Septal Ablation Versus Surgical Myomectomy for Hypertrophic Obstructive Cardiomyopathy.

PURPOSE OF REVIEW: Patients with hypertrophic cardiomyopathy (HCM) who have left ventricular outflow tract obstruction (LVOTO) often experience severe symptoms and functional limitation. Relief of LVOTO can be achieved by two invasive interventions, i.e., surgery myectomy and alcohol septal ablation (ASA), leading in experienced hands to a dramatic improvement in clinical status. Despite extensive research, however, the choice of the best option in individual patients remains challenging and poses numerous clinical dilemmas. RECENT FINDINGS: Invasive strategies have been recently incorporated in recommendations for the diagnosis and treatment of HCM on both sides of the Atlantic. These guidelines are based on a bulk of well-designed but retrospective studies as well as on expert opinions. Evidence now exists that adequate evaluation and management of HCM requires a multidisciplinary team capable of choosing the best available options. Management of LVOTO still varies largely based on local expertise and patient preference. Following the trend that has emerged for other cardiac diseases amenable to invasive interventions, the concept of a "HCM heart team" is coming of age.

Strategies for the sustainable management of orange peel waste through anaerobic digestion.

The processing of oranges is a major industry worldwide and leads to the production of large amounts of orange peel waste (OPW). Energy production through anaerobic digestion of OPW is a promising option; however, the high content of essential oil, mainly composed of d-limonene, a well-known antioxidant, can cause the inhibition of the biological activity. In this paper, different pretreatment methods were tested (e.g. ensiling, aeration, thermal and alkaline treatments) to optimize the anaerobic digestion of OPW focusing on d-limonene removal. The raw and pretreated substrates were characterized and their biochemical methane production was measured. The results demonstrated the ability of some of the treatments to reduce d-limonene content up to 80%. A relatively high biomethane potential production of OPW (up to about 500 NmL CH4 g-1VS) was measured. The importance of the acclimation of inoculum and the risk connected to the accumulation of inhibiting substances in the reactor is discussed.

Effect of three pretreatment techniques on the chemical composition and on the methane yields of Opuntia ficus-indica (prickly pear) biomass.

Opuntia ficus-indica (OFI) is an emerging biomass that has the potential to be used as substrate in anaerobic digestion. The goal of this work was to investigate the effect of three pretreatment techniques (thermal, alkaline, acidic) on the chemical composition and the methane yield of OFI biomass. A composite experimental design with three factors and two to three levels was implemented, and regression modelling was employed using a total of 10 biochemical methane potential (BMP) tests. The measured methane yields ranged from 289 to 604 NmL/gVSadded; according to the results, only the acidic pretreatment (HCl) was found to significantly increase methane generation. However, as the experimental values were quite high with regards to the theoretical methane yield of the substrate, this effect still needs to be confirmed via further research. The alkaline pretreatment (NaOH) did not noticeably affect methane yields (an average reduction of 8% was recorded), despite the fact that it did significantly reduce the lignin content. Thermal pretreatment had no effect on the methane yields or the chemical composition. Scanning electron microscopy images revealed changes in the chemical structure after the addition of NaOH and HCl. Modelling of the cumulated methane production by the Gompertz modified equation was successful and aided in understanding kinetic advantages linked to some of the pretreatments. For example, the alkaline treatment (at the 20% dosage) at room temperature resulted to a µmax (maximum specific methane production rate [NmLCH4/(gVSadded·d)]) equal to 36.3 against 18.6 for the control.

A 35-year monitoring of an Italian landfill: Effect of recirculation of reverse osmosis concentrate on leachate characteristics.

"Fossetto" landfill (Monsummano Terme - Tuscany, Italy) started operation in 1988 as a controlled landfill accepting mixed municipal solid waste collected without any attempt of recycling. Then, progressively, following the evolution of the state-of-the-art, it adopted biogas extraction and valorisation systems and mechanical-biological treatment for incoming waste (both since 2003). Finally, since 2006, in the plant is performed on-site reverse osmosis leachate treatment with the concentrated leachate being recirculated back into the landfill body. Recently a new landfill cell, separate from the others, was put in operation adding a capacity of 200,000 m3 to the already available 1,095,000 m3. This plant can provide long term leachate composition data to study the evolution and impact of changing landfill technology and waste composition on various parameters. The rise in leachate production (+84 % in 2018-2022 respect to the period before recirculation) cannot be totally attributable to recirculation but could be also linked to the increase in the amount of landfilled waste. The concentration of certain parameters (NH4+, Cl- and to a less extent of COD) increased (+60 %, +58 %, +17 % respectively in the last five years with respect to the period before recirculation); however, this increase did not influence the performance of the treatment plant. Nevertheless, the overall leachate management would benefit from an optimized reinjection system.

