Effects of untreated two‐phase olive mill pomace on potted olive plantlets

Two‐phase pomace represents an important environmental problem in Mediterranean areas. With its high organic content, direct application of two‐phase pomace in the field is recommended to improve soil organic carbon levels and fertility. However, this does not consider any antagonistic effects that this application might have on root proliferation and biomass partitioning. We studied the effects of untreated two‐phase pomace on properties of growth substrate, and on shoot and root growth and biomass allocation of potted olive plantlets. A pot experiment was carried out in a greenhouse over 90 days, with five levels of two‐phase pomace and using two olive cultivars. The effects on shoot growth, leaf pigment content and maximum quantum efficiency of photosystem II (ΦPSII) were assessed each month. After 90 days, the shoot and root biomass of the olive plants was quantified, along with total organic matter, and carbon, nitrogen and polyphenol contents of the growth substrate and shoots, and the fine root nutritional status. Two‐phase pomace increased the total organic matter, total nitrogen and polyphenol contents of the growth substrate. It significantly altered biomass partitioning in the olive plantlets, with reduced shoot dry mass and leaf area, and new shoot formation. It also increased fine and total root dry mass for all two‐phase pomace levels except 40%. There were no significant differences in leaf pigment content and ΦPSII across the treatment levels. Therefore, application of untreated two‐phase pomace at more than 4% induces a severe imbalance in olive plantlet biomass partitioning, and shoot and root growth.     

Composting of the solid fraction of olive mill wastewater with olive leaves: organic matter degradation and biological activity

The flocculated solid fraction of olive mill wastewaters, obtained from two different olive oil extraction systems (FOMW1 and FOMW2) was composted, with olive leaves (OL) as bulking agent, by the static pile system (Rutgers). The dynamic of organic matter (OM) degradation during composting and its relationship with the basal respiration and fluorescein diacetate (FDA) hydrolytic activity, as indicators of biological activity, were studied. Two mixtures were prepared: C1, from 65% FOMW1 plus 35% OL; and C2, from 74% FOMW2 plus 25% OL and 1% urea. The biooxidative phase of composting in C1, which had a high initial C/N ratio, was long, leading to a high OM degradation, mainly of the lignocellulosic compounds. The water-soluble organic carbon content, C/N ratio and the urea supplied as a N source for the C2 compost make this mixture more adequate for composting, as it had a shorter composting time than C1, and developed a microbial population with a high metabolic activity. The results for basal respiration in C1 and C2 were correlated at a high probability level with those of FDA hydrolysis, and both parameters can be used for establishing the degree of biological stability of the composting material.     

Carbon mineralization and distribution of nutrients within different particle-size fractions of commercially produced olive mill pomace

Composting is a realistic option for disposal of olive mill pomace (OMP) by making it suitable as a soil amendment for organic farming. The chemical and physical characteristics and contribution of particle-size fractions to total nutrients and carbon mineralization of seven commercial composts of OMP (COMP) were investigated. Higher proportions of manure, co-composted with OMP, reduced the organic matter (OM), total carbon and C:N ratio of the product, but increased the content of nutrients and fine particles. The fine particles had higher nutrient contents, but less OM and carbon and, unlike larger particles, did not exhibit any phytotoxicity. Less than 1.5% of added carbon was mineralized in whole compost, but a lower rate was found with larger particles. Separation of COMP by particle size fractionation and application as a soil conditioner is recommended for better optimization of COMP with the <1 mm fraction providing the higher quality compost.     

Quality evaluation of co-composted wheat straw, poultry droppings and oil seed cakes

Poultry droppings, neem cake, castor cake, jatropha cake and grass clippings were used separately as organic nitrogen additives to decrease the high C:N ratio of wheat straw. Composting was carried out aerobically in presence of fungal consortium developed by including Aspergillus awamori, Aspergillus nidulans, Trichoderma viride and Phanerochaete chrysosporium. The degraded product was characterized to assess the technical viability of organic nitrogen supplements as well as fungal consortium in improving the quality of compost and hastening the process of decomposition of high lignocellulolytic waste. Evaluation of maturity showed that mixture of wheat straw, poultry dropping and jatropha cake had the lowest C:N ratio of 10:1, the highest humic acid fraction of 3.15%, the lowest dehydrogenase activity and a germination index exceeding 80% in 60 days of decomposition. Inoculated and grass clipping amended wheat straw–poultry dropping mixture resulted in compost with highest humus content of 11.8% and C:N ratio of 13.5, humic acid fraction of 2.84% and germination index of 59.66%. Fungal consortium was effective in improving the humus content of all the composted mixtures. In some treatments, germination index could not be correlated with C:N ratio. Non edible oil seed cake supplemented substrate mixtures did not respond to fungal inoculation as far as C:N ratio was concerned.     

