Biofuels Bioproducts & Biorefining-Biofpr最新文献

The use of mixed microalgae offers an effective solution for the management of contamination risks in cultivation while enhancing economic viability. In this study, mixed microalgae were used for the first time for the removal of copper (Cu) and nickel (Ni) from aqueous solutions. The characteristics of the adsorbents were examined thoroughly, and the adsorption process was assessed using isotherms, kinetics, and thermodynamics. Particle size, concentration, contact time, temperature, and pH were among the variables assessed. The findings demonstrated that, at an initial concentration of 100 mg L^–1 and a pH of 6, the maximum adsorption of Cu with a particle size of 1 mm (90.20%) took place in 60 min. The highest adsorption rate (78.25%) was found for Ni. Microalgae performed best over 180 min at room temperature and at pH values that promoted metal dissolution. The removal percentages of wet and dried microalgae were comparable, and the wet adsorbent was more economical. It was feasible to remove both metals at the same time. Up to three cycles of adsorbent reuse were possible, with sodium hydroxide treatment offering superior removal to hydrochloric acid. Thermodynamic analysis demonstrated that this process, which results in a disordered state, is exothermic and spontaneous.

This study demonstrates the feasibility of extracting lecithin from oil industry byproducts in an eco-friendly manner, with minimal use of water and without harmful chemicals. Liposomes can be generated directly from this extracted lecithin, enhancing the value of these byproducts and enabling the production of catalytic gold nanoparticles (AuNPs). Thin-layer chromatography of the extracted lecithin revealed a phospholipid composition primarily consisting of phosphatidylethanolamine and phosphatidylcholine, and surface tension studies demonstrated similar behavior between the extracted and commercial lecithin. Liposome formation using sustainable lecithin (LPn) resulted in structures that were stable for at least 10 days, exhibiting a low polydispersity index (0.395) and uniform size (approximately 214 ± 7 nm). Gold nanoparticles were synthesized successfully in LPn loaded with [HAuCl₄] by using different photoreduction methods: ultraviolet (UV) lamp, pulsed laser 355 nm, and sunlight irradiation. The AuNPs exhibited characteristic sizes (ranging from 5.03 to 6.78 nm) and optical properties typical of nanoparticles, including a distinct surface plasmon resonance. As a proof of concept, we also demonstrated that the synthesized AuNPs exhibited catalytic activity in UV-induced cis-trans isomerization reactions. Overall, the study highlights the potential of sustainable soy lecithin extraction for diverse applications, including nanoparticle synthesis and catalysis.

Bio-based 2,3-butanediol (2,3-BDO) production on a large scale depends on critical factors, such as culture medium, oxygen supply, pH and biosafety. In this study, three strategies for reducing culture medium costs were investigated: carbon/nitrogen (C/N) ratio; low-cost nitrogen sources (crude yeast extract, brewer's yeast extract, corn steep liquor, urea, sodium nitrate, ammonium chloride, ammonium sulfate and dibasic ammonium phosphate); and microbial pH autoregulation. Batch fermentations were performed in a microaerobic environment using wild-type and safe Paenibacillus peoriae NRRL BD 62. The yield and selectivity of 2,3-BDO were used as control variables. A ratio between 2,3-BDO production and glucose consumption (Y_P/S) of almost 80% and an optical purity of 87% levo-2,3-BDO, with no acetoin accumulation, were achieved in an NH₄Cl-based medium at C/N = 8.5 g/g and without external pH control, considering an initial glucose of 10 g/L. Based on Free on Board prices, a 63% savings in culture medium costs was achieved by replacing commercial yeast extract at pH 5. Validation assays with higher initial glucose concentrations showed a Y_P/S of 0.40 g/g and an optical levo-/meso-2,3-BDO ratio of 1:0.8, with negligible acetoin accumulation. Therefore, the NH₄Cl-based medium at C/N = 8.5 g/g and without pH control was considered economically promising for high-yield and high-selectivity bio-based 2,3-BDO production.

