Reduction of the phenolic components in olive-mill wastewater by an enzymatic treatment and its impact on durum wheat (Triticum durum Desf.) germinability

Olive Mill Waste-Water Extract Enriched in Hydroxytyrosol and Tyrosol Modulates Host-Pathogen Interaction in IPEC-J2 Cells

The dietary supplementation of olive oil by-products, including olive mill waste-water (OMWW) in animal diets, is a novel application that allows for their re-utilization and recycling and could potentially decrease the use of antibiotics, antimicrobial resistance risk in livestock species, and the occurrence of intestinal diseases. Salmonella serovar typhimurium is one of the most widespread intestinal pathogens in the world, causing enterocolitis in pigs. The aim of this study was to investigate the effect of an OMWW extract enriched in polyphenols (hydroxytyrosol and tyrosol) in the immune response of an intestinal porcine epithelial cell line (IPEC-J2) following S. typhimurium infection. Cells were pre-treated with OMWW-extract polyphenols (OMWW-EP, 0.35 and 1.4 µg) for 24 h and then infected with S. typhimurium for 1 h. We evaluated bacterial invasiveness and assayed IPEC-J2 gene expression with RT-qPCR and cytokine release with an ELISA test. The obtained results showed that OMWW-EP (1.4 µg) significantly reduced S. typhimurium invasiveness; 0.35 µg decreased the IPEC-J2 gene expression of IL1B, MYD88, DEFB1 and DEFB4A, while 1.4 µg down-regulated IL1B and DEFB4A and increased TGFB1. The cytokine content was unchanged in infected cells. This is the first study demonstrating the in vitro immunomodulatory and antimicrobial activity of OMWW extracts enriched in polyphenols, suggesting a protective role of OMWW polyphenols on the pig intestine and their potential application as feed supplements in farm animals such as pigs.

Olive mill wastewater treatment using natural adsorbents: phytotoxicity on durum wheat (Triticum turgidum L. var. durum) and white bean (Phaseolus vulgaris L.) seed germination

This research was undertaken to optimize the phenolic compound removal from Olive Mill Wastewater (OMW) by sawdust and red clay as natural adsorbents. Fractional factorial experimental design at 25-1 was used in order to optimize the experimental conditions for high removal efficiency. Statistics ANOVA analysis, Fisher's test, and Student's test suggested that the adsorbent dose has the most significant influence on polyphenol removal for both adsorbents. The maximum removal of polyphenols by sawdust reached 49.6% at 60 °C by using 60 g/L of adsorbent dose, pH 2, reaction time of 24 h, and agitation speed of 80 rpm. Whereas, for red clay, 48.08% of polyphenols removal was observed under the same conditions for sawdust except the temperature of 25 °C instead of 60 °C. In addition, the thermodynamic parameters suggested spontaneous process for both adsorbents, endothermic for the sawdust and exothermic for red clay. Furthermore, the phytotoxicity effect of OMW on durum wheat (Triticum turgidum L. var. durum) and white bean (Phaseolus vulgaris L.) seed germination was investigated. The obtained results showed that the untreated OMW inhibited the seed germination of T. turgidum and P. vulgaris seeds. OMW treatment with red clay followed by dilution (95% water) resulted in 87 and 30% germination of P. vulgaris and T. turgidum, respectively. While, the treatment of OMW with sawdust and dilution at 95% resulted in 51 and 26% germination of P. vulgaris and T. turgidum, respectively.

Transcriptomic Analysis of Colorectal Cancer Cells Treated with Oil Production Waste Products (OPWPs) Reveals Enrichment of Pathways of Mitochondrial Functionality

Oil production waste products (OPWPs) derive from olive mill and represent a crucial environmental problem due to their high polyphenolic content able to pollute the ground. One option to reduce the OPWPs' environmental impact is to exploit polyphenols' biological properties. We sought to analyze the transcriptomic variations of colorectal cancer cells exposed to the OPWPs extracts and hydroxytyrosol, the major component, to recognize unknown and ill-defined characteristics. Among the top affected pathways identified by GSEA, we focused on oxidative phosphorylation in an in vitro system. Colorectal cancer HCT116 and LoVo cells treated with hydroxytyrosol or OPWPs extracts showed enhancement of the respiratory chain complexes' protein levels, ATP production and membrane potential, suggesting stimulation of mitochondrial functions. The major proteins involved in mitochondrial biogenesis and fusion events of mitochondrial dynamics were positively affected, as by Western blot, fostering increase of the mitochondrial mass organized in a network of elongated organelles. Mechanistically, we proved that PPARγ mediates the effects as they are mimicked by a specific ligand and impaired by a specific inhibitor. OPWP extracts and hydroxytyrosol, thus, promote mitochondrial functionality via a feed-forward regulatory loop involving the PPARγ/PGC-1α axis. These results support their use in functional foods and as adjuvants in cancer therapy.

Sustainable vs. Conventional Approach for Olive Oil Wastewater Management: A Review of the State of the Art

The main goal of this review is to collect and analyze the recently published research concerning the conventional and sustainable treatment processes for olive mill wastewater (OMW). In the conventional treatment processes, it is noticed that the main objective is to meet the environmental regulations for remediated wastewater without considering the economical values of its valuable constituents such as polyphenols. These substances have many important environmental values and could be used in many vital applications. Conversely, sustainable treatment processes aim to recover the valuable constituents through different processes and then treat the residual wastewater. Both approaches’ operational and design parameters were analyzed to generalize their advantages and possible applications. A valorization-treatment approach for OMW is expected to make it a sustainable resource for ingredients of high economical value that could lead to a profitable business. In addition, inclusion of a recovery process will detoxify the residual OMW, simplify its management treatment, and allow the possible reuse of the vast amounts of processed water. In a nutshell, the proposed approach led to zero waste with a closed water cycle development.

