Waste Biorefinery Research Articles

Corn biomass as a feedstock for biorefinery: a bibliometric analysis of research on bioenergy, biofuel and value‐added products

AbstractLimited research has been dedicated to exploring the potential reuse and creation of value‐added products from corn stover. Existing gaps in current research underscore the need for waste biorefineries that adhere to the principles of a circular bioeconomy to maximize the value of corn stover. This review uses bibliometric analysis from the past decade to examine the potential and pathways for converting corn stover into energy and value‐added products within the biorefinery framework. The data were processed using the Web of Science® database and analyzed with the VosViewer® bibliometric software's, Bibliometrix package in R and Gephi, generating keyword‐based maps. A total of 2557 experimental articles and 30 reviews on corn stover research were analyzed. The bibliometric study revealed that the primary research focuses on pretreatment technologies for converting corn stover into value‐added products, bioenergy and biofuels. The main technologies employed include acid, alkaline and enzymatic hydrolysis, as well as torrefaction anaerobic digestion and steam explosion. The pretreatment processes yield sugars, xylooligosaccharides and organic acids. Additionally, the studies explored the use of corn stover biochar for soil remediation and adsorption processes. This review aims to enhance the understanding of technological pathways explored in previous research, contributing to the evaluation of sustainable processes for utilizing corn stover byproducts. Ultimately, it promotes environmentally conscious agroindustry practices that align with circular economy principles and sustainable development.

Scenarios, prospects, and challenges related to supercritical fluid impregnation in the food industry: a scoping review (2018–2023)

AbstractSupercritical fluid impregnation (SFI) is an emerging technique for the incorporation of target compounds into solid matrices. It has attracted attention in the food industry, where it can be applied. As it does not use organic solvents and supercritical CO2 is the most commonly used fluid, SFI is considered to be an ecofriendly and ‘green’ strategy. A review of the literature is essential in order to understand the complex interactions that occur in SFI. This is a scoping review of SFI applied to the food industry from 2018 to 2023. The search used the Web of Science, Scopus, and Science Direct databases. Guiding questions were identified, publications related to the topic were selected, and the information was extracted, organized, and grouped. An overview of the SFI, its operational characteristics, challenges, prospects, and strategies is presented. Initially, 329 records were found; 38 publications were eventually selected for inclusion in this scoping review. The results indicate that the packaging sector has been the focus of publications. However, trends include applications of SFI in micronization, developing of food waste biorefineries, and food protection from direct impregnation. This scoping analysis is therefore a powerful tool for creating new research into the application of SFI to food.

Synthesis and characterization of hierarchically porous carbon anodes from furfural biorefinery residues for sustainable lithium-ion batteries

This study aims to valorize abundant lignocellulosic residues from furfural biorefineries into hierarchically porous carbon anodes for sustainable lithium-ion batteries (LIBs). Simultaneously, it addresses the growing demand for high-performance anode materials by leveraging renewable waste feedstocks. Sugarcane bagasse waste residues obtained after furfural extraction were used as the precursor. The furfural-derived bagasse residue (FDBR) underwent pyrolysis at 700 °C to produce a carbon-rich char, which was further activated using KOH and steam at 900 °C for 15–60 minutes to enhance porosity development. Comprehensive physicochemical characterizations, including proximate analysis, N2 adsorption-desorption, SEM-EDX, FTIR, and TGA/DTG, and Raman spectroscopy were performed to evaluate the properties of the synthesized activated carbons. The results demonstrated the successful generation of high surface area (405.8 m2/g) activated carbons with a hierarchical pore structure comprising micropores and mesopores. SEM and EDX analyses revealed a uniform, porous morphology enriched with 10.41 % at oxygen-containing functional groups. FTIR spectra confirmed the presence of hydroxyls, carbonyls, and carboxylic acid groups, beneficial for pseudocapacitive charge storage. The Raman analysis revealed a highly disordered and amorphous carbon structure with a significant concentration of defects, as evidenced by a high-intensity ratio (ID/IG ≈ 1.2–1.4) of the disordered carbon band to the graphitic band. The activated carbons exhibited a high initial discharge capacity of 1055 mAh/g in lithium half-cells, significantly exceeding the theoretical limit of commercial graphite anodes (372 mAh/g). This superior capacity was attributed to the high surface area, hierarchical porosity, and pseudocapacitive contributions from the oxygen functionalities. However, rapid capacity fading from 1055 to ∼250 mAh/g was observed over 100 cycles at a C/2 rate. The capacity retention stabilized at ∼88 % after 47 cycles, indicating irreversible capacity losses. These limitations were ascribed to the disordered amorphous structure, instability of the solid-electrolyte interphase, lithium trapping by oxygen groups, and structural changes during cycling. Optimizing activation conditions, incorporating conductive additives/coatings, exploring alternative binders, and surface functionalization are proposed to improve long-term cycling stability. Overall, this study demonstrates the feasibility of upcycling furfural biorefinery waste into sustainable LIB anodes while highlighting challenges and potential solutions for enhancing their electrochemical performance.

