Agricultural Biomass Waste Conversion into Value-Added Products

A special issue of Agronomy (ISSN 2073-4395). This special issue belongs to the section "Agricultural Biosystem and Biological Engineering".

Deadline for manuscript submissions: 31 July 2024 | Viewed by 5941

Special Issue Editors

Special Issue Information

Dear Colleagues,

The academic and industrial interest in the conversion of biomass waste of agricultural origin into products with high added value has assumed ever greater importance in recent years. The topic, central to the mitigation of CO2 emissions and the intelligent exploitation of resources, embraces very different scientific-industrial sectors. Some examples are (but they are not limited to) the extraction of secondary plant metabolites such as polyphenols and their characterization and application in the pharmaceutical, cosmetic and food fields; enzymatic or microorganism-mediated biotransformations of lignocellulosic waste for energy purposes (biofuels) or as sources of innovative materials such as biopolymers or their precursors.

The Special Issue therefore aims to collect the latest scientific advances in the aforementioned topics. We would like to invite researchers and scholars to participate in this Special Issue by submitting a contribution in their field of expertise. Both original research papers and reviews are welcome.

Dr. Giuseppe Squillaci
Dr. Alessandra Morana
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 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. Agronomy 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 2600 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

  • agricultural waste
  • biomass
  • waste valorization
  • waste conversion
  • polyphenols
  • biotransformations
  • biofuels
  • bioactive products

Published Papers (5 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

12 pages, 1112 KiB  
Article
Ultrasound-Assisted Alkaline Pretreatment of Biomass to Enhance the Extraction Yield of Valuable Chemicals
by Adina I. Gavrila, Anamaria Vartolomei, Ioan Calinescu, Mircea Vinatoru, Oana C. Parvulescu, Grigore Psenovschi, Petre Chipurici and Adrian Trifan
Agronomy 2024, 14(5), 903; https://doi.org/10.3390/agronomy14050903 (registering DOI) - 26 Apr 2024
Viewed by 286
Abstract
As a renewable and sustainable resource, lignocellulosic biomass serves as a crucial raw material for the production of biofuels, biochemicals, and various value-added products. This paper aims to develop and optimize a mild alkaline treatment of sawdust assisted by ultrasound, along with enzymatic [...] Read more.
As a renewable and sustainable resource, lignocellulosic biomass serves as a crucial raw material for the production of biofuels, biochemicals, and various value-added products. This paper aims to develop and optimize a mild alkaline treatment of sawdust assisted by ultrasound, along with enzymatic hydrolysis of the pretreated material. The alkaline sonochemical pretreatment emerged as the optimal approach to enhance the susceptibility of cellulose to subsequent enzymatic hydrolysis to improve the yield of reducing sugars. A comparative study was performed using various ultrasonic applicators (horn and bath) and conventional assisted alkaline pretreatment. The ultrasonic-assisted pretreatment revealed a higher delignification of 68% (horn) and 57% (bath) compared with conventional pretreatment. Processes were optimized using a statistical analysis based on a 23 factorial design. The ratios between sawdust and alkaline solution (RSL = 0.5–1.5 g/100 mL), US amplitude (A = 20–60%), and working temperature (t = 30–50 °C) were selected as process factors. The optimal operating conditions to maximize the reducing sugar yield (138.15 mg GE/gsubstrate) were found as follows: a solid/liquid ratio of RSL,opt = 1.25 g/100 mL, US amplitude of Aopt = 60%, and pretreatment temperature of topt = 50 °C. The overall outcomes clearly confirmed the intensification of delignification by ultrasound-assisted alkaline pretreatment. Full article
(This article belongs to the Special Issue Agricultural Biomass Waste Conversion into Value-Added Products)
Show Figures

