Bioresource Technology Reports最新文献

Nanobubble technology was used to enhance anaerobic digestion (AD) of thermal-hydrolysis pre-treated sewage sludge for bioenergy recovery. The prepared air, CO₂, and H₂ nanobubble solutions, with concentrations of 9.88–10.2 × 10⁷ bubbles/mL, remained stable for at least 7 days. After adding them into AD reactors, significantly higher CH₄ production (37.1 %) was observed for the CO₂ nanobubble treatment, followed by air (25.6 %) and H₂ (14.5 %) nanobubble treatments, compared to the control group. CO₂ nanobubble treatment performed the best in improving acidogenesis/acetogenesis, resulting in significantly higher volatile fatty acid generation during the initial 3–4 days. A comparison of reactors supersaturated and non-saturated with oxygen has demonstrated most of the biogas uplift observed to result from the nanobubbles rather than from initial oxygen soluble levels, demonstrating the crucial role of nanobubbles in upgrading AD. This study demonstrates, for the first time, that nanobubbles can provide additional benefits when combined with stablished sludge pre-treatment technologies.

Biological methanation is a promising sustainable energy technology. To intensify ex-situ biomethanation, a 3-L bubble column reactor was operated continuously under thermophilic conditions, with and without colonized biochips. Studies in batch reactors showed biofilm formation on biochips, with an archaea:bacteria ratio of 5.7 compared to 3.2 in planktonic phase with Methanothermobacter being the dominant archaea. Using colonized biochips in the bubble column increased methane production rate (MPR) nearly threefold, achieving a steady MPR of 15.7 ± 0.5 NL_CH4/L_r.d at 84.4 ± 0.9 % methane content. Gas retention time (GRT) was 0.3 h, with 97.4 % and 96.5 % conversion of H₂ and CO₂, respectively. Volatile fatty acid (VFA) production was under 40 mg/L per day, indicating dominant hydrogenotrophic methanogenic (HM) pathway. The results suggest biofilm formation significantly enhances MPR in ex-situ methanation reactors, advancing towards industrial application.

The use of advanced biotechnological methods with agro-industrial waste is an outstanding approach for low-cost production. This study aimed to enhance rhamnolipid production by Pseudomonas aeruginosa PAO1 using agro-industrial waste and statistical modeling. The Box-Behnken model significantly increased rhamnolipid yield by 7.6-fold (661.7 ± 2.57 mg/L) at 40 g/L glycerol, 20 g/L glucose, 30 g/L peptone, pH 9, and 40 °C for 5 days. The replacement of glycerol and glucose with prickly pear peel (Opuntia ficus-indica) resulted in an increase of rhamnolipids to 847.3 ± 4.5 mg/L. The rhamnolipid concentration increased to 1521 mg/L after optimizing the air flow rate and agitation speed in the pilot-scale bioreactor. The rhamnolipids showed antimicrobial activity against Candida albicans, Escherichia coli, and Staphylococcus aureus strains. A concentration of 115 mg/L resulted in a 42.3 % reduction of the surface tension from 65 to 37.5 mN/m. The optimization processes using agricultural waste are promising approaches for future low-cost industrial production.

This paper reports investigations in food waste hydrolysis using ternary approach that combines statistical optimization, ultrasound-assisted enhancement of hydrolysis kinetics, and molecular simulations that provide physical insight into the process. Initial optimization of hydrolysis parameters (Box–Behnken design) resulted in total reducing sugar yield of 263.4 mg/g biomass in 42 h. Sonication of hydrolysis mixture at 35 kHz at 20 % duty cycle yielded 4× reduction in hydrolysis time with 22 % enhancement in TRS yield (320 mg/g biomass). Analysis of GLCM's secondary structure through FTIR spectra deconvolution revealed significant changes induced by sonication. Sonication led to reduction in α-helix, and increase in random coil content. Molecular dynamics simulations unveiled majority of amino acid residues associated with GLCM binding pocket in α-helix and random coil regions. Consequently, sonication widened the binding pockets, facilitating easier transport of substrate and product. This effect translated into faster kinetics of enzymatic food waste hydrolysis.

The sustainable management of Urban Solid Waste (USW) is one of the most relevant global environmental challenges. Food waste (FW) constitutes a significant fraction of USW. One way to valorize FW is by producing biofuels and high-value-added chemicals. Therefore, this study aimed to produce 1,3-propanediol (1,3-PDO) from vinasse obtained after ethanolic fermentation of FW. Following the chemical characterization, the optimum composition of hydrolysate was generated from experimental design 2³ + 3(0). Assay 7, with 69.12 g/L of glucose and 2.60 g/L of glycerol, was selected from the statistical analyses. Fermentation assays by Meyerozyma caribbica produced 26.88 g/L of ethanol and 6.36 g/L of glycerol. After ethanolic distillation, Lentilactobacillus diolivorans produced 1,3-propanediol with 74.28 % efficiency. This shows that the integrated production of ethanol and 1,3-PDO is a promising alternative for the biorefinery of FW.