Valorization of cheese-making residues in biorefineries using different combinations of dark fermentation, hydrothermal carbonization and anaerobic digestion

Dark fermentation (DF), hydrothermal carbonization (HTC) and anaerobic digestion (AD) are applied, in different combinations, to cheese whey (CW), which is the liquid effluent from the precipitation and removal of milk casein during the cheese-making process. The aim and novelty of this research is to investigate the production of various biofuels (H2-rich gas, hydrochar and biogas) in cascade, according to the waste biorefinery concept. The simplest case is the direct AD of CW. The second investigated possibility is the preliminary HTC of CW, producing hydrochar, followed by the AD of the process water from which hydrochar is separated by filtration. The third possibility is based on DF of CW, followed by the AD of the fermentate (F) from DF. The final possibility is based on DF of CW, followed by HTC of the F, and then AD of the process water. Accordingly, the physical and chemical properties of CW, F, resulting hydrochar and process water (PW), and biomethane potentials of CW, F, and process waters are studied to determine the energy and carbon balances of all variants. In brief, the first variant, direct AD of CW, is believed to be the most energy efficient method.

Dose-dependent effects of different parabens on food waste biorefinery for volatile fatty acids production: Insight into specific fermentation processes, substrates transformation and microbial metabolic traits

Parabens are largely concentrated in food waste (FW) due to their large consumption as the widely used preservative. To date, whether and how they affect FW resource recovery via anaerobic fermentation is still largely unknown. This work unveiled the hormesis-like effects of two typical parabens (i.e., methylparaben and n-butylparaben) on VFAs production during FW anaerobic fermentation (i.e., parabens increased VFAs by 6.73–14.49 % at low dose but caused 82.51–87.74 % reduction at high dose). Mechanistic exploration revealed that the parabens facilitated the FW solubilization and enhanced the associated substrates' biodegradability. The low parabens enriched the functional microorganisms (e.g., Firmicutes and Actinobacteria) and upregulated those critical genes involved in VFAs biosynthesis (e.g., GCK and PK) by activating the microbial adaptive capacity (i.e., quorum sensing and two-component system). Consequently, the metabolism rates of fermentation substrates and subsequent VFAs production were accelerated. However, due to increased biotoxicity of high parabens, the functional microorganisms and relevant metabolic activities were depressed, resulting in the significant reduction of VFAs biosynthesis. Structural equation modeling clarified that microbial community was the predominant factor affecting VFAs generation, followed by metabolic pathways. This work elucidated the dose-dependent effects and underlying mechanisms of parabens on FW anaerobic fermentation, providing insights for the effective management of FW resource recovery.

A novel application of Chlorella sorokiniana for green hydrogen production via microbial electrolysis and Waste Biorefinery

