Bioresource Technology Reports最新文献

The aim of this study was to assess the feasibility of moderate thermal treatment (70 °C for one hour) of digestate in combination with post-digestion targeting residual biomethane potentials from three full-scale biogas plants digesting food waste (FW), agricultural waste (AW) and a mixture of AW and manure (AWM). Dissolved organic carbon (DOC), biomethane production, and digestate quality were investigated. For the study six laboratory-scale continuously stirred tank biogas reactors working as post-digesters, with thermally-treated and non-treated digestate were used. DOC for thermally-treated digestates increased significantly (t-test, p < 0.05); FW-digestate (110–200 %), AW-digestate (24–92 %) and for AWM-digestate (4–73 %). Indexes for corresponding DOC quality showed lower apparent organic molecular weights and decreased aromaticity (with the exception of FW-digestate). Thermal treatment of digestate improved the biomethane production during post-digestion by 21–22 % (FW-digestate) and 9 % (AW-digestate). For AMW-digestate no clear positive effect was observed, most likely due to biogas plant operational process disturbances.

This study presents a comprehensive biochemical predictive approach for assessing biogas production kinetics across ten lignocellulosic substrates in batch operation. The methodology employs a range of kinetic and regression models, all grounded in the substrates' chemical composition. Among the kinetic models, the cone model demonstrated superior performance, achieving an average error of 1.67 % in describing biogas production from all substrates. The quadratic Monod type model followed closely, with an error of 1.96 %. Among the regression models, on the other hand, the logistic function model exhibited enhanced predictive capabilities, yielding an average error of 6.02 %, while the Chen and Hashimoto one showed a higher error of 60.54 %. The findings underscore the potential of precise biogas production forecasting and tracking the daily rates of gas generation, rather than solely relying on cumulative gas yields at the end of the process.

Agricultural and food waste materials are rich resources of valuable biomolecules, including proteins, carbohydrates, fats, minerals, fibers, etc. Improper disposal methods such as landfill decay or open burning significantly contributed to environmental pollution and global warming. Therefore, there is an urgent need to explore sustainable approaches for utilizing these residues without harming the natural environment. One promising possibility involves leveraging these residues to cultivate microorganisms for the production of value-added products like enzymes, organic acids, and biofuels. Solid-state fermentation has emerged as a promising practice for producing commercially important enzymes utilizing agricultural crop wastes. This study aims to provide an overview of various agricultural and food wastes utilized in enzyme production through solid-state fermentation. Industrial enzymes such as amylases, xylanases, pectinases, lipases, cellulases, fructosyl-transferases, and lactases are among those explored. The review encompasses a diverse range of microbial commodity capable of utilizing these low-cost underutilized materials for growth and development, ultimately yielding a variety of industrial important enzymes.

Anaerobic digestion (AD) is a common treatment for sludge reduction and stabilization. Simultaneously reductions in sludge chemical oxygen demand (COD), cytotoxicity, and estrogenicity are desired for safer handling and reuse. We investigated the impact, mechanism, and control strategy of ozonation (common sludge biodegradability method) on AD, methane production, and sludge cytotoxicity and estrogenicity modulations. Results revealed that ozone treatment could boost the methane production potential and rate by up to 36.5 and 69.2 %, respectively, but only after partial sludge digestion. Ozone modulated sludge cytotoxicity and estrogenicity, significantly improving this effect (maximum reductions of 28 and 23 %, respectively) by introducing anaerobically digested sludge to the ozonation module due to lowered volatile solids (VS) compared to raw sludge and less competition from the abundant biodegradable organics. Results support introducing ozone during AD for simultaneous COD reduction, and cytotoxicity and estrogenicity control.

The demand for defossilization and decarbonization resulting from the climate crisis and the lack of storable renewable energy has brought biomethane back into focus. Methanogenic microorganisms can be used to convert renewable energy into biomethane. In a pressurized H-cell reactor, we demonstrate the electroactivity of four different methanogenic archaea under conditions of direct and indirect electromethanogenesis. The cathodes were adjusted to a potential of −300 mV (direct electromethanogenesis) and − 700 mV (indirect electromethanogenesis) relative to a standard hydrogen electrode. At −300 mV, no significant methane formation was observed in all four cultures. At a potential of −700 mV, Methanococcus maripaludis achieved an average daily methane production rate of 61 mmol/m² per day. The highest methane concentration of 199.4 mmol/m² and the highest coulombic efficiency of 74.0 % were reached within 72 h by Methanococcus maripaludis.

