Bioresource Technology最新文献

Efficient bioconversion of acetate-rich lignocellulosic biomass into value-added chemicals remains a major challenge due to the toxicity of acetic acid. In this study, we developed an acid-tolerant Issatchenkia orientalis strain (IoDY01H) capable of producing 3-hydroxypropionic acid (3-HP), a key bioplastic precursor, from glucose, xylose, and acetate. Using a Cas9-based genome editing system with a hygromycin B resistance marker, we introduced heterologous genes encoding xylose utilization and β-alanine-based 3-HP biosynthetic pathways into the I. orientalis genome. Metabolomic analysis revealed that acetate supplementation redirected metabolic flux toward amino acid and lipid metabolism while reducing tricarboxylic acid (TCA) cycle intermediates. Acetate enhanced 3-HP production; however, the accumulation of β-alanine suggests that the activity of β-alanine-pyruvate aminotransferase may have been limited under acidic conditions. Consistent with this, fermentation at pH 5.5 resulted in higher 3-HP titers than at pH 3.5. Using pretreated hemp stalk hydrolysate as a feedstock, the engineered strain achieved a 3-HP titer of 8.7 g/L via separate hydrolysis and fermentation (SHF), outperforming simultaneous saccharification and fermentation (SSF). These findings demonstrate the feasibility of producing 3-HP from acetate-rich biomass using engineered non-conventional yeast and highlight I. orientalis as a promising microbial chassis for industrial bioconversion.

A highly efficient denitrifying bacterial strain (Acinetobacter sp. LF10) was isolated in this study, strain LF10 efficiently removed ammonium (98.02 ± 0.43 %), nitrate (90.35 ± 1.68 %), and nitrite (86.84 ± 2.41 %) from aquatic systems through coordinated assimilatory and dissimilatory nitrate reduction pathways coupled with ammonium assimilation. Compared with the traditional denitrification process, strain LF10 has the potential to reduce greenhouse gas (N₂O) emissions. Strain LF10 not only has strong temperature adaptability (15-35 ℃), but also has the advantage of maintaining a high ammonia nitrogen removal rate under low C/N conditions. Strain LF10 has demonstrated great potential in the treatment of aquaculture wastewater. LF10 can maintain strong competitiveness in biofilters and significantly enhance the nitrogen removal performance of biofilters under normal temperature (31.0 ± 2.4 ℃) and low temperature (15.0 ± 0.3 ℃) conditions. The average total nitrogen removal rates were 94.67 ± 0.64 % and 84.72 ± 17.03 %, respectively. These attributes position LF10 as a highly promising candidate for nitrogen removal in aquaculture wastewater treatment, offering considerable potential for the resource utilization of wastewater in sustainable aquaculture practices.

This study investigates the composition of aqueous phase (AP) from 24 HTL trials of two different municipal sewage sludge (MSS) samples, using homogeneous (Na₂CO₃, Li₂CO₃, K₂CO₃, Ba(OH)₂) and heterogeneous (Fe₂O₃, CeO₂, NiO/MoO₃, MoS₂, Ni/NiO, SnO₂, FeS) catalysts. Principal Component Analysis (PCA) was applied to assess the influence of feedstock and catalyst on AP composition i.e. formation of water soluble components. MSS1-derived AP showed a higher proportion of oxygenated aliphatics (13.9-33.7 %), while MSS2 had elevated N-heterocyclic aromatics (19.6-43.3 %). Homogeneous catalysts increased concentration of phenols (up to 26.3 %) and carboxylic acids, with K₂CO₃ almost doubling the carboxylic acid derivatives. Heterogeneous catalysts affected nitrogen and total organic carbon contents. Whereas Fe₂O₃ increases the aliphatic N-heterocycles from 20.6 % to 30.2 % (MSS1) and from 12.7 % to 21.0 % (MSS2), FeS strongly decreases the aromatic hydrocarbons from 9.5 % to 1.1 % (MSS1). PCA analysis confirmed distinct clustering patterns based on the interactions of the feedstock and catalyst, highlighting their synergistic effects. Phenol and cresol were present in the highest concentrations for both sludge, ranged up to 15.6 % and 15.4 % for MSS1 and 12.6 % and 12.9 % for MSS2, respectively. Among the oxygenated aliphatics the most abundant were cyklopenten-1-one, ethanone and their derivatives. N-heterocyclics were represented by a broad mix of pyrazine, pyridine, pyridinole, pyrrolidine, piperidine and their derivatives. The study demonstrates that feedstock properties significantly affect the AP composition, additionally it highlights the role of catalysts applied. These findings provide key insights into optimizing HTL conditions for industrial-scale applications and supporting effective AP by-product management strategies.

Kitchen waste (KW), comprising 30 %-60 % of municipal solid waste, could be converted to bio-oil via alkaline-catalyzed solvothermal liquefaction (STL) without energy-intensive drying. This study systematically investigated six catalysts (K₂CO₃, Na₂CO₃, KHCO₃, NaHCO₃, KOH, NaOH) for product distribution and nitrogen migration in STL versus hydrothermal liquefaction (HTL). Results demonstrate K₂CO₃'s superiority in ethanol-water co-solvent, synergistically enhancing bio-oil yield to 57.18 % (calorific value 35.49 MJ/kg) while achieving directional denitrification - reducing nitrogen content to 22.99 wt.% via pH-driven protein deamidation. Sulfur content decreased to 0.13 wt.% through sulfide decomposition. Critically, this method optimized bio-oil composition: light fractions (<343 °C) reached 82.10 % and hydrocarbons increased to 14.47 %, significantly outperforming HTL. Moreover, ethanol solvent recycling maintained 35.16 % bio-oil yield after three reuse cycles (distillation and antioxidants required), exceeding conventional HTL conversion (67.72 %). This work establishes three advances: (1) K₂CO₃-ethanol synergy enables high-yield, low-nitrogen bio-oil; (2) Alkaline catalysis directionally removes N/S impurities; (3) Multi-cycle solvent reuse sustains efficient oil production, providing a sustainable pathway for wet waste valorization.