Polyphenols Extracts from Oil Production Waste Products (OPWPs) Reduce Cell Viability and Exert Anti-Inflammatory Activity via PPARγ Induction in Colorectal Cancer Cells

Olive oil production is associated with the generation of oil production waste products (OPWPs) rich in water-soluble polyphenols that represent serious environmental problems. Yet OPWPs can offer new opportunities by exploiting their bioactive properties. In this study, we chemically characterized OPWPs polyphenolic extracts and investigated their biological activities in normal and colorectal cancer cells. Hydroxytyrosol (HTyr), the major constituent of these extracts, was used as the control. We show that both HTyr and the extracts affect cell viability by inducing apoptosis and cell cycle arrest. They downregulate inflammation by impairing NF-κB phosphorylation and expression of responsive cytokine genes, as TNF-α and IL-8, at both mRNA and protein levels, and prevent any further increase elicited by external challenges. Mechanistically, HTyr and the extracts activate PPARγ while hampering pro-inflammatory genes expression, acting as a specific agonist, likely through a trans-repression process. Altogether, OPWPs polyphenolic extracts show stronger effects than HTyr, conceivably due to additive or synergistic effects of all polyphenols contained. They display anti-inflammatory properties and these results may pave the way for improving OPWPs extraction and enrichment methods to reduce the environmental impact and support their use to ameliorate the inflammation associated with diseases and tumors.

Machine Learning Approach to Predict Quality Parameters for Bacterial Consortium-Treated Hospital Wastewater and Phytotoxicity Assessment on Radish, Cauliflower, Hot Pepper, Rice and Wheat Crops

Raw hospital wastewater is a source of excessive heavy metals and pharmaceutical pollutants. In water-stressed countries such as Pakistan, the practice of unsafe reuse by local farmers for crop irrigation is of major concern. In our previous work, we developed a low-cost bacterial consortium wastewater treatment method. Here, in a two-part study, we first aimed to find what physico-chemical parameters were the most important for differentiating consortium-treated and untreated wastewater for its safe reuse. This was achieved using a Kruskal–Wallis test on a suite of physico-chemical measurements to find those parameters which were differentially abundant between consortium-treated and untreated wastewater. The differentially abundant parameters were then input to a Random Forest classifier. The classifier showed that ‘turbidity’ was the most influential parameter for predicting biotreatment. In the second part of our study, we wanted to know if the consortium-treated wastewater was safe for crop irrigation. We therefore carried out a plant growth experiment using a range of popular crop plants in Pakistan (Radish, Cauliflower, Hot pepper, Rice and Wheat), which were grown using irrigation from consortium-treated and untreated hospital wastewater at a range of dilutions (turbidity levels) and performed a phytotoxicity assessment. Our results showed an increasing trend in germination indices and a decreasing one in phytotoxicity indices in plants after irrigation with consortium-treated hospital wastewater (at each dilution/turbidity measure). The comparative study of growth between plants showed the following trend: Cauliflower > Radish > Wheat > Rice > Hot pepper. Cauliflower was the most adaptive plant (PI: −0.28, −0.13, −0.16, −0.06) for the treated hospital wastewater, while hot pepper was susceptible for reuse; hence, we conclude that bacterial consortium-treated hospital wastewater is safe for reuse for the irrigation of cauliflower, radish, wheat and rice. We further conclude that turbidity is the most influential parameter for predicting bio-treatment efficiency prior to water reuse. This method, therefore, could represent a low-cost, low-tech and safe means for farmers to grow crops in water stressed areas.

Treatment of Winery Wastewater with a Combination of Adsorption and Thermocatalytic Processes

The release of winery wastewater (WW) into the environment, without proper treatment, can cause severe problems to freshwater quality and natural fauna and flora. Therefore, in this work a treatment process was studied, combining adsorption and thermocatalytic oxidation processes. In a more specific way, it optimized the combination of activated sodium bentonite (Na-Mt) and potassium persulfate (KPS)/sodium percarbonate (SPC) as oxidant agents. With the combination of best operational conditions of adsorption ([Na-Mt] = 5.0 g/L, pH = 3.0, V = 500 mL, agitation 350 rpm, T = 298 K, t = 24 h) and thermocatalytic oxidation processes (S2O82−/H2O2 ratio = 1:0.25, S2O82−/H2O2 dosage = 0.1:0.025 (g/g), pH = 7.0, T = 343 K, agitation 350 rpm, t = 2 h), a total organic carbon, chemical oxygen demand and total polyphenols removal of 76.7, 81.4 and >99% was achieved, respectively. Finally, it was evaluated the effect of the treatment processes in the germination index (GI) of different plant seeds. A GI > 80% was achieved, showing a low phytotoxicity effect of the processes applied in the winery wastewater treatment.

Combination of Coagulation-Flocculation-Decantation and Ozonation Processes for Winery Wastewater Treatment

This research assessed a novel treatment process of winery wastewater, through the application of a chemical-based process aiming to decrease the high organic carbon content, which represents a difficulty for wastewater treatment plants and a public health problem. Firstly, a coagulation–flocculation–decantation process (CFD process) was optimized by a simplex lattice design. Afterwards, the efficiency of a UV-C/ferrous iron/ozone system was assessed for organic carbon removal in winery wastewater. This system was applied alone and in combination with the CFD process (as a pre- and post-treatment). The coagulation–flocculation–decantation process, with a mixture of 0.48 g/L potassium caseinate and 0.52 g/L bentonite at pH 4.0, achieved 98.3, 97.6, and 87.8% removals of turbidity, total suspended solids, and total polyphenols, respectively. For the ozonation process, the required pH and ferrous iron concentration (Fe²⁺) were crucial variables in treatment optimization. With the application of the best operational conditions (pH = 4.0, [Fe²⁺] = 1.0 mM), the UV-C/ferrous iron/ozone system achieved 63.2% total organic carbon (TOC) removal and an energy consumption of 1843 kWh∙m⁻³∙order⁻¹. The combination of CFD and ozonation processes increased the TOC removal to 66.1 and 65.5%, respectively, for the ozone/ferrous iron/UV-C/CFD and CFD/ozone/ferrous iron/UV-C systems. In addition, the germination index of several seeds was assessed and excellent values (>80%) were observed, which revealed the reduction in phytotoxicity. In conclusion, the combination of CFD and UV-C/ferrous iron/ozone processes is efficient for WW treatment.

Olive Mill Wastewater as Renewable Raw Materials to Generate High Added-Value Ingredients for Agro-Food Industries

Olive oil production represents an agro-industrial activity of vital economic importance for many Mediterranean countries. However, it is associated with the generation of a huge amount of by-products, both in solid and liquid forms, mainly constituted by olive mill wastewater, olive pomace, wood, leaves, and stones. Although for many years olive by-products have only been considered as a relevant environmental issue, in the last decades, numerous studies have deeply described their antioxidant, anti-inflammatory, immunomodulatory, analgesic, antimicrobial, antihypertensive, anticancer, anti-hyperglycemic activities. Therefore, the increasing interest in natural bioactive compounds represents a new challenge for olive mills. Studies have focused on optimizing methods to extract phenols from olive oil by-products for pharmaceutical or cosmetic applications and attempts have been made to describe microorganisms and metabolic activity involved in the treatment of such complex and variable by-products. However, few studies have investigated olive oil by-products in order to produce added-value ingredients and/or preservatives for food industries. This review provides an overview of the prospective of liquid olive oil by-products as a source of high nutritional value compounds to produce new functional additives or ingredients and to explore potential and future research opportunities.

