Advantages and limits of robot-assisted laparoscopic surgery: preliminary experience

BACKGROUND

In the last few years, robotics has been applied in clinical practice for a variety of laparoscopic procedures. This study reports our preliminary experience using robotics in the field of general surgery to evaluate the advantages and limitations of robot-assisted laparoscopy.

METHODS

Thirty-two consecutive patients were scheduled to undergo robot-assisted laparoscopic surgery in our units from March 2002 to July 2003. The indications were cholecystectomy, 20 patients; right adrenalectomy, two points; bilateral varicocelectomy, two points; Heller's cardiomyotomy, two points; Nissen's fundoplication, two points; total splenectomy, one point; right colectomy, one point; left colectomy, 1 point; and bilateral inguinal hernia repair, one point. In all cases, we used the da Vinci surgical system, with the surgeon at the robotic work station and an assistant by the operating table.

RESULTS

Twenty-nine of 32 procedures (90.6%) were completed robotically, whereas three were converted to laparoscopic surgery. Conversion to laparoscopy was due in two patients to minor bleeding that could not be managed robotically and to robot malfunction in the third patient. There were no deaths. Median hospital stay was 2.2 days (range, 2-8).

CONCLUSIONS

The main advantages of robot-assisted laparoscopic surgery are the availability of three-dimensional vision and easier instrument manipulation than can be obtain with standard laparoscopy. The learning curve to master the robot was >or= 10 robotic procedures. The main limitations are the large diameter of the instruments (8 mm) and the limited number of robotic arms (maximum, three). We consider these technical shortcomings to be the cause for our conversions, because it is difficult to manage bleeding episodes with only two operating instruments. The benefit to the patient must be evaluated carefully and proven before this technology can become widely accepted in general surgery.

Advances in understanding - genetic basis of intellectual disability

Intellectual disability is the most common developmental disorder characterized by a congenital limitation in intellectual functioning and adaptive behavior. It often co-occurs with other mental conditions like attention deficit/hyperactivity disorder and autism spectrum disorder, and can be part of a malformation syndrome that affects other organs. Considering the heterogeneity of its causes (environmental and genetic), its frequency worldwide varies greatly. This review focuses on known genes underlying (syndromic and non-syndromic) intellectual disability, it provides a succinct analysis of their Gene Ontology, and it suggests the use of transcriptional profiling for the prioritization of candidate genes.

Transcutaneous oxygen tension monitoring after successful revascularization in diabetic patients with ischaemic foot ulcers

OBJECTIVE

To monitor transcutaneous oxygen tension (TcPO2) after percutaneous transluminal angioplasty (PTA) in diabetic patients with ischaemic foot ulcers.

RESEARCH DESIGN AND METHODS

Twenty-three diabetic patients with ischaemic foot ulcers who underwent successful revascularization by PTA (SR group) were retrospectively selected. Twenty diabetic patients who underwent unsuccessful revascularization (UR group) were also included. Transcutaneous oxygen tension was measured at the dorsum of the foot before and 1 (+/- 1), 7 (+/- 1), 14 (+/- 1), 21 (+/- 1) and 28 (+/- 1) days after the surgical procedure.

RESULTS

After PTA, TcPO2 progressively improved in the SR group, reaching its peak 4 weeks after angioplasty. A concomitant decrease of cutaneous carbon dioxide tension (TcPCO2) was also observed immediately after PTA which reached the lowest levels 3 weeks later. In the UR group, TcPO2 showed a slight improvement immediately after PTA but remained stable throughout the observation, while TcPCO2 levels did not change. Finally, the percentage of SR patients with a TcPO2 > or = 30 mmHg was 38.5% 1 week after PTA, while it increased to 75% 3 weeks later.

CONCLUSION

Transcutaneous oxygen tension monitoring showed that after successful revascularization it takes 3-4 weeks for cutaneous oxygenation to improve and reach the optimal levels for wound healing. Transcutaneous carbon dioxide tension monitoring may be more useful to identify the negative outcome of a revascularization procedure. Our findings suggest that, when the surgical approach can be delayed, the best timing to perform a more aggressive debridement or minor amputations is 3-4 weeks after successful revascularization.