Waste biorefineries have significant potential to utilize microbial electrolysis cells (MECs) to convert waste into energy carriers and bioproducts with added value, potentially resulting in a carbon- and energy-negative system. Various feedstocks (such as sodium acetate, glucose, glycerol, and wastewater) are used in MEC for biohydrogen production. This study used the three different wastewaters as substrates in the MEC for biohydrogen production. The remaining dried microalgal biomass was then analyzed to identify value-added compounds. Under conditions of 18±3°C, domestic wastewater (DWW) produced maximum biohydrogen (22.78±0.25 mL/L). Combined domestic wastewater and algal extracted supernatant (CDAES) resulted in a higher yield (30.82±0.25 mL/L), and modified wastewater (MWW) exhibited the highest production (40.86±0.25 mL/L). The biohydrogen production values in this study exceed those reported in the latest research, considering the applied voltage of 0.5 V. Scanning electron microscope (SEM) images confirmed the formation of rod-shaped and round-shaped microbial communities on the anode surface. The cultivation conditions for Chlorella sorokiniana in a multi-cultivator system were set (23–26°C, 98 μmol m−2 s−1, pH 7.0 ± 0.5, and CO2 0.04 %). The Gas Chromatography-Mass Spectrometry (GC-MS) analysis of dried algal biomass has revealed eighteen bioactive compounds with diverse applications in pharmacy, food, and cosmetics. Thus, the algal extracted supernatant incorporated into wastewater demonstrated an innovative and economical feedstock for MEC. Additionally, bioactive compounds play a prominent role in the success of integration technologies, opening a new avenue for research.

A perspective towards sustainable and economically viable approach of waste biorefineries through lignin valorization

A perspective towards sustainable and economically viable approach of waste biorefineries through lignin valorization

Repurposing lignin rich biorefinery waste streams into the next generation of sustainable solid fuels

Value added lignin rich waste sludges from biorefinery processes are, as yet untapped valuable feedstocks that can be reformed into clean, high quality solid fuels. By water washing sludges produced from base hydrolyzed waste, a material stripped of water-soluble alkali and alkaline earth metals (ash) can be obtained. This work shows how leached bagasse, barley and wheat straw sludges can be valorised into clean, low ash solid biofuels that can be used to supplement global energy demands. Repurposed lignin rich sludges of 1.00–2.00 mm particle size feedstocks were found to exhibit calorific values +17.3 %, +16.8 % and +11.7 % for bagasse, wheat, and barley straw sludges, respectively higher than their untreated waste counterparts. Additionally, by employing densification in the absence of a binder, <0.25 mm particles of leached sludge feedstocks were found to experience 16.0 % (bagasse), 12.0 % (wheat) and 4.0 % (barley) increases to their calorific values. This provides options for sustained energy from waste production and consumption campaigns, diversifying feedstock options for green solid fuels

Sustainable Development of Food Waste Biorefineries

The sustainable development of food waste biorefineries is crucial for a number of reasons, and these reasons have environmental, economic, and social dimensions [...]

Thermal performance analysis of optimized biomass conversion in developing organic waste biorefinery to achieve sustainable development goals

To make energy sector sustainable, waste to energy system should be used, as statistics of the International Energy Agency (IEA) shows that the lack of renewable energy and environmental degradation are the major pressing problems confronting the global community. However, in south Asian regions, the situation escalates as a result of severe dependency on conventional energy sources, coupled with the limitations and challenges involved in maintaining a green environment and Waste-to-Energy (WtE) strategies. In this region, energy majorly relies on imported conventional fuel. In addition to harming the environment, imported fossil fuel has also increased the risk of geopolitical unrest. In the current research, rice husk is used as a bio-organic waste that is produced in large volumes and a significant byproduct of agro-based biomass sector. In this research, sample composition of rice husk is demineralized in 5% hydro-chloric acid for different burning ratios and the modified thermo-chemical methodology was used to the acidified rice husk at three different heating rates (20 °C min−1, 30 °C min−1 and 40 °C min−1) respectively in thermogravimetric analyzer (TGA). Proximate, thermal and kinetic analysis was used for observing the degradation patterns of demineralized rice husk. Proximate analysis revealed that the leaching of rice husk has successfully infused HCl, resulting in substantial rise in fixed carbon (FC) and calorific value (CV) by 10.53 % and 10.82 % respectively, along with decrease in the carbon footprint of about 60.55%. Thermogravimetric (TG) and derivative thermogravimetric (DTG) curves have shown decreasing behavior of conversion efficiency to the increase in flow rate, with the maximum drop of 12.7 % observed at 40 °C. With the use of the TGA equipment, the conversion efficiency was evaluated based on the sample's peak weight loss. The current study has reported synergistic effect of flow and heating rate on the degradation temperatures, activation energy and reactivity of acidified rice husk. Lowest activation energy 180.46 kJ permole with highest reactivity of 0.01192345 %*min °C was observed at 40 ml and 20 °C combination. Accordingly, degradation temperatures of burning profiles increased due to lower convective cooling and higher temperature gradient within the particle of rice husk sample. In addition, pre-exponential data and slopes of TG curves have validated the results of activation energy obtained from TGA experimentation. The sustainable biomass conversion approach is envisioned to significantly refine the waste bio refinery system to achieve SDGs.

