Search Results (12)

Sustainable oil and gas development demands eco-friendly and cost-effective drilling fluids. Water-based drilling fluids (WBDFs) are preferred over oil-based alternatives for their lower environmental impact, but they often suffer from excessive fluid loss in permeable formations, leading to thick filter cakes, reduced mud weight, and operational delays. Conventional chemical additives mitigate this issue but pose environmental and health risks due to their toxicity and non-biodegradability. This study explores the use of biodegradable additives extracted from avocado seed (AS), rambutan shell (RS), tamarind shell (TS) and banana trunk (BT) biomass in four particle sizes of 300, 150, 75 and 32 μm to improve filtration control in WBDFs. All four materials were crushed by ball milling and characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray (EDX). In accordance with API Spec 13A recommendations, several water-based drilling fluids (WBDFs), including reference fluid and modified fluids formulated with biodegradable additives at a fixed percentage of 3 wt% and varied particle sizes, were prepared. The rheological and filtration properties of the formulated drilling fluids were investigated by conducting industry-standard rheology and filtration tests under LPLT conditions (100 psi, 25 °C) and HPHT conditions (1500 psi, 75 °C). The results show that 32 μm tamarind shell powder delivered the strongest performance, reducing fluid loss by 82.4% under HPHT conditions and producing the thinnest mud cake (0.33 mm); it also reduced fluid loss by 72.8% under LPLT conditions, outperforming the other biodegradable materials. Full article

This study introduces the preparation and tailoring of the catalytic properties of a novel biomass-based composite to produce a sustainable biolubricant, trimethylolpropane fatty acid triester (TFATE), via the transesterification of fatty acid methyl esters (FAMEs). This novel catalyst was prepared from avocado seed and chicken eggshell residues using a Taguchi experimental design to determine the best synthesis conditions. The variables tested in the catalyst preparation included CaO impregnation time and temperature, mass ratio of CaO/char, and activation temperature. The transesterification conditions to obtain TFATE were analyzed using the best eggshell-/char-based catalyst, and the reaction kinetics were measured at 120 and 150 °C. The results showed an endothermic reactive system with calculated kinetic rate constants of 7.45 × 10⁻³–10.31 × 10⁻³ L/mmol·min, and an activation energy of 15 kJ/mol. This new catalyst achieved 90% TFATE formation under optimized reaction conditions. Reuse tests indicated that catalyst deactivation occurred due to active-site poisoning, despite very low calcium leaching. Catalyst characterization confirmed the relevance of the crystalline structure and CaO loading on the avocado char surface to obtain the best catalytic properties, while ¹H nuclear magnetic resonance analysis proved TFATE formation. This low-cost catalyst can be an alternative for enhancing sustainable biolubricant production with the aim of replacing petrochemical-based counterparts. Full article

The transition towards sustainable biofuels requires innovative strategies to maximize the utilization of agroindustrial biomass. Accordingly, the aim of this study was to evaluate avocado stone biomass as a renewable substrate for producing glucose and bioethanol, and to characterize potential co-products from the pretreatment stream, including avocado phenolic compounds. It was found that the whole avocado stone and the seed contained 41.7% and 42.8% of starch, respectively, accounting for more than 78% of the glucans. Using microwave-diluted acid pretreatment and multi-response optimization, a direct conversion of ~90% of glucans to glucose was achieved from avocado stone biomass at 1% w/v sulfuric acid, 140 °C, and 5 min. It also enabled minimizing inhibitor presence and reducing energy requirements. Then, the glucose-rich hydrolyzate was efficiently fermented into bioethanol (~24 g/L in 12 h) using Saccharomyces cerevisiae, without needing detoxification or enzyme addition. Additionally, the process yielded a lignin-rich solid fraction with an enhanced higher heating value (about 1.4 times) compared to the original biomass and an extract with phenolic compounds like caffeoylquinic acids and hydroxytyrosol, which enhances the valorization potential of this underutilized biomass. The overall balance can be 240 kg/t of bioethanol, along with 2.5 kg/t of phenolic compounds and 376 kg/t of lignin-rich solid. Finally, this work exemplified, in a real-world scenario, how we can fully leverage these often-overlooked, non-edible sources of starch to achieve the green transition and circularity. Full article