Heart failure: molecular, genetic and epigenetic features of the disease.

Factors that compete to establish heart failure (HF) are not completely known. In the last years the several technological improvements allowed us to deeply study the molecular and genetic aspects of this complex syndrome. This new approach to HF based on molecular biology new discoveries shows us more clearly the pathophysiological bases of this disease, and a future scenery where the genetics may be useful in the clinical practice, as screening of high risk populations, as well as in the diagnosis and therapy of underlying myocardial diseases. The purpose of this review was to analyse the molecular, genetic and epigenetic factors of HF. We described the molecular anatomy of the sarcomere and the pathogenesis of the heart muscle diseases, abandoning the previous monogenic theory for the concept of a polygenic disease. Different actors play a role to cause the illness by themselves, modifying the expression of the disease and, eventually, the prognosis of the patient.

Excimer laser technology in percutaneous coronary interventions: Cardiovascular laser society's position paper.

Excimer Laser Coronary Atherectomy (ELCA) is a well-established therapy that emerged for the treatment of peripheral vascular atherosclerosis in the late 1980s, at a time when catheters and materials were rudimentary and associated with the most serious complications. Refinements in catheter technology and the introduction of improved laser techniques have led to their effective use for the treatment of a wide spectrum of complex coronary lesions, such as thrombotic lesions, severe calcific lesions, non-crossable or non-expandable lesions, chronic occlusions, and stent under-expansion. The gradual introduction of high-energy strategies combined with the contrast infusion technique has enabled us to treat an increasing number of complex cases with a low rate of periprocedural complications. Currently, the use of the ELCA has also been demonstrated to be effective in acute coronary syndrome (ACS), especially in the context of large thrombotic lesions.

Peripheral arterial disease has a strong impact on cardiovascular outcome in patients with acute coronary syndromes: from the START Antiplatelet registry.

BACKGROUND: Peripheral arterial disease (PAD) was reported to increase the risk of new cardiovascular events in patients with acute coronary syndromes (ACS). However, most of the evidence comes from randomized clinical trials. We aimed to assess the impact of PAD on cardiovascular outcome and treatment decisions in ACS patients in a current real-life setting. METHODS: START-ANTIPLATELET is a multicenter registry enrolling ACS patient. Baseline clinical characteristics and treatment at discharge were recorded and follow-up was repeated at 6-months and 1-year. PAD was defined as intermittent claudication and/or previous revascularization. RESULTS: Among 1442 patients enrolled, 103 (7.1%) had PAD. PAD patients were older (71.8 ± 10.6vs66.2 ± 12.6 yrs., p < 0.0001), more frequently hypertensive (90.3vs68.6%, p< 0.0001), hypercholesterolemic (66vs52%, p= 0.037), diabetic (51.5vs24%, p= 0.0001), obese (28.2vs19.3%, p= 0.029) and with previous TIA (7.8vs2.8%, p= 0.005) or stroke (11.7vs3.1%, p< 0.0001). Clinical presentation and acute treatment were similar in non-PAD and PAD patients, but the latter were discharged significantly less frequently on dual antiplatelet therapy (DAPT) (68.9vs85%, p= 0.005). After a median follow-up time of 11.1 months, major cardio/cerebrovascular event-free survival [MACCE, including cardiovascular death, MI, TIA and stroke, target-vessel revascularization (TVR) and major arterial ischemic events] was significantly shorter (9.0vs11.2 months, p= 0.02; HR 3.2, 2.4-8.4) in PAD patients and net adverse cardiovascular events (NACE = MACCE plus major hemorrhages) were significantly more frequent (19.1%vs10.5%, p = 0.049). CONCLUSIONS: PAD identifies a subgroup of ACS patients at significantly increased cardiovascular risk, but these patients tend to be undertreated. Patients admitted for ACS should be screened for PAD and optimal medical therapy at discharge should be implemented.

Effect of body mass index reduction on serum hepcidin levels and iron status in obese children.

