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13 pages, 1540 KiB

Open AccessArticle

A Comprehensive Approach of Eucalyptus globulus Acid Sulfite Pretreatment for Enzymatic Hydrolysis

by Vera L. D. Costa, Ana P. Costa, Maria E. Amaral and Rogério M. S. Simões

Appl. Sci. 2020, 10(11), 3764; https://doi.org/10.3390/app10113764 - 29 May 2020

Cited by 1 | Viewed by 1764

The effect of different acid sulfite pretreatment conditions on released components in the hydrolysates and the pretreated solid residues’ response to enzymatic hydrolysis for Eucalyptus globulus chips was investigated. Sodium bisulfite (0–15%), and sulfuric acid (0–5%) were used to pretreat chips at 170 [...] Read more.

The effect of different acid sulfite pretreatment conditions on released components in the hydrolysates and the pretreated solid residues’ response to enzymatic hydrolysis for Eucalyptus globulus chips was investigated. Sodium bisulfite (0–15%), and sulfuric acid (0–5%) were used to pretreat chips at 170 °C and 190 °C, for as long as 30 min. The hydrolysates were analyzed through high-performance liquid chromatography (HPLC) and spectrophotometry. Overall porosity and pores larger than 2.65 nm (size of a typical cellulase) on the solid residues were estimated using glucose and two dextrans with different hydrodynamic radii as probes. The external specific surface area was analyzed by dynamic light scattering. The solid residues underwent enzymatic hydrolysis with an enzymatic cocktail. Very high (84–95%) carbohydrate conversion was achieved for either an extensively delignified biomass or a biomass with very high content of sulfonated residual lignin (23.4%), since internal porosity enables enzymes accessibility. At least 5% sodium bisulfite and 1% sulfuric acid was required to attain a carbohydrate release above 90% in the enzymatic hydrolysis. Results suggest that the presence of sulfonated lignin does not impair the enzymatic hydrolysis rate and extent. The increase of pretreatment temperature had a positive effect mainly on the initial rate of carbohydrates release in the enzymatic hydrolysis. The increase of the wood material dimensions from pins to conventional chips significantly decreased the hemicellulose removal in acid sulfite pretreatment but had a small effect on the enzymatic yield. Full article

(This article belongs to the Special Issue Biomass Research and Applications)

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13 pages, 1459 KiB

Open AccessArticle

Bifunctional Heterogeneous Catalyst for Biodiesel Production from Waste Vegetable Oil

by Samya Elias, Ademola M Rabiu, Benjamin I Okeleye, Vincent Okudoh and Oluwaseun Oyekola

Appl. Sci. 2020, 10(9), 3153; https://doi.org/10.3390/app10093153 - 1 May 2020

Cited by 36 | Viewed by 4267

Abstract

Bifunctional solid catalysts facilitate the esterification of free fatty acids (FFA) into alkyl esters alongside the transesterification reaction, which allows for the use of waste vegetable oils with high water and FFA contents for biodiesel production. This makes the process economically viable and [...] Read more.

Bifunctional solid catalysts facilitate the esterification of free fatty acids (FFA) into alkyl esters alongside the transesterification reaction, which allows for the use of waste vegetable oils with high water and FFA contents for biodiesel production. This makes the process economically viable and greener, as the waste fats and oils are readily available. The concurrent esterification and transesterification of waste palm oil (WPO) and waste sunflower oil (WSO) with methanol was investigated in the presence of calcium oxide on alumina catalyst in a conventional batch process. The catalyst characterization showed the existence of calcium oxide aluminates (calcined at 750 °C), which exhibited crystalline phases with porous/spongy-like particles. The high concentration of CaO in CaO/Al₂O₃ was a favorable support material in the heterogeneously-catalyzed transesterification reactions. The optimum catalyst parameters for the production of fatty acid methyl esters (FAMEs) were observed at 65 °C for 4 h with a methanol-to-oil ratio of 9:1, 60% (waste palm oil, or WPO) and 80% (waste sunflower oil, or WSO), CaO/Al₂O₃ (% wt/wt) catalyst ratio as well as 4% CaO/Al₂O₃ concentration (% wt.) for WSO and WPO. The simultaneous esterification/transesterification reactions at optimum conditions on WPO and WSO led to high yield of FAMEs of 89, 61 and 55% for WPO and 54, 75 and 98% for WSO at catalyst ratios (wt %) of 60, 70 and 80% respectively. The use of bifunctional heterogeneous catalyst (CaO/Al₂O₃) with waste vegetable oil can result in high performance and the upscaling of biodiesel production. Full article