Treatment of wastewater containing oil and grease by biological method- a review

One of the complex environmental problems that triggers at present is oily wastewater contamination arising out of the activities related to engineering vehicular (automobile) workshop or garage, kitchens in houses and restaurants, gas stations, metal finishing house, petrochemical industry, edible oil production unit etc. Oily wastewater discharge is a major issue of environmental pollution in the present decade as some of its constituents are hazardous in nature. Hence, appropriate treatment technology for oily wastewater needs to be addressed. Biological treatment (BT) technique would be the best option in this regard, because it has multiple advantages over various other techniques as available today. BT degrades effectively the harmful constituents of oily wastewater into innocuous products that are environment friendly and it is considered to be the economical method. The resulting effluent of pretreatment followed by biological treatment of oily wastewater can be reused after conforming discharge limits. Again, numerous research works in these days have optimized the function and result of existing laboratory and pilot scale treatment technologies. This review paper describes a comprehensive understanding of the origin and characteristics, existing techniques in laboratory and pilot scale, screening of different methods, justification for advocating biological methods for treatment of oily wastewater.

Biochar production from Cypress sawdust and olive mill wastewater: Agronomic approach

Olive mill wastewater (OMW) is nowadays considered as a serious source pollution. At the same time, it contains high amounts of nutrients, especially potassium and phosphorus that could be recovered for agricultural purposes. The aim of the current experimental research work is to investigate the agronomic potential use of OMW based biochar produced from the slow pyrolysis at 500 °C of raw cypress sawdust (CS) impregnated with OMW (ICS-OMW-B). In order to understand the contribution of OMW, two additional biochars were produced from raw cypress sawdust (RCS-B) and cypress sawdust pretreated with potassium chloride (ICS-K-B). Results indicated that RCS impregnation by OMW significantly improved the produced biochar's chemical properties, especially its nutrients contents. Furthermore, in comparison with the other biochars, ICS-OMW-B application as an organic fertilizer showed promising results in terms of produced fresh and dry masses, as well as potassium bioavailability as assessed in test experiments with ryegrass. For instance, the dry matter masses of the rye-grass treated with ICS-OMW-B were about 23, 34 and 50 wt% higher than the ones measured for the tests using RCS-B, ICS-K-B and synthetic K-fertilizer as amendments, respectively. Besides, this biochar has a potential effect on the suppression of various pathogens existing in the tested agricultural soil. All these results demonstrated that the biochar generated from the slow pyrolysis of impregnated sawdust with OMW could be considered as attractive and promising organic fertilizer for acidic agricultural soils.

Physicochemical and microbiological characterization of olive mill wastewater (OMW) from different regions of northern Morocco

This work examined the influence of crop season, extraction system and production site on the composition of fresh olive mill wastewater collected from northern Morocco. ANOVA analysis showed that most of the traits were largely affected by the extraction system (≥60% of total variance). Comparison among extraction systems showed significant differences for all traits, except for chlorides. Three phase centrifugation system (C3) displayed the highest value of total phenols, while all the remaining traits were higher in two phase centrifugation system (C2). Concerning crop seasons, we noticed a general decrease in values of total solids, chemical oxygen demand, chlorides, C/N ratio and total aerobic mesophilic flora, from 2014 to 2016 season; in contrast, an increase in suspended solids, total kjeldahl nitrogen and proteins was detected. OMW with highest total phenols content and then more acidic were collected during 2015 season. Between production sites, Bni Frassen produced OMW with the highest values for salt and total phenols, but the lowest ones were obtained for microbiological traits. OMW from Taza were rich in total kjeldahl nitrogen and proteins. An increase in organic load indicators was observed in Bouchfaa. Principal component analysis (PCA) explained about 82% of total variability: 58%, 16% and 8% for principal component 1 (PC1), PC2 and PC3, respectively. Extraction system fitted the variability of PC1. PC2 was mainly explained by production sites, while PC3 separated crop seasons. Correlation studies showed significant relationships especially among the traits expressing organic load, while microbiological counts were largely associated to total phenols and pH.

Industrial scale bio-detoxification of raw olive mill wastewaters by the use of selected microbial yeast and bacterial strains to obtain a new source for fertigation

The Olive Mill Wastewaters (OMWs) are one of the most important agro-industrial wastes of the Mediterranean Countries and the disposal by draining them onto land has been proved to be damaging for soils, plants and groundwater due to their polluting power. The present report describes a new method for bio-detoxification of undiluted fresh OMW based on the driven selection of aerobic yeasts and bacteria. The identified yeast Candida boidinii A5y and the bacterium Paenibacillus albidus R32b strains allowed the treatment of freshly produced raw OMW characterized by very high COD value and phenolic content, when applied as sequential inoculum. The treated OMW showed the absence of antimicrobial effects and a strongly reduction of phytotoxic activity on the germination of several plant seeds. The process was successfully validated on an industrial scale without any pre-treatment, dilution and/or supplementation of the raw waste. Bio-detoxified OMW produced by this sustainable and low-cost process would be suitable for new non-chemical fertigation or soilless applications. The described procedure represents a virtuous example of circular economy efficaciously applied for a depleting agri-food resource.

Deriving valorization of phenolic compounds from olive oil by-products for food applications through microencapsulation approaches: a comprehensive review

Nowadays, olive oil consumption is correlated to many health benefits, essentially due to the presence of antioxidants, especially phenolic compounds, which fostered its intensive production worldwide. During olive oil extraction, through continuous or discontinuous processes, many olive oil by-products are generated. These by-products constitute an environmental problem regarding its management and disposal. They are phytotoxic and biotoxic due to their high content of phenolic compounds, presenting contrastingly relevant health benefits due to their potent radical scavenging activities. In the framework of the disposal and management of olive oil by-products, treatment, and valorization approaches are found. As currently, the majority of the valorization techniques applied have a null market value, alternative strategies for the obtainment of innovative products as fortified foods are being investigated. The recovery and valorization strategies of olive oil by-products may comprise extraction and further encapsulation of bioactive compounds, as an innovative valorization blueprint of phenolic compounds present in these by-products. The majority of phenolic compounds present in olive oil by-products possess limited application on the food industry since they are promptly amended by environmental factors like temperature, pH, and light. Consequently, they must be protected previously ending in the final formulation. Prior to foods fortification with phenolic-rich extracts obtained from olive oil by-products, they should be protected through microencapsulation approaches, allowing a sustained release of phenolic compounds in the fortified foods, without losing their physicochemical properties. The combined strategies of extraction and microencapsulation will contribute to promoting the sustainability of the olive oil sector and aid the food industry to obtain reinvented added-value products.