Unlocking peach juice byproduct potential in food waste biorefineries: Phenolic compounds profile, antioxidant capacity and fermentable sugars

This work assesses an integrated pathway for the revalorization of peach byproduct (PB) within a biorefinery. PB was subjected to an oven-drying (OD) treatment for its evaluation as a storage treatment. It was compared to freeze-drying and untreated material in terms of antioxidant capacity (AOC), phenolic compounds (PC) profile and fermentable sugar production. OD reduced the water content to less than 15 % while preserving the bound hydrolysable polyphenols, which were the more abundant PC (≈64 %) with the highest AOC. Drying treatments hampered polysaccharide accessibility, but some enzyme preparations released 60–70 g/L of fermentable sugars at relatively high solids loading (10 %). This study proposes a novel enzyme-based strategy for the valorisation of fermentable sugars and antioxidant compounds from PB. The sugars can be fermented into several building blocks while the solid residue enriched in recalcitrant phenolic compounds and proteins could be used to develop novel functional products for food/feed sectors.

Thermally enhanced solid-liquid separation process in food waste biorefinery: modelling the anaerobic digestion of solid residues.

The biochemical valorization potential of food waste (FW) could be exploited by extracting decreasing added-value bio-based products and converting the final residues into energy. In this context, multi-purpose and versatile schemes integrating thermal and biochemical conversion processes will play a key role. An upstream thermal pretreatment + solid-liquid separation unit was here proposed to optimize the conversion of the liquid fraction of FW into valuable chemicals through semi-continuous fermentation process, and the conversion of the residual solid fraction into biomethane through anaerobic digestion. The solid residues obtained after thermal pretreatment presented a higher soluble COD fraction, which resulted in higher methane production with respect to the raw residues (0.33 vs. 0.29 Nm3CH4 kg-1VSfed) and higher risk of acidification and failure of methanogenesis when operating at lower HRT (20d). On the contrary, at HRT = 40 d, the pretreatment did not affect the methane conversion rates and both tests evidenced similar methane productions of 0.33 Nm3CH4 kg-1VSfed. In the reactor fed with pretreated residue, the association of hydrogenotrophic methanogens with syntrophic bacteria prevented the acidification of the system. Modelling proved the eligibility of the FW solid residues as substrates for anaerobic digestion, given their small inert fractions that ranged between 0% and 30% of the total COD content.

Optimizing Green Bean Yield: Controlled Nitrogen Release with Nano-Urea-Modified Apatite

Controlled-release fertilizers (CRFs) have drawn significant attention because of their ability to improve plant nutrient uptake efficiency and mitigate environmental pollution. Current commercial CRFs need improvement to reduce synthesizing costs and to apply biodegradable materials and/or biorefinery wastes. In this study, CRFs were synthesized by treating nano-apatite with urea at different apatite:urea ratios (1:1 and 1:4). The biodegradable polymers, alginate, and lignin extracted from agricultural residue and paper manufacturing waste were used as single (alginate) and double (alginate and lignin) coating layers to form CRFs. In lab experiments, the N release behavior was studied in both water and soil. A cultivation experiment was carried out to study the efficiency of CRFs in the yield of green bean plants. The CRFs were applied with 3 N levels (75, 50, and 25% of the recommended dose). Both types of CRFs significantly increased the N release period to 24 days compared to 5 days for commercial urea. The total yield increased by 88 and 98% by applying double- and single-coated CRFs, respectively, at 75% N of the recommended dose compared with the full dose of conventional urea. In conclusion, applying CRFs at an N level of 25% of the recommended amount obtained the same yield as the full dose of conventional urea. KEYWORDS biodegradable coating, hydroxyapatite, lignin, nano-fertilizer, nitrogen efficiency, snap beans

Structural and thermal investigation of lignocellulosic biomass conversion for enhancing sustainable imperative in progressive organic refinery paradigm for waste-to-energy applications