Banana peels are an environmentally benign alternative to toxic reducing agents. Banana peel-reduced graphene oxide (BRGO) showed high performance in the adsorption of metal and dye ions. Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and a Zeta potential analyzer were used to characterize the BRGO. Different influencing factors such as pH, dose, concentration, duration, and temperature, were studied to evaluate the efficiency of the adsorbent. The Langmuir and Freundlich isotherm models were fitted for Cr (VI) and acid dye adsorption. The maximum adsorption capacity (q_m) of BRGO for Cr (VI) and AV54 dye were 135.87 and 110.74 mg/g, respectively. The pseudo-second-order kinetic model was better suited for Cr (VI) and AV54 dye adsorption, which indicated chemical adsorption. Thermodynamically, the adsorption exhibited spontaneity and was endothermic. Regeneration and reuse of adsorbents were also studied for potential use in treating tannery effluent.

Pisifera Palm kernel shells (PPKS) were torrefied at 260, 280, and 300 °C, and ASTM methods were used to determine variations in their ultimate and proximate parameters. Iron nanoparticles were synthesized via coprecipitation of FeCl₃.6H₂O and NaBH₄, characterized, and used as catalysts in the thermal degradation of torrefied PPKS. Torrefied PPKS samples showed moderate MC (9.26–10.73 %), high carbon content (46.74 %), AC (2.77–3.39 %), VM (49.48–54.12 %), and FC (31.76 %–38.49 %). At 300 °C, the calorific value of the untreated PPKS increased by 13.3 % to 18.02 kJ/mol, making it suitable as a solid fuel. An increase in heating rate enhances faster decomposition and higher devolatization of torrefied PPKS at lower temperatures. Hemicellulosic components degrade at a reduced temperature as compared to cellulosic and lignin components. The 47.58 % Fe in the nanoparticle made it a good catalyst for the thermal degradation of PPKS. The E_a expended on catalyzed torrefied PPKS was lower as compared to torrefied PPKS calculated via the Coats-Redfern kinetic model. Torrefaction improved untreated PPKS by achieving higher fuel quality and calorific value, suitable physical properties, and a suitable chemical composition. The nano-Fe was suitable to reduce E_a needed for the thermal degradation of torrefied PPKS.

Microbial Fuel Cells (MFCs) are a substitute for fossil-fuel-based electricity generation. They are innovative bioelectrochemical systems that use microbial catalysts to convert organic waste directly into electrical energy. However, MFCs face several commercialization challenges, including expensive Proton Exchange Membranes (PEMs), making them unaffordable. The present research aims to develop cost-effective, environmentally friendly, high-performance PEM to make MFC technology more viable. The study analyzed using MFCs with different PEMs with native microflora and Serratia marcescens (AATB1) as biocatalysts to produce bioelectricity and treat septic tank wastewater (STWW). The experiment included a control group with sterile STWW. The study involves fabricating and characterizing the optimized Novel Cement Supported Conductive Salts PEM (NCSCS PEM) using SEM, TGA, and EIS techniques. The commercial Nafion 117 and salt bridge were used to compare NCSCS PEM in MFCs. The anode biofilm was investigated using CV, CLSM, and SEM. The MFCs with Nafion 117, NCSCS PEM, and Salt bridge produced power densities of 126.6 ± 1.06 mW/m², 204.04 ± 0.87 mW/m², and 188.26 ± 1.13 mW/m², respectively. Moreover, Our study shows a greater PEM cost reduction with commercial Nafion 117 PEM in terms of consumed cost of $7.04, $0.21, and $2.41 for making MFCs with Nafion 117 (9 cm²), NCSCS PEM (15 cm³) (with 97.02 % reduced cost) and salt bridge (15 cm³) (with 65.77 % reduced cost) respectively. Our MFC setup cost was reduced by 70.29 % by replacing Nafion 117 with durable NCSCS PEM. Using our cost-effective, better-performing, durable NCSCS in MFC makes the MFC technology or any other technology that needs PEM feasible on a larger scale.

This research investigates optimizing food waste (FW) concentrations for enhanced methane production in anaerobic digestion (AD) systems. Various FW concentrations (10, 20, 30, 40, 50, and 100 % v/v) were assessed for their impact on methane yield, pH stability, volatile fatty acid (VFA) levels, and microbial community composition. The study found that FW concentrations up to 20 % v/v maximized methane production, achieving a peak yield of 140.20 mL CH₄/gVS within an ideal pH range of 6.00–7.00. However, higher FW concentrations (>30 % v/v) significantly reduced methane output, with 100 % v/v halting production due to excessive VFA accumulation and pH drops. Key microbial players included acetoclastic methanogens like Methanosaeta and hydrogenotrophic methanogens such as Methanospirillum. These findings emphasize the importance of managing FW concentrations to maintain AD system efficiency, providing valuable insights into sustainable waste management and renewable energy production.

This study aimed to develop practical biorefinery process for bio-valorizing felled oil palm trunk (OPT) as a sole feedstock for lactic acid (LA) production. OPT was separated into oil palm sap (OPS), vascular bundle (OPT-VB), and parenchyma (OPT-PA) fractions. OPS containing high amounts of sugars (38.69 g/L) and nitrogen (0.63 g/L), could be used directly for LA production by Lactobacillus acidophilus and also as base medium for simultaneous saccharification and fermentation (SSF) of OTP-VB and OPT-PA. The repeated SSF efficiently utilized cellulosic OPT-VB and produced LA up to 50–71 g/L during five cycles. Due to high water-absorbing and swelling properties of OPT-PA, it could not be initially added at high loadings. It was then intermittently added through fed-batch SSF, which effectively produced LA of 72.85 ± 1.61 g/L. These strategies have shown the efficient biorefinery process for biovalorization of OPT and may also be applicable to other similar agricultural wastes.