Changes in physical,chemical and microbial parameters during the composting of municipal sewage sludge

Changes in physical, chemical and microbial parameters were investigated during the composting of municipal sewage sludge. Raw sewage sludge (30% dry matter) was mixed with compost from sewage sludge (85% dry matter) in 3:1 ratio (v/v). The mixture was divided into 4 windrows which were composted under the same conditions except the turning factor. The turning was every 7, 10, 15 days and according to the temperature which must be (55–65°C) for windrow 1 (W1), windrow 2 (W2), windrow 3 (W3) and windrow 4 (W4), respectively. Water was added to adjust the moisture content (40–60%). The composting process consisted of 2 periods; fermentation (12 weeks) and maturation (4 weeks). The results showed that the temperature reached the maximum after 12 weeks for W1 and 11 weeks for W2, W3 and W4 and then decreased. The final compost was nearly odourless and black, especially in case of W4. The general trend indicates a decrease in organic matter, organic carbon and nitrogen (N), whereas ash, potassium (K) and phosphorus (P) increased and consequently C/K and C/P ratios decreased. There was a slight increase in C/N ratio. The pH increased and then decreased to near neutrality at the end. The mesophilic bacteria increased during the fermentation period and decreased after that, whereas the thermophilic ones increased with increasing of temperature, decreased after 2 weeks and increased again during the fermentation period and then decreased. The mesophilic and thermophilic fungi were present during the first week and disappeared after that. The final compost was pathogens-free as indicated by the counts of coliforms and Salmonella.     

Crude and acid oils from olive pomace as alternative fat sources in growing-finishing pigs

The inclusion of crude and acid oils from olive pomace can lead to more unsaturated meat products and, especially in the case of olive pomace acid oil, achieve a more economically and environmentally sustainable swine production. The objective of this trial was to study the effect of dietary supplementation with crude and acid oils from olive pomace, which are rich in monounsaturated fatty acids (FAs) and have differing free FA content, on growth performance, digestibility, carcass parameters and FA profile of Longissimus muscle (LM) and backfat in growing-finishing pigs compared to the conventional crude palm oil. A total of 224 male and female pigs [(Landrace × Large White) × Duroc] were randomly distributed into 48 pens according to initial BW (58.7 ± 9.71 kg, mean ± SD) and sex. Four experimental treatments were randomly assigned (n = 12 pens/treatment; 4–5 pigs/pen) for the growing (0–42 days) and finishing (40–62 days) phases. Treatments consisted of a basal diet supplemented with 5% (as-fed basis) palm oil (PO), olive pomace oil (O), olive pomace acid oil (OA) or a mixture (M) of PO and OA at 50/50. No differences were found in the growth performance results between PO, O or M, but animals fed OA showed a lower gain to feed ratio than M (P = 0.008). No differences were found in apparent ileal digestibility among treatments, however, animals fed O and OA showed the highest values of total FA apparent total tract digestibility, while those fed PO had the lowest values, and M had intermediate values (P < 0.001). No differences were observed in carcass composition among treatments. In relation to backfat and the LM FA profile, O and OA treatments led to a higher unsaturated FA to saturated FA ratio and a lower content in saturated FA than PO. Moreover, O showed a higher intramuscular fat (IMF) content in LM than PO (P = 0.037). It is concluded that olive pomace oil is an interesting alternative fat source that can be included at 5% in growing-finishing pig diets, leading to meat products with more IMF, rich in monounsaturated FA, reaching high FA digestibility values and good pig performance parameters. Alternatively, olive pomace acid oil blended with conventional palm oil did not negatively impact fat utilisation nor performance. Including these fat by-products reduced feeding costs and led to a more efficient and environmentally sustainable production.     