Iron deficiency has been linked to obesity. Hepcidin is the main regulator of iron homeostasis and is higher in obese children compared to controls. To gain insight into the link between obesity and hepcidin, we performed an intervention study in 15 obese children. These children were subjected to a 6-month weight loss program and underwent physical examination and iron status and absorption as well as hepcidin, interleukin-6 and leptin serum levels evaluation at baseline and after the weight loss program. After the program all children reduced their body mass index standard deviation score (BMI SDS) of at least 0.5. We observed a significant decrease in hepcidin (P=0.003) and leptin levels (P=0.005), and a significant increase in iron absorption (P=0.02). A direct correlation between the measure of hepcidin and leptin reduction was observed and this correlation appeared significant (r²=0.33, P=0.003) when adjusted for interleukin-6 and BMI SDS variations. In conclusion, we have shown that, in obese children, BMI reduction is associated with hepcidin reduction, potentially improving iron status and absorption. Implications of these findings could be considered in the management of obese children with poor iron status.

Use of NaCl saline hydration and N-Acetyl Cysteine to prevent contrast induced nephropathy in different populations of patients at high and low risk undergoing coronary artery angiography.

AIM: Contrast-induced nephropathy (CIN) is most commonly defined as acute renal failure occurring within 48-72 h of exposure to intravascular radiographic contrast medium that is not attributable to other causes. In international literature a 25% increase in serum creatinine levels or an increase in absolute values of 0.5 mg/dL from baseline has been suggested to define CIN. The reported incidence of CIN varies widely, ranging from 2% to 50%. This variability results from differences in the presence or absence of risk factors. With a retrospective analysis authors evaluated the use of NaCl saline hydration and N-acetyl cysteine (NAC) to prevent CIN in different populations of patients at high and low risk undergoing coronary artery angiography. METHODS: From January 2007 to December 2008, 597 patients underwent coronary artery angiography with a low osmolarity contrast agent. Nephrotoxic drugs such as diuretics, metformin, ACE-I and ARBs were stopped at least 24 h before the procedure. The population was divided into two groups: group A (high risk 342 patients, 57.2%) identified for the presence of at least one risk factor such as diabetes, age >65 years, baseline creatinine >1.4 mg/dL and group B (low risk 255 patients, 42.8%) for the absence of any of the risk mentioned above. Only group A was treated with a saline hydration (1 mL/kg/h) plus NAC 600 mg 12 h before and 12 h after the procedure. RESULTS: The overall incidence of CIN was 6.7% (40 patients). In particular, the incidence of CIN was 4.4% (15 patients) in the group A and 9.8% (25 patients) in the group B respectively (P=0.017). Interestingly, the Contrast Index (volume administrated/theoretical maximum volume) was significantly lower in group B (P<0.005). In the multivariate analysis, including risk factors such as age, diabetes, hypertension, hypercholesterol-mia, current smoke, baseline creatinine level, Contrast Index and hydration, the last variable was the only one inversely correlated independently with the incidence of CIN (P=0.001). CONCLUSIONS: The hydration with saline and NAC is an effective and low-cost tool in preventing CIN in patients undergoing coronary artery angiography and, according to the current guidelines, should be used in all high-risk patients. Present results show that even in patients at low risk for CIN, hydration could be useful: in fact, despite the Contrast Index was significantly lower in this population, the incidence of CIN was greater, thus suggesting a potential role for hydration also in the low-risk population.

Impact of mechanical street cleaning and rainfall events on the quantity and heavy metals load of street sediments.

The paper presents and analyses the results of a street sediments monitoring campaign carried out during dry weather in order to quantify the impact of mechanical street cleaning and rainfall events on the quantity and heavy metals load of street sediments. The study has been carried out in an experimental catchment in a medium traffic street of a residential/commercial area in the city of Reggio Calabria (Italy). Thanks to acquired data, it was possible to assess the amount and the degree of pollution of street sediments, the efficiency of mechanical street cleaning in terms of sediments and pollutants removal, the wash-off of street sediments during rainfall events and the related potential impact on receiving water bodies. The results obtained confirm that street sweeping is generally scarcely effective as a practice for urban storm run-off quality control and that run-off is, on the contrary, quite effective in street sediments removal especially for smaller particles. Moreover, chemical analyses indicate that, although the concentration of heavy metals is higher in sediments particles having a diameter lower than 0.075 mm, the greatest part of the pollutants load is associated to larger particles.