Reuse of Food Waste and Wastewater as a Source of Polyphenolic Compounds to Use as Food Additives

The problem of waste and byproducts generated from agro-industrial activities worldwide is an increasing concern in terms of environmental sustainability. In this ambit, the quantity of food wastes—produced in all steps of the whole food chain—is enormous, and it may be forecasted that food waste could amount to more than 120 billion tonnes by 2020. The reuse of food waste and wastewater as source of polyphenolic compounds could be an interesting discussion in this ambit. In fact, polyphenols obtained in this way might be used for food and non-food purposes by means of new, improved, and safe extraction methods. In light of the opportunity represented by the treatment of agro-industrial waste, different systems concerning the winemaking and olive oil production industries have also been discussed as describing approaches applicable to other sectors. More research is needed before considering recovery of phenolic compounds from wastewater as an economically convenient choice for the food sector.

Phytotoxicity assessment of olive mill wastewater treated by different technologies: effect on seed germination of maize and tomato

The phytotoxicity effect of olive mill wastewater (OMWW) treated in a combined system regrouping pretreatment by filtration on olive stones and coagulation-flocculation, and anaerobic digestion (AD) on seed germination of maize and tomato was evaluated through germination tests in petri dishes and growth tests in pots. Three samples, referenced as AD-40, AD-60, and AD-80, were collected from the anaerobic reactor operating with an influent at 40, 60, and 80% OMWW/water (% v/v). Concentrations between 25 and 100% were used for maize and between 5 and 25% were used for tomato using raw and pretreated samples, while anaerobic samples were used without dilution. For maize, 100% and 75% OMWW were very phytotoxic and completely prohibited seed germination, while phytotoxicity was decreased following dilution at 25% and 50% OMWW. Maize germinability was found highly enhanced when watered with anaerobic samples. For tomato, high dilution was required to reduce the phytotoxicity of raw and pretreated OMWW and a high relative germination percentage was registered at 5, 10, and 15% OMWW, while for samples anaerobically treated, a high phytotoxicity is still observed. Growth tests, showed more favorable results for maize watered with raw and pretreated samples at 25% OMWW and with biological samples. For tomato and with the exception of 25% OMWW and AD-80, seeds respond positively to all samples. It was concluded that if the OMWW will be used for irrigating maize, it could be directly used after anaerobic digestion, while for tomato further dilution is required. The phenolic profile analysis of the tested samples coupled with the results of the germination tests showed that the OMWW phytotoxicity appears to be determined by not only the monomeric phenols but also by other toxic components unaffected by the applied treatments.

The long term effect of Olive Mill Wastewater (OMW) on organic matter humification in a semi-arid soil

This study investigates the performance of soil and OMW microfloras in OMW organic matter humification in soil. In order to highlight the role of OMW and soil microfloras in the processes of OMW organic matter humification, either OMW or soil was sterilized with autoclaving. The study was carried out in microcosms of 1l containing 500 g of raw or sterilized soil, to which was added 200 ml of raw or sterilized OMW. After 24 months of incubation, the amount of phenolic compounds in the different microcosms was statistically indifferent compared to the control. However, TG-DTA and FTIR analysis of soil humic acids showed that recalcitrant OMW phenolic compounds remain in soil humus in the microcosm: sterilized OMW + raw soil, even after 24 months. Results show that humic acids detected in presence of OMW microflora are loaded with proteins and carbonated compounds and deprived of phenolic compounds and aliphatics with long chain, while humic acids detected in absence of OMW microflora are loaded with phenolic compounds.

Deployment of olive-stone waste as a substitute growing medium component for Brassica seedling production in nurseries

In the Mediterranean region, olive-stone waste (OSW) is accumulated and considered of environmental and human health constraints. In this study, OSW was used for peat (P) replacement in growing media for Brassica seedling production. Cauliflower, broccoli, and cabbage were seeded in growing media consisted of 0-20-40-60% OSW. The mixture of OSW with peat increased growing media bulk density and reduced the total pore space and available water and air at root system. A Considerable amount of minerals were provided into the growing media with the OSW, while their availability was increased with the raised pH values. Seed emergence percentage decreased with high ratio of OSW which also increased mean emergence time. The addition of OSW decreased plant height, leaf number, and fresh weight in all three examined species. The OSW decreased stomatal conductance (in cauliflower and cabbage) and chlorophylls content (including broccoli). The insertion of OSW affected the mineral accumulation in plants with decreases in nitrogen and sodium content and increases in potassium and calcium. OSW increased to some extent for cauliflower and broccoli or unchanged for cabbage polyphenolic content and antioxidant activity (ABTS, FRAP). Cellular damage was caused by the addition of OSW by increasing the lipid peroxidation and the production of hydrogen peroxide, and as a consequence, the plant antioxidative (catalase, superoxide dismutase) enzyme metabolism increased. The current study demonstrates that up to 20% of OSW can substitute peat for cauliflower, broccoli, and cabbage seedling production while cabbage was performed better under the increased OSW-caused stress.