Figure 1

17 pages, 1269 KiB  
Article
Onion Peel as a Potential Source of Antioxidants and Antimicrobial Agents
by Nataša Joković, Jelena Matejić, Jelena Zvezdanović, Zorica Stojanović-Radić, Nemanja Stanković, Tatjana Mihajilov-Krstev and Nirit Bernstein
Agronomy 2024, 14(3), 453; https://doi.org/10.3390/agronomy14030453 - 24 Feb 2024
Viewed by 1363
Abstract
Dry outer onion leaves resulting from the industrial processing of onions are currently discarded as agricultural waste, although some studies have demonstrated that onion peel has beneficial biological effects. Considering the traditional applications of onion peel, the present study evaluated comparatively the chemical [...] Read more.
Dry outer onion leaves resulting from the industrial processing of onions are currently discarded as agricultural waste, although some studies have demonstrated that onion peel has beneficial biological effects. Considering the traditional applications of onion peel, the present study evaluated comparatively the chemical and biological characteristics of four types of onion peel extracts, utilizing methanol, ethanol, acetone, or ethyl acetate as the extracting solvent. The extracts were analyzed for their chemical composition, antioxidant potential, and antimicrobial activity. The chemical analysis by UHPLC-DAD-ESI/MS identified 23 compounds in the extracts, belonging to phenolic acids and flavonoids. Quercetin was the main compound in all extracts, ranging in concentrations from 14.91 mg/g DW in the ethanol extract to 48.53 mg/g DW in the methanol extract. The highest contents of total phenols and flavonoids were found in the acetone extract, and the methanol extract demonstrated the highest antioxidant activity in DPPH and ABTS assays. The antimicrobial potential of the extracts was screened using a microdilution method against a spectrum of gastrointestinal microorganisms. The results revealed that all four extracts have significant antimicrobial potential against the tested microorganisms, of which the ethanol extract demonstrated the highest antimicrobial potency. Full article
(This article belongs to the Special Issue Agricultural Biomass Waste Conversion into Value-Added Products)
Show Figures

Figure 1

26 pages, 3925 KiB  
Article
Green Waste from Cucumber (Cucumis sativus L.) Cultivation as a Source of Bioactive Flavonoids with Hypolipidemic Potential
by Daniil N. Olennikov and Nina I. Kashchenko
Agronomy 2023, 13(9), 2410; https://doi.org/10.3390/agronomy13092410 - 18 Sep 2023
Cited by 1 | Viewed by 1570
Abstract
Cucumber is an important agricultural crop that is cultivated under greenhouse conditions. Cucumber cultivation generates substantial quantities of green waste that require proper disposal. The lack of data on the chemical composition of cucumber greens and their biological activity emphasizes the necessity for [...] Read more.
Cucumber is an important agricultural crop that is cultivated under greenhouse conditions. Cucumber cultivation generates substantial quantities of green waste that require proper disposal. The lack of data on the chemical composition of cucumber greens and their biological activity emphasizes the necessity for research on useful products resulting from this widely available waste. Our examination of the flavonoid contents in the leaves and stems of 30 cucumber cultivars revealed 6 cultivars with high flavonoid contents. In addition, the cutting time did not cause negative effects, and we observed a positive effect with 0.05–0.10% organomineral fertilizer application on the flavonoid levels in the greens. Liquid chromatography–mass spectrometry detected 38 apigenin derivatives, including acylated and non-acylated cucumerins and C-, O-, and C,O-glycosides. Among these, 12 known flavonoids and 18 novel compounds were identified. The concentrations of these compounds in the six flavonoid extracts varied at 39.85–181.53 mg/g for the non-acylated flavones, 14.67–293.31 mg/g for the cucumerins, and 401.73–892.17 mg/g for the acylated flavones. Oral administration of the total flavonoid extracts (at a dosage of 100 g/kg/day) resulted in a hypolipidemic effect in hyperlipidemic hamsters, with subsequent normalization of their serum lipid profiles, malondialdehyde levels, and liver antioxidative enzyme activities. These results substantiate the lipid-lowering potential of cucumber waste extracts. Our investigation of the selected flavonoid activity showed that isovitexin-2′′-O-glucoside-6′′-O-p-coumarate (administered at 50 g/kg/day) had the highest hypolipidemic potency. These results can contribute to the practical use of cucumber green waste and the development of novel supplements for diseases linked to high-fat consumption. Full article
(This article belongs to the Special Issue Agricultural Biomass Waste Conversion into Value-Added Products)
Show Figures

