peer review by expert researchers of biomass/waste valorisation. Review articles by experts in such fields of research are also strongly encouraged to be submitted for publication in this Special Issue.

Prof. Rafael Luque
Prof. Luís Adriano Santos do Nascimento
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 papers will be 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. Molecules 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 2000 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

  • waste valorisation
  • biomass
  • lignocellulosic
  • lipidic
  • biofuels
  • biorefinery

Published Papers (9 papers)

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Research

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Open AccessArticle
Photocatalytic Cleavage of β-O-4 Ether Bonds in Lignin over Ni/TiO2
Molecules 2020, 25(9), 2109; https://doi.org/10.3390/molecules25092109 - 30 Apr 2020
Abstract
It is of great importance to explore the selective hydrogenolysis of β-O-4 linkages, which account for 45–60% of all linkages in native lignin, to produce valued-added chemicals and fuels from biomass employing UV light as catalyst. TiO2 exhibited satisfactory catalytic [...] Read more.
It is of great importance to explore the selective hydrogenolysis of β-O-4 linkages, which account for 45–60% of all linkages in native lignin, to produce valued-added chemicals and fuels from biomass employing UV light as catalyst. TiO2 exhibited satisfactory catalytic performances in various photochemical reactions, due to its versatile advantages involving high catalytic activity, low cost and non-toxicity. In this work, 20 wt.% Ni/TiO2 and oxidant PCC (Pyridinium chlorochromate) were employed to promote the cleavage of β-O-4 alcohol to obtain high value chemicals under UV irradiation at room temperature. The Ni/TiO2 photocatalyst can be magnetically recovered and efficiently reused in the following four consecutive recycling tests in the cleavage of β-O-4 ether bond in lignin. Mechanism studies suggested that the oxidation of β-O-4 alcohol to β-O-4 ketone by oxidant PCC first occurred during the reaction, and was followed by the photocatalysis of the obtained β-O-4 ketone to corresponding acetophenone and phenol derivates. Furthermore, the system was tested on a variety of lignin model substrates containing β-O-4 linkage for the generation of fragmentation products in good to excellent results. Full article
(This article belongs to the Special Issue Advances in Conversion of Biomass and Waste to Chemicals and Fuels)
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Open AccessArticle
The Effect of Thermomechanical Pretreatment on the Structure and Properties of Lignin-Rich Plant Biomass
Molecules 2020, 25(4), 995; https://doi.org/10.3390/molecules25040995 - 23 Feb 2020
Abstract
The cooperative thermomechanical properties of plant-derived polymers have been studied insufficiently, although this feedstock has a very high potential. In the present paper, we analyzed the changes in the structure and physicochemical properties of lignin-rich biomass induced by thermomechanical pretreatment. Low-temperature treatment allows [...] Read more.
The cooperative thermomechanical properties of plant-derived polymers have been studied insufficiently, although this feedstock has a very high potential. In the present paper, we analyzed the changes in the structure and physicochemical properties of lignin-rich biomass induced by thermomechanical pretreatment. Low-temperature treatment allows one to retain the original supramolecular structure of the cell walls, while an appreciably high disintegration degree is reached. This increases the reactivity of the material in the subsequent heterogeneous reactions. Mechanical pretreatment at medium temperatures (10 °C), when almost all cell wall polymers except for low-molecular-weight lignin are in the glassy state, enhances the mobility of cell wall polymers and causes sufficient cellulose disordering, while the specific surface area is not significantly increased. High-temperature pretreatment of reed biomass is accompanied by pore formation and lignin release from the cell wall structure, which opens up new prospects for using this biomass as a matrix to produce core–shell-structured sorbents of heavy metals. The energy consumed by mechanochemical equipment for the activation of reed biomass was determined. Full article
(This article belongs to the Special Issue Advances in Conversion of Biomass and Waste to Chemicals and Fuels)
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Open AccessFeature PaperArticle
Towards the Properties of Different Biomass-Derived Proteins via Various Extraction Methods
Molecules 2020, 25(3), 488; https://doi.org/10.3390/molecules25030488 - 23 Jan 2020
Cited by 1
Abstract
This study selected three representative protein-rich biomass—brewer’s spent grain (BSG), pasture grass (PG), and cyanobacteria (Arthrospira platensis; AP) for protein extraction with different extraction methods (alkaline treatment, aqueous extraction, and subcritical water extraction). The yield, purity, molecular weight, oil–water interfacial tension, [...] Read more.