Toxicity evaluation of olive oil mill wastewater and its polar fraction using multiple whole-organism bioassays

Olive mill wastewater (OMW) as a by-product of olive oil extraction process has significant polluting properties mainly related to high organic load, increased COD/BOD ratio, high phenolic content and relatively acidic pH. Raw OMW from Slovenian Istria olive oil mill and its polar fraction were investigated in this study. Chemical characterization of OMW polar fraction identified tyrosol as the most abundant phenolic product, followed by catechol. Lethal and sub-lethal effects of OMW matrix and its polar fraction were tested using a battery of bioassays with model organisms: bacteria Vibrio fischeri, algae Chlorella vulgaris, water fleas Daphnia magna, zebrafish Danio rerio embryos, clover Trifolium repens and wheat Triticum aestivum. Raw OMW sample was the most toxic to V. fischeri (EC₅₀ = 0.24% of OMW sample final concentration), followed by D. magna (EC₅₀ = 1.43%), C. vulgaris (EC₅₀ = 5.20%), D. rerio (EC₅₀ = 7.05%), seeds T. repens (EC₅₀ = 8.68%) and T. aestivum (EC₅₀ = 11.58%). Similar toxicity trend was observed during exposure to OMW polar fraction, showing EC₅₀ values 2.75-4.11 times lower comparing to raw OMW. Tested samples induced also sub-acute effects to clover and wheat (decreased roots, sprouts elongation); and to zebrafish embryos (increased mortality, higher abnormality rate, decreased hatching and pigmentation formation rate). A comprehensive approach using a battery of bioassays, like those used in this study should be applied during ecotoxicity monitoring of untreated and treated OMW.

In vitro activity of antimicrobial compounds against Xylella fastidiosa, the causal agent of the olive quick decline syndrome in Apulia (Italy)

Olive quick decline syndrome (OQDS) causes severe damages to the olive trees in Salento (Apulia, Italy) and poses a severe threat for the agriculture of Mediterranean countries. DNA-based typing methods have pointed out that OQDS is caused by a single outbreak strain of Xylella fastidiosa subsp. pauca referred to as CoDiRO or ST53. Since no effective control measures are currently available, the objective of this study was to evaluate in vitro antimicrobial activities of different classes of compounds against Salento-1 isolated by an OQDS affected plant and classified as ST53. A bioassay based on agar disk diffusion method revealed that 17 out of the 32 tested antibiotics did not affect bacterial growth at a dose of 5 μg disk-1. When we assayed micro-, ultra- and nano-filtered fractions of olive mill wastewaters, we found that the micro-filtered fraction resulted to be the most effective against the bacterium. Moreover, some phenolics (4-methylcathecol, cathecol, veratric acid, caffeic acid, oleuropein) were active in their pure form. Noteworthy, also some fungal extracts and fungal toxins showed inhibitory effects on bacterial growth. Some of these compounds can be further explored as potential candidate in future applications for curative/preventive treating OQDS-affected or at-risk olive plants.

A phytotoxic impact of phenolic compounds in olive oil mill wastewater on fenugreek "Trigonella foenum-graecum"

The objective of this study is the determination of the chemical structure of nine phenolic molecules responsible for the phytotoxic action on the germination of the plant species "Trigonella foenum-graecum". The phytotoxic action was evaluated by calculating the germination index of the plant species for a period of 5 days of incubation. The analysis of the physicochemical properties of phenolic molecules shows that hydrophobicity is a key factor in phytotoxicity. The sublethal concentration varies as follows: hydroquinone (0.91 mM), 4-aminophenol (0.85 mM), phenol (0.75 mM), gallic acid (0.59 mM), caffeic acid (0.56 mM), 3,5-di-tert-butylcatechol (0,45 mM), quercetin (0.33 mM), oleuropein (0.3 mM), and catechol (0.13 mM). Phytotoxicity varies depending on the nature and position of the substituents on the aromatic ring. The reactivity of this type of molecule is partly linked to the presence of catechol function that can play the main role in phytotoxicity of the Fenugreek.

Biostimulant Potential of Humic Acids Extracted From an Amendment Obtained via Combination of Olive Mill Wastewaters (OMW) and a Pre-treated Organic Material Derived From Municipal Solid Waste (MSW)

Olive mill wastewaters (OMW) contain significant levels of phenolic compounds with antimicrobial/phytotoxic activity and high amounts of undecomposed organic matter that may exert negative effects on soil biology. Among OMW detoxification techniques, those focusing on oxidative degradation of phenolic compounds are relevant. The composting (bio-oxidation) process in particular, exploits exothermic oxidation reactions by microorganisms to transform the organic matrix of OMW into an amendment biologically stable and feasible to use in agriculture. This process consists of an active phase during which organic compounds are rapidly decomposed, and a curing phase characterized by a slow breakdown of the remaining materials with the formation of humic substances (HS) as by-products. In this study, bio-oxidation of OMW was performed using a pre-treated organic material derived from municipal solid waste (MSW). The obtained amendment (OMWF) was stable and in accordance with the legislative parameters of mixed organic amendments. HS were then extracted from OMWF and MSW (control amendment, Amd-C), and differences in structural properties of their humic acid (HA) fraction were highlighted via spectroscopy (Fourier Transform Infrared) and Dynamic Light Scattering. To assay a potential use of HA as biostimulants for crops, 12-day old Zea Mays L. plants were supplied with HA at 0.5 mg and 1 mg C L-1 for 2 days. HA from both amendments increased plant growth, but HA from OMWF was more effective at both dosages (plus 35-37%). Also, HA from OMWF enhanced both nitrogen assimilation and glycolysis by increasing the activity of nitrate reductase (∼1.8-1.9 fold), phosphoglucose isomerase (PGI) (∼1.8-2 fold) and pyruvate kinase (PK) (∼1.5-1.8 fold), while HA from Amd-C targeted glycolysis preferentially. HA from OMWF, however, significantly stimulated plant nutrition only at lower dosage, perhaps because certain undetermined compounds from detoxified OMW and incorporated in HA altered the root membrane permeability, thus preventing the increase of nutrient uptake. Conversely, HA from Amd-C increased nutrient accumulation in maize at both dosages. In conclusion, our results indicate that the amendment obtained via OMW composting using MSW had a reduced pollution load in terms of phenolic compounds, and HA extracted from OMWF could be used as valuable biostimulants during maize cultivation.

Effect of compost tea containing phosphogypsum on potato plant growth and protection against Fusarium solani infection

Three composts made of industrial wastes were prepared by mixing olive oil mill waste water (OMW), olive pomace, coffee grounds, and phosphogypsum (0, 10, and 30%). Potato plants (Solanum tuberosum) cultivated in a greenhouse were used to screen compost tea suppressive ability. All compost tea treatments inhibited Fusarium solani growth and improved plant growth and response to F. solani infection. The antagonistic effects of the different treatments were associated with a marked increase of the antioxidant enzymes and PR (pathogenesis related) protein expression and a decrease of disease severity. These results also showed that plant growth and disease suppression were improved by application of phosphogypsum-supplemented compost teas (A10 and A30). This enhancement can be attributed to the influence of phosphogypsum on nutrient elements and microbial diversity in the resulting compost teas.