Figure 1

18 pages, 1845 KiB  
Article
Biomass Identification from Proximate Analysis: Characterization of Residual Vegetable Materials in Andean Areas
by Borja Velázquez Martí, Juan Gaibor-Chávez, John Eloy Franco Rodríguez and Isabel López Cortés
Agronomy 2023, 13(9), 2347; https://doi.org/10.3390/agronomy13092347 - 09 Sep 2023
Viewed by 951
Abstract
This work was aimed at the characterization of residual generated biomass from pruned tree species present in the Andean areas of Ecuador as a source of energy, both in plantations and in urban areas, as a response to the change in the energy [...] Read more.
This work was aimed at the characterization of residual generated biomass from pruned tree species present in the Andean areas of Ecuador as a source of energy, both in plantations and in urban areas, as a response to the change in the energy matrix proposed by the Ecuadorian government. From the proximate analysis (volatiles, ashes, and fixed carbon content), elemental analysis (C, H, N, S, O, and Cl), structural analysis (cellulose, lignin, and hemicellulose content), and higher heating value, the studied species were pine (Pinus radiata), cypress (Cupressus macrocarpa), eucalyptus (Eucalyptus globulus), poplar (Populus sp.), arupo (Chionanthus pubescens), alder (Alnus Acuminata), caper spurge (Euphorbia laurifolia), and lime (Sambucus nigra L.) trees. We evaluated the influence of the presence of leaves in the biomass. From this characterization, we developed a method based on obtaining the main components for the identification of the biomass’s species. If the origin of the biomass was unknown, this method enabled us to identify the species, with all its characteristics. If the origin of the biomass was unknown, this innovative method enabled the identification of the species from the lignocellulosic biomass, with all of its characteristics. Finally, we developed regression models that relate the higher heating value to the elemental, proximate, and structural composition. Full article
(This article belongs to the Special Issue Agricultural Biomass Waste Conversion into Value-Added Products)
Show Figures

Figure 1

16 pages, 2731 KiB  
Article
A Promising, Highly Effective Nitrate Sorbent Derived from Solid Olive Mill Residues
by José M. Angosto, José M. Obón, María J. Roca, Mercedes Alacid and José A. Fernández-López
Agronomy 2023, 13(5), 1325; https://doi.org/10.3390/agronomy13051325 - 09 May 2023
Cited by 1 | Viewed by 1077
Abstract
Olive mill residues have been valorized by chemical modification with amines to improve their adsorption capacity and to be used as a low-cost bioadsorbent for nitrate removal. The Taguchi method was used to optimize the process. By performing a three-factor analysis with three [...] Read more.
Olive mill residues have been valorized by chemical modification with amines to improve their adsorption capacity and to be used as a low-cost bioadsorbent for nitrate removal. The Taguchi method was used to optimize the process. By performing a three-factor analysis with three levels, it was possible to significantly reduce the number of experiments to be performed and to obtain the best working conditions. The results of the Taguchi method showed that the highest adsorption capacity was 110 mg·g−1 with a functionalized biomass dose of 1 g·L−1 using an initial nitrate concentration of 500 mg·L−1. Field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR) were used to characterize the surface morphology and study the chemical changes that occurred in the biomass. For the best conditions of the Taguchi approach, the kinetic and equilibrium aspects of the adsorption process were analyzed. The adsorption isotherms obtained were successfully fitted to the Freundlich (R2 = 0.98) and Langmuir (R2 = 0.97) models. The kinetics of the process were studied, and the data obtained fit very well to the pseudo-second-order model (R2 = 0.99). The adsorption values obtained suggest that it is a bioadsorbent with great potential for nitrate retention in aqueous solutions. Full article
(This article belongs to the Special Issue Agricultural Biomass Waste Conversion into Value-Added Products)
Show Figures

Figure 1

Back to TopTop