Quadratus Lumborum Block versus Fascia Iliaca Compartment Block for Acetabular Fracture Surgery by Stoppa Method: A Double-Blind, Randomized, Noninferiority Trial

Background

Acetabular fracture surgeries are frequently accompanied by protracted and severe perioperative pain, and there is no consensus on optimal pain relief management.

Aim

This study aimed at comparing the analgesic efficacy of fascia iliaca compartment block (FICB) and quadratus lumborum block (QLB) in patients with acetabular fractures undergoing surgery using the Stoppa method.

Methods

In this double-blind, randomized, noninferiority clinical trial, adult patients undergoing spinal anesthesia for acetabular fracture surgery, in Imam Hossein Hospital, Tehran, Iran (IRCT20191114045435N1), were randomly divided into two groups: FICB (n = 22) and QLB (n = 24). The visual analog scale (VAS) was used to assess the pain intensity at different times for all participants. In addition, the dose of fentanyl required to induce the patient to sit for spinal anesthesia and the pain intensity were evaluated. Moreover, the duration of analgesia and the total amount of morphine consumed in the first 24 h following surgery were evaluated, analyzed, and compared between the two study groups.

Results

FICB and QLB demonstrated effective comparative postoperative analgesic profiles following acetabular fracture surgery; however, no significant differences in VAS values were observed between the two groups during the study. FICB experienced reduced cumulative fentanyl consumption during spinal anesthetic placement, whereas QLB had a significantly lower total morphine demand in the initial postoperative 24 h period.

Conclusion

The lateral QLB and FICB can be introduced as effective routes for analgesia in acetabular fracture surgery using the Stoppa method. Clinical Trial Registration. The study was prospectively registered in the clinical trials registry system, on 2021-02-17, with registration number: IRCT20191114045435N1.

Platelet-rich plasma versus corticosteroid: a randomized controlled trial on tennis elbow patients resistant to nonsurgical treatments

Background

Although some studies on tennis elbow indicate corticosteroid (CS) effectiveness in the short term, according to the role of race, this study evaluates the efficacy of platelet-rich plasma (PRP) compared with CS for a more cost-effective treatment.

Methods

This randomized controlled trial included 30 positive-resisted wrist extension patients with a minimum five visual analog scale (VAS) pain score. Participants were randomly assigned to treatment or control groups via computer-generated randomization and were matched for baseline and clinical characteristics. Cases received either 40 mg of prednisolone acetate or 2 ml of PRP, followed for 1 month. VAS and Disabilities of the Arm, Shoulder, and Hand (DASH) scores were the primary outcomes.

Results

The median VAS and the mean DASH scores had a statistically significant difference in the PRP and CS groups before and after injection (P<0.001).The mean DASH difference between preinjection and follow-up time in the PRP and CS groups was 59.72±14.17 and 43.16±10.87, respectively, with a mean difference of 16.55 (95% CI 7.10-26.00) and a significant difference (P=0.001).The mean VAS pain score difference in preinjection and follow-up time had a statistically significant difference between the PRP and CS groups (P=0.026), and the mean VAS pain score difference in the CS group was 6.46±1.50 and 7.73±0.96 in the PRP group.

Conclusion

In conclusion, larger studies with parallel groups and more diverse CS doses and types with baseline matching are needed to confirm the short-term benefits of PRP. Investigating the effects of different CS doses using ultrasound techniques is recommended.

Efficacy of Low-Level Laser Therapy for the Treatment of Nonspecific Chronic Neck Pain: Low-Level Laser Therapy vs. Sham Laser