Preliminary evaluation of the anaerobic biodegradability of three biobased materials used for the production of disposable plastics.

Biodegradable plastics have been introduced to the market to substitute "traditional", non-biodegradable, petro-based plastics to alleviate plastic pollution. Biochemical methane potential tests were carried out on compostable bags made of MaterBi®, biodegradable bottle wine corks and cellulosic plates to examine the anaerobic biodegradability of those materials. The impact of four factors: type of pretreatment (predigestion, mechanical, alkaline, predigestion and alkaline), digestion duration, type of inoculum and temperature were statistically evaluated through regression modeling. Anaerobic tests on compostable and polyethylene bags (control) were carried out in mesophilic (35 °C) and thermophilic (55 °C) conditions, while tests on bottle wine corks and cellulosic plates were carried out in mesophilic conditions only. After 15 days of digestion, a dry mass reduction of 22.8 ±â€¯6.2 % and 27.6 ±â€¯14.0 % for mesophilic and thermophilic tests respectively was recorded for MaterBi®. Chemical pretreatment with NaOH led to a mass reduction of 78.2 ±â€¯7.2 % and was the only statistically significant factor to affect both methane yields and dry mass loss. A higher digestion temperature led to an increased mass loss without a concurrent increase in methane production. The cellulosic plates were completely degraded (99.9 ±â€¯0.03 % mass reduction), while the wine bottle corks weight did not change.

Novel insights into the role of cardiotrophin-1 in cardiovascular diseases.

Cardiotrophin-1 (CT-1), a member of interleukin (IL)-6 family, was originally isolated for its ability to induce a hypertrophic response in neonatal cardiac myocytes. This cytokine mediates a pleiotropic set of growth and differentiation activities through a unique receptor system, consisting of IL-6 receptor (IL-6R) and a common signal transducer, the glycoprotein 130 (gp130). Both in humans and in mice, CT-1 mRNA has been detected in several tissues, such as liver tissue, adipose tissue, and tissues in the respiratory and nervous systems; in each of these tissues it performs different functions. Predominant actions of CT-1 are on the heart, where it is synthesized and where it provides first myocardial protection by promoting cell survival and proliferation, it carries on its haemodynamic effects and endocrine properties, and finally, it predisposes the heart to pathological conditions. The aim of this review is to describe the pathophysiological mechanisms through which CT-1 carries out its activities, especially on the heart, and its potential contribution as a disease marker in clinical cardiology. Recent studies have confirmed its active role in promoting structural changes typical of most common cardiovascular disease, such as hypertension, valve diseases, congestive heart failure, and coronary artery disease. In fact, CT-1 induces myocyte hypertrophy and collagen synthesis, thereby participating in the progression of ventricular remodelling, which results in cardiac muscle failure at the latest stage. CT-1 plasma levels are elevated in patients with hypertension and coronary artery diseases, and they are also correlated with the severity of valve diseases and heart failure. Therefore, CT-1 may represent a diagnostic, staging, and prognostic biomarker of cardiovascular diseases.

A child cohort study from southern Italy enlarges the genetic spectrum of hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is the most frequent genetic cardiovascular disorder worldwide. It is the leading cause of sudden cardiac-related death in young people and a major cause of cardiac failure and death in elderly people. However, HCM frequently goes undiagnosed until the appearance of overt signs and symptoms, thereby delaying prophylactic and therapeutic measures. We screened patients for sarcomeric genes associated with HCM to obtain information that could be useful for an early diagnosis and so limit the severe consequences of silent HCM. We recruited 39 families with HCM from southern Italy and found mutations in 41% of families (12 with familial HCM and 4 with sporadic HCM). The remaining 23 families (59%) were negative for myofilament gene mutations. Of the 12 mutations identified, 8 were novel. Screening of the other family members available revealed that 27 had mutations; 11 of these individuals had no signs or symptoms suggestive of HCM. This study, besides characterizing the spectrum of mutations in another childhood population, and revealing an even greater genetic heterogeneity than formerly recognized, may increase genotype-phenotype correlations, and thus may help to identify asymptomatic candidates for early preventive or therapeutic measures.

In sewer processes: mathematical model development and sensitivity analysis.

