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A special issue of Fermentation (ISSN 2311-5637). This special issue belongs to the section "Industrial Fermentation".

Deadline for manuscript submissions: closed (30 June 2023) | Viewed by 32289

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Special Issue Editor

Dr. Emmanuel Atta-Obeng

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Guest Editor

Science and Technology Center, Coppin State University, Baltimore, MD, USA
Interests: natural sciences; biomass; waste
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Minimizing our dependence on fossil-based resources and reducing solid and liquid wastes represent the main challenges of our modern society. A bio-economy is defined as “the global industrial transition of sustainably utilizing renewable aquatic and terrestrial biomass resources in energy, intermediate, and final products for economic, environmental, social and national security benefit. The efficient utilization of lignocellulosic biomass has tremendous potential to reduce our excessive dependence on fossil fuels.

The concept of an integrated biorefinery embraces a circular economy by making use of the entire waste stream, recycling secondary products, and valorizing co-products aside from producing bioenergy. Lignocellulosic biomass such as forestry, pulp and paper, municipal solid wastes, food, and agricultural and crop residues are considered promising renewable resources. Their large availability prevents ethical conflicts such as choosing between food versus fuel related to the use of edible crops. Biomass is composed primarily composed of three biopolymers: cellulose, hemicellulose and lignin. These have been exploited in many applications such as value-added chemicals, liquid fuels, and carbon-based functional materials using thermal, thermochemical, biochemical and chemical conversion strategies.

Structural and compositional differences in biomass lead to recalcitrance during pretreatment or decomposition. Recent fractionation approaches aim at obtaining clean compositional fractions which serve as raw materials for a portfolio of chemical products thereby increasing the profitability of the entire biorefining industry. The aim of this Special Issue is to cover recent green pretreatment and fractionation approaches that emphasize waste reduction.

This is the second edition of the Special Issue "Biomass and Waste Valorization", the first one can be found here: https://www.mdpi.com/journal/fermentation/special_issues/biomass_waste.

I would like to invite authors to submit original innovative research articles and review papers on advances, gaps and perspectives including but not limited to:

Catalysts in waste and biomass valorization processes.
Biochemical approaches in waste and biomass conversion.
Thermochemical technologies in waste and biomass conversion.
Life cycle analysis/forest bio-economy.

Dr. Emmanuel Atta-Obeng
Guest Editor

Manuscript Submission Information

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

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Fermentation is an international peer-reviewed open access monthly 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 2100 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

biomass valorization
circular economy platform
chemicals
catalytic separation
bio-economy circular economy
life cycle
residues biorefinery
value added products
energy
biofuels
biomaterials

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Research

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17 pages, 1798 KiB

Open AccessArticle

Integrated Production of Xylitol, Ethanol, and Enzymes from Oil Palm Empty Fruit Bunch through Bioprocessing as an Application of the Biorefinery Concept

by Efri Mardawati, Maisyarah Isnaini S. Nawawi, Viola Caroline, Tania Widani Imanisa, Putri Amanda, Melbi Mahardika, Nanang Masruchin, Hana Nur Fitriana, Nova Rachmadona and Mohd Nizam Lani

Fermentation 2023, 9(10), 882; https://doi.org/10.3390/fermentation9100882 - 29 Sep 2023

Viewed by 1769

Abstract

Oil palm empty fruit bunch (OPEFB), an abundant source of lignocellulosic biomass waste, is rich in hemicellulose and is converted into xylose for xylitol production. The remaining cellulose-rich residue can be efficiently hydrolyzed into glucose, which serves as a substrate for bioethanol and enzymes. This process aligns with an integrated biorefinery model aimed at optimizing the utilization of OPEFB. This study optimizes a two-stage enzymatic hydrolysis fermentation for OPEFB conversion into value-added products. Using a 4% NaOH pretreatment, lignin was degraded while preserving hemicellulose and cellulose. This hydrolysis yielded 12.27 g/L of xylose and 36.86 g/L of glucose. Ethanol production, using varied fermentation media, achieved maximum concentrations of 0.043 g/L for xylitol and 21.35 g/L for ethanol, with substrate-to-product yields of 0.005 g/g and 0.374 g/g, respectively. Furthermore, enzyme production by Aspergillus niger was assessed on multiple parameters, recording a peak cellulase activity of 55.16 ± 20.24 U/mL and enzyme weight of 42.748 kDa. The OPEFB substrate yielded the highest protein content of 0.00942 ± 0.00010 mg/mL. These findings demonstrate the feasibility and efficiency of the two-stage enzymatic hydrolysis strategy in facilitating integrated biorefinery processes for efficient and sustainable OPEFB utilization. Full article