Effect of light intensity and nutrients supply on microalgae cultivated in urban wastewater: Biomass production, lipids accumulation and settleability characteristics

Microalgae cultivation systems fed with wastewater as source of nutrients represents the principal sustainable condition to produce microalgal biomass to be converted conveniently to biofuels. In order to optimize microalgae growth and their lipid content, the effect of light intensity and nutrients load in real wastewater was investigated through batch microalgal cultivation tests. A microalgal polyculture was used as inoculum and grown for 10 days in batch at different conditions of light intensity (i.e. 20, 50 and 100 μmol s^-1m^-2) and nutrients concentration in wastewater. Experimental results showed that biomass productivity decreased for rich nutrients conditions and increased for high light intensities. The highest lipid mass content (29%) was found for high light intensity condition (100 μmol s^-1m^-2). Furthermore, microalgae settleability tests, conducted at the end of the cultivation time, resulted in the highest biomass recovery efficiency (72%) for low light intensity and nutrients supply conditions.

From microcephaly to megalencephaly: determinants of brain size

Expansion of the human brain, and specifically the neocortex, is among the most remarkable evolutionary processes that correlates with cognitive, emotional, and social abilities. Cortical expansion is determined through a tightly orchestrated process of neural stem cell proliferation, migration, and ongoing organization, synaptogenesis, and apoptosis. Perturbations of each of these intricate steps can lead to abnormalities of brain size in humans, whether small (microcephaly) or large (megalencephaly). Abnormalities of brain growth can be clinically isolated or occur as part of complex syndromes associated with other neurodevelopmental problems (eg, epilepsy, autism, intellectual disability), brain malformations, and body growth abnormalities. Thorough review of the genetic literature reveals that human microcephaly and megalencephaly are caused by mutations of a rapidly growing number of genes linked within critical cellular pathways that impact early brain development, with important pathomechanistic links to cancer, body growth, and epilepsy. Given the rapid rate of causal gene identification for microcephaly and megalencephaly understanding the roles and interplay of these important signaling pathways is crucial to further unravel the mechanisms underlying brain growth disorders and, more fundamentally, normal brain growth and development in humans. In this review, we will (a) overview the definitions of microcephaly and megalencephaly, highlighting their classifications in clinical practice; (b) overview the most common genes and pathways underlying microcephaly and megalencephaly based on the fundamental cellular processes that are perturbed during cortical development; and (c) outline general clinical molecular diagnostic workflows for children and adults presenting with microcephaly and megalencephaly.

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.

Current emerging SARS-CoV-2 pandemic: Potential direct/indirect negative impacts of virus persistence and related therapeutic drugs on the aquatic compartments

The purpose of the present work is to provide a complete overview of possible direct/indirect implications on the quality of aquatic compartments due to the recent SARS-CoV-2 outbreak. With this aim, the environmental impacts are mainly related to i) the virus persistence in sewage and wastewaters, and ii) possible fate in aquatic compartments of drugs tested and administered to SARS-CoV-2 infected patients. Because SARS-CoV-2 spread is very recent, and there is a lack of specific studies on this strain, the virus persistence in wastewaters, the parameters influencing the persistence, as well as the detection methodologies are referenced to the general coronaviruses group. However, the present detailed report of up-to-date knowledge on this topic can provide a useful source for further studies focusing on more deepened investigations of SARS-CoV-2 behaviour in the environment. Such a perspective is significant not only for the control of virus diffusion but also represents a crucial point for the identification of produced alteration to the environmental quality.

Treatments of asbestos containing wastes

Since the second half of the twentieth century, many studies have indicated inhalation of asbestos fibers as the main cause of deadly diseases including fibrosis and cancer. Consequently, since the beginning of the 80s, many countries started banning production and use of asbestos containing products (ACP), although still present in private and public buildings. Due to some extraordinary catastrophic events and/or the aging of these products, people's health and environmental risk associated with the inhalation of asbestos fibers keeps being high even in those countries where it was banned. For these reasons, many communities are developing plans for an environmental and sanitary safe asbestos removal and management. Asbestos containing wastes (ACW) are usually disposed in controlled landfills, but this practice does not definitively eliminate the problems related with asbestos fiber release and conflicts with the ideas of sustainable land use, recycling, and closing material cycles. Consequently, many scientific papers and patents proposed physical, chemical, and biological treatments aimed to the detoxification of ACW (or the reduction of their health effects) and looking for the adoption of technologies, which allow the reuse of the end-products. By including recent relevant bibliography, this report summarizes the status of the most important and innovative treatments of ACW, providing main operating parameters, advantages, and disadvantages.