This study reports the separation of methyl ethyl ketone (MEK), a relevant compound in the biorefinery context, from aqueous solutions using activated carbons derived from avocado seed biomass. Two synthesis routes were explored via chemical and thermal activation with H₂SO₄ and KOH. A Taguchi experimental design was applied to tailor synthesis conditions, with MEK adsorption capacity as the target property. Adsorption kinetics and isotherms were evaluated to determine the thermodynamic behavior of MEK separation using the best-performing activated carbons. The carbon activated with H₂SO₄ achieved the highest adsorption capacity (142 mg g⁻¹) at 20 °C and pH 4, surpassing KOH-based materials. This enhanced performance correlated to increased surface area and acidic oxygenated functionalities. However, higher pH and temperature reduced the adsorption efficiency for all adsorbents. Comprehensive characterization was performed using XRD, XRF, FTIR, SEM, N₂ adsorption–desorption isotherms, pH at point of zero charge, and surface acidity/basicity analysis via Boehm titration. Thermodynamic data and surface characterization indicated that MEK adsorption occurs via a double-layer mechanism dominated by electrostatic interactions and hydrogen bonding. The findings highlight an optimized approach for tailoring avocado-based activated carbons to efficiently recover MEK from aqueous media, supporting its potential application in downstream purification of fermentation broths for biofuel production and energy transition processes. Full article

In wet subtropical environments, perennial groundcovers are common in horticultural plantations to protect the soil from erosion. However, there has been little investigation into whether seeding annual cover crops into the perennial groundcovers provides additional soil services including carbon and nutrient cycling in these systems. To investigate this, farmer participatory field trials were conducted in commercial avocado, macadamia, and coffee plantations in the wet Australian subtropics. Cover crops were direct-seeded into existing inter-row groundcovers in winter (cool season cover crops), and into the same plots the following summer (warm season cover crops). Inter-row biomass was quantified at the end of winter and summer in the control (no cover crop) and cover crops treatments. Soil carbon and nutrient cycling parameters including hot water extractable carbon, water soluble carbon, autoclavable citrate-extractable protein and soil enzyme activities were quantified every two months from early spring (September) 2021 to late autumn (May) 2022. Seeded cover crops produced 500 to 800 kg ha⁻¹ more total inter-row biomass over winter at the avocado coffee sites, and 3000 kg ha⁻¹ biomass in summer at the coffee site. However, they had no effect on biomass production in either season at the macadamia site. Soil functional parameters changed with season (i.e., time of sampling), with few significant effects of cover crop treatments on soil function parameters across the three sits. Growing a highly productive annual summer cover crop at the coffee site led to suppression and death of perennial groundcovers, exposing bare soil in the inter-row by 3 weeks after termination of the summer cover crop. Annual cover crops seeded into existing perennial groundcovers in tree crop systems had few significant impacts on soil biological function over the 12-month period, and their integration needs careful management to avoid investment losses and exacerbating the risk of soil erosion on sloping lands in the wet subtropics. Full article

