The greater sustainability of agricultural and industrial wastes (non-woody biomass) when compared to the widely used high-quality forestry biomass encourages their usage in small-scale thermal ...devices (residential and domestic applications). However, the typical significant ash and alkali-compounds content of agro-industrial wastes may form undesirable deposits over the heat exchange surfaces that could require additional cleaning systems (thus increasing the cost and complexity of the boilers). This work analyses the fouling tendency of exhausted olive cake and almond shells when used in a biomass boiler (with a nominal thermal capacity of 55 kW) at partial and nominal load, trying to highlight the main mechanism leading to the deposits growth depending on the fuel properties and load. Inertial impaction of coarse fly ash governs deposition at partial load for almond shells, this is attributed to the low K, Cl and S content and the lower bed temperature reached (431 °C vs 528 °C at nominal load). Among the deposition mechanisms associated to K-salts condensates, direct condensation on the incipient layers dominates over thermophoresis of submicron particles at nominal load. Although no additional maintenance procedures seem to be required when using almond shells, it is highly recommended to remove K/Cl components from exhausted olive cake through prior water leaching or by using additives to retain these species in the bottom ash.
With the purpose to evaluate the effects of dietary olive cake, a source of bioactive phenolic compounds, as feed supplementation of lactating dairy cows on fatty acid composition, volatile organic ...compounds, and microbiological profiles of Provola cheese, we performed a two-arm study where control and experimental administered cows derived dairy have been compared.
Our panel of analyses include metabolomics, physicochemical detected variables, culture dependent and independent analyses, and a stringent statistical approach aimful at disclosing only statistically significant results.
Looking at the physicochemical variable's profiles, a higher content of unsaturated fatty acids, polyunsaturated fatty acid, and conjugated linoleic acids as well of proteins were observed in experimental cheese samples, indicating the beneficial effect of dietary supplementation. Furthermore, based on volatilome composition, a clear cluster separation between control and experimental cheeses was obtained, mainly related to terpenes degradation, able of influencing their aroma and taste. Microbiological results showed a decrease of some spoilage related microbial groups in experimental cheeses, probably due to the inhibitory effect exerted by polyphenols compounds, that contrarily did not affect the core taxa of all cheese samples. This paper confirmed the promising utilization of olive by-product in farming practices to obtain more sustainable and safe dairy food products with lower environmental impact, mainly in Sicily and Mediterranean area, where waste disposal poses serious environmental and economic problems.
Although combustion ashes are usually used in soils, little attention is paid to the CO2 sequestration potential of this practice. The present study aims to quantify carbon sequestration as carbonate ...compounds in a tailored synthetic calcareous soil treated with biomass ash from a gasification power plant that uses olive cake. It is estimated that after ash amendment, 14.5g CO2 remained fixed per kg of fly biomass ash, 16.5g CO2 per kg of bottom biomass ash with plant cultivation and 19.7g CO2 per kg of bottom biomass ash without plant cultivation. This inorganic C fixation plus the organic (black) C contained in the ashes made the reutilization of ashes as K fertilizer a relevant practice due to its C resilience and rate, with a yearly C sequestering potential of ca. 8% of ‘Soil carbon 4 per mille’ goal, an initiative launched at the COP21.
•Olive cake ashes capture CO2 after biomass combustion.•Biomass combustion ashes can be reused as fertilizer.•CO2 remains fixed after biomass ashes are added to a calcareous soil.•Additional C is fixed as black C is already in ashes.•The C sequestering potential of biomass ashes is significant.
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•K2CO3–activated carbon was produced from olive pomace (DOC-AC).•Best DOC-AC exhibited 0.39 cm3/g micropore volume and 988.75 m2/g SBET.•Langmuir and pseudo-second-order models best ...fit the adsorption equilibrium and kinetic data, respectively.•The maximum adsorption capacity for DOC-AC were 359.39 mg/g for MB and 157.58 mg/g for AB 29.•Dyes adsorption efficiency were > 70 % after six successive regeneration cycles.
The K2CO3 activation of defatted olive cake in N2 atmosphere was attempted for activated carbon (DOC-AC) preparation to test its ability for the adsorption of methylene blue (MB) and acid blue 29 (AB 29). The optimum conditions obtained by Box–Behnken design was 3.0 g/g impregnation ratio, 800 °C activation temperature, and 120 min activation time. These conditions led to 20.84 % carbon yield and 98.92 % MB, and 94.63 % AB 29 removal. The best DOC-AC showed a highly porous structure with 988.75 m2/g SBET and 0.53 cm3/g total pore volume. Batch mode adsorption was performed at different initial dye concentrations (25–400 mg/L), pH (3–11), temperature (30–50 °C), and contact time (0–26 h). The kinetic and equilibrium adsorption data of both dyes were fitted to pseudo-second-order and Langmuir models, respectively. Monolayer adsorption capacities were 359.38 mg/g for MB and 157.58 mg/g for AB 29. After six successive regeneration cycles, the adsorption efficiency for both dyes was > 70 %, indicating good potential of the DOC-AC for commercial applications.