(This article belongs to the Special Issue Biomass Research and Applications)

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15 pages, 5506 KiB

Open AccessArticle

Comparing the Physicochemical Properties of Upgraded Biomass Fuel by Torrefaction and the Ashless Technique

by Lkhagvadorj Sh, Byoung-Hwa Lee, Young-Joo Lee and Chung-Hwan Jeon

Appl. Sci. 2019, 9(24), 5519; https://doi.org/10.3390/app9245519 - 15 Dec 2019

Cited by 18 | Viewed by 2663

Abstract

The purpose of this study was to investigate and compare the influence of torrefaction and an ashless process on the physical and chemical properties of pitch pine sawdust (PSD) and kenaf as types of woody and herbaceous biomass. The physicochemical properties of the [...] Read more.

The purpose of this study was to investigate and compare the influence of torrefaction and an ashless process on the physical and chemical properties of pitch pine sawdust (PSD) and kenaf as types of woody and herbaceous biomass. The physicochemical properties of the materials pretreated by the ashless process with torrefaction including proximate and ultimate analysis, hydrophobicity, grindability, morphology, and structure were analyzed. The results showed that when ashless Kenaf was torrefied, the high heating rate and atomic ratios of O/C and H/C increased. The tendency of the torrefied, ashless Kenaf to absorb water decreased, and it became more hydrophobic (approximately 0% for the uptake rate of moisture). In addition, the grindability of the torrefied, ashless Kenaf was substantially improved compared to that of pretreated PSD. Brunauer–Emmett–Teller and scanning electron microscopy results showed that when Kenaf was pretreated, particles easily lost their fibrous structure and cracked as the number of macropores decreased. These results indicate that the herbaceous biomass of Kenaf, when pretreated with both torrefaction and the ashless process, exhibits improved physicochemical properties compared to the woody PSD. Full article

(This article belongs to the Special Issue Biomass Research and Applications)

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42 pages, 5949 KiB

Open AccessArticle

A Generalized Model of Complex Allometry I: Formal Setup, Identification Procedures and Applications to Non-Destructive Estimation of Plant Biomass Units

by Héctor Echavarria-Heras, Cecilia Leal-Ramirez, Enrique Villa-Diharce and Juan Ramón Castro-Rodríguez

Appl. Sci. 2019, 9(22), 4965; https://doi.org/10.3390/app9224965 - 18 Nov 2019

Cited by 4 | Viewed by 3015

Abstract

(1) Background: We previously demonstrated that customary regression protocols for curvature in geometrical space all derive from a generalized model of complex allometry combining scaling parameters expressing as continuous functions of covariate. Results highlighted the relevance of addressing suitable complexity in enhancing the [...] Read more.

(1) Background: We previously demonstrated that customary regression protocols for curvature in geometrical space all derive from a generalized model of complex allometry combining scaling parameters expressing as continuous functions of covariate. Results highlighted the relevance of addressing suitable complexity in enhancing the accuracy of allometric surrogates of plant biomass units. Nevertheless, examination was circumscribed to particular characterizations of the generalized model. Here we address the general identification problem. (2) Methods: We first suggest a log-scales protocol composing a mixture of linear models weighted by exponential powers. Alternatively, adopting an operating regime-based modeling slant we offer mixture regression or Takagi–Sugeno–Kang arrangements. This last approach allows polyphasic identification in direct scales. A derived index measures the extent on what complexity in arithmetic space drives curvature in arithmetical space. (3) Results: Fits on real and simulated data produced proxies of outstanding reproducibility strength indistinctly of data scales. (4) Conclusions: Presented analytical constructs are expected to grant efficient allometric projection of plant biomass units and also for the general settings of allometric examination. A traditional perspective deems log-transformation and allometry inseparable. Recent views assert that this leads to biased results. The present examination suggests this controversy can be resolved by addressing adequately the complexity of geometrical space protocols. Full article

(This article belongs to the Special Issue Biomass Research and Applications)

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12 pages, 2790 KiB

Open AccessArticle

Optimization of Processing Parameters to Increase Thermal Conductivity of Rice Straw Fiber Film

by **anglan Ming, Haitao Chen and Donghai Wang

Appl. Sci. 2019, 9(21), 4645; https://doi.org/10.3390/app9214645 - 1 Nov 2019

Cited by 8 | Viewed by 2532

Abstract

Biodegradable mulching film (BMF) is a promising alternative to petroleum-based plastic mulching film. Thermal conductivity is an important quality factor of BMF that affects the heat transfer between ambient to soil and plant growth. The objective of this research was to enhance the [...] Read more.