Microbial fuel cells (MFCs), as a green energy technology that simultaneously enables electricity generation and wastewater treatment, exhibit performance that is highly dependent on the structural distribution of the microbial community. In this study, we investigated the effect of magnetic field (MF)-coupled magnetic carbon dots (N-CD/Fe₃O₄) as a selective pressure on the structure of mixed microbial communities in an intermittent pulsating fluidized-bed bioelectrochemical reactor. Under a moderate magnetic field (15 mT), N-CD/Fe₃O₄ were effectively adsorbed onto microbial cells and subsequently aggregated, significantly enhancing electron transfer within the community. The maximum power density reached 38.43 mW/m², which is about 5.07 times that of the blank control group. 16S rRNA and metagenomic analyses showed that the MF (15 mT) group exhibited significant enrichment of typical electroactive bacteria (40.32 %), such as Geobacter, which directly contributed to improved power production performance. In contrast, under a stronger magnetic field (60 mT), the abundance of typical electroactive bacteria (17.94 %) decreased, while atypical electroactive (38 %) and metabolically complementary bacteria that facilitate syntrophic cooperation (42.85 %) showed adjusted abundances, forming a functionally more balanced microbial community with improved adaptability to real wastewater conditions. This study demonstrates that by tuning magnetic field intensity and coupling with magnetic carbon dots, the structure and function of microbial communities can be directionally regulated, providing an effective strategy for developing electroactive inocula with enhanced power generation and wastewater adaptability.

This study comprehensively investigates microwave-assisted pyrolysis of agroforestry waste into quality biochar through systematic evaluation of process variables, operating modes, and quantification techniques to address key challenges for production optimization. Building on this, 92 systematic experiments were conducted across various agroforestry residues, evaluating more than ten control parameters classified by their impact on yield and quality: primary (power, time, temperature, heating-rate, feedstock), secondary (moisture content, particle size, sweep-gas flow, susceptor use), and tertiary (reactor configuration, control modes). Four operating modes were investigated: constant power with/without high-temperature alarm, fixed temperature, and controlled heating-rate; and two novel metrics (carbonized amount and absolute yield) were studied alongside traditional metrics to more accurately quantify biochar production and quality. Microwave power and residence time emerged as the primary drivers of yield and carbonization, while heating rate and target temperature acted as fundamental dependent factors. Constant-power operation without alarm achieved the highest reproducibility and absolute yield (up to 33.85 %), whereas controlled ramping produced biochars with HHV > 30 MJ/kg and fixed carbon > 70 %. Under optimal conditions of 500 W, 20-40 min residence time, 400-500 °C, 10-15 % moisture content, and < 3.15 mm particle size, energy efficiency reached up to 54.1 % while maintaining superior biochar quality. This comprehensive framework enables tunable, scalable microwave-pyrolysis protocols for sustainable biochar production from biomass wastes.

This study developed an integrated strategy combining simultaneous saccharification and culture (SSC), low-frequency ultrasound treatment with repeated-batch culture (RBC) for Neurospora intermedia mycoprotein production from soy whey and okara. Results showed that soy whey served as a desired substrate for mycoprotein production, and adding okara increased both mycoprotein yield and productivity by balancing the carbon-to-nitrogen ratio. Ultrasound treatment further increased the mycoprotein yield and shortened the production time by facilitating material exchange and improving cellulase activity. Finally, this integrated strategy was applied in shake-flask and 5 L fermenter systems, and their mycoprotein productivities of 1.79 ± 0.03 and 2.11 ± 0.04 g/L/12 h were achieved, showing 98.72 % and 189.04 % increases compared with those in soy whey alone with batch culture (BC). Moreover, the chemical and biological oxygen demand removal ratios reached 73.41 ± 0.69 % and 94.38 ± 0.78 %. Overall, this study offers an efficient, economical and environmentally sustainable way for mycoprotein production from agriculture and food industry waste.

Sulfate-reducing bacteria (SRB) can treat Acid and Metalliferous Drainage (AMD); however, process stability is challenging. This study evaluated microbial entrapment technology as an alternative solution by entrapping SRB in a porous hydrogel matrix, creating a stable microenvironment, while allowing diffusion of nutrients and gases. Two sequencing batch reactors (SBRs) were operated over 210 days: one with entrapped SRB (ESRB) and the other with non-entrapped SRB. The ESRB system exhibited greater sulfate reduction efficiency and operational resilience. It maintained rates of 0.71 ± 0.06 and 0.86 ± 0.05 g SO₄^2-/L/day during two 25-day operational periods with temperature drops from 24 °C to 15 °C. The non-entrapped SRB system dropped to 0.00 ± 0.00 and 0.12 ± 0.03 g SO₄^2-/L/day, respectively. Microbial community analysis revealed an increased proportion of SRB in the ESRB system. Compression tests and OD₆₀₀ confirmed bead integrity and biomass retention. This study supports the applicability of ESRB for AMD treatment.