(This article belongs to the Special Issue Advanced Research in Biomass and Waste Valorization)

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15 pages, 706 KiB

Open AccessArticle

Application of Biorefinery Concept to the Production of Bromelain, Ethanol, and Xylitol from Pineapple Plant Waste

by Efri Mardawati, Selly Harnesa Putri, Hana Nur Fitriana, Desy Nurliasari, Devi Maulida Rahmah, Rosanti, Ikhsan Maulana, Awaly Ilham Dewantoro, Euis Hermiati and Roostita Lobo Balia

Fermentation 2023, 9(9), 816; https://doi.org/10.3390/fermentation9090816 - 6 Sep 2023

Cited by 4 | Viewed by 2811

Abstract

The massive potential of pineapple fruit production can produce a sizable amount of waste, around 75% (w/w) of pineapple weight, contributing to global environmental problems. For this reason, biorefinery techniques are urgently needed to convert pineapple plantation waste into high-value-added bioproducts including bromelain, various sugars, xylooligoscharide, xylitol, and ethanol. The purpose of this study was to examine the effectiveness of converting pineapple plantation waste into bromelain, xylitol, and ethanol. In this study, the activity of the bromelain enzyme was tested in each part of the pineapple plant waste. The configuration of the hydrolysis and fermentation processes used to make ethanol and xylitol from the rest of the pineapple plant waste from bromelain extraction was also investigated. Bromelain is a proteolytic enzyme found in pineapple plants and can be isolated from every part of pineapple plant waste. Enzyme activity under several conditions, such as crude extract, pure extract, and dried extract, has been studied to determine the best conditions for the downstream process of this enzyme’s production in the future. The purification of bromelain involved the utilization of the precipitation method followed by dialysis, whereas the drying process of bromelain employed the freeze-drying method. The bromelain enzyme specific activity is shown to be highest in the pineapple stem, as observed in crude-extract (1.45 ± 0.06 CDU/mg), purified-extract (10.38 ± 0.06 CDU/mg), and dried-extract (12.05 ± 0.43 CDU/mg) conditions. Using the pineapple stem to extract bromelain can produce lignocellulosic waste, which is made up of 39.47% starch, 19.96% hemicellulose, 36.44% cellulose, and 6.05% lignin. The high content of starch, cellulose, and hemicellulose has the potential to be used as feedstock for ethanol and xylitol fermentation. In this study, ethanol and xylitol fermentation were carried out using two methods: separate hydrolysis and fermentation methods (SHF) and semi-simultaneous saccharification and fermentation methods (semi-SSF). As a result, fermentation using the semi-SSF method produced ethanol with a higher titer and yield (22.12 ± 0.05 g/L and 0.44 ± 0.00 g/g, respectively). However, the production of xylitol was found to be insignificant, regardless of whether it was obtained using SHF or semi-SSF. The purification of bromelain involved the utilization of the precipitation method followed by dialysis, whereas the drying process of bromelain employed the freeze-drying method. Full article

(This article belongs to the Special Issue Advanced Research in Biomass and Waste Valorization)

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15 pages, 2096 KiB

Open AccessArticle

By-Product from Livestock Waste Recovery System Used as Fertilizer: Bioactive Compounds and Antioxidant Activity of Tomato Fruit as Affected by Fertilization under Field and Greenhouse Conditions

by Faqinwei Li, Yongheng Yuan, Nanding Han, Xiaojue Li, Ruijie Bai, Jorge Magaña and Naoto Shimizu