Biodegradable mulching film (BMF) is a promising alternative to petroleum-based plastic mulching film. Thermal conductivity is an important quality factor of BMF that affects the heat transfer between ambient to soil and plant growth. The objective of this research was to enhance the thermal conductivity of fiber film through an environmentally friendly agent and optimized processing conditions. Response surface methodology (RSM) was used to optimize the processing conditions. With optimized process conditions of 70 g/m² basis weight, 1.5% wet strength agent content, 0.5% neutral sizing agent content, 15% charcoal addition ratio, and 55 °SR beating degree, the films showed satisfactory thermal conductivity (0.0714 W/m·K) and high dry and wet tensile strengths (33.4 and 12.2 N). The addition of charcoal increased the thermal conductivity of the film by 34.31%. This promising result shows the biodegradable fiber film is able to increase soil temperature and meet the required temperature for crop growth. Full article

(This article belongs to the Special Issue Biomass Research and Applications)

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12 pages, 1169 KiB

Open AccessArticle

Assessment of the Possibility of Using Hemp Biomass (Cannabis Sativa L.) for Energy Purposes: A Case Study

by Artur Kraszkiewicz, Magdalena Kachel, Stanisław Parafiniuk, Grzegorz Zając, Ignacy Niedziółka and Maciej Sprawka

Appl. Sci. 2019, 9(20), 4437; https://doi.org/10.3390/app9204437 - 19 Oct 2019

Cited by 44 | Viewed by 5602

Abstract

During testing, the possibility of using hemp biomass for energy purposes was assessed. The criteria assessed were the physical and chemical properties of hemp biomass, as well as the combustion process of straw and briquettes made of it in a low-power boiler. The [...] Read more.

During testing, the possibility of using hemp biomass for energy purposes was assessed. The criteria assessed were the physical and chemical properties of hemp biomass, as well as the combustion process of straw and briquettes made of it in a low-power boiler. The results were made and compared with currently applicable standards. Technical and chemical properties of hemp biomass are comparable with the best plants used for energy purposes. Studies have also shown the susceptibility of hemp biomass compaction. However, large emissions recorded during the combustion of the tested forms of biofuels from hemp straw in light of applicable standards disqualify this fuel for use in grate-type heating devices with air fed under the grate. It would be advisable to carry out research on the total costs of pellet production and their use in heating devices with a retort burner, while taking into account this biofuel’s ashes’ susceptibility of sintering. Full article

(This article belongs to the Special Issue Biomass Research and Applications)

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15 pages, 3964 KiB

Open AccessArticle

Compression of Biomass Substances—A Study on Springback Effects and Color Formation in Pellet Manufacture

by Stefan Frodeson, Pär Lindén, Gunnar Henriksson and Jonas Berghel

Appl. Sci. 2019, 9(20), 4302; https://doi.org/10.3390/app9204302 - 14 Oct 2019

Cited by 17 | Viewed by 2482

Abstract

In order to increase the use of a variated raw material base for pellet production with a maintained density level, knowledge of the biomaterials’ ability to counteract any springback effects is essential. In this study, the springback effects were investigated for single press [...] Read more.

In order to increase the use of a variated raw material base for pellet production with a maintained density level, knowledge of the biomaterials’ ability to counteract any springback effects is essential. In this study, the springback effects were investigated for single press produced pellets from cellulose, hemicelluloses, pectin, and two woods at different moisture contents. The change in pellet coloring was also tested through a spectrophotometer for both xylan and carboxymethyl cellulose (CMC) pellets. The results show that the density of xylan pellets is much higher than glucomannan, for both green and cured pellets, and that the length of the pellets, as well as springback contribution, differ between the hemicelluloses. The study also presents results showing that both xylan and CMC pellets have a mutually identical spectrum and that the changes in the structure of xylan are not only related to moisture content, but are also pressure-related. The study also postulates that the color difference of the xylan pellets is a result of physical changes in the structure, as opposed to being of a chemical nature. Full article