The microbial population in the pig’s gastrointestinal tract can be influenced by incorporating fibrous by-products into the diets. This study investigated the impact of including two types of dried ...olive cake (OC) in pigs’ diets on fecal bacterial composition. The correlation between fecal microbiota and growth performance, nutrient digestibility, gut fermentation pattern and slurry gas emissions was also evaluated. Thirty male Pietrain x (Landrace x Large white) pigs (47.9 ± 4.21 kg) were assigned to three groups: a control group (C), a group fed a diet with 20% partially defatted OC (20PDOC), and a group fed a diet with 20% cyclone OC (20COC) for 21 days. Fecal samples collected before and after providing the experimental diets were analyzed for the V3-V4 region of the 16S rRNA gene. Pigs were weighed, and feed intake was recorded throughout the study. Potential ammonia and methane emissions from slurry were measured. No significant differences in alpha diversity indexes were found. The taxonomic analysis revealed that Firmicutes and Bacteroidota phyla were dominant at the phylum level across all groups. Differential abundance analysis using ALDEx showed significant differences among groups for various bacteria at the phylum, genus, and species levels at the end of the experiment. Pigs from 20PDOC and 20COC groups exhibited increased abundances of health-promoting bacteria, such as Plactomycetota at the phylum level and Allisonella and an unidentified genus from the Eggerthellaceae family at the genus level. These changes influenced short-chain fatty acids’ (SCFA) concentration in slurries, leading to greater acetic, butyric, caproic and heptanoic acids in OC-fed groups, especially 20COC pigs. A volatility analysis revealed significant positive correlations ( p < 0.05) between Uncultured_Bacteroidales and Unculured_Selenomonadaceae and energy digestibility. Monoglobus and Desulfovibrio showed a positive significant ( p < 0.05) correlation with total SCFA, indicating a high impact on gut fermentation. However, growth performance parameters and potential gas emission displayed no significant correlations with a specific bacterial genus. In conclusion, our results suggest that OC inclusion into pig diets could positively modulate and contribute to the gut microbiota’s favorable composition and functionality. Also, nutrient digestibility and gut fermentation patterns can be associated with specific microbial populations.
In this study, the olive cake was successfully developed and applied as a substrate to produce a lignin-based catalyst for biodiesel production. Three lignin-based solid acid catalysts were prepared ...from the incomplete carbonized alkali lignin using concentrated sulfuric acid. The catalyst underwent a detailed characterization analysis in terms of its functional groups of active sites, surface area, acid sites density and morphological structure. For the catalytic activity test, prepared catalysts were studied for their ability to catalyze both esterification and transesterification reactions of waste vegetable oil (WVO) ≈2 FFA (% w/w).
The results revealed that a sulfonated lignin-derived acid catalyst has a high potential to esterify waste vegetable oil to about (92%) conversion. Furthermore, it demonstrated about 57% conversion to fatty acid methyl esters (FAME) under the following optimum condition: sulfonation time of 1 h, catalyst loading of 10 wt %, the methanol-to-WVO molar ratio of 35:1, a reaction temperature of 65 °C and reaction time of 6 h. Also, the results showed that the lignin-based acid catalyst can be reused at least ten times with high FFA conversion (>75%).
•Olive cake was incompletely carbonized followed by sulfonation to produce a catalyst.•Chemistry and the texture properties of the catalysts were studied.•The catalyst activity was proportional to the SO3H acid densities and surface area.•The catalyst has a high potential to esterify waste vegetable oil.
•Adding cellulase and xylanase enzymes to olive cake increases feed intake and fibre digestibility.•Feeding growing lambs with olive cake treated with fibrolytic enzymes increases daily weight ...gain.•Treatment with exogenous fibrolytic enzymes upgrades the value of olive cake as an ingredient in finishing lamb diets.
This research evaluated the effects of the addition of a blend of exogenous fibrolytic enzymes composed of a mixture of cellulase and xylanase (CX) to a high-fibre diet on growth performance of meat lambs. The diet contained olive cake (OC), and CX was added to this fibrous by-product at 0 (control, no addition of CX), 4 (CX04) or 16 (CX16) ml of the enzyme preparation per kg OC dry matter. The study was planned according to a quintuplicated 3 × 3 Latin square design, with three experimental treatments (control, CX04, CX16), three 21-day periods (14-day adaptation plus 7-day collection period) and 15 weaned male lambs (Queue Fine de l'Ouest) randomly assigned to the 5 replicates (3 lambs in each replicate). Intake of both dry matter and organic matter were increased (P < 0.05) by 4 % with CX addition. Fibre digestibility was increased (P < 0.05) by 6 % (CX04) and 8 % (CX16) as compared with control. Blood serum biochemistry were not affected (P > 0.05) by CX, except cholesterol concentration that was increased (P < 0.05). As compared with lambs fed the control diet, average daily weight gain was increased (P < 0.05) by 6 and 10 % when lambs were fed CX04 and CX16 diets, respectively. These results indicate that the supplementation of OC-based lamb diets with CX, even at relative low concentrations, improves lamb growth performance as a result of increasing feed intake and enhancing fibre digestibility with no adverse effects on animal health.
In this work, olive cake was treated by applying the alkali hydrolysis process in order to produce an adsorbent material for biodiesel purification. The treatment was performed with an aqueous ...solution of 7.5 wt% NaOH in a solid-to-liquid mass ratio of 1:6 at 90 °C followed by filtration, washing, drying, and sieving. The structure and composition of the delignified residue were investigated by XRD, FT-IR, BET, and SEM analysis to better understand its properties as an adsorbent. The study revealed that using an adsorbent of size <90-μm, 2 wt% adsorbent to biodiesel ratio and contact time of 40 min resulted in higher yield and better fuel properties compared to those purified using water washing method. At the same time, such enhanced properties fulfilled the ASTM 6751 and EN 14214 biodiesel standards. Therefore, the alkali residue can act as a replacement for commercial adsorbents for biodiesel purification. Further, the adsorption isotherm of this alkali residue was adequately described by the Freundlich model.
•Olive cake was alkali hydrolyzed to produce an adsorbent for biodiesel purification.•Chemistry and the texture properties of the adsorbent were studied.•The effect of adsorbent particle size, loading, and purification time was studied.•The adsorption isotherm was described by the Freundlich model.•Alkali treated olive cake has perfect regeneration performance.
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