The depletion of finite fossil fuel reserves and the severe environmental degradation resulting from human activities have compelled the expeditious development and application of sustainable waste to energy technologies. To encapsulate energy and environment in sustainability paradigm, bio waste based energy production is need to be forged in organic bio refinery setup. According to world bioenergy association, biomass can cover 50 % of the primary energy demand of the world. Therefore, the present study focuses on reforming the energy mix for a clean energy generation, where, sample composition of cotton stalk was acidified in dilute (5% wt.) hydrochloric acid (HCL) for analyzing material burnout patterns in biomass conversion systems utilized in organic bio refinery sector. Advanced thermochemical burning technique, which includes pyrolysis and combustion was applied at four different leaching times from 0 to 180 min under nitrogen environment from 0 °C to 500 °C and air from 500 °C to 900 °C, respectively. Different analyses including proximate, ultimate, gross calorific value (GCV), thermos-gravimetric, kinetic, XRD, FTIR, SEM-EDS were used for analyzing the degradation of demineralized cotton stalk at different treatment rates. Proximate study demonstrated that cotton stalk leaching for 180 min has efficiently infused HCL, leading in a significant increase in fixed carbon and higher heating value of 20.23 % and 12.48%, respectively, as well as a reduction in carbon footprint of around 54.80%. The findings of proximate was validated by GCV analysis and CHNS analysis as value of carbon and hydrogen has shown increasing behavior with the time delay in demineralization Thermo-gravimetric and derivative thermo-gravimetric data analyses shows an increasing trend of conversion efficiency, with the maximum increase of 98 % reported for sample 3H.TT.DEM. XRD characterization has reported 23° to 25° angle for all the observed peaks. Sample 3H.TT.DEM has shown maximum angle inclination along with matured crystalline peak. The latter observations has been validated by FTIR spectroscopy as sample 3H.TT.DEM has reported maximum O–H group formation. Sample 3H.TT.DEM has reported lowest activation energy of 139.51 kJ*mole-1 and lowest reactivity of 0.000293649%*min 0C, due to moderate and stable reactiveness. In SEM examination, increment in pore size and number of pores within the structural matrix of cotton stalk was observed with the enhancement in acidulation process. Furthermore, in EDS analysis, 3H.TT.DEM has shown most balanced distribution of the elements. In this research, sustainable transformation of biomass is envisioned to improve the waste bio refinery system, significantly contributing to the achievement of Sustainable Development Goals 7, 12 and 13.

Valorization and biorefinery of local agricultural and textile wastes through mycelium composites for structural applications

Abstract Manufacturing of mycelium-based composites is an emerging biorefinery technology toward the development of environmentally positive materials within the circular economy: it benefits from waste and industrial by-products upcycling while excelling in biodegradability. This study investigates the compressive behavior of materials repurposed from local agricultural wastes (tree nuts and crop wastes in California’s Central Valley), using the fungal mycelium of Pleurotus ostreatus and Ganoderma lucidum, well-known edible and medicinal species. We also explore the hybridization of these mycelium-based composites with local textile waste fibers as reinforcements. Following guidelines from several ASTM standards, the compressive behavior of these composites is analyzed to determine the impact of biomass processing, composition, fungal species used, and post-processing strategy. We propose a post-processing strategy based on a short exposure to sodium chloride solutions in ambient conditions, to de-activate mycelium and prevent its fruiting, replacing the established energy-intensive heat-based post-processing. This work aims at contributing to the decarbonization of the built environment and the construction industry in particular, through materials designed with upcycled waste (agricultural and textile), fungal mycelium and low-carbon footprint processes.

Pulsed electric field technology as a promising pre-treatment for enhancing orange agro-industrial waste biorefinery.