Fermentation 2023, 9(8), 714; https://doi.org/10.3390/fermentation9080714 - 27 Jul 2023

Cited by 2 | Viewed by 1600

Abstract

Conversion of livestock manure into organic fertilizer is a sustainable strategy in crop production. In contrast to composted manure, the agronomic characteristics of an anaerobic digestion by-product, digestate, have not been well characterized. This study aimed to investigate the effects of digestate and compost, derived from a pilot-scale livestock waste recycling system, on bioactive compounds in tomato fruits. Both field and greenhouse experiments were conducted to compare the effects of these two organic fertilizers with the application of chemical fertilizer. These comparisons were made by evaluating their influence on tomato yield and bioactive compound contents and antioxidant activity of fruits. The experiment included a control (no fertilizer) and three fertilization treatments with the same nitrogen dose: chemical fertilizer, digestate, and compost. The results revealed that the application of digestate and compost yielded similar results in terms of tomato production, surpassing both the chemical fertilizer application and the control group under both field and greenhouse conditions. Fertilization exhibited a significant influence on the bioactive compound contents and antioxidant capacity of the fruits. Furthermore, the application of digestate and compost led to an increase in the concentration of sugars, phenolic compounds, and several organic acids in the fruits while simultaneously reducing the citric acid levels in comparison to the chemical fertilizer treatment. Moreover, the application of both organic fertilizers improved the total phenol and total flavonoid contents in tomato fruits, and the antioxidant capacity in fruits was significantly higher than that of the chemical fertilizer treatment. In conclusion, the application of digestate or compost derived from the livestock waste recycling system reduced use of chemical fertilizers and resulted in higher tomato yields and fruit with considerably superior bioactive compounds. The results suggested that using digestate or compost as an alternative to inorganic fertilizers for tomato cultivation could assist farmers in increasing productivity, improving the content of bioactive compounds in tomato fruit, and promoting agricultural waste management. Full article

(This article belongs to the Special Issue Advanced Research in Biomass and Waste Valorization)

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16 pages, 1981 KiB

Open AccessArticle

Biofuel Production from Mango and Orange Peel and Tapioca Shells by Fermentation Using Consortium of Bacteria: Agricultural and Food Waste Valorization

by Tamilselvan Vinotha, Narendrakumar Umamaheswari, Jeganathan Pandiyan, Khalid A. Al-Ghanim, Marcello Nicoletti and Marimuthu Govindarajan

Fermentation 2023, 9(7), 678; https://doi.org/10.3390/fermentation9070678 - 19 Jul 2023

Cited by 3 | Viewed by 3498

Abstract

Lignocellulosic substrates are considered to be crucial substrates for the production of biofuels. The main objective of the study is to attempt to produce bioethanol using bio-wastes such as mango peels, orange peels, and tapioca shells as renewable sources by employing three bacteria viz., Enterobacter cloacae (ICBP1), Pseudomonas aeruginosa (ICBP7), and Bacillus cereus (ICBP15), which were chosen to produce cellulase enzymes using the submerged fermentation method, which is a novel method for the production of bioethanol. The “zone of clearance” in bacterial growth on CMC agar plates determined the choice. The mixed culture infected units produced a more reduced sugar, i.e., the presence of aldehyde and ketones except sucrose. At 72 h, greater than 41.0 ± 0.48 mL and 0.83 ± 0.07% of ethanol was recovered. This contrasts with the reduced quantities at 24 and 48 h. SDS-PAGE examination showed that the three cellulose-producing bacterial strains (ICPB1, ICPB7, and ICPB15) had enzyme molecular weights of 80–100, 20–30, and 14–20 kDa, respectively, compared to the other 17 isolates. Fourier-transform infrared (FTIR) spectroscopy was used to estimate the bioethanol. The spectrum bands from 1700 to 1800 cm⁻¹ showed bioethanol’s unique absorption characteristics, and GC-MS confirmed 31.38% ethanol. The findings of the research demonstrate that the utilization of fermentation technology, specifically employing microbes, to produce bioethanol from bio-wastes such as fruits and vegetables has the potential to address the worldwide fuel energy requirements. Full article