This study selected three representative protein-rich biomass—brewer’s spent grain (BSG), pasture grass (PG), and cyanobacteria (Arthrospira platensis; AP) for protein extraction with different extraction methods (alkaline treatment, aqueous extraction, and subcritical water extraction). The yield, purity, molecular weight, oil–water interfacial tension, and thermal stability of the obtained proteins derived from different biomass and extraction methods were comprehensively characterized and compared. In the view of protein yield and purity, alkaline treatment was found optimal for BSG (21.4 and 60.2 wt.%, respectively) and AP (55.5 and 68.8 wt.%, respectively). With the decreased oil–water interfacial tension, the proteins from all biomass showed the potential to be emulsifier. BSG and AP protein obtained with chemical treatment presented excellent thermal stability. As a novel method, subcritical water extraction is promising in recovering protein from all three biomass with the comparable yield and purity as alkaline treatment. Furthermore, the hydrolyzed protein with lower molecular weight by subcritical water could promote its functions of foaming and emulsifying. Full article
(This article belongs to the Special Issue Advances in Conversion of Biomass and Waste to Chemicals and Fuels)
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Open AccessArticle
Pathogen Reduction Potential in Anaerobic Digestion of Organic Fraction of Municipal Solid Waste and Food Waste
Molecules 2020, 25(2), 275; https://doi.org/10.3390/molecules25020275 - 09 Jan 2020
Cited by 1
Abstract
Anaerobic digestion (AD) is a commonly used method of processing waste. Regardless of the type of the used digestate (fertilizer, feedstock in case of solid-state fermentation, raw-material in case of thermal treatment) effective pathogen risk elimination, even in the case of high pathogen [...] Read more.
Anaerobic digestion (AD) is a commonly used method of processing waste. Regardless of the type of the used digestate (fertilizer, feedstock in case of solid-state fermentation, raw-material in case of thermal treatment) effective pathogen risk elimination, even in the case of high pathogen concentration is essential. An investigation of the survival time and inactivation rate of the Salmonella Senftenberg W775, Enterococcus spp., and Ascaris suum eggs during thermophilic anaerobic digestion performed on laboratory scale and confirmation of hygienization in full-scale operation were performed in this study. Except for sanitization efficiency, the AD process performance and stability were also verified based on determination of pH value, dry matter content, acidity, alkalinity, and content of fatty acids. The elimination of pathogen was met within 6.06 h, 5.5 h, and about 10 h for the Salmonella Senftenberg W775, Enterococcus spp., and Ascaris suum, respectively in the laboratory trials. The obtained results were confirmed in full-scale tests, using 1500 m3 Kompogas® reactors, operating in MBT Plant located in Poland. Sanitization of the digestate was achieved. Furthermore, the process was stable. The pH value, suspended solids, and ammonium content remained stable at 8.5, 35%, and 3.8 g/kg, respectively. The acetic acid content was noted between almost 0.8 and over 1.1 g/kg, while the concentration of propionic acid was noted at maximum level of about 100 mg/kg. The AD conditions could positively affect the pathogen elimination. Based on these results it can be found that anaerobic digestion under thermophilic conditions results in high sanitation efficiency. Full article
(This article belongs to the Special Issue Advances in Conversion of Biomass and Waste to Chemicals and Fuels)
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Open AccessFeature PaperArticle
Single-Step Methylation of Chitosan Using Dimethyl Carbonate as a Green Methylating Agent
Molecules 2019, 24(21), 3986; https://doi.org/10.3390/molecules24213986 - 04 Nov 2019
Cited by 2
Abstract
N,N,N-Trimethyl chitosan (TMC) is one chitosan derivative that, because of its improved solubility, has been studied for industrial and pharmaceutic applications. Conventional methods for the synthesis of TMC involve the use of highly toxic and harmful reagents, such as methyl iodide and [...] Read more.