Two-phase olive mill waste composting: enhancement of the composting rate and compost quality by grape stalks addition

Two-phase olive mill waste (TPOMW) is a semisolid sludge generated by the olive oil industry. Its recycling as a soil amendment, either unprocessed or composted, is being promoted as a beneficial agricultural practice in the Mediterranean area. One of the major difficulties when composting TPOMW is the compaction of the material due to its dough-like texture, which leads to an inadequate aeration. For this reason, the addition of bulking agents is particularly important to attain a proper composting process. In this study we followed the evolution of two composting mixtures (A and B) prepared by mixing equal amounts of TPOMW and sheep litter (SL) (in a dry weight basis). In pile B grape stalks (GS) were added (10% dry weight) as bulking agent to study their effect on the development of the composting process and the final compost quality. The incorporation of grape stalks to the composting mixture changed the organic matter (OM) degradation dynamics and notably reduced the total amount of lixiviates. The evolution of several maturation indices (C/N, germination index, water soluble carbon, humification indices, C/N in the leachates) showed a faster and improved composting process when GS were added. Moreover, chemical (NH₄ ⁺, NO₃ ⁻, cation exchange capacity, macro and micronutrients, heavy metals) and physical properties (bulk and real densities, air content, total water holding capacity, porosity) of the final composts were analysed and confirmed the superior quality of the compost where GS were added.     

Novel static composting method for bioremediation of olive mill waste

This paper presents results obtained on the evaluation of static composting process aimed at bioremediation of the hazardous solid olive mill waste (OMW). The static composting process carried out in gas-permeable polyethylene bags followed the fluctuating temperature and oxygen profiles similar to those seen in aerated composting systems. Static composting resulted in apparent increases and decreases in values for total nitrogen and C:N ratios respectively during the process. The amount of nitrogen (>3%) in the composting end product was in agreement with the Italian legislation (Decreto Legislativo 29 aprile 2010, n. 75) specification for nitrogen fertilizer. A gradual decrease in polyphenols during the storage of compost resulted in a non-phytotoxic composted organic matter high in humic substances. Different respirometric tests also stated high biological stability of the end compost product.     

Bench-scale and packed bed sorption of methylene blue using treated olive pomace and charcoal

A combination of olive pomace after solvent extraction and charcoal produced from the solid waste of olive oil press industry was used as an adsorbent for the removal of methylene blue (MB) dye from aqueous solutions. Batch tests showed that up to 80% of dye was removed when the dye concentration was 10 mg/ml and the sorbent concentration was 45 mg/ml. An increase in the olive pomace concentration resulted in greater dye removal from aqueous solution, and an increase in MB dye concentration at constant adsorbent concentration increased the dye loading per unit weigh of adsorbent. In the kinetic of the adsorbent process, the adsorption data followed the second-order kinetic model better than first order kinetic model. Charcoal showed higher sorption capacity (uptake) than that of olive pomace. In the fixed bed adsorption experiment, the breakthrough curves showed constant pattern behavior, typical of favorable isotherms. The breakthrough time increased with increasing bed height, decreasing flow rate and decreasing influent concentration and methylene blue dye uptake. The uptake of MB dye was significantly increased when a mixture of olive pomace and charcoal was packed in the column in a multi-layer fashion. Different models were used to describe the behavior of this packed-sorption process.     

Rotary drum composting of vegetable waste and tree leaves

High rate composting studies on institutional waste, i.e. vegetable wastes, tree leaves, etc., were conducted on a demonstration-scale (3.5 m³) rotary drum composter by evaluating changes in some physico-chemical and biological parameters. During composting, higher temperature (60–70 °C) at inlet zone and (50–60 °C) at middle zone were achieved which resulted in high degradation in the drum. As a result, all parameters including TOC, C/N ratio, CO₂ evolution and coliforms were decreased significantly within few days of composting. Within a week period, quality compost with total nitrogen (2.6%) and final total phosphorus (6 g/kg) was achieved; but relatively higher final values of fecal coliforms and CO₂ evolution, suggested further maturation. Thus, two conventional composting methods namely windrow (M1) and vermicomposting (M2) tried for maturation of primary stabilized compost. By examining these methods, it was suggested that M2 was found suitable in delivering fine grained, better quality matured compost within 20 days of maturation period.     