The FRAXopathies: definition, overview, and update

The fragile X syndrome, fragile X tremor ataxia syndrome, and premature ovarian insufficiency are conditions related to the X chromosome folate-sensitive fragile site FRAXA. Therefore, we propose that they are considered as a family of disorders under the general designation of FRAXopathies. The present review will outline the main clinical and molecular features of these disorders, with special emphasis on the pathogenic mechanisms that lead to distinct phenotypes, starting from related mutations. The understanding of these mechanisms is already generating promising therapeutic approaches.

Profiling PI3K-AKT-MTOR variants in focal brain malformations reveals new insights for diagnostic care

Focal malformations of cortical development including focal cortical dysplasia, hemimegalencephaly and megalencephaly, are a spectrum of neurodevelopmental disorders associated with brain overgrowth, cellular and architectural dysplasia, intractable epilepsy, autism and intellectual disability. Importantly, focal cortical dysplasia is the most common cause of focal intractable paediatric epilepsy. Gain and loss of function variants in the PI3K-AKT-MTOR pathway have been identified in this spectrum, with variable levels of mosaicism and tissue distribution. In this study, we performed deep molecular profiling of common PI3K-AKT-MTOR pathway variants in surgically resected tissues using droplet digital polymerase chain reaction (ddPCR), combined with analysis of key phenotype data. A total of 159 samples, including 124 brain tissue samples, were collected from 58 children with focal malformations of cortical development. We designed an ultra-sensitive and highly targeted molecular diagnostic panel using ddPCR for six mutational hotspots in three PI3K-AKT-MTOR pathway genes, namely PIK3CA (p.E542K, p.E545K, p.H1047R), AKT3 (p.E17K) and MTOR (p.S2215F, p.S2215Y). We quantified the level of mosaicism across all samples and correlated genotypes with key clinical, neuroimaging and histopathological data. Pathogenic variants were identified in 17 individuals, with an overall molecular solve rate of 29.31%. Variant allele fractions ranged from 0.14 to 22.67% across all mutation-positive samples. Our data show that pathogenic MTOR variants are mostly associated with focal cortical dysplasia, whereas pathogenic PIK3CA variants are more frequent in hemimegalencephaly. Further, the presence of one of these hotspot mutations correlated with earlier onset of epilepsy. However, levels of mosaicism did not correlate with the severity of the cortical malformation by neuroimaging or histopathology. Importantly, we could not identify these mutational hotspots in other types of surgically resected epileptic lesions (e.g. polymicrogyria or mesial temporal sclerosis) suggesting that PI3K-AKT-MTOR mutations are specifically causal in the focal cortical dysplasia-hemimegalencephaly spectrum. Finally, our data suggest that ultra-sensitive molecular profiling of the most common PI3K-AKT-MTOR mutations by targeted sequencing droplet digital polymerase chain reaction is an effective molecular approach for these disorders with a good diagnostic yield when paired with neuroimaging and histopathology.

Model calibration and validation for OFMSW and sewage sludge co-digestion reactors

