Biofuels Bioproducts & Biorefining-Biofpr最新文献

Corn cobs consist primarily of a lignocellulosic material comprising hemicellulose, cellulose, and lignin in a crystalline state, which is resistant to microbial saccharification. Bioethanol production from corn cobs has rarely been attempted, especially using chemical pretreatment methods.

The present study deals with the production and purification of fungal (Phanerochaete chrysosporium MTCC 787 and Pleurotus florida PAU 22-01) extracellular ligninolytic enzymes – lignin peroxidase (LiP), manganese peroxidase (MnP), and laccase (Lac) – followed by their utilization for the biological pretreatment of corn cobs along with saccharification using commercial cellulase. Crude LiP, MnP, and Lac demonstrated specific activity of 2.23, 2.1, and 2.63 U/mg, respectively.

The one-step purification of crude enzyme using diethyl amino ethyl (DEAE) cellulose ion exchange chromatography resulted in 11.3, 10.1 and 8.62-fold purification of LiP, MnP and Lac activity, respectively, with corresponding specific activity of 25.1 U/mg (LiP), 21.2 U/mg (MnP) and 22.7 U/mg (Lac) in the partially purified ligninozymes. Using the latter, biological pretreatment of 2.5 g corn cobs in a reaction volume of 30 mL containing approximately 200 units of Lac, Lip and MnP enzymes (in phosphate buffer, pH 6) resulted in a maximum of 78.4% delignification with a saccharification efficiency of 97.1% using commercial cellulases.

Biochar, a solid material derived from a thermochemical process, has received significant attention due to its usefulness in various sectors. Previous studies have been conducted to improve the properties and quality of this material by altering the thermochemical processes, treating the feedstock, hybridizing the feedstock, and so forth, but little has been done on the effect of varying the reactor's configuration. This research aims to study the effect of varying the stainless-steel-based combustion compartment volume of a biomass-fueled top-lit updraft gasifier on the groundnut shell biochar. The biochar yields for reactors ranged from 34.9% to 51.2%. The sample produced in the smallest combustion compartment volume showed the highest carbon content, according to energy dispersive X-ray spectroscopy (EDX) analysis. Potassium, another major element, decreased as the combustion compartment was reduced. Scanning electron microscopy (SEM) analysis revealed that the biochar samples produced had an irregular shape and rough surfaces, and reducing the combustion compartment volume resulted in larger particles on the surface. Fourier transform infrared (FTIR) spectroscopy analysis showed similarities and differences in peaks observed for all the samples. The biochar samples produced can find applications in wastewater treatment, energy conversion and storage, and soil amendment, and the findings contribute to the design and optimization of biomass-based gasifiers.

This article presents the results of an experimental study evaluating the performance of a molten carbonate fuel cell (MCFC) using dairy biogas as a fuel source. Dairy biogas, a renewable byproduct of dairy farming, was compared with hydrogen in terms of operational efficiency. The investigation focuses on the performance parameters and efficiency metrics of MCFCs when powered by dairy biogas, relative to natural gas and hydrogen. The results demonstrate that while dairy biogas can power MCFCs, its efficiency and fuel utilization rates are lower than those of conventional fuels. This study contributes to an understanding of alternative, sustainable fuel sources for MCFC operations. During the study, the performance parameters of dairy biogas were compared with hydrogen, which served as a benchmark fuel. It was observed that in comparison with natural gas, commonly used as a fuel, dairy biogas showed lower efficiency rates and reduced fuel-utilization factors. This suggests that although dairy biogas can be used as a fuel source for MCFCs, its effectiveness might not be on par with traditional fuels like natural gas.

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.