Using long-term averted goats for selective grazing in olive groves

Conditioned taste aversion (CTA) is a useful tool to modify animal feed preferences, allowing the implementation of selective grazing to control weeds in tree orchards without damaging the trees or affecting fruit production. LiCl is commonly used for inducing CTA. However, studies investigating the long-term persistence of CTA by LiCl in small ruminants are scarce. With this aim, we evaluated the efficiency of two LiCl doses (AV1 and AV2, 175 and 200 mg/kg BW, respectively) and a control (C, 0 mg/kg BW) for averting non-lactating dairy goats (n=15) to olive tree leaves. Aversion induction was reinforced on day 9 in those goats that consumed >10 g of olive leaves. Mid-term aversion effectiveness was assessed by five double-choice feeding tests (days 16, 24, 31, 38 and 53) of 30 min each, where 100 g of olive leaves were offered side-by-side with 390 g of Italian rye-grass (as-fed). Long-term aversion effectiveness was assessed in C, AV1 and AV2 goats by grazing for 30 min in paddocks with a simulated olive tree (days 59, 90, 121, 182 and 420). Moreover, C and AV2 goats were compared under on-field conditions (days 143, 211 and 363) in a commercial olive grove also for 30 min. The CTA proved to be established with a single LiCl dose in all goats and persisted for 4 and 55 days in AV1 and AV2 goats, respectively (P<0.001). However, 80% AV1 and 20% AV2 goats needed to be reinforced at day 9. When grazing under simulated olive tree and commercial olive grove conditions, the CTA goats, especially AV2 group, avoided the contact with the olive trees and minimally used a bipedal stance to feed leaves, than control goats. On average, time proportion spent consuming olive leaves and sprouts was much greater (P<0.05) for C (50.7±9.1%) than for AV1 (14.4±3.9%) and AV2 (3.1±0.9%). In conclusion, the 200 mg LiCl/kg BW dose was more effective than the 175 mg LiCl/kg BW dose for inducing an effective long-term CTA to olive tree leaves in goats.     

橄榄果渣乙醇提取物成分分析及抗氧化和抑菌性能研究

橄榄果渣中生物活性成分丰富。本文主要研究橄榄果渣提取物成分及其对灰葡萄孢的抑菌性能。首先以橄榄果渣为原料,采用加热回流法,分别以H₂O、50%乙醇、70%乙醇和90%乙醇为提取剂,得到四种提取物并采用HPLC和GC-MS对提取物进行成分分析。其次测定了提取物的总酚含量、抗氧化性和对灰葡萄孢的抑菌性能。研究表明,90%乙醇提取物的酚类含量较高,抗氧化水平优良,并且对灰葡萄孢有明显的抑制作用。该研究为橄榄果渣活性成分在抑菌性能方面的研究提供了一定的理论依据。     

Co-composting of soybean residues and leaves in Hong Kong

The goal of this project was to evaluate the feasibility of co-composting of soybean residues and leaves and the effects of turning frequency on compost quality. Soybean residues were mixed with leaves and sawdust in 1:1:3 (w/w wet weight) for achieving a C/N ratio of about 30. Three heaps of about 4 m3 of compost mixtures were prepared receiving a turning frequency of daily (pile A), 3-day (pile B) and weekly (pile C) turning. Different turning frequencies did not significantly affect the changes in pH and volatile solids throughout the composting period. High turning frequency caused a lower electrical conductivity and NH4-N contents as well as a shorter duration of thermophilic phase, because of a high heat loss by evaporation and volatilization of ammonia in the pile. The highest C decomposition of 4% occurred in the pile with a 3-day turning period, which coincided with the higher-nitrogen content in this treatment. All treatments with different turning frequencies reached maturation at 63 days as indicated by the soluble organic carbon, soluble NH4-N, C/N ratio and cress seed germination index. However, increasing the aeration during composting period was beneficial in accelerating the maturation process. Taking into consideration less labour and lower operation costs as compared to daily turning, it can be suggested that a 3-day turning frequency would be more appropriate for reaching acceptable quality of compost and ease in operation.     