In the processing of orange juice, 50-70% of the fresh fruit weight is converted into organic waste. Orange processing waste (OPW) primarily consists of peels, seeds, and pulp. Improper disposal of this residue can lead to greenhouse gas emissions, environmental pollution, and the wastage of natural resources. To address this ecological issues, recent research has focused on developing innovative process designs to maximize the valorization of OPW through biorefinery strategies. However, the current challenge in implementing these methods for industrial waste management is their significant energy consumption. In response to these challenges, recent studies have explored the potential of employing pulsed electric field (PEF) technology as a pre-treatment to improve energy efficiency in biorefinery processes. This non-thermal and emerging technology can enhance the mass transfer of intracellular components via electroporation of cell walls, thereby resulting in shorter processing times, lower energy inputs, greater retention of thermosensitive components, and higher extraction yields. In this regard, this review offers a comprehensive discussion on the innovative biorefinery strategies to the valorization of OPW, with a specific focus on recent studies assessing the technical feasibility of methodologies for the extraction of phytochemical compounds, dehydration processes, and bioconversion methods. Recent studies that discussed the potential of PEF technology to reduce energy demand by increasing the mass transfer of biological tissues were emphasized.

FACILE PRODUCTION OF 4-HYDROXYBENZOIC ACID FROM OIL PALM EMPTY FRUIT BUNCH CELL WALLS BY ALKALI DEGRADATION AT ROOM TEMPERATURE

Oil palm empty fruit bunches are biorefinery waste produced from the oil palm factory. Palm lignin is partially ended with p-hydroxybenzoylated structure, which is a promising resource to produce 4-hydroxybenzoic acid. Herein, 4-hydroxybenzoic acid is produced by the degradation of oil palm empty fruit bunch cell walls with sodium hydroxide solution at room temperature without lignin isolation. The 4-hydroxybenzoic acid was obtained as the only main monomeric product from the process. The yield of 4-hydroxybenzoic acid can reach 7.87&amp;#37; based on the amount of oil palm empty fruit lignin. The sodium hydroxide concentration is the most important factor that affects the 4-hydroxybenzoic acid production yield and selectivity. The possible 4-hydroxybenzoic acid production routes were proposed. And the production route is considered to be formed mainly by the cleavage of C-O bonds at the &amp;gamma;-hydroxyl position of the syringyl unit in oil palm empty fruit bunch lignin.

Editorial: Integrated waste biorefineries: achieving sustainable development goals

Editorial: Integrated waste biorefineries: achieving sustainable development goals

Avocado Waste Biorefinery: Towards Sustainable Development

The increasing demand for avocado consumption has led to a vast generation of waste products. Despite the high nutritional value of avocados, the waste generated from their processing poses a significant environmental challenge. Therefore, the development of a sustainable approach to avocado waste management is a major concern. Biorefinery presents a promising approach to the valorization of avocado waste components, including the seed, peel, and pulp residues. This paper explores the potential of avocado waste biorefinery as a sustainable solution to produce bio-based products. Several approaches, including extraction, hydrolysis, fermentation, and biodegradation, to obtain valuable products such as starch, oil, fiber, and bioactive compounds for food or feed goods have been proposed. The review also highlights the approaches towards addressing challenges of energy security and climate change by utilizing avocado waste as a source to produce biofuels such as biogas, biodiesel, and bioethanol. In conclusion, the development of avocado waste biorefinery presents a promising avenue for sustainable development. This process can efficiently convert the avocado waste components into valuable bio-based products and clean energy sources, contributing to the attainment of a circular economy and a more sustainable future.

Substrate-related factors and kinetic studies of Carbohydrate-Rich food wastes on enzymatic saccharification

Food waste biorefinery is a sustainable approach to producing green chemicals, however the essential substrate-related factors hindering the efficacy of enzymatic hydrolysis have never been clarified. This study explored the key rate-limiting parameters and mechanisms of carbohydrate-rich food after different cooking and storing methods, i.e., impacts of compositions, structural diversities, and hornification. Shake-flask enzymatic kinetics determined the optimal dosages (0.5 wt% glucoamylase, 3 wt% cellulase) for food waste hydrolysis. First order kinetics and simulation results determined that reaction coefficient (K) of cooked starchy food was ∼ 3.63 h−1 (92 % amylum digestibility) within 2 h, while those for cooked cellulosic vegetables were 0.25–0.5 h−1 after 12 h of hydrolysis. Drying and frying reduced ∼ 71–89 % hydrolysis rates for rice, while hydrothermal pretreatment increased the hydrolysis rate by 82 % on vegetable wastes. This study provided insights into advanced control strategy and reduced the operational costs by optimized enzyme doses for food waste valorization.