N,N,N-Trimethyl chitosan (TMC) is one chitosan derivative that, because of its improved solubility, has been studied for industrial and pharmaceutic applications. Conventional methods for the synthesis of TMC involve the use of highly toxic and harmful reagents, such as methyl iodide and dimethyl sulfate (DMS). Although the methylation of dimethylated chitosan to TMC by dimethyl carbonate (DMC, a green and benign methylating agent) was reported recently, it involved a formaldehyde-based procedure. In this paper we report the single-step synthesis of TMC from chitosan using DMC in an ionic liquid. The TMC synthesised was characterised by 1H NMR spectroscopy and a functionally meaningful degree of quaternisation of 9% was demonstrated after a 12-h reaction time. Full article
(This article belongs to the Special Issue Advances in Conversion of Biomass and Waste to Chemicals and Fuels)
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Open AccessArticle
Genome-Wide and Functional View of Proteolytic and Lipolytic Bacteria for Efficient Biogas Production through Enhanced Sewage Sludge Hydrolysis
Molecules 2019, 24(14), 2624; https://doi.org/10.3390/molecules24142624 - 18 Jul 2019
Cited by 1
Abstract
In this study, we used a multifaceted approach to select robust bioaugmentation candidates for enhancing biogas production and to demonstrate the usefulness of a genome-centric approach for strain selection for specific bioaugmentation purposes. We also investigated the influence of the isolation source of [...] Read more.
In this study, we used a multifaceted approach to select robust bioaugmentation candidates for enhancing biogas production and to demonstrate the usefulness of a genome-centric approach for strain selection for specific bioaugmentation purposes. We also investigated the influence of the isolation source of bacterial strains on their metabolic potential and their efficiency in enhancing anaerobic digestion. Whole genome sequencing, metabolic pathway reconstruction, and physiological analyses, including phenomics, of phylogenetically diverse strains, Rummeliibacillus sp. POC4, Ochrobactrum sp. POC9 (both isolated from sewage sludge) and Brevundimonas sp. LPMIX5 (isolated from an agricultural biogas plant) showed their diverse enzymatic activities, metabolic versatility and ability to survive under varied growth conditions. All tested strains display proteolytic, lipolytic, cellulolytic, amylolytic, and xylanolytic activities and are able to utilize a wide array of single carbon and energy sources, as well as more complex industrial by-products, such as dairy waste and molasses. The specific enzymatic activity expressed by the three strains studied was related to the type of substrate present in the original isolation source. Bioaugmentation with sewage sludge isolates–POC4 and POC9–was more effective for enhancing biogas production from sewage sludge (22% and 28%, respectively) than an approach based on LPMIX5 strain (biogas production boosted by 7%) that had been isolated from an agricultural biogas plant, where other type of substrate is used. Full article
(This article belongs to the Special Issue Advances in Conversion of Biomass and Waste to Chemicals and Fuels)
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Open AccessArticle
Development and Optimization of the Biological Conversion of Ethane to Ethanol Using Whole-Cell Methanotrophs Possessing Methane Monooxygenase
Molecules 2019, 24(3), 591; https://doi.org/10.3390/molecules24030591 - 07 Feb 2019
Cited by 1
Abstract
The biological production of ethanol from ethane for the utilization of ethane in natural gas was investigated under ambient conditions using whole-cell methanotrophs possessing methane monooxygenase. Several independent variables including ethane concentration and biocatalyst amounts, among other factors, were optimized for the enhancement [...] Read more.