Avocado is a rich source of numerous nutrients, such as micro- and macroelements, essential unsaturated fatty acids, and vitamins essential for the correct functioning of the body. Consequently, its consumption has significantly increased in recent years. The primary edible part of the fruit is the flesh, while the seed is still considered biowaste. Currently, various methods for utilization of this biowaste are being explored, prompting the authors of this work to investigate the catalytic properties of ground avocado seeds. Dried, ground avocado seeds were used as the catalyst in the environmentally friendly oxidation of limonene with oxygen. The process was carried out in mild conditions, without the use of any solvent and at atmospheric pressure. The studies examined the influence of temperature (70–110 °C), the amount of the catalyst (0.5–5.0 wt%), and the reaction time (15–360 min). The analyses of the post-reaction mixtures were performed using the gas chromatography method (GC). The maximum value of the conversion of limonene obtained during the tests was 36 mol%. The main products of this process were as follows: 1,2-epoxylimonene, carveol, and perillyl alcohol. Also, the following compounds were determined in the post-reaction mixtures: carvone and 1,2-epoxylimonene diol. The studied process is interesting, taking into account both the management of waste in the form of avocado seeds and possible wide applications of limonene transformation products in medicine, cosmetics and the food industry. Given that limonene is now increasingly being extracted from waste orange peels, this is also a good way to manage the future naturally derived limonene and reduce the amount of waste orange peels. The presented studies fit perfectly with the goals of sustainable development and circular economy and may be the basis for the future development of “green technology” for obtaining value-added oxygenated derivatives of limonene. These studies show the use of waste biomass in the form of avocado seeds to obtain a green catalyst. In this context, our research presents an effective way of waste valorization. Full article

This study evaluated the adsorbent capacity of the Ecuadorian avocado (Persea americana Hass.) seed and peel wastes as an alternative method for cadmium (Cd), mercury (Hg), lead (Pb), and nickel (Ni) ion removal from aqueous solutions. The laboratory microscale process was performed using fixed-bed columns containing 1 g of 600 μm particles of biomaterial pretreated with ethanol and ethylene glycol. Subsequently, metal solutions of different concentrations were eluted and measured by flame atomic absorption spectroscopy. Results showed that fixed-bed columns allow efficient adsorption of Pb (2.6 mg/g) with ethanol pretreatment. Lower adsorption capacity was achieved for Cd, Hg, and Ni ions. Favorable adsorption with high retention capacity was found for Pb⁺² for the ethanol pretreated bio-adsorbent at higher concentrations (120 mg/L). Lower removal percentages were found for Cd⁺², Hg⁺², and Ni⁺²; Ni showed the lowest adsorption capacities and negative R_L values, suggesting inefficient adsorbent development. Regeneration of Cd, Hg, and Pb ions from avocado peel and seed showed the highest recovery when 1 mol/L HCl solution was used. Regarding the adsorption isotherms, the Langmuir model was the one that best fit our data, demonstrating that adsorption takes place in a uniform monolayer and that each contaminant ion occupies a single site. Full article

Biopolymers derived from biomass can provide the advantages of both biodegradability and functional qualities from a circular economy point of view, where waste is transformed into raw material. In particular, avocado seeds can be considered an interesting residue for biobased packaging applications due to their high starch content. In this work, avocado seed starch (ASS)-based films containing different glycerol concentrations were prepared by solvent casting. Films were also reinforced with starch nanocrystals (SNCs) obtained through the acid hydrolysis of ASS. The characterization of the extracted starch and starch nanocrystals by scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis has been reported. Adding 1% of SNCs increased elastic modulus by 112% and decreased water vapor permeability by 30% with respect to neat matrix. Interestingly, the bioactive compounds from the avocado seed provided the films with high antioxidant capacity. Moreover, considering the long time required for traditional plastic packaging to degrade, all of the ASS-based films disintegrated within 48 h under lab-scale composting conditions. The results of this work support the valorization of food waste byproducts and the development of reinforced biodegradable materials for potential use as active food packaging. Full article

Biochar has proven its potential in removing heavy metal ions from water. The objective of this study was to evaluate locally obtained biomass feedstocks for biochar production and their efficiency as a sorbent for aqueous lead (Pb²⁺) removal. The biomass feedstocks consisted of avocado seed, avocado peel, grapefruit peel, and brown seaweed, which represent agricultural and marine biomasses. The biochar materials were produced in two different methods: (1) a laboratory tube furnace at 300 °C and (2) a Do-It-Yourself (DIY) biochar maker, “BioCharlie Log”. The biochars were characterized for selected physicochemical properties, and batch adsorption tests with 10 mg Pb²⁺ L⁻¹ were conducted. All biochars exhibited >90% Pb²⁺ removal with the avocado seed and grapefruit peel biochars being the most effective (99%) from the tube-furnace-produced biochars. BioCharlie-produced-biochars showed similar Pb²⁺ removal (90–97%) with brown seaweed and avocado seed biochars being the most effective (97%). Land-based biochars showed a higher carbon content (>53%) than the brown seaweed biochar (28%), which showed the highest ash content (68%). Our results suggested that oxygen-containing surface functional groups in land-based biochar and mineral (ash) fraction in marine-based biochar play a key role in Pb²⁺ removal. Full article