Microwave (MW)-assisted catalytic pyrolysis represents a promising method for transforming petroleum-based plastic waste into valuable chemicals, offering a pathway towards more sustainable circular economy. In this study, catalytic pyrolysis of low-density polyethylene (LDPE) was conducted under MW irradiation. The influence of various catalyst types (HZSM-5, Ga/ZSM-5, Ga/Ni/ZSM-5, Ga/Co/ZSM-5, and Ga/Cu/ZSM-5) on product yield and distribution was examined. The results revealed that the Ga/ZSM-5 catalyst yielded the maximum liquid oil, approximately 41%. Ga/Ni/ZSM-5 performed excellently in the production of long-chain olefins, constituting about 27% of the liquid fraction. However, Ga/Co/ZSM-5 led to the production of heavy pyrolysis oil containing nearly 25% long-chain paraffins, rendering it unsuitable for producing high-value chemicals. Conversely, the Ga/Cu/ZSM-5 catalyst yielded an aromatic-rich pyrolysis oil, with benzene derivatives constituting approximately 90% of the liquid oil fraction, thus proving to be a suitable catalyst for the intended application. The liquid product distribution was compared with a petroleum assay by SimDist, and this suggested that utilizing the HZSM-5 catalyst could yield an 86.4% naphtha fraction. The study also revealed that the Ga/Cu/ZSM-5 catalyst generated the largest amounts of hydrogen and syngas, as determined by a MicroGC analysis of the gas products. This catalyst also exhibited the maximum coke deposition (1.35%) postreaction, which was attributed to its high aromatic hydrocarbon content in the pyrolysis oil and maximal hydrogen release. A comparison of fresh and spent catalyst properties was conducted to gain insights into catalyst activity and to correlate the effects of metal doping on product distribution. These findings underscore the potential of MW-assisted catalytic pyrolysis, particularly with the Ga/Cu/ZSM-5 catalyst, for the efficient conversion of plastic waste into valuable chemicals, thereby contributing to sustainable resource utilization and environmental conservation.

Magnusiomyces capitatus A4C, a mycelium-forming and lipase-producing yeast-like fungus, was employed in a five-level factorial design to optimize the collective and interactive influences of carbon, nitrogen and emulsifying sources and their possible effects on cell-bound lipase (CBL) and cell biomass production. The cell culture of M. capitatus A4C was incubated along with biomass support particles (BSPs) to immobilize the enzyme while anchoring CBL on their surfaces. Among the BSPs tested, CBL immobilized on loofah sponge under optimized conditions showed a substantial hydrolytic activity of 12.7 U mL⁻¹ and a cell-loading capacity of 0.61 g g⁻¹ of BSPs. Immobilized CBL was applied for biodiesel production via transesterification and esterification. The conversion percentage of triacylglycerides was approximately 100% at 24 h with the addition of water at 1:1 (v/v). The conversion of oleic acid into biodiesel via esterification was 100% at 48 h in the presence of 15% (v/v) isooctane. Further, biodiesel production was scaled up using a packed bed reactor. The batch production of biodiesel in a packed bed reactor through transesterification was 96.2%, with a circulation flow rate of 5.5 mL min⁻¹ for 18 h. On the other hand, oleic acid conversion into biodiesel via esterification was 99.5%, with a circulation flow rate of 5.5 mL min⁻¹ for 24 h. Further investigation revealed that the immobilized biocatalyst exhibited higher stability with esterification (85.3% fatty acid methyl ester) after ten repeated cycles.

The pyrolysis of water hyacinth is gaining attention and acceptance as a resource recovery technique due to its availability and economic viability. However, the presence of lignin, one of the three major biomass fractions, presents significant challenges for profitable water hyacinth processing for biofuel production. Fungal pretreatment of water hyacinth for lignin breakdown has been explored but the application of Trichoderma atroviride as a pretreatment for pyrolysis is relatively novel. The efficacy of T. atroviride pretreatment in improving water hyacinth's pyrolytic products using a fixed-bed reactor was therefore investigated in this study. The optimization process was studied using a central composite design in response surface methodology with Design Expert 13. Delignification of the biomass was established because the elemental analysis showed a 25.42% increase in cellulose content and a 23.40% and 3.37% decrease in lignin and hemicellulose content, respectively. The biomass pretreatment applied influenced the physical and chemical characteristics of the pyrolytic products. The highest pyrolysis oil yield increased by 25.81% at 575 °C and particle size 2290 μm, and the highest char yield decreased by 4.23% at 273 °C and particle size 1500 μm. This research is crucial for policy and research conversations as it offers a scientific basis for the application of T. atroviride pretreatment in biomass pyrolysis technology and emphasizes the optimal utilization of water hyacinths to obtain socio-environmental benefits.