Introduction: The most common type of neck pain is chronic nonspecific pain. There are conflicting opinions about the beneficial effects of a low-level laser in reducing chronic nonspecific neck pain. The aim of this study was to evaluate the efficacy of low-level laser therapy (LLLT) for the treatment of non-specific chronic neck pain. Methods: This study was conducted as a prospective randomized clinical trial. Forty-four patients were randomly divided into two groups: (1) Intervention group (n=22): LLLT in the red spectra range with a wavelength of 980 (nm) and a power of 16 (J/cm2 ) was irradiated in the affected areas of the neck, the muscles along the spine, and the upper trapezius; (2) sham group (n=22): A low-level laser was irradiated with a passive probe (non-laser red light) in the affected areas of the neck, the muscles along the spine, and the upper trapezius. The treatment protocol consisted of 12 sessions (15 minutes, three times a week, for four weeks). These patients were evaluated for pain using the visual analog scale (VAS) (0-10). The patients were followed up for four weeks. Results: This study showed a statistically significant reduction in chronic nonspecific neck pain in the LLLT group (P<0.05). Conclusion: It is concluded that LLLT was effective in reducing chronic nonspecific neck pain. LLLT is a non-invasive, safe and effective method that can improve chronic nonspecific neck pain in patients in the short term.

SARS-CoV-2 and HIV co-infection; clinical features, diagnosis, and treatment strategies: A systematic review and meta-analysis

Background and aim

Coronavirus disease 2019 (COVID-19) in people living with human immunodeficiency virus (HIV) who has a compromised immune system can be associated with more significant risks for severe complications. To date, no comprehensive study has been performed to evaluate HIV in patients with COVID-19. In the present study, we assessed the status of patients co-infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and HIV as a systematic review and meta-analysis.

Methods

A systematic literature search strategy was conducted via reviewing original research articles published in Medline, Web of Science, and Embase databases in 2019 and 2020. Statistical analysis was performed using STATA software, version 14.0 (Stata Corporation, College Station, Texas, USA), to report the prevalence of HIV among patients with COVID-19. Case reports/case series were also evaluated as a systematic review.

Results

Sixty-three studies (53 case reports/case series and ten prevalence studies) were included in our study. A meta-analysis of prevalence studies showed that HIV infection among patients with COVID-19 was reported in 6 countries (Uganda, China, Iran, USA, Italy, and Spain) with an overall frequency of 1.2% [(95% CI) 0.8–1.7] among 14,424 COVID-19 patients. According to the case reports and case series, 111 patients with HIV have been reported among 113 patients with COVID-19 from 19 countries. Most of the cases were in the USA, China, Italy, and Spain.

Conclusion

The small number of SARS-CoV-2-HIV co-infected patients reported in the literature makes it difficult to draw precise conclusions. However, since people with HIV are more likely to develop more severe complications of COVID-19, targeted policies to address this raised risk in the current pandemic should be considered. Our findings highlight the importance of identifying underlying diseases, co-infections, co-morbidities, laboratory findings, and beneficial treatment strategies for HIV patients during the COVID-19 pandemic.

[Specular microscopy findings in active uveitis]

PURPOSE

To study the effect of ocular inflammation in active uveitis on the corneal endothelium.

MATERIALS AND METHODS

This is a prospective cross-sectional study involving 63 eyes of 38 patients with active newly-diagnosed uveitis. Eighty-four eyes of 42 non-uveitic subjects served as a control group. All patients underwent detailed ophthalmic examination, laser flare photometry, and non-contact specular microscopy. Eyes with uveitis had a follow-up visit at one month after initiation of treatment, including laser flare photometry and specular microscopy.

RESULTS

The mean age of the active uveitis patients was 33 (range: 9-67 years) with 21 men (55%) and 17 women (45%). For the uveitis patients at baseline, the mean flare value was 32ph/ms (range: 15-100ph/ms) with flare photometry value ≥50ph/ms in 13 eyes (21%) and<50ph/ms in 50 eyes (79%). At baseline, cell density (CD) of the uveitis patients was similar to CD in control eyes (p꞊0.16). The percent of hexagonality was significantly lower (p<0.0001), and the coefficient of variance (CV) (p<0.0001) and central corneal thickness (CCT) (p<0.0001) were significantly higher than in the control group. After one month, there was a significant decrease in flare photometry values (p<0.0001), with a mean flare value of 14.5ph/ms (range: 4-60ph/ms). In the active uveitis group, the overall results of specular microscopy did not significantly vary between the initial examination and the 1-month examination. For eyes with flare photometry value ≥50ph/ms at baseline, CD and hexagonal cell count significantly increased on the 1-month examination (p꞊0.01 and p꞊0.02 respectively), while CV and CCT decreased significantly at the one-month follow-up visit (p꞊0.007/p꞊0.03 respectively). For eyes with flare photometry value at baseline <50ph/ms, there was no significant differences in specular microscopy results between the initial examination and the 1-month examination.