The Olive Mill Wastewater Decontamination with Photocatalysis Based on Tio2: Effect of Operational Parameters

ABSTRACT: This work aims to obtain treated olive mill wastewater (OMW) that can be used in other processes such as irrigation in agricultural production. The oxidative degradation and adsorption kinetics of the OMW were investigated by means of photo-catalysis in the presence of TiO2. The UV irradiation was chosen for this reaction rather than visible light since it eliminated 97% of the color versus 40 % with visible. It was also capable of reducing total organic carbon (TOC) and total phenolic compounds (TPhC) sufficiently after 4h of treatment. The extent of photocatalytic degradation increased with increasing TiO2 concentration up to 1 g/L, above which degradation rate declined. Furthermore, the OMW treatment didn’t require a pH value adjustment; whereas it was enhanced with the addition of hydrogen peroxide. The catalyst activity on repeated use was evaluated and after four successive cycles, its efficiency was maintained. Various commercial photocatalysts were tested and compared for OMW degradation efficiency.

Use of phenolic compounds from olive mill wastewater as valuable ingredients for functional foods

Olive mill wastewater (OMW) is a pollutant by-product from the virgin olive oil production. Its high content in phenolic compounds makes them play an important role for their use in foods, for their high antioxidant significance. The present paper gives an overview on the techniques for OMW valuable ingredient separation, focusing on the most effective ones for their use in food products as functional ingredients. We report on effective methods to recover OMW phenolics, and give several examples on the use these extracts in foods. When added into vegetable oils, their effect on retarding lipid oxidation improves the oxidative status of the product, whilst several challenges need to be faced. OMW phenolic extracts were also used in food emulsions, milk products or other model systems, showing promising results and little or no negative impact on the sensory characteristics or other properties. Their possible use as antimicrobial agents is also another promising approach, as positive results were obtained when applied in meat products. Other examples of using natural phenolic extracts from other sources are suggested also for OMW extracts, to expand their use and thus to improve the nutritional and technological quality of foods.

Phytotoxic effects of irrigation water depending on the presence of organic and inorganic pollutants

Irrigation is one of the most important uses of surface waters in the agricultural region of Vojvodina province (Serbia). The aim of the study was to assess the quality of water from Stara Tisa meander, based on the levels of pollution with metals, volatile compounds (VOC), pharmaceuticals, pesticides, and pathogenic bacteria, on sunflower, cabbage, cucumber, maize, barley, buckwheat, sorghum, radish, beans, and white mustard. Microbiological analysis was carried out using the dilution method and phytotoxicity assay according to ISTA filter paper method (germination energy (GE), germination (G), root and shoot length, fresh and dry weight). The sample was slightly contaminated with domestic, industrial, and agricultural xenobiotics and had low levels of nitrogen substances, metals, and organic micropollutants. Pesticides, metolachlor, tebuconazole, propiconazole, imidacloprid, and thiametoxam were detected at levels exceeding the maximum admissible concentrations (MACs), i.e., the sum value for neonicotinoids. The number of saprophytic (2.27 × 10(6) CFU mL(-1)) and coliform bacteria (5.33 × 10(2) CFU mL(-1)) was very high. The total number of sulphite reducing clostridia (10 cells mL(-1)) and Escherichia coli (5 cells mL(-1)) was very low. The GE and G of all tested plants, except sunflower, were not influenced by the total chemism of water sample. However, it inhibited root lengths of sunflower, cucumber, maize, and barley and stimulated shoot lengths of all species except maize and white mustard. These results indicate that it can be used for irrigation of cabbage and radish from the chemical point of view, but the microbiological traits should be considered prior to consumption since they are consumed raw. The overall results suggest that water from Stara Tisa should be purified before using for agricultural purposes.

Assessment of Coriolopsis gallica-treated olive mill wastewater phytotoxicity on tomato plants

The aim of the present study was to evaluate the phytotoxicity of olive mill wastewater (OMW) after being treated by the white-rot fungus Coriolopsis gallica. For this, the effect of irrigation with treated OMW (TOMW) and untreated OMW (UOMW) on tomato plants (Lycopersicon esculentum) for 3 weeks was studied. The control plants were irrigated with distilled water. Agronomic tests were performed in pot experiments in a greenhouse using the randomized complete block (RCB) experimental design. The relative leaf height (RLH), as a morphological parameter, and the content of total phenols in the roots and total chlorophyll [Cha + Chb] and reducing sugars in the leaves, as physiological parameters, were selected as responses of the experimental design. The results obtained showed that [Cha + Chb] in the leaves of tomato growth under TOMW was enhanced by 36.3 and 19.4 % compared to the plant growth under UOMW and to the controls, respectively. Also, reducing sugar concentrations were closed to those of the control plants, ranging from 0.424 to 0.678 g/L for the different dilutions tested. However, the plants irrigated with UOMW showed lower reducing sugar concentrations ranging from 0.042 to 0.297g/L. The optimum RLH (0.537) was observed in the plants irrigated with TOMW diluted at (1:4), this value being higher than that observed in the controls (0.438). Our study proved that the irrigation with TOMW significantly improved tomato growth and photosynthesis activity over those irrigated with UOMW. Optimization of TOMW as a fertilizer was obtained for a dilution of 1:4. From the obtained results, it can be concluded that OMW treated by C. gallica holds potential to be used as a fertilizer for tomato plants. Graphical Abstract ᅟ Please provide a caption for the graphical abstract.The graphical abstract is improved and sent as attachment Please replace it.

Utilization of vinasses as soil amendment: consequences and perspectives

Vinasses are a residual liquid generated after the production of beverages, such as mezcal and tequila, from agave (Agave L.), sugarcane (Saccharum officinarum L.) or sugar beet (Beta vulgaris L.). These effluents have specific characteristics such as an acidic pH (from 3.9 to 5.1), a high chemical oxygen demand (50,000-95,000 mg L(-1)) and biological oxygen demand content (18,900-78,300 mg L(-1)), a high total solids content (79,000 and 37,500 mg L(-1)), high total volatile solids 79,000 and 82,222 mg L(-1), and K(+) (10-345 g L(-1)) content. Vinasses are most commonly discarded onto soil. Irrigation of soil with vinasses, however, may induce physical, chemical and biochemical changes and affect crop yields. Emission of greenhouse gases (GHG), such as carbon dioxide, nitrous oxide and methane, might increase from soils irrigated with vinasses. An estimation of GHG emission from soil irrigated with vinasses is given and discussed in this review.