Fertilizer overuse causes negative impacts on the environment and crop yields. Therefore, the production of slow-release fertilizers from biogas sludge is a potential solution for waste reuse and sustainable use of fertilizers. Granular fertilizers containing primary macronutrients (N, P and K) were formulated using biogas sludge and supplementary chemical compounds before coating with a thin film of glutaraldehyde cross-linked gelatin. The coating films reduced the release rates of N and P effectively. The application of formulated biogas fertilizers resulted in the competitive yield and growth rate of mustard greens over the 45-days cultivation compared to the application of commercial fertilizers. Particularly, the application of coated biogas fertilizers led to less nutrient losses in drainage water while maintained a balanced supply of available nutrients and beneficial bacteria in soils. This study emphasizes the feasibility to reuse biogas sludge for slow-release fertilizers production in improving fertilizer use efficiency and soil fertility.

The cork manufacturing process generates cork boiling wastewater, characterized by high COD and phenolic compounds content. The main aim of this study is the advanced valorization of these spills through a green and efficient process with two main stages. Firstly, most of the organic matter was removed by an optimal design of a precipitation with calcium. The resulting depuration rates were in the ranges 37–53 % for COD and 70–87 % for TPC. Secondly, the precipitates generated were subjected to a biodigestion process with production of methane (up to 234 L CH₄·kg VS⁻¹) and fertilizers. In conclusion, good recovery of interesting by-products and a good yield of depuration were achieved with the technology proposed, avoiding the use of toxic reagents and demonstrating the potential of concentrate precipitates from CBWs as substrates for biodigestion.

In recent years, waste pulp incineration has become a problem due to the large amount of carbon dioxide emissions. The effect of ammonium dihydrogen phosphate (ADP) as an additive agent was investigated by pyrolyzing ADP-supplemented pulp, and the yields of carbon fixation, phosphorus recovery, and nitrogen recovery were calculated. An ADP/pulp ratio of 0.01 mol/g was found to be the optimal amount of ADP addition according to the pyrolysis profile, N fixation, carbon yield, and surface properties. The addition of ADP significantly increased the carbon fixation yield from approximately 30 % to over 80 %. The product activated carbon with ADP possessed surface area of 730 m²/g, which was a 2.4-fold increase compared to 300 m²/g without ADP. In addition, the effect of ADP on intramolecular dehydration of pulp was quantitatively discussed by identifying the amount of water, which was about three water molecules from a 2-unit repetition of pulp structure.

The study evaluates the production of ethanol from waste barley, a potential raw material for biofuel production. The objective of this research is to understand the processes involved in this type of production, including the challenging issue of mycotoxin contamination. These toxins can be metabolized by microorganisms during the fermentation process, making the material suitable for animal feed. The selection of articles was made through Scopus and VOSviewer, which were analyzed to understand the feasibility of producing bioethanol from residual barley. Concluding that residual barley is a viable option for bioethanol production, as it contains significant amounts of starch. Furthermore, it can bring economic and environmental benefits, presenting advantages for the entire production chain, aligning with the principles of a circular economy by utilizing waste that would otherwise be discarded. The research also highlights the importance of adopting sustainable practices in biofuel production.

The rise in global population strains agro-industrial waste management, positioning single-cell protein (SCP) production as a cost-effective solution. Evaluating eight agro-waste residues identified wheat bran with a high solid recovery rate (67.15 %). SCP production increased from 1.29 ± 0.23 gL⁻¹ to 21.05 ± 0.33 gL⁻¹, achieving a microbial conversion efficiency of 90.88 % by Paradendryphiella arenariae (PG1). Nucleic acid content in SCP was reduced by 31 % using NaOH and 36 % via heat shock, significantly enhancing SCP quality, digestibility, and safety. SCP's impact on Caenorhabditis elegans (C. elegans) revealed a maximum lifespan of 18 ± 0.2 days, notable pharyngeal pumping rates (117 ± 2.541 and 67 ± 3.473 min⁻¹ on days 5 and 10), and body bending rates (115.3 ± 0.86 and 44.8 ± 0.28 min⁻¹ on days 5 and 10). This comprehensive approach demonstrates the promise of SCP production in sustainable waste management, resource optimization, and detailed toxicity analysis in C. elegans, broadening the potential applications of SCP in various fields.