This study proposes a novel one-pot method to produce 2,5-furandicarboxylic acid (FDCA), which effectively simplifies the preparation process of FDCA by directly utilizing the biomass raw material corncob and its derived carbon-based catalysts. In this work, we first prepared two different carbon-based catalysts from corncobs: a ruthenium-supported catalyst (Ru/C) and a sulfonated carbon catalyst. After detailed characterization and performance testing, these two catalysts were used to catalyze the pretreated corncob mixture to produce FDCA. Under optimized conditions, even using 0.12 g of Ru/C catalyst at a microwave power of 200 W, the yield of FDCA can reach 27 mol%. In comparison, the FDCA yield of the sulfonated carbon catalyst under the same conditions was 19 mol%. This work not only demonstrates the possibility of efficient production of FDCA by utilizing biomass resources and a simplified chemical conversion process, but also highlights the importance of selecting appropriate catalysts and controlling reaction conditions in improving yields. Through this method, we can promote the development of biomass conversion technology in a more efficient and environmentally friendly direction, providing technical support for the commercial production of bio-based chemicals.

Significant progress has recently been made in the biosynthesis of germacrene A using microbial cell factories. Germacrene A is a crucial precursor for the synthesis of anti-cancer active compounds. However, its hydrophobic characteristics lead to its aggregation in cell membranes and cause severe cytotoxicity. In the present study, we found that rhamnolipids (RLs), as toxicity antidotes, could promote the production of germacrene A. An optimal RLs concentration of 1.25 g L⁻¹ resulted in an increase of over 30% in the germacrene A titer at both shake flask and bioreactor scales. Mechanistic analysis showed that the addition of RLs could dramatically reduce aqueous-phase surface tension and cell surface hydrophobicity (CSH), and increase the cell membrane permeability. This, in turn, promoted an efficient transfer of germacrene A from cell membrane to extraction phases. The addition of RLs also increased the adenosine triphosphate (ATP) concentration and the nicotinamide adenine dinucleotide (NAD⁺/NADH) ratio, while reducing reactive oxygen species (ROS) levels. Correspondingly, gene transcripts for key enzymes associated with germacrene A biosynthesis, the respiratory chain, and ROS scavenging were upregulated significantly. This study provides an effective RLs-regulated fermentation method for the biosynthesis of hydrophobic natural products.

Recurring environmental challenges and the global energy crisis have led to intensified research on alternative energy sources. Hydrogen has emerged as a promising solution, produced through electrochemical, thermochemical, and biological methods. This study presents the advantages and disadvantages of these technologies. It also provides pertinent data on hydrogen production, identifying world-leading countries in hydrogen production, such as the USA, Japan, and China, and the government policies that they have adopted. It reports market trends such as hydrogen synthesis by water electrolysis, the high cost of the electrolyzers used, and incentives for the carbon market to become competitive with other alternative energy sources. It also highlights startups from around the world that are developing innovative methodologies for producing hydrogen. The study concludes that integrating hydrogen production concepts with social, environmental, and industry interests is essential.

The efficient use of vinasse, the primary byproduct of sugarcane ethanol production, is important for the economic and environmental sustainability of the industry. Few studies have quantified the soil health response to long-term vinasse application, even though this byproduct is generally applied as a potassium (K) source in sugarcane fields. The Soil Management Assessment Framework (SMAF) was used to assess the integrated soil health response in soils with contrasting textures. Chemical, physical, and biological indicators were selected, measured, and integrated into a soil health index for clay- and sandy-textured soils in Brazil. Overall, the application of vinasse improved soil health components in both soils. The results showed that the benefits of vinasse go beyond increasing the K content. Vinasse application showed increased soil organic carbon content, nutrient recycling, and soil physical quality. The long-term application of vinasse increased the soil health from 49% to 62% in the clayey soil and from 43% to 61% in the sandy clay soil. The findings therefore revealed the potential of vinasse application to reduce the need for synthetic fertilizer and promote the circular economy and soil health regardless of soil type. This study verifies that the long-term application of vinasse to sandy- and clay-texture soils in Brazil has both economic and environmental benefits because it recycles an important ethanol byproduct and enhances soil health.