Until now the majority of sewer networks in Italy have been built and managed considering small as well as local wastewater treatment plants (WWTPs). However, pushed by Italian and EU regulations, centralised and large WWTPs are becoming more common in Italy. One major technical aspect caused by the changing from local to centralised WWTPs is the development of significant in-sewer processes. These processes are also emphasized by the building of long interceptor sewers characterized by high hydraulic retention times and absence of tributary sewers. In this paper a model derived from the well known WATS model (Wastewater Aerobic/anaerobic Transformation in Sewers) has been set up and applied to an Italian case study located in Palermo. To assure a good degree of reliability the model needs a number of parameters that can be measured or calibrated by the combined use of field data and laboratory analyses. To support the planning of the experimental activity a sensitivity analysis to assess the influence of each model parameter has been carried out. Indeed, the sensitivity analysis allowed identifying the most significant model parameters. As a matter of the fact, by means of sensitivity analysis it was possible not only to pin down the most important model parameters but also to address the field survey towards the most sensitive model parameters in order to optimize the model application. The results are interesting and enabled to reduce the number of parameters to be calibrated from 24 to 14. More specifically, COD fractions, Y(Hw) and mu(H) showed a strong influence on the model results addressing the field campaign to an accurate evaluation of their value.

Effect of the recirculation of a reverse osmosis concentrate on leachate generation: A case study in an Italian landfill.

"Fossetto" landfill has been operating in the municipality of Monsummano Terme (Pistoia Province, Italy) since 1988; the authorized volume for landfilling is about 1,000,000 m3; at the moment the plant is being mainly used to dispose of mechanically and biologically treated residual municipal solid waste. Since September 2006, an in-situ reverse osmosis leachate treatment plant has been operating to treat leachate. The treated water is being discharged into a small nearby stream while the concentrated leachate is being recirculated back into the landfill body following Italian Regulations and an authorization from the local authority (Pistoia Province). This paper presents monitoring results on leachate generation rates and composition for the past fifteen years. A moderate increase of the concentration of some of the monitored parameters occurred (e.g. ammonium, chlorides) and a decrease for most heavy metals. The increase of concentrations for Cl- and NH4+ was more evident in the leachate coming from the wells closer to reinjection area. However, the change in leachate composition did not affect the quality of the effluent from the leachate treatment plant. The annual volume of the generated leachate increased significantly right after the recirculation started.

Valorisation of citrus processing waste: A review.

This study analyses the quantitative and qualitative characteristics of citrus peel waste and discusses the systems for its valorisation. Citrus peel waste (CPW) is the main residue of the citrus processing industries and is characterised by a seasonal production (which often requires biomass storage) as well as high water content and concentration of essential oils. The disposal of CPW has considerable constraints due to both economic and environmental factors. Currently this residue is mainly used as food for animals, thanks to its nutritional capacity. If enough agricultural land is available close to the processing industries, the use of CPW as organic soil conditioner or as substrate for compost production is also possible, thus improving the organic matter content of the soil. Recently, the possibility of its valorisation for biomethane or bioethanol production has been evaluated by several studies, but currently more research is needed to overcome the toxic effects of the essential oils on the microbial community. Considering the high added value of the compounds that can be recovered from CPW, it has promising potential uses: in the food industry (for production of pectin, dietary fibres, etc.), and in the cosmetic and pharmaceutic industries (extraction of flavonoids, flavouring agents and citric acid). However, in many cases, these uses are still not economically sustainable.

[The role of natriuretic peptides in heart failure]. / Ruolo dei peptidi natriuretici nello scompenso cardiaco.

Over the last decades, there has been a significant increase in incidence and prevalence of heart failure, a major cause of cardiac morbidity and mortality. Measurements of neurohormones, in particular B-type natriuretic peptide (BNP), can significantly improve diagnostic accuracy, and also correlate with long-term morbidity and mortality in patients with chronic heart failure presenting to the emergency department. BNP is secreted by cardiac ventricles mainly in response to wall stress and neurohormonal factors like the sympathetic nervous system, endothelins, and the rennin-angiotensin-aldosterone system. BNP increases myocardial relaxation and oppose the vasoconstrictive, sodium retaining, and natriuretic effects caused by vasoconstrictive factors. BNP is the first biomarker to prove its clinical value for the diagnosis of left ventricular systolic and diastolic dysfunction but also for the right ventricular dysfunction, guiding prognosis and therapy management. Emerging clinical data will help further refine biomarker-guided therapeutic and monitoring strategies involving BNP.