The biological production of ethanol from ethane for the utilization of ethane in natural gas was investigated under ambient conditions using whole-cell methanotrophs possessing methane monooxygenase. Several independent variables including ethane concentration and biocatalyst amounts, among other factors, were optimized for the enhancement of ethane-to-ethanol bioconversion. We obtained 0.4 g/L/h of volumetric productivity and 0.52 g/L of maximum titer in optimum batch reaction conditions. In this study, we demonstrate that the biological gas-to-liquid conversion of ethane to ethanol has potent technical feasibility as a new application of ethane gas. Full article
(This article belongs to the Special Issue Advances in Conversion of Biomass and Waste to Chemicals and Fuels)
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Open AccessArticle
High-Quality Biodiesel Production from Buriti (Mauritia flexuosa) Oil Soapstock
Molecules 2019, 24(1), 94; https://doi.org/10.3390/molecules24010094 - 28 Dec 2018
Cited by 1
Abstract
The buriti palm (Mauritia flexuosa) is a palm tree widely distributed throughout tropical South America. The oil extracted from the fruits of this palm tree is rich in natural antioxidants. The by-products obtained from the buriti palm have social and economic [...] Read more.
The buriti palm (Mauritia flexuosa) is a palm tree widely distributed throughout tropical South America. The oil extracted from the fruits of this palm tree is rich in natural antioxidants. The by-products obtained from the buriti palm have social and economic importance as well, hence the interest in adding value to the residue left from refining this oil to obtain biofuel. The process of methyl esters production from the buriti oil soapstock was optimized considering acidulation and esterification. The effect of the molar ratio of sulfuric acid (H2SO4) to soapstock in the range from 0.6 to 1.0 and the reaction time (30–90 min) were analyzed. The best conditions for acidulation were molar ratio 0.8 and reaction time of 60 min. Next, the esterification of the fatty acids obtained was performed using methanol and H2SO4 as catalyst. The effects of the molar ratio (9:1–27:1), percentage of catalyst (2–6%) and reaction time (1–14 h) were investigated. The best reaction conditions were: 18:1 molar ratio, 4% catalyst and 14 h reaction time, which resulted in a yield of 92% and a conversion of 99.9%. All the key biodiesel physicochemical characterizations were within the parameters established by the Brazilian standard. The biodiesel obtained presented high ester content (96.6%) and oxidative stability (16.1 h). Full article
(This article belongs to the Special Issue Advances in Conversion of Biomass and Waste to Chemicals and Fuels)
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Review

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Open AccessReview
Catalytic Production of Jet Fuels from Biomass
Molecules 2020, 25(4), 802; https://doi.org/10.3390/molecules25040802 - 12 Feb 2020
Cited by 1
Abstract
Concerns about depleting fossil fuels and global warming effects are pushing our society to search for new renewable sources of energy with the potential to substitute coal, natural gas, and petroleum. In this sense, biomass, the only renewable source of carbon available on [...] Read more.
Concerns about depleting fossil fuels and global warming effects are pushing our society to search for new renewable sources of energy with the potential to substitute coal, natural gas, and petroleum. In this sense, biomass, the only renewable source of carbon available on Earth, is the perfect replacement for petroleum in producing renewable fuels. The aviation sector is responsible for a significant fraction of greenhouse gas emissions, and two billion barrels of petroleum are being consumed annually to produce the jet fuels required to transport people and goods around the world. Governments are pushing directives to replace fossil fuel-derived jet fuels with those derived from biomass. The present mini review is aimed to summarize the main technologies available today for converting biomass into liquid hydrocarbon fuels with a molecular weight and structure suitable for being used as aviation fuels. Particular emphasis will be placed on those routes involving heterogeneous catalysts. Full article
(This article belongs to the Special Issue Advances in Conversion of Biomass and Waste to Chemicals and Fuels)
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