(This article belongs to the Special Issue Advanced Research in Biomass and Waste Valorization)

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14 pages, 3237 KiB

Open AccessArticle

Purification and Characterization of Xylanase Produced by Aspergillus fumigatus Isolated from the Northern Border Region of Saudi Arabia

by Fuad Ameen

Fermentation 2023, 9(7), 595; https://doi.org/10.3390/fermentation9070595 - 26 Jun 2023

Cited by 4 | Viewed by 3399

Abstract

The purpose of the current work is to produce xylanase from certain agro-industrial wastes in an efficient and effective manner. The culture conditions for three strains of Aspergillus fumigatus are optimized in submerged fermentation (SmF). The most prolific strain (A. fumigatus KSA-2) produces the maximum xylanase at pH 9.0, 30 °C, after 7 days using yeast extract as a nitrogen supply. Aspergillus fumigatus KSA-2 is utilized to produce xylanase at optimum conditions from several agro-industrial wastes. Wheat bran is found to be the most fermentable material, yielding 66.0 U per gram dry substrate (U/gds). The generated xylanase is partly purified using 70% ammonium sulphate, yielding 40 g of dry enzyme powder from 400 g wheat bran. At pH 6.0 and 45 °C, the synthesized xylanase displayed its maximum activity (20.52 ± 1.714 U/mg). In the current study, the effect of ions and inhibitors on xylanase activity is investigated. Both Cu²⁺ and Mn²⁺ ions boost the specific activity over the control by 10.2% and 128.0%, respectively. The xylanase enzyme generated has a maximum activity of 4.311 ± 0.36 U/mL/min and the greatest specific activity of 20.53 ± 1.714 U/mg for birchwood xylan, showing a strong affinity for this substrate as opposed to the other xylan and non-xylan substrates. Full article

(This article belongs to the Special Issue Advanced Research in Biomass and Waste Valorization)

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13 pages, 2031 KiB

Open AccessArticle

Use of Kiwi Waste as Fuel in MFC and Its Potential for Use as Renewable Energy

by Segundo Rojas-Flores, Magaly De La Cruz-Noriega, Luis Cabanillas-Chirinos, Santiago M. Benites, Renny Nazario-Naveda, Daniel Delfín-Narciso, Moisés Gallozzo-Cardemas, Felix Díaz, Emzon Murga-Torres and Walter Rojas-Villacorta

Fermentation 2023, 9(5), 446; https://doi.org/10.3390/fermentation9050446 - 8 May 2023

Cited by 9 | Viewed by 2445

Abstract

This research aimed to use kiwi waste as fuel to generate bioelectricity through microbial fuel cells. It was possible to generate an electrical current and voltage peaks of 3.807 ± 0.102 mA and 0.993 ± 0.061 V on day 11, showing an electrical conductivity of 189.82 ± 3.029 mS/cm and an optimum operating pH of 5.966 ± 0.121. The internal resistance of the cells was calculated using Ohm’s Law, resulting in a value of 14.957 ± 0.394 Ω, while the maximum power density was 212.68 ± 26.84 mW/m² at a current density of 4.506 A/cm². Through the analysis of the FTIR spectra carried out on the substrate, a decrease in the characteristic organic peaks was observed due to their decomposition during the electricity-generation process. In addition, it was possible to molecularly identify the bacteria Comamonas testosteroni, Sphingobacterium sp., and Stenotropho-monas maltophila adhered to the anodized biofilm. Finally, the capacity of this residue to generate bioelectricity was demonstrated by lighting an LED bulb with a voltage of 2.85 V. Full article

(This article belongs to the Special Issue Advanced Research in Biomass and Waste Valorization)