Multistage process for the production of bioethanol from almond shell

This work describes the feasibility of using almond shell as feedstock for bioethanol production. A pre-treatment step was carried out using 4% NaOH for 60min at 121°C followed by 1% sulfuric acid for 60min at 121°C. Enzymatic saccharification of the pre-treated almond shell was performed using Penicillium occitanis enzymes. The process was optimized using a hybrid design with four parameters including the incubation time, temperature, enzyme loads, and polyethylene glycol (PEG) concentration. The optimum hydrolysis conditions led to a sugar yield of 13.5%. A detoxification step of the enzymatic hydrolysate was carried out at pH 5 using 1U/ml of laccase enzyme produced by Polyporus ciliatus. Fermenting efficiency of the hydrolysates was greatly improved by laccase treatment, increasing the ethanol yield from 30% to 84%. These results demonstrated the efficiency of using almond shell as a promising source for bioethanol production.

Agronomic application of olive mill wastewater: Effects on maize production and soil properties

This study investigates the effect of direct amendment of olive mill wastewater (OMW) on the fertility of soil, described as poor in the area of Marrakech (semi-arid region) in Morocco. The treated plots were amended with untreated OMW generated by a traditional extraction process at the amount of 10 L/m(2)/year during two consecutive years. Results of these two years treatments with crude OMW at relatively high dose reveal an important increase in soil physicochemical characteristics, namely electric conductivity (EC), Na(+,) K(+), phosphorus, nitrogen, organic matter and soluble phenolic compounds. EC of treated soil was enhanced from 0.34 to 2.91 mS/cm as compared to the control soil. After spreading OMW in soil, the amounts of its nutritive elements increased by 81% for nitrogen, 66% for phosphorus and 88% for potassium. The accumulation of phenolic compounds and the increase of total peroxidase activity in plants provide evidence of their protective role against the physiological stress induced by OMW. However, this enrichment in mineral and nutritive elements decreased three months after OMW application, revealing OMW biodegradation in the studied calcareous soil. In parallel, an increase in the contents of the soluble phenolic compounds on the upper layer of soil was denoted and maize plants growth was efficiently raised. Significant amelioration was obtained notably in terms of fresh and dry weight of leaves, leaves area, spikes fresh and dry weight, 100 seeds weight and straw yield (37, 54, 27, 24, 14 and 9% respectively). Along with the correct choice of convenient soils notably calcareous ones and tolerant crops such as maize, this method could constitute an efficient approach for avoiding problems attributed to the uncontrolled disposal of these effluents and an effective strategy to regenerate degraded soils and represents an economical alternative that provides a local fertilizer.

Investigation of olive mill wastewater (OMW) ozonation efficiency with the use of a battery of selected ecotoxicity and human toxicity assays

The effects of olive mill wastewater (OMW) on a battery of biological assays, before and during the ozonation process, were investigated in order to assess ozone's efficiency in removing phenolic compounds from OMW and decreasing the concomitant OMW toxicity. Specifically, ozonated-OMW held for 0, 60, 120, 300, 420, 540min in a glass bubble reactor, showed a drastic reduction of OMW total phenols (almost 50%) after 300min of ozonation with a concomitant decrease of OMW toxicity. In particular, the acute toxicity test primarily performed in the fairy shrimp Thamnocephalus platyurus (Thamnotoxkit F™ screening toxicity test) showed a significant attenuation of OMW-induced toxic effects, after ozonation for a period of 120 and in a lesser extent 300min, while further treatment resulted in a significant enhancement of ozonated-OMW toxic effects. Furthermore, ozonated-OMW-treated mussel hemocytes showed a significant attenuation of the ability of OMW to cause cytotoxic (obtained by the use of NRRT assay) effects already after an ozonation period of 120 and to a lesser extent 300min. In accordance with the latter, OMW-mediated oxidative (enhanced levels of superoxide anions and lipid peroxidation by-products) and genotoxic (induction of DNA damage) effects were diminished after OMW ozonation for the aforementioned periods of time. The latter was also revealed by the use of cytokinesis block micronucleus (CBMN) assay in human lymphocytes exposed to different concentrations of both raw- and ozonated-OMW for 60, 120 and 300min. Those findings revealed for a first time the existence of a critical time point during the OMW ozonation process that could be fundamentally used for evaluating OMW ozonation as a pretreatment method of OMW.

Evaluation of phytotoxicity effect of olive mill wastewater treated by different technologies on seed germination of barley (Hordeum vulgare L.)

Olive-mill wastewater (OMW) is a by-product effluent of olive oil extraction process that is produced in large amount in the Mediterranean region. OMW is believed to induce phytotoxic effect on organisms including seed germination and plant growth. The objective of this study was to evaluate the impact of untreated and treated OMW with different techniques on seed germination of barley (Hordeum vulgare L.). The following treatments were investigated: (1) tap water (control); (2) OMW treated by aerobic biological technology in a Jacto Reactor (JR); (3) OMW treated by solar fenton oxidation (SFO); (4) OMW treated by microfiltration followed by nanofiltration (MF+NF); (5) OMW treated by microfiltration followed by reverse osmosis (MF+RO) process; (6) diluted OMW with tap water (25 % OMW); (7) diluted OMW with tap water (50 % OMW); (8) diluted OMW with tap water (75 % OMW); and (9) untreated OMW (100 % OMW). A germination test was conducted in an incubator at temperature of 23 (∘)C. In each petri dish, a filter paper was mounted and ten seeds of barley were placed on the filter paper. Five milliliter of water were added to each petri dish. The seed germination was determined by counting the number of germinated seeds to calculate the percentage of germination (G %). Germination rate index (GRI), seed vigor index (SVI), and phytotoxicity index (PI) were also calculated. Then, the dry weights and lengths of the shoots and the roots of the germinated seeds were measured. The results show that 100, 75, and 50 %OMW were very phytotoxic and completely prohibited seed germination. However, phytotoxicity decreased significantly following treatments of OMW with all techniques investigated and by the 25 % OMW dilution, as results of removing the phenols and other phytotoxic organic compounds from the OMW or by diluting it. This was evidenced by relative enhancement of the dry weights and lengths of shoot and root as well as the G %, GRI, SVG, and PI. It was concluded that if OMW will be used for irrigating crops, it has to be first treated or diluted with tap water at a ratio of 1:3 OMW:water at least. The most efficient treatment techniques in reducing the phytotoxicity of OMW were the MF+RO, followed by SFO and JR.