CONCLUSIONS

In eyes with newly-diagnosed uveitis and active anterior chamber inflammation, specular microscopy shows transient qualitative abnormalities of the corneal endothelium that depend on the severity of the anterior chamber inflammation as measured by the laser flare meter.

Preoperative Smoking Cessation and its Association with Postoperative Complications and Length of Hospital Stay in Patients Undergoing Herniorrhaphy

BACKGROUND

To assess the effect of preoperative smoking cessation on postoperative complications in patients undergoing herniorrhaphy.

MATERIALS AND METHODS

This prospective study was conducted on 163 consecutive patients, undergoing herniorrhaphy. Demographic characteristics and postoperative complications were compared between smokers (group A), patients who reduced smoking by 50% (group B), and patients who completely quit smoking (group C).

RESULTS

The mean age of the patients was 42.9 (SD=10.3) years. Group A (n=77), group B (n=27), and group C (n=59) were not significantly different in terms of age, body mass index (BMI), medical history, laboratory data, smoking habit, type of hernia, type of anesthesia, the American Society of Anesthesiologists (ASA) class, repair method, surgery approach, and duration surgery (P>0.05 for all). However, significant differences were observed between group B and group A, group C and group A, and group C and group B regarding postoperative complications, such as wound healing complications and length of hospital stay (LOS) (P<0.05 for all).

CONCLUSION

Decreased preoperative smoking is associated with the reduced risk of respiratory, cardiovascular, and wound healing complications and decreased LOS in patients undergoing herniorrhaphy.

A case report of appendicitis within an Amyand's hernia: A surprising finding in diagnostic laparoscopy

•

Patients with concomitant symptoms of appendicitis and inguinal hernia should have a diagnostic suspicion of amyand hernia.

•

Laparoscopy can be used as a diagnostic and therapeutic modality in amyand hernia patients.

•

Laparoscopy helps to better determine the degree of inflammation of the hernia sac to decide on hernia repair.

Introduction

Amyand hernia is a rare type of hernia in which the appendix is ​​located inside the hernia sac.Its diagnosis is very difficult in the Pre-operative period and it is usually presented as an intraoperative finding.

Presentation of case

A 21-year-old male who presented to our emergency department with peri-umbilical pain associated with nausea and vomiting. On examination he had a tenderness in the inguinal canal. He underwent diagnostic laparoscopy. Operative finding was amyand hernia with inflamed appendix in hernia sac. Laparoscopic appendectomy and tissue repair was performed for him.

Discussion

There are several preoperative diagnostic modalities for amyand hernia including abdominal CT scan and ultrasound. Diagnostic laparoscopy can be used as one of the diagnostic modalities for this type of hernia. Amyand hernia treatment includes appendectomy and inguinal hernia repair, which can vary depending on the severity of inflammation of the inguinal area.

Conclusion

based on our study another diagnostic modality in case of clinical suspicion of amyand hernia is diagnostic laparoscopy which is useful approach in all forms of incarcerated hernias to assess contents and avoid unnecessary laparotomy.

Effect of Benson's Relaxation Technique on Propofol Consumption and Preoperative Anxiety of Patients Undergoing Cataract Surgery

Background

Benson’s relaxation (BR) technique is a suitable non-pharmacological approach to reduce preoperative anxiety (PA).

Objectives

This study aimed to investigate the effect of BR therapy on PA and the induction and maintenance dose of propofol during cataract surgery (CS).

Methods

Seventy-two patients were randomly divided into two experiments or BR and control groups. The Amsterdam and Spielberger State-Trait Anxiety inventory (STAI) scores were used to assess PA directly two days and a half-hour before the CS. The control group did not receive any preoperation intervention or relaxation. Benson’s relaxation method was performed three times, each time for 20 minutes, including two days before surgery, a night before surgery, and an hour before the surgery in the presence of a researcher by an audio file. The induction and maintenance dose of anesthetic drug was recorded and compared between the two groups.