Avocado (Persea americana) is a widely consumed fruit and a rich source of nutrients and phytochemicals. Its industrial processing generates peels and seeds which represent 30% of the fruit. Environmental issues related to these wastes are rapidly increasing and likely to double, according to expected avocado production. Therefore, this work aimed to evaluate the potential of hexane and ethanolic peel (PEL-H, PEL-ET) and seed (SED-H, SED-ET) extracts from avocado as sources of neuroprotective compounds. Minerals, total phenol (TPC), total flavonoid (TF), and lipid contents were determined by absorption spectroscopy and gas chromatography. In addition, phytochemicals were putatively identified by paper spray mass spectrometry (PSMS). The extracts were good sources of Ca, Mg, Fe, Zn, ω-6 linoleic acid, and flavonoids. Moreover, fifty-five metabolites were detected in the extracts, consisting mainly of phenolic acids, flavonoids, and alkaloids. The in vitro antioxidant capacity (FRAP and DPPH), acetylcholinesterase inhibition, and in vivo neuroprotective capacity were evaluated. PEL-ET was the best acetylcholinesterase inhibitor, with no significant difference (p > 0.05) compared to the control eserine, and it showed neither preventive nor regenerative effect in the neuroprotection assay. SED-ET demonstrated a significant protective effect compared to the control, suggesting neuroprotection against rotenone-induced neurological damage. Full article

Since ancient times, plants have been used as preservatives, spices, flavorings and as natural remedies to prevent or treat diseases owing to the biological activity correlated with the bioactive compounds they contain. The avocado fruit (Persea americana), native to Mexico and Guatemala, has been traditionally used for its pleasant organoleptic characteristics, high nutritional value and health benefits, but its residual biomass (seeds, skin and tree leaves) is also valuable in therapeutic terms. For this reason, the present investigation reviews the pharmacological potential of avocado waste. It can serve as a source of antioxidants, as well as hypotensive, anti-analgesic, photoprotective, antibacterial, and anti-inflammatory agents, and can be used to treat skin disorders. The main active components seem to be phenolic compounds. The content of phenolic compounds in waste extracts varied from 6 to 307 g/kg dry weight, depending on the waste type and extraction conditions, among others. In particular, our results suggested that using water as a solvent, a high amount of phenolic compounds can be obtained from the peel (266 g/kg dry weight), and this was correlated with major antioxidant activity. Therefore, the peels can be applied to obtain antioxidants, and water can be used as an environmentally friendly extraction solvent to obtain various valuable compounds of its chemical composition for food and pharmacological applications. Full article

Agroindustry residues can be used to produce valuable chemicals such as lactic acid, which is a primary chemical platform with many industrial applications. Biotechnological processes are the main approach of lactic acid production; however, culture media has an important impact on their costs. As a result, researchers are exploring various methods of production that use residual or waste biomass as raw materials, most of which are rich in lignocellulose. Nevertheless, starch and micronutrients such as those contained in avocado seeds stand out as promising feedstock for the bioprocess as well. In this study, the lactogenic Escherichia coli strain JU15 was evaluated for producing d-lactate using an avocado seed hydrolysate medium in a controlled stirred-tank bioreactor. The highest lactic acid concentration achieved was 37.8 g L⁻¹ using 120 g L⁻¹ as the content of initial reducing sugars. The results showed that d-lactate can be produced from avocado seed, which hydrolysates to 0.52 g L⁻¹ h⁻¹ using the engineered E. coli JU15. This study may serve as a starting point to further develop bioprocesses for producing metabolites using avocado seed hydrolysates. Full article