Olive mill wastewater biodegradation potential of white-rot fungi--Mode of action of fungal culture extracts and effects of ligninolytic enzymes

Forty-nine white-rot strains belonging to 38 species of Basidiomycota were evaluated for olive-mill wastewater (OMW) degradation. Almost all fungi caused high total phenolics (>60%) and color (⩽ 70%) reduction, while COD and phytotoxicity decreased to a lesser extent. Culture extracts from selected Agrocybe cylindracea, Inonotus andersonii, Pleurotus ostreatus and Trametes versicolor strains showed non-altered physicochemical and enzymatic activity profiles when applied to raw OMW in the presence or absence of commercial catalase, indicating no interaction of the latter with fungal enzymes and no competition for H2O2. Hydrogen peroxide's addition resulted in drastic OMW's decolorization, with no effect on phenolic content, suggesting that oxidation affects colored components, but not necessarily phenolics. When fungal extracts were heat-treated, no phenolics decrease was observed demonstrating thus their enzymatic rather than physicochemical oxidation. Laccases added to OMW were reversibly inhibited by the effluent's high phenolic load, while peroxidases were stable and active during the entire process.

Comparative examination of the olive mill wastewater biodegradation process by various wood-rot macrofungi

Olive mill wastewater (OMW) constitutes a major cause of environmental pollution in olive-oil producing regions. Sixty wood-rot macrofungi assigned in 43 species were evaluated for their efficacy to colonize solidified OMW media at initially established optimal growth temperatures. Subsequently eight strains of the following species were qualified: Abortiporus biennis, Ganoderma carnosum, Hapalopilus croceus, Hericium erinaceus, Irpex lacteus, Phanerochaete chrysosporium, Pleurotus djamor, and P. pulmonarius. Fungal growth in OMW (25%v/v in water) resulted in marked reduction of total phenolic content, which was significantly correlated with the effluent's decolorization. A. biennis was the best performing strain (it decreased phenolics by 92% and color by 64%) followed by P. djamor and I. lacteus. Increase of plant seeds germination was less pronounced evidencing that phenolics are only partly responsible for OMW's phytotoxicity. Laccase production was highly correlated with all three biodegradation parameters for H. croceus, Ph. chrysosporium, and Pleurotus spp., and so were manganese-independent and manganese dependent peroxidases for A. biennis and I. lacteus. Monitoring of enzymes with respect to biomass production indicated that Pleurotus spp., H. croceus, and Ph. chrysosporium shared common patterns for all three activities. Moreover, generation of enzymes at the early biodegradation stages enhanced the efficiency of OMW treatment.

Effects of olive mill wastewater physico-chemical treatments on polyphenol abatement and Italian ryegrass (Lolium multiflorum Lam.) germinability

Direct spreading on agricultural lands may represent an environmentally friendly disposal method and a possible use of water and nutrients from olive mill wastewaters (OMWs). However, the agronomic use of OMWs is limited, among others by polyphenols, which exert phytotoxic effects. Activated charcoal (AC) has been recognized as a very effective agent for polyphenol abatement, as it enables an irreversible process of phenol adsorption. Addition of calcium hydroxide (Ca(OH)2) has also been described as a cheap and effective method in polyphenols abatement. However, the effects of Ca(OH)2 addition to OMW on seed germination are unclear. In this paper, the effects of AC and/or Ca(OH)2 on OMW polyphenols abatement, and Lolium multiflorum seed germination have been investigated. The highest polyphenols removal, approximately 95%, was observed when 80 g L(-1) of AC was added to OMWs (the maximum dose in this investigation). The addition of Ca(OH)2 not only improved the effectiveness of the AC treatment but also resulted in a significant rise in Lolium seed germination at the highest AC doses (60 and 80 g L(-1)). Considering the high salinity (7300 μS cm(-1)) of these wastewaters, low quantities of Ca(OH)2 may also exert a protective effect on soil structure counteracting the sodium-induced dispersion through the binding action of calcium cation on clays and organic matter.

Enhanced reduction of phenol content and toxicity in olive mill wastewaters by a newly isolated strain of Coriolopsis gallica

The search for novel microorganisms able to degrade olive mill wastewaters (OMW) and withstand the toxic effects of the initially high phenolic concentrations is of great scientific and industrial interest. In this work, the possibility of reducing the phenolic content of OMW using new isolates of fungal strains (Coriolopsis gallica, Bjerkandera adusta, Trametes versicolor, Trichoderma citrinoviride, Phanerochaete chrysosporium, Gloeophyllum trabeum, Trametes trogii, and Fusarium solani) was investigated. In vitro, all fungal isolates tested caused an outstanding decolorization of OMW. However, C. gallica gave the highest decolorization and dephenolization rates at 30 % v/v OMW dilution in water. Fungal growth in OMW medium was affected by several parameters including phenolic compound concentration, nitrogen source, and inoculum size. The optimal OMW medium for the removal of phenolics and color was with the OMW concentration (in percent)/[(NH4)2SO4]/inoculum ratio of 30:6:3. Under these conditions, 90 and 85 % of the initial phenolic compounds and color were removed, respectively. High-pressure liquid chromatography analysis of extracts from treated and untreated OMW showed a clear and substantial reduction in phenolic compound concentrations. Phytotoxicity, assessed using radish (Raphanus sativus) seeds, indicated an increase in germination index of 23-92 % when a 30 % OMW concentration was treated with C. gallica in different dilutions (1/2, 1/4, and 1/8).

Biodegradation of organic compounds during co-composting of olive oil mill waste and municipal solid waste with added rock phosphate

Liquid and solid olive oil mill waste was treated by com posting in a mixture with the organic part of municipal solid waste and rock phosphate. The transformations that occurred during the process were evaluated by physical, chemical and spectroscopic analyses. After five months of com posting, the final compost presented a C/N ratio under 20, an NH4+/NO3(-)] ratio under 1 and a pH around neutral. A high level of organic matter decomposition paralleled a notable abatement of phenols and lipids. The results show the effective dissolution of mineral elements during composting. This transformation was followed by Fourier transform infrared which showed a decrease in the absorption bands of aliphatic bonds (2925 and 2855 cm(-1)) and carbonyls of carboxylic origin (1740 cm (-1)). In addition to the increase in humic substances and the improvement of germination indices, the parameters studied confirm the stability and the maturity of the composts. The absence of phytotoxicity opens the way to agricultural spreading.