A mathematical model has recently been proposed by the authors to simulate the biochemical processes that prevail in a co-digestion reactor fed with sewage sludge and the organic fraction of municipal solid waste. This model is based on the Anaerobic Digestion Model no. 1 of the International Water Association, which has been extended to include the co-digestion processes, using surface-based kinetics to model the organic waste disintegration and conversion to carbohydrates, proteins and lipids. When organic waste solids are present in the reactor influent, the disintegration process is the rate-limiting step of the overall co-digestion process. The main advantage of the proposed modeling approach is that the kinetic constant of such a process does not depend on the waste particle size distribution (PSD) and rather depends only on the nature and composition of the waste particles. The model calibration aimed to assess the kinetic constant of the disintegration process can therefore be conducted using organic waste samples of any PSD, and the resulting value will be suitable for all the organic wastes of the same nature as the investigated samples, independently of their PSD. This assumption was proven in this study by biomethane potential experiments that were conducted on organic waste samples with different particle sizes. The results of these experiments were used to calibrate and validate the mathematical model, resulting in a good agreement between the simulated and observed data for any investigated particle size of the solid waste. This study confirms the strength of the proposed model and calibration procedure, which can thus be used to assess the treatment efficiency and predict the methane production of full-scale digesters.

Distal pancreas surgery: outcome for 19 cases managed with a laparoscopic approach

BACKGROUND

In the past decade, laparoscopy has shown its efficacy also for advanced surgery. In this report, the authors retrospectively review their experience with the distal pancreas.

METHODS

From April 1999 to October 2004, 19 patients underwent a laparoscopic procedure for pathologies of the distal pancreas. The authors performed one distal pancreatectomy (DP) with conservation of the spleen and section of the splenic vessels, four distal splenopancreatectomies (DSP), one DSP plus a left adrenalectomy, two enucleations, seven DPs with conservation of the spleen and the splenic vessels, and four cystojejunostomies.

RESULTS

One procedure was converted to open surgery because of a hemorrhagic complication. No other significant intraoperative complications occurred. The postoperative course was characterized by one bleed managed conservatively, two pancreatic fistulas (one requiring a second operation), one abscess drained under echographic view, and one reactive pancreatitis. The mean postoperative stay was 8.5 days. The histologic report showed 16 benign diseases and 3 malignant tumors. The mean follow-up period was of 42 months. The patient who had DP spleen preservation with section of the splenic vessels reported mild pain in the left hypochondrium, probably attributable to chronic splenic ischemia, during the first 3 postoperative months. One incisional hernia occurred in the patient who underwent conversion to an open procedure, and one patient affected by adenocarcinoma died 10 months after the operation.

CONCLUSIONS

The authors can affirm that laparoscopy for the distal pancreas is a successful procedure in terms of results and surgical feasibility. Prospective studies are necessary to confirm their positive impression.

Single-layer versus double-layer closure of the enterotomy in laparoscopic right hemicolectomy with intracorporeal anastomosis: a single-center study

BACKGROUND

The aim of our study was to evaluate the short-term outcomes of totally laparoscopic right colectomy, in particular to compare the incidence of leakage of the ileocolic anastomosis after either single-layer (SL) or double-layer (DL) enterotomy closure.

METHODS

From March 2010 to July 2014, 162 patients underwent laparoscopic right colectomy with intracorporeal ileocolic anastomosis. The enterotomy was closed with either SL (77 patients) or DL technique (85 patients). Short-term outcomes in both groups were retrospectively analyzed.

RESULTS

Median time to perform the ileocolic anastomosis was similar in the two groups (17 min in SL versus 20 min in DL, p = 0.109). DL closure was associated with a significantly lower incidence of anastomotic leakage (1.2 % in DL vs 7.8 % in SL, p = 0.044). Shorter hospital stay was also observed in the DL group.

CONCLUSIONS

Adoption of DL closure of the enterotomy resulted in significantly improved outcome. We strongly recommend a double-layer closure technique when performing an intracorporeal enterocolic anastomosis.

Insertion of 16 amino acids in the BAR domain of the oligophrenin 1 protein causes mental retardation and cerebellar hypoplasia in an Italian family

We observed a three-generation family with two maternal cousins and an uncle affected by mental retardation (MR) with cerebellar hypoplasia. X-linked inheritance and the presence of cerebellar malformation suggested a mutation in the OPHN1 gene. In fact, mutational screening revealed a 2-bp deletion that abolishes a donor splicing site, resulting in the inclusion of the initial 48 nucleotides of intron 7 in the mRNA. This mutation determines the production of a mutant oligophrenin 1 protein with 16 extra amino acids inserted in-frame in the N-terminal BAR (Bin1/amphiphysin/Rvs167) domain. This is the first case of a mutation in OPHN1 that does not result in the production of a truncated protein or in its complete loss. OPHN1 (ARHGAP41) encodes a GTPase-activating (GAP) protein belonging to the GRAF subfamily characterized by an N-terminal BAR domain, followed by a pleckstrin-homology (PH) domain and the GAP domain. GRAF proteins play a role in endocytosis and are supposed to dimerize via their BAR domain, that induces membrane curvature. The extra 16 amino acids cause the insertion of 4.4 turns in the third alpha-helix of the BAR domain and apparently impair the protein function. In fact, the clinical phenotype of these patients is identical to that of patients with loss-of-function mutations.

