Biofuels Bioproducts & Biorefining-Biofpr最新文献

Levulinic acid (LA) is one of the top bio-based platform molecules that can be converted into many valuable chemicals. Herein, we report the sustainable synthesis of LA acid from various sugars using heteropolyacid catalysts. By using a Box–Behnken design of experiment, both LA yield (up to 69 mol%) and complete suppression of parasitic humin formation could be achieved within a 5 h reaction time at 140°C using fructose as a substrate. The effects of various reaction parameters like temperature, sugar concentration, addition of organic co-solvent and reaction time on LA yield and humin formation were examined in a three-dimensional space. Moreover, the results could be successfully transferred to other sugars like glucose or cellobiose, paving the way for an atom-efficient and sustainable LA synthesis process.

The decarbonization potential of hydrogen offers increasing usage paths in the fight against climate change resulting in a growing demand for climate-neutral hydrogen. This challenge is met by producing hydrogen microbially from renewable substrates as an alternative to ‘green hydrogen’ from water electrolysis. Initial results have shown that coupling dark fermentation and anaerobic digestion is not only possible but also advantageous. Specifically, by integrating dark fermentation in existing biogas plants, the overall physical efficiency of the process's substrate turnover can be increased by up to 50% through providing hydrogen in addition to biogas. The achieved test results are examined based on limit-oriented physical efficiency evaluation to show the potential for optimization of the substrate turnover in biological concepts based on modeling. Finally an overview of a commissioned demonstration plant is given, which will provide further insights into the feasibility of the dark fermentation on an industrial scale.

The paper explores the potential of the main state economic incentive (Conto Termico) designed to promote the use of renewable energy sources for heating and cooling purposes in residential buildings, aiming to reduce primary air emissions from residential biomass combustion (RBC). For this purpose, an emission reduction scenario involving the technological transition of biomass residential heating appliances was implemented in the lowland small-medium municipalities of the Lombardy region in Italy, where households are connected to the natural gas grid but RBC is often practiced for economic reasons, contributing to severe air pollution problems related especially to particulate matter (PM) emissions. This technological turnover scenario (i.e. all biomass appliances in the area replaced by state-of-the-art pellet appliances) resulted in a significant reduction of particulate matter emissions, while having only a minimal impact on NO_x emissions. The incentivized cost for technological turnover (€15/kg_{PM10 avoided}) was in line with the social costs associated with health impacts related to PM10 in a rural setting such as the study area. Given the one-off investment support provided by a recently adopted national decree (DM 15/09/2022), biomethane emerges as a promising renewable energy alternative to decrease PM and NO_x emissions from RBC in Lombardy region, characterized by an extensive natural gas distribution network and potential waste feedstock for biomethane production. Despite the still elevated production costs, an analysis restricted to the incentivized segment reveals that supporting biomethane production through investment incentives is more cost-effective (€8/kg_{PM10 avoided}) than promoting technological turnover.

The growing interest in bamboo fibers for pulp, paper, and board production in the USA necessitates a comprehensive financial viability assessment. This study conducts a detailed technoeconomic analysis (TEA) of bamboo fiber production, primarily for the consumer hygiene tissue market although it is also applicable to other industrial uses. The economic viability of two pulping methods – alkaline peroxide mechanical pulping (APMP) and ammonium bisulfite chemical pulping (ABS) – was explored within three different pulp mill settings to supply pulp to two nonintegrated tissue and towel mills in South Carolina, USA. The target was to produce wet lap bamboo bleached pulp at 50% consistency and 70% ISO brightness. Despite higher initial capital invesment and operating costs, ABS achieved a lower minimum required selling price – USD 544 to 686 per bone dry metric ton (BDt = 1000 BDkg) – in comparison with USD 766 to 899 BDt⁻¹ for APMP. This price advantage is partly due to an additional revenue stream (lignosulfonate byproduct), which not only boosts revenue but also circumvents the need for expensive chemical recovery systems. When compared with traditional kraft pulping, both methods require significantly lower capital investments, with minimum required selling prices (estimated to achieve 16% IRR) below current market rates for extensively used bleached kraft pulps in the USA tissue industry. The economic benefits derive from several factors: the low cost of bamboo as raw material, reduced capital needs for new pulping technologies, lower transportation costs from the pulp mill to tissue and towel manufacturing facilities, and the high market price of bleached kraft pulp.