Prediction of high on-treatment platelet reactivity in clopidogrel-treated patients with acute coronary syndromes.

BACKGROUND: About 40% of clopidogrel-treated patients display high platelet reactivity (HPR). Alternative treatments of HPR patients, identified by platelet function tests, failed to improve their clinical outcomes in large randomized clinical trials. A more appealing alternative would be to identify HPR patients a priori, based on the presence/absence of demographic, clinical and genetic factors that affect PR. Due to the complexity and multiplicity of these factors, traditional statistical methods (TSMs) fail to identify a priori HPR patients accurately. The objective was to test whether Artificial Neural Networks (ANNs) or other Machine Learning Systems (MLSs), which use algorithms to extract model-like 'structure' information from a given set of data, accurately predict platelet reactivity (PR) in clopidogrel-treated patients. METHODS: A complete set of fifty-nine demographic, clinical, genetic data was available of 603 patients with acute coronary syndromes enrolled in the prospective GEPRESS study, which showed that HPR after 1month of clopidogrel treatment independently predicted adverse cardiovascular events in patients with Syntax Score >14. Data were analysed by MLSs and TSMs. ANNs identified more variables associated PR at 1month, compared to TSMs. RESULTS: ANNs overall accuracy in predicting PR, although superior to other MLSs was 63% (95% CI 59-66). PR phenotype changed in both directions in 35% of patients across the 3 time points tested (before PCI, at hospital discharge and at 1month). CONCLUSIONS: Despite their ability to analyse very complex non-linear phenomena, ANNs or MLS were unable to predict PR accurately, likely because PR is a highly unstable phenotype.

Neopterin induces pro-atherothrombotic phenotype in human coronary endothelial cells.

BACKGROUND: Inflammation plays a pivotal role in atherothrombosis. Recent data indicate that serum levels of neopterin, a marker of inflammation and immune modulator secreted by monocytes/macrophages, are elevated in patients with acute coronary syndromes and seem to be a prognostic marker for major cardiovascular events. The aim of the present study was to determine whether neopterin might affect the thrombotic and atherosclerotic characteristics of human coronary artery endothelial cells (HCAECs). METHODS AND RESULTS: In HCAECs, neopterin induced TF-mRNA transcription as demonstrated by real time polymerase chain reaction and expression of functionally active tissue factor (TF) as demonstrated by procoagulant activity assay, and of cellular adhesion molecules (CAMs) as demonstrated by FACS analysis, in a dose-dependent fashion. These neopterin effects were prevented by lovastatin, a HMG-CoA reductase inhibitor. Neopterin-induced TF and CAMs expression was mediated by oxygen free radicals through the activation of the transcription factor, nuclear factor-kappa B (NF-kappaB), as demonstrated by electrophoretic mobility shift assay and by suppression of CAMs and TF expression by superoxide dismutase and by NF-kappaB inhibitor, pyrrolidine-dithio-carbamate ammonium. CONCLUSIONS: These data indicate that neopterin exerts direct effects on HCAECs by promoting CAMs and TF expression and support the hypothesis that neopterin, besides representing a marker of inflammation, might be an effector molecule able to induce a pro-atherothrombotic phenotype in cells of the coronary circulation.

Effect of the concentration of essential oil on orange peel waste biomethanization: Preliminary batch results.

The cultivation of orange (Citrus×sinensis) and its transformation is a major industry in many countries in the world, it leads to the production of about 25-30Mt of orange peel waste (OPW) per year. Until now many options have been proposed for the management of OPW but although they are technically feasible, in many cases their economic/environmental sustainability is questionable. This paper analyse at lab scale the possibility of using OPW as a substrate for anaerobic digestion. Specific objectives are testing the possible codigestion with municipal biowaste, verifying the effect on methane production of increasingly high concentration of orange essential oil (EO, that is well known to have antioxidant properties that can slower or either inhibit biomass activity) and obtaining information on the behaviour of d-limonene, the main EO component, during anaerobic digestion. The results indicate that OPW can produce up to about 370LnCH4/kgVS in mesophilic conditions and up to about 300LnCH4/kgVS in thermophilic conditions. The presence of increasingly high concentrations of EO temporary inhibits methanogenesis, but according to the results of batch tests, methane production restarts while d-limonene is partially degraded through a pathway that requires its conversion into p-cymene as the main intermediate.