Laparoscopic Deloyers procedure for tension-free anastomosis after extended left colectomy: technique and results

BACKGROUND

The Deloyers procedure, which includes inversion of the right colon around the axis of the ileocolic vessels, can be used to achieve a well vascularized, tension-free colorectal anastomosis after extended left colectomy. The aim of this study is to report our technique and outcome in a series of ten consecutive patients who underwent right colonic transposition by laparoscopic approach.

METHODS

Charts were retrospectively reviewed to analyze postoperative outcome and bowel function. A video was recorded to demonstrate the procedure.

RESULTS

Conversion was required in one (10%) patient due to extensive adhesions. No intraoperative complications were recorded. Anastomotic leakage occurred in one (10%) case and was managed with peritoneal lavage and ileostomy. Six months after surgery, all patients reported a median number of 2.5 (range 2-3) bowel movements per day with solid stool consistency. Neither anastomotic stricture nor bowel ischemia was found at 1-year endoscopic follow-up.

CONCLUSION

Our experience shows that laparoscopic right colonic transposition is a safe and feasible procedure and provides good functional outcomes.

Laparoscopic adrenalectomy for malignant neoplasm: Our experience in 15 cases

BACKGROUND

We report our experience with laparoscopic adrenalectomy (LA) for malignant pathologies that in some cases required a multiorgan resection.

METHODS

In this study, we retrospectively reviewed a group of 15 patients (10 men, and five women) who underwent an operation for primitive or metastatic adrenal malignant tumors.

RESULTS

The sizes of the lesions ranged from 3.5 to 8.5 cm (average 3.6). We performed 11 adrenalectomies (four right and seven left), two left adrenalectomies with distal spleno-pancreatectomy, one right adrenalectomy with nephrectomy, and one laparoscopic exploration that showed a peritoneal spreading. Six patients, with a follow-up ranging from 3 to 24 months (mean 13.6 months), are disease free; the others developed metastatic repetitions or local recurrences.

CONCLUSIONS

LA could be performed always respecting the oncological principles of radical excisions. This approach in our patients has been associated with low morbidity, low intraoperative blood loss, short hospital stay, and fast functional recovery.

Cavernous artery revascularization in vasculogenic impotence: new simplified technique

A new simplified technique of cavernous artery revascularization is presented. The arterial inflow to the corpora is obtained through a counterflow end-to-end anastomosis of the inferior epigastric artery to the proximal stump of the transected dorsal penile artery. The revascularization of the cavernous artery occurs through the common penile artery. This operation is particularly suitable for patients showing pudendal or common penile artery obstruction at arteriography. Optimal distal perfusion is obtained by a cross end-to-side anastomosis of the distal stump of the dorsal artery to the contralateral dorsal penile artery. To date 5 patients have been operated on using this method with good functional results in 80 per cent.

Proximal variants in CCND2 associated with microcephaly, short stature, and developmental delay: A case series and review of inverse brain growth phenotypes

Cyclin D2 (CCND2) is a critical cell cycle regulator and key member of the cyclin D2-CDK4 (DC) complex. De novo variants of CCND2 clustering in the distal part of the protein have been identified as pathogenic causes of brain overgrowth (megalencephaly, MEG) and severe cortical malformations in children including the megalencephaly-polymicrogyria-polydactyly-hydrocephalus (MPPH) syndrome. Megalencephaly-associated CCND2 variants are localized to the terminal exon and result in accumulation of degradation-resistant protein. We identified five individuals from three unrelated families with novel variants in the proximal region of CCND2 associated with microcephaly, mildly simplified cortical gyral pattern, symmetric short stature, and mild developmental delay. Identified variants include de novo frameshift variants and a dominantly inherited stop-gain variant segregating with the phenotype. This is the first reported association between proximal CCND2 variants and microcephaly, to our knowledge. This series expands the phenotypic spectrum of CCND2-related disorders and suggests that distinct classes of CCND2 variants are associated with reciprocal effects on human brain growth (microcephaly and megalencephaly due to possible loss or gain of protein function, respectively), adding to the growing paradigm of inverse phenotypes due to dysregulation of key brain growth genes.