The production of value-added products from sewage sludge is considered to be one of the solutions for the sustainable management of sludge in wastewater treatment plants (WWTPs). The presence of carbon, nitrogen, and phosphorus sources has made the sewage sludge of WWTPs a valuable and low-cost substrate for the production of fermentative products. In the current study, a process was developed for microbial lipid production from two types of sewage sludge from a WWTP in northern Isfahan: anaerobic digester inlet sludge (DIS) and anaerobic digester outlet sludge (DOS). This process was based on the release of volatile fatty acids (VFAs) from the sludge by combinations of γ-ray irradiation, anaerobic digestion, and acidogenic fermentation followed by utilization of VFAs in a microbial process by the oleaginous yeast Cryptococcus aureus UIMC65. After γ-ray irradiation, the acidogenic fermentation of the treated sludge released 72% of the organic matter content of the sludge with acidification efficiency of 12% leading to 0.516 g L⁻¹ VFAs. The oleaginous fermentation of the released VFAs for 7 days was accompanied by production of 1.58 g L⁻¹ dry cell biomass with 40% lipid content. The results of this study indicate that the sewage sludge from urban WWTP has the potential to be used for the production of microbial lipids.

This review examines the role of deep eutectic solvents (DESs) in the biorefinery process. It covers the characteristics and classification of two-component DESs, their preparation methods, and their physicochemical properties. The various applications of DES systems in biomass pretreatment, including lignin and hemicellulose removal, production of cellulose nanofibers, and the extraction of proteins, lipids, and phenolic compounds, among others, are explored. The synthesis of platform molecules using DES is also discussed. Finally, this review provides some tools that may be useful for researching the involvement of DES systems in high- or low-biomass biorefineries.

The hemicellulose (HMC) fraction of lignocellulosic biomass is a biorenewable precursor for platform molecules such as furfural and 5-hydroxymethylfurfural. However, this fraction is often not valorized. This study presents a novel method to produce high-purity HMC from industrial HMC hydrolysate streams utilizing antisolvent precipitation in a spinning disc reactor (SDR) for potential application in a biorefinery. Spinning disc reactors are ideal intensified precipitation technologies due to their continuous processing ability, high mixing rates, short residence times, and scalability potential. The effects of three different antisolvents (ethanol, acetone, and ammonium sulfate), disc speed, flow rate, and antisolvent (AS) : solvent (S) mass ratio on the yield, purity, and particle size of sugar precipitates were investigated. Ethanol was the preferred antisolvent, yielding the greatest average recovery of solid precipitate of 32% at a 10:1 AS:S ratio and high sugar purity of more than 97%. Acetone failed to produce a solid precipitate, and ammonium sulfate contaminated the product, rendering both antisolvents unsuitable. The SDR overcame mixing limitations at all hydrodynamic conditions tested so that only the AS:S ratio affected product yield significantly, increasing the ethanol AS:S from 1:1 to 10:1, enhancing average solid recovery from 4 to 32%. Optimal SDR operating conditions were 600 rpm disc rotation speed and 8 mL s⁻¹ total flow rate, maximizing product throughput and minimizing energy consumption, with a residence time less than 1 s. In a continuously operated scaled-up system, 485 L of HMC hydrolysate could be processed per day, demonstrating the SDR to be a promising method of intensifying HMC recovery at scale in a biorefinery.