Bio-degradation of lignin in olive pomace by freshly-isolated species of Basidiomycete

The solid waste (pomace) from olive oil processing cannot be used directly as an animal feed, but it was thought that an appropriate series of fermentations might improve its nutritional value. As a first step, typical samples of pomace were subjected, after an alkaline pre-treatment, to delignification by Phanerochaete chrysosporium (ATCC 19343), Oxysporus sp., Schizophyllum commune, Hyphoderma sp. or Ganoderma sp.; the last four species being freshly isolated from decaying wood collected in a woodland in Jordan. The relative activity of the species was judged by the levels of ligninase or laccase secreted and the extent of lignin degradation under a range of experimental conditions. Oxysporus sp. (ca. 69%) and S. commune (ca. 53%) gave significantly higher levels of breakdown of the lignified material than the other recent isolates. P. chrysosporium (ca. 60%) was not as active as in previously reported studies, and it may be that culturing the fungus on a standard laboratory medium had reduced its ability to generate ligninase. Further work is needed to establish whether the delignified pomace could be further processed into a feed for poultry.     

Composting of tannery effluent with cow manure and wheat straw

Wastewater from the leather industry in León (Guanajuato, México) is discharged into the Turbio river without treatment. Tannery wastewater contains utilizable nutrients, but also toxic organic compounds which might affect soil processes and plant growth, and pathogens, which might pose a threat to the local farming community. Tannery effluent was composted with cow manure and wheat straw for 90 days to reduce pathogens and toxic organic compounds and monitored. The compost was characterized by an electrolytic conductivity (EC) of 28.1 ms cm(-1), cation exchange capacity of 17.7 meq 100 g(-1), an absorbance at 645 nm of 0.0175, a respiration rate of 0.062 mg CO2-C kg(-1) compost-C day(-1), pH 8.5 and C:N ratio 7:1 with a germination index for cress (Lepidium sativum) of 48% after 90 days. Less than 10 faecal coliforms and no Salmonella sp., Shigella sp. or eggs of helminthes were detected in the compost while total coliforms decreased by log10 of 2. Total concentrations of lead (Pb) were 8.9 mgkg(-1) dry compost, chromium (Cr) 77 mg kg(-1) dry compost, cadmium (Cd) 0.4 mg kg(-1) dry compost, copper (Cu) 10.3 mg kg(-1) dry compost and sodium (Na) 14,377 mg kg(-1) dry compost. The compost characteristics indicated that it was mature, but the germination index for cress of less than 50% suggested possible remaining phytotoxic compounds. However, the large salt concentrations (especially Na), might have inhibited cress development and thus reduced the germination index. The large salt concentration might thus limit the use of this kind of compost.     

Characters of aerated compost tea from immature compost that limit colonization of bean leaflets by Botrytis cinerea

Aims: The aim was to produce and characterize an aerated compost tea (ACT) that suppressed growth of the plant pathogen Botrytis cinerea. Methods and Results: Three different open‐windrow composts were sampled weekly from the early secondary mesophilic stage until maturity. Each 10 kg of compost sample was extracted in 30 l of aerated water for 24, 48 or 72 h. Relative to water, all batches of ACT applied to detached bean leaflets reduced lesion development following single‐point inoculations of B. cinerea. There was a significant linear, inverse relationship between the internal windrow temperature of compost (≤51°C) used to prepare ACT and the extent of lesion development. Bacterial diversity in ACTs from one windrow was highest using compost sampled at 48°C. The compost weight‐to‐water volume ratios of 1 : 3, 1 : 10 or 1 : 30, using compost sampled from a fourth windrow at 50°C, also produced ACTs that reduced the growth of B. cinerea on bean leaflets. The ‘1 : 3’ ACT, and to a lesser degree the same ACT filtered to remove micro‐organisms, inhibited the germination of B. cinerea conidia. Conclusions: ACT produced using the methods reported here suppressed the growth of B. cinerea on bean leaflets, with an abundant and diverse microbial community likely to contribute to pathogen suppression. Significance and Impact of the Study: This is the first report of the use of immature compost to produce a pathogen‐suppressive ACT, suggesting that compost stage is an important production variable.     