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14 pages, 1805 KiB

Open AccessArticle

Initial Study of Fungal Bioconversion of guishe (Agave lechuguilla Residue) Juice for Bioherbicide Activity on Model Seeds

by José Humberto Sánchez Robles, Cristina Fernanda Luna Enríquez, Ana G. Reyes, Marisol Cruz Requena, Leopoldo J. Ríos González, Thelma K. Morales Martínez, Juan A. Ascacio Valdés and Miguel A. Medina Morales

Fermentation 2023, 9(5), 421; https://doi.org/10.3390/fermentation9050421 - 27 Apr 2023

Cited by 1 | Viewed by 1936

Abstract

In agriculture, weed management is a significant concern because their uncontrolled proliferation decreases soil quality for food crops. Allelopathy is a natural phenomenon in which the activity of allelochemical compounds inhibits the germination and growth of invasive plants as a defense mechanism. Among allelochemicals are polyphenols, which may affect genetic material or crucial enzyme activities for proper physiological function. Agroindustrial residues are a vast source of polyphenolic compounds with allelochemical activity. The bagasse of Agave Lechuguilla, known as guishe, is an abundant residue in México. The guishe has been characterized before by its polyphenolic content. Based on that, a fungal bioconversion process was developed to increase the availability of the allelochemicals in the guishe juice. First, guishe juice was obtained by mechanical pressed and characterized by spectrophotometric analysis. Results showed (g/L): 5.62 flavonoids, 0.64 of hydrolyzable polyphenols, 12.67 of reducing sugars, and 23.3 total sugars. The compounds detected by HPLC-ESI-MS were pterostilbene, hydroxycaffeic, caffeoyltartaric, and 4-O-glucoside coumaric acids, considered allelopathic. After the fungal bioprocess, (+)-gallocatechin and 3,7-Dimethyl quercetin were detected as additional compounds of interest. The flavonoid and hydrolyzable polyphenol content were modified to the highest accumulation of 1.57 and 14.9 g/L at 72 h, meaning a 2.45- and 2.22-fold increase. A bioprocess guishe juice (BGJ) was obtained at the compound accumulation peak of 72 h and evaluated in an allelopathic assay on model seeds (tomato and corn). Results show that BGJ inhibits up to 96.67% of corn seeds and up to 76.6% of tomato seeds compared to positive control. Full article

(This article belongs to the Special Issue Advanced Research in Biomass and Waste Valorization)

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11 pages, 1596 KiB

Open AccessArticle

In-House Extracted Soybean Protein Can Reduce the Enzyme Dosage in Biomass Saccharification

by Igor R. Simões, Mariana G. Brondi and Cristiane S. Farinas

Fermentation 2023, 9(2), 142; https://doi.org/10.3390/fermentation9020142 - 31 Jan 2023

Cited by 2 | Viewed by 1972

Abstract

Bioconversion of the complex carbohydrates present in lignocellulosic biomass into simple sugars, in order to obtain biofuels and bio-based products, is still limited by the low performance of the enzymatic saccharification reaction and the high cost of cellulolytic enzymes. Low-cost additives such as soybean protein can reduce the unproductive adsorption of cellulases onto lignin, increasing conversion rates and reducing enzyme losses. Here, investigation was made of the effects of different soybean protein fractions, extracted in-house, on the enzymatic saccharification of hydrothermally pretreated sugarcane bagasse. The glucose released during biomass saccharification increased by up to 76% in the presence of the in-house extracted soybean protein, compared to the control (without additive). A remarkable finding was that the technique allowed the enzyme loading to be decreased four-fold. The results suggested that the alkali-extracted proteins presented high surface hydrophobicity, which enhanced their interaction with lignin and reduced the unproductive binding of cellulases. Among the main soybean protein fractions, glycinin had the best effect in improving saccharification, which could have been due to its higher hydrophobicity. Hence, in-house extracted soybean proteins seem to be interesting alternative additives capable of increasing the lignocellulosic biomass conversion efficiency in future biorefineries. Full article

(This article belongs to the Special Issue Advanced Research in Biomass and Waste Valorization)