Combined yeast and microalgal cultivation in a pilot-scale raceway pond for urban wastewater treatment and potential biodiesel production

A mixed culture of oleaginous yeast Lipomyces starkeyi and wastewater native microalgae (mostly Scenedesmus sp. and Chlorella sp.) was performed to enhance lipid and biomass production from urban wastewaters. A 400 L raceway pond, operating outdoors, was designed and used for biomass cultivation. Microalgae and yeast were inoculated into the cultivation pond with a 2:1 inoculum ratio. Their concentrations were monitored for 14 continuous days of batch cultivation. Microalgal growth presented a 3-day initial lag-phase, while yeast growth occurred in the first few days. Yeast activity during the microalgal lag-phase enhanced microalgal biomass productivity, corresponding to 31.4 mgTSS m^-2 d^-1. Yeast growth was limited by low concentrations in wastewater of easily assimilated organic substrates. Organic carbon was absorbed in the first 3 days with a 3.7 mgC L^-1 d^-1 removal rate. Complete nutrient removal occurred during microalgal linear growth with 2.9 mgN L^-1 d^-1 and 0.96 mgP L^-1 d^-1 removal rates. Microalgal photosynthetic activity induced high pH and dissolved oxygen values resulted in natural bactericidal and antifungal activity. A 15% lipid/dry weight was measured at the end of the cultivation time. Fatty acid methyl ester (FAME) analysis indicated that the lipids were mainly composed of arachidic acid.

Effect of arsenic on nitrification of simulated mining water

Mining and mineral processing of gold-bearing ores often release arsenic to the environment. Ammonium is released when N-based explosives or cyanide are used. Nitrification of simulated As-rich mining waters was investigated in batch bioassays using nitrifying cultures enriched in a fluidized-bed reactor (FBR). Nitrification was maintained at 100mg AsTOT/L. In batch assays, ammonium was totally oxidized by the FBR enrichment in 48 h. As(III) oxidation to As(V) occurred during the first 3h attenuating arsenic toxicity to nitrification. At 150 and 200mg AsTOT/L, nitrification was inhibited by 25%. Candidatus Nitrospira defluvii and other nitrifying species mainly colonized the FBR. In conclusion, the FBR enriched cultures of municipal activated sludge origins tolerated high As concentrations making nitrification a potent process for mining water treatment.

Biological inverse fluidized-bed reactors for the treatment of low pH- and sulphate-containing wastewaters under different COD/SO4(2-) conditions

The feasibility of removing sulphate using low-density polypropylene pellets as carrier material in two lactate-fed sulphidogenic inverse fluidized-bed reactors was investigated. Two different COD/sulphate ratios and two different feed-sulphate concentrations were used for the operation of the reactors. During the 242 days of operation, the robustness of the system was studied by suddenly decreasing the feed pH to 3.00. A 10% fluidization degree was used since the carrier material adopted showed not to be adequate to attain a satisfactory immobilization of the biomass with higher fluidization degrees. This resulted in a failure of the process when the feed pH was intentionally decreased to 3.00 in reactor 2, operated with a COD/sulphate ratio of 4.00. On the contrary, when a slightly acidic feed solution was fed to reactor 2, a 97% sulphate reduction efficiency was obtained. In reactor 1, operated with a COD/sulphate ratio of 0.67 throughout the experiment, COD removal and sulphate reduction efficiencies reached the highest values of 75% and 35%, respectively. Higher efficiencies were not achieved also due to the accumulation of acetate and the most likely presence of microbial competition between sulphate reducers and other microorganisms.