(This article belongs to the Special Issue Biomass Research and Applications)

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14 pages, 3599 KiB

Open AccessArticle

Exploring an Integrated Manure-Seawater System for Sustainable Cyanobacterial Biomass Production

by Mekiso Yohannes Sido

Appl. Sci. 2019, 9(18), 3888; https://doi.org/10.3390/app9183888 - 16 Sep 2019

Cited by 1 | Viewed by 2983

Abstract

Cyanobacterial biomass is important for biofuel and biofertilizer, however, biomass production requires expensive chemical growth nutrients. To address this issue, we explored the use of inexpensive growth nutrient media from an integrated manure-seawater system for cyanobacterial biomass production. Salt-tolerant cyanobacterial strain HSaC and [...] Read more.

Cyanobacterial biomass is important for biofuel and biofertilizer, however, biomass production requires expensive chemical growth nutrients. To address this issue, we explored the use of inexpensive growth nutrient media from an integrated manure-seawater system for cyanobacterial biomass production. Salt-tolerant cyanobacterial strain HSaC and salt-sensitive cyanobacterial strain LC were tested to evaluate the potential of integrated manure-seawater media for sustainable cyanobacterial biomass production. As a prerequisite for seawater experiments, strain HSaC was grown at different NaCl concentrations (0 mM, 60 mM, 120 mM, 180 mM, 240 mM and 300 mM) to identify the optimum salt concentration. The highest biomass yield and photosynthetic pigment contents were obtained at 120 mM NaCl concentration. The highest exo-polysaccharide (EPS) content was obtained at 180 mM NaCl concentration. The treatments for the manure-seawater media were cow manure, pig manure, chicken manure and BG11, each with distilled water, diluted seawater and non-diluted seawater. The highest biomass and photosynthetic pigment yield for cyanobacterial strains LC and HSaC were obtained from 0.5 dS/m and 10 dS/m diluted seawater integrated with cow manure, respectively, but pig and chicken manure performed poorly. Overall, the biomass production and photosynthetic pigment results from cow manure-seawater were relatively better than those from the reference media (BG11). Based on the current findings, it is concluded that the growth nutrients from integrated cow manure-seawater can wholly substitute for the BG11 without affecting cyanobacterial growth, thereby reducing the usage of expensive chemical growth media. Thus, the results of study help to enhance the biomass production of both salt-sensitive and salt-tolerant cyanobacteria for sustainable biofuel and biofertilizer production. Full article

(This article belongs to the Special Issue Biomass Research and Applications)

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11 pages, 876 KiB

Open AccessArticle

Sargassum muticum Hydrothermal Extract: Effects on Serum Parameters and Antioxidant Activity in Rats

by Elena M. Balboa, Rosendo Millán, Herminia Domínguez and Cristina Taboada

Appl. Sci. 2019, 9(12), 2570; https://doi.org/10.3390/app9122570 - 25 Jun 2019

Cited by 7 | Viewed by 2953

Abstract

Sargassum muticum was processed by hydrothermal extraction under previously optimized non-isothermal conditions (up to 187 °C). The alginate free crude hydrolysate was further concentrated by ultrafiltration, operating in diafiltration mode to produce an extract (SmE) enriched in the fucoidan and the phlorotannin fractions [...] Read more.

Sargassum muticum was processed by hydrothermal extraction under previously optimized non-isothermal conditions (up to 187 °C). The alginate free crude hydrolysate was further concentrated by ultrafiltration, operating in diafiltration mode to produce an extract (SmE) enriched in the fucoidan and the phlorotannin fractions and with low mineral content and antiradical capacity equivalent to that of Trolox. In order to explore the potential of this concentrated product for food or feed additive, the in vivo antioxidant potential was assessed. Male Sprague–Dawley rats were fed SmE dissolved in distilled water at doses of 0.5, 1.0 or 2.0 g kg⁻¹, administered via an intragastric tube daily for three weeks. The weight and organ gain was not significantly affected in the different groups in relation to the control group fed a standard diet. Serum glucose was significantly lowered in the groups receiving the higher SmE doses, liver GPx levels were reduced and liver TBARS levels decreased in rats administered the extract, but no effect on SOD activity in either liver or erythrocytes was observed. Full article

(This article belongs to the Special Issue Biomass Research and Applications)

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