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15 pages, 1668 KiB

Open AccessArticle

Mutagenesis of Novel Clostridial fusants for Enhanced Green Biobutanol Production from Agriculture Waste

by Pallavi Roy and Yaser Dahman

Fermentation 2023, 9(2), 92; https://doi.org/10.3390/fermentation9020092 - 20 Jan 2023

Cited by 3 | Viewed by 1658

Abstract

In an earlier investigation, novel Clostridial fusants were introduced and demonstrated an ability to produce biobutanol at the relatively high temperature of 45 °C. The objective of the present study is to further improve the fused strains through examining the impact of mutation agents on their stability, tolerance to biobutanol toxicity and biofuel production capability. The results for the mutated strains showed enhanced resistance to biobutanol by the fused strains and better biobutanol generation by cells. Furthermore, the results showed high biobutanol production (14.7–15 g/L), with a total Acetone, Biobutanol and Ethanol (ABE) yield of 0.6 g/g. Moreover, mutated strains showed tolerance to biobutanol toxicity up to 15 g/L, which is equivalent to a ~15% increase over literature values. The oxygen tolerance study showed improved performance by the mutated anaerobic fusant. In general, the mutation of fused clostridium strains using UV and EMS leads to the identification of stronger robust strains that show higher tolerance to oxygen and biobutanol toxicity and achieved higher yield. Full article

(This article belongs to the Special Issue Advanced Research in Biomass and Waste Valorization)

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11 pages, 3083 KiB

Open AccessArticle

Amelioration of Biogas Production from Waste-Activated Sludge through Surfactant-Coupled Mechanical Disintegration

by Vijetha Valsa, Geethu Krishnan S, Rashmi Gondi, Preethi Muthu, Kavitha Sankarapandian, Gopalakrishnan Kumar, Poornachandar Gugulothu and Rajesh Banu Jeyakumar

Fermentation 2023, 9(1), 57; https://doi.org/10.3390/fermentation9010057 - 9 Jan 2023

Viewed by 2268

Abstract

The current study intended to improve the disintegration potential of paper mill sludge through alkyl polyglycoside-coupled disperser disintegration. The sludge biomass was fed to the disperser disintegration and a maximum solubilization of 6% was attained at the specific energy input of 4729.24 kJ/kg TS. Solubilization was further enhanced by coupling the optimum disperser condition with varying dosage of alkyl polyglycoside. The maximum solubilization of 11% and suspended solid (SS) reduction of 8.42% were achieved at the disperser rpm, time, and surfactant dosage of 12,000, 30 min, and 12 μL. The alkyl polyglycoside-coupled disperser disintegration showed a higher biogas production of 125.1 mL/gCOD, compared to the disperser-alone disintegration (70.1 mL/gCOD) and control (36.1 mL/gCOD). Full article

(This article belongs to the Special Issue Advanced Research in Biomass and Waste Valorization)

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14 pages, 2159 KiB

Open AccessArticle

Valorization of Fourth-Range Wastes: Evaluating Pyrolytic Behavior of Fresh and Digested Wastes

by Elia Judith Martínez, Rubén González, Marcos Ellacuriaga and Xiomar Gómez

Fermentation 2022, 8(12), 744; https://doi.org/10.3390/fermentation8120744 - 15 Dec 2022

Cited by 5 | Viewed by 1753

Abstract

Changes in daily habits and a stressful lifestyle create modifications in consumer preferences and open opportunities to new market products. This is the case of fourth-range products in which the industrial sector generates a waste stream of high quality. Valorization of this type of waste as a single stream is desirable to avoid lowering quality with other low-grade materials. Anaerobic digestion of fourth-range wastes was studied under discontinuous and semi-continuous conditions. A high carbon content characterizes the organic material composed of fruit and vegetable wastes. The fast degradation of the substrate indicated no limitations associated with the hydrolysis stage, as observed from kinetic parameters estimated from batch assays. However, the easiness of degradation did not translate into short hydraulic retention times when operating under semi-continuous conditions. Additionally, the insufficient amount of nutrients prevented the development of a well-balanced digestion process. Specific methane production was 325 mL CH₄/g VS added at a hydraulic retention time of 30 days. However, solid accumulation was observed at the end of the experiment, indicating that conditions established did not allow for the complete conversion of the organic material. Digestate evaluation using thermal analysis under inert conditions showed a thermal profile evidencing the presence of complex components and a high tendency to char formation. Full article