The global energy system is in transition. It is attempting to reach net-zero greenhouse gas emissions by 2050. The systemic changes mean that the role of bioenergy will change. The potential of bioenergy to make a flexible contribution to the energy system is key for the achievement of global emission reduction ambitions and the functioning of the low-carbon energy system and economy. As the volume of sustainably available biomass resources is limited, defining the contributions from bioenergy to a low-carbon energy system and finding balances – and ideally synergies – between the different possible energy and climate system services that biomass can provide will be very important. The recognized system services include, among others, the flexible operation of bioenergy plants to integrate variable renewable energy sources and to provide negative carbon dioxide (CO₂) emissions. Interest in flexible operation of bioenergy value chains, bioenergy with carbon capture and utilization as well as synergies with renewable hydrogen-based value chains has increased recently. The objective of this paper is to present a holistic definition of flexible bioenergy as a system service based on the work conducted in International Energy Agency (IEA) Bioenergy Technology Collaboration Programme's Task 44 Flexible Bioenergy and System Integration, and to provide some practical examples. The paper also presents the different bioenergy system services and considers their definitions and interactions, as this is important in energy system design. The definition of flexible bioenergy shows that the flexibility provision from bioenergy goes far beyond the traditional definition of providing short-term flexibility in the power sector. Indicators to demonstrate the value of services as well as further quantitative assessment of synergies and trade-offs are needed to valorize the different services from bioenergy and create viable business cases.

This research focuses on the impact of pulsed feeding of corn residues on biogas production from pig manure. It also analyzes the properties and microbial diversity in the resulting product. The study highlights the increasing global demand for pork and the resulting environmental challenges, such as effluent management, and suggests that biogas production can be a sustainable solution. The research was conducted at a model farm in Argentina and involved evaluating biogas production and microbial variability at different stages of the pulsed feeding process. The results showed a significant decrease in the chemical and biochemical oxygen demands after the degassing process, indicating a reduction in organic matter. The biogas composition improved with an increase in methane and a reduction in volatile fatty acids. There was also an increase in biogas and methane production and a decrease in methane production lag time, indicating an improvement in anaerobic digestion efficiency. Microbiological analysis revealed a reduction in microbial diversity during pulsed feeding, indicating the adaptation of the microbial community to new conditions. Overall, the study demonstrates the potential of pulsed feeding of corn residues to enhance biogas production from pig manure, with significant implications for effluent management in pork production and sustainable biogas production.

The human body can easily convert β-carotene into retinol (a precursor of vitamin A), a significant ingredient in dietary supplements. The need for commercial natural pigment production, including β-carotene, has led to intensive research in this area. Processing after biosynthesis is a vital stage that involves the use of nontoxic solvents, efficient mechanical disruption of cells, and the isolation of the required compounds. With the growing popularity of green extraction methods and the increasing market demand for carotenoids due to their health benefits, the use of clean, nontoxic, flash-hydrolyzed biomass for carotenoid production presents a significant advantage. Furthermore, the remaining biomass can serve as a protein source for animal feed, thereby aligning with the principles of the biorefinery concept. In this study, our aim was to optimize the disruption of cells in two microalgal species using flash hydrolysis (FH). We applied two distinct levels of pressure and four separate temperature conditions over a brief residence time. Following this, we employed an ethanol extraction method to assess the efficiency of carotenoid pigment extraction. Flash hydrolysis is a chemical-free subcritical water-based continuous-flow process, injected with wet biomass slurry at a high temperature (150–250 °C) for a very short time (8–12 s) to obtain bioproducts. In this study, we discovered that the pigment β-carotene constituted 0.04 to 0.3% of the dry biomass in the case of Chlorella vulgaris. Bands of lutein and zeaxanthin were also observed in the thin layer chromatography (TLC) analysis of the treated slurry. This was achieved under conditions of an effective temperature of 200 °C and a pressure of 1700 psi. The Arthrospira platensis (1Tex), β-carotene yield was 0.014 to 0.021% of dry biomass. Some lutein and zeaxanthin bands were also found in the treated slurry with an effective temperature of 150 °C and 1000 psi pressure. This study reports pigment extraction by FH for the first time. It is a viable process to scale up high-value natural products like carotenoids from microalgae at the industrial level without adverse environmental impacts. Due to low residence time, the temperature does not have a negative effect on pigments; cell rupture was accomplished effectively using water as a solvent. A considerable amount of pigment could be recovered from microalgae at specific combinations of temperature and pressure depending on the type of cell wall that microalgae possess.