Characterization of compost produced from separated pig manure and a variety of bulking agents at low initial C/N ratios

The aim of this study was to investigate the composting of separated pig manure solids with or without a variety of bulking agents at a low initial C/N ratio (12.5-23.3). Compost stability was investigated using an oxygen uptake rate (OUR) test and compost maturity was investigated using a germination index test. All treatments showed typical patterns of compost temperature. Temperatures above 60 °C were achieved by Day 2, followed by a thermophilic phase (50-60 °C), which lasted for 1 to 2 weeks followed by a cooling phase. The stability of one of treatments which did not contain any bulking agent - OUR of 25 mmol O₂ kg⁻¹ OM hour⁻¹ - was negatively affected by its initial high water content (69%). The addition of a bulking agent and initial water content below 60% were necessary to compost the separated solid fraction of pig manure at a low initial C/N ratio.     

Long-chain fatty alcohols from pomace olive oil modulate the release of proinflammatory mediators

Pomace olive oil is a by-product of olive oil extraction that is traditionally produced and consumed in Spain. The nonglyceride matter of this oil is a good source of interesting minor compounds, like long-chain fatty alcohols, which are present free or as part of waxes. In the present study, long-chain fatty alcohols were isolated from the nonglyceride fraction of pomace olive oil, and the composition was identified and quantified. The major components of long-chain fatty alcohols were tetracosanol, hexacosanol and octacosanol. We investigated the ability of long-chain fatty alcohols from pomace olive oil to inhibit the release of different proinflammatory mediators in vitro by cells involved in inflammatory processes. Long-chain fatty alcohols significantly and dose-dependently decreased nitric oxide production by RAW 264.7 murine macrophages stimulated with lipopolysaccharide. Western blot analysis showed that nitric oxide reduction was a consequence of the inhibition of inducible nitric oxide synthetase expression. Long-chain fatty alcohols also reduced tumor necrosis factor-alpha and prostaglandin E(2) production, although the potency of inhibition for the latter was lower. On the other hand, long-chain fatty alcohols significantly reduced thromboxane A(2) production in rat peritoneal neutrophils stimulated with the calcium ionophore A-23187. The reduction of eicosanoid release was related to the inhibition of phospholipase A(2) enzyme activity by long-chain fatty alcohols, reaching an inhibitory concentration 50% value of 6.2 microg/ml. These results showed that long-chain fatty alcohols may have a protective effect on some mediators involved in the inflammatory damage development, suggesting its potential value as a putative functional component of pomace olive oil.     

Bio-degradation of olive mill wastewater sludge by its co-composting with agricultural wastes

The use of maize straw (MS) or cotton waste (CW) as bulking agents in the composting of olive mill wastewater (OMW) sludge was compared by studying the organic matter (OM) mineralisation and humification processes during composting and the characteristics of the end products. Both composts were prepared in a pilot-plant using the Rutgers static-pile system. The use of CW instead of MS to compost OMW sludge extended both the thermophilic and bio-oxidative phases of the process, with higher degradation of polymers (mainly lignin and cellulose), a greater formation of nitrates, higher total nitrogen losses and a lower biological nitrogen fixation. The CW produced a compost with a more stabilised OM and more highly polymerised humic-like substances. In the pile with CW and OMW sludge, OM losses followed a first-order kinetic equation, due to OM degradation being greater at the beginning of the composting and remaining almost constant until the end of the process. However, in the pile with MS and OMW sludge this parameter followed a zero-order kinetic equation, since OM degraded throughout the process. The germination index indicated the reduction of phytotoxicity during composting.     

Validation of thermal composting process using olive mill solid waste for industrial scale cultivation of Agaricus bisporus

The production of a substrate containing destoned olive mill solid waste for the cultivation of Agaricus bisporus (Lange) Imbach on an industrial scale was studied. A standard mushroom compost (C) mainly made from straw and poultry manure was compared with the experimental compost (EC) containing the same ingredients as (C) but with added olive mill solid waste (10.6% w/w). Microbial indicators such as counts of heterotrophic microbes and actinomycetes were higher in EC than in C. In addition, compost selectivity as indicated by higher mushroom yield and biological efficiency of EC was higher than that of C. Market quality of the mushrooms produced in both C and EC were comparable. These findings support our work that olive mill solid waste can be used safely in thermal composting process to produce a selective substrate for industrial-scale cultivation of A. bisporus. This study also demonstrates an environmentally sustainable system to manage solid waste from olive oil extraction processes thus overcoming environmental pollution brought about by irrational disposal of the waste on farm lands.