(This article belongs to the Special Issue Advanced Research in Biomass and Waste Valorization)

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14 pages, 3590 KiB

Open AccessArticle

Exploring the Valorization of Buckwheat Waste: A Two-Stage Thermo-Chemical Process for the Production of Saccharides and Biochar

by Yongheng Yuan, Faqinwei Li, Nanding Han, Bingyao Zeng, Yoshiaki Imaizumi, Risu Na and Naoto Shimizu

Fermentation 2022, 8(11), 573; https://doi.org/10.3390/fermentation8110573 - 22 Oct 2022

Cited by 4 | Viewed by 2012

Abstract

To realize the utilization of the valorization of buckwheat waste (BW), a two-stage thermal-chemical process was explored and evaluated to produce saccharides and biochar. During the first stage, BW underwent a hydrothermal extraction (HTE) of varying severity to explore the feasibility of saccharides production; then, the sum of saccharides yields in the liquid sample were compared. A higher sum of saccharides yields of 4.10% was obtained at a relatively lower severity factor (SF) of 3.24 with a byproducts yield of 1.92 %. During the second stage, the contents of cellulose, hemicellulose, and lignin were analyzed in the residue after HTE. Enzymatic hydrolysis from the residue of HTE was inhibited. Thus, enzymatic hydrolysis for saccharides is not suitable for utilizing the residue after HTE of BW. These residues with an SF of 3.24 were treated by pyrolysis to produce biochar, providing a higher biochar yield of 34.45 % and a higher adsorption ability (based on methyl orange) of 31.11 % compared with pyrolysis of the raw BW. Meanwhile, the surface morphology and biomass conversion were analyzed in this study. These results demonstrate that the two-stage thermal-chemical process is efficient for treating BW and producing saccharides and biochar. This work lays a foundation for the industrial application of BW, and for improving the economic benefits of buckwheat cultivation. Full article

(This article belongs to the Special Issue Advanced Research in Biomass and Waste Valorization)

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Review

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15 pages, 1571 KiB

Open AccessReview

Methods for Intensifying Biogas Production from Waste: A Scientometric Review of Cavitation and Electrolysis Treatments

by Viktoriia Chubur, Dmytro Danylov, Yelizaveta Chernysh, Leonid Plyatsuk, Vladimir Shtepa, Nils Haneklaus and Hynek Roubik

Fermentation 2022, 8(10), 570; https://doi.org/10.3390/fermentation8100570 - 21 Oct 2022

Cited by 8 | Viewed by 3646

Abstract

This article presents future trends in research using microbiological methods to intensify bioprocesses for biogas production. The pretreatment by combinations of physical and chemical methods, such as cavitation and electrolysis, is considered. The approach of the article involved reviewing the residual area on the intensification technologies of anaerobic digestion with current methods to improve the quality and quantity of biogas. The most valuable reported positive results of the pretreatment of biological raw materials in the cavitation process were reviewed and are presented here. A model of the effect of electrolysis on the species diversity of bacteria in anaerobic digestion was developed, and changes in the dominance of the ecological and trophic systems were revealed on the basis of previous studies. The stimulating effect on biogas yield, reduction in the stabilization period of the reactor, and inactivation of microorganisms at lower temperatures is associated with different pretreatment methods that intensify anaerobic digestion. More research is recommended to focus on the electrolysis treatment of different types of waste and their ratios with optimization of regime parameters, as well as in combination with other pretreatments to produce biomethane and biohydrogen in larger quantities and in better qualities. Full article

(This article belongs to the Special Issue Advanced Research in Biomass and Waste Valorization)

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