Results

The mean propofol consumption was significantly reduced during the induction of anesthesia in the intervention group compared to the control group (0.99 ± 0.29 versus 1.29 ± 0.49; P = 0.005) as well as the maintenance of anesthesia (84.66 ± 17.98 versus 108.33 ± 34.38, P = 0.001). The results of the post-intervention Amsterdam anxiety score showed a significant decrease in the intervention group compared to the control group (P = 0.032, F = 9.61, Eta2 = 0.12). The control group showed a higher Spielberger state score compared to the intervention group as well as the Spielberger trait (P < 0.001, F = 14.78, Eta2 = 0.18).

Conclusions

The BR method effectively reduces the level of PA in patients undergoing CS. Moreover, it reduces the need for anesthetic drug, propofol, during surgery.

Infection Rate of Reamed versus Unreamed Intramedullary Nailing in Open Tibia Fractures

Background: Intramedullary nailing (IM nailing) is the standard of care for the treatment of most diaphyseal lower extremity fractures. A few studies have assessed and compared the infection rate following reamed and unreamed IM nailing in open long bone fractures. In the present study, we attempted to compare the infection rate between two procedures in open fractures of tibia. Methods: In this prospective study, we included consecutive patients suffering from open fractures of tibia (Gustilo subtypes II or IIIA) who required IM nailing. Patients younger than 16 years old, other Gustilo types (I, IIIB, and IIIC), fractures reaching to the tibial plateau articular surface, and simultaneous fractures of other bones in the extremity were excluded. All patients were followed up for one year to assess the postoperative infection rate. Results: Of 59 patients, 37 underwent reamed IM nailing and 22 underwent unreamed IM nailing. In reamed group, 4 cases (10.8%) experienced an infection requiring reoperation and antibiotic therapy, while in the unreamed group, it was 5 cases (22.7%). The difference between the groups was not statistically significant. Conclusion: Reamed and unreamed IM nailing procedures for fractures of tibia have similar outcome regarding long-term postoperative infections that require reoperation and antibiotic therapy.

[Retinal artery occlusion and anterior ischemic optic neuropathy associated with factor V Leiden mutation: A case report]

Factor V is a pro-coagulant cofactor required for the transformation of prothrombin into thrombin. Thrombin activates factor V, which is then deactivated by protein C. A mutation in factor V is responsible for the formation of factor V Leiden, resistant to activated protein C. The association of this mutation with venous thromboses has been established. Its association with arterial occlusions is still controversial. We report the case of a central retinal artery occlusion associated with a non-arteritic anterior optic neuropathy associated with a Leiden mutation of factor V (FVL). The presence of FVL has been associated with lack of reperfusion and rapid progression to neovascularization. It seems that FVL intervenes mainly during the reperfusion phase after the occurrence of arterial thrombosis.

Evaluation of native microalgae from Tunisia using the pulse-amplitude-modulation measurement of chlorophyll fluorescence and a performance study in semi-continuous mode for biofuel production

BACKGROUND

Microalgae are attracting much attention as a promising feedstock for renewable energy production, while simultaneously providing environmental benefits. So far, comparison studies for microalgae selection for this purpose were mainly based on data obtained from batch cultures, where the lipid content and the growth rate were the main selection parameters. The present study evaluates the performance of native microalgae strains in semi-continuous mode, considering the suitability of the algal-derived fatty acid composition and the saponifiable lipid productivity as selection criteria for microalgal fuel production. Evaluation of the photosynthetic performance and the robustness of the selected strain under outdoor conditions was conducted to assess its capability to grow and tolerate harsh environmental growth conditions.

RESULTS

In this study, five native microalgae strains from Tunisia (one freshwater and four marine strains) were isolated and evaluated as potential raw material to produce biofuel. Firstly, molecular identification of the strains was performed. Then, experiments in semi-continuous mode at different dilution rates were carried out. The local microalgae strains were characterized in terms of biomass and lipid productivity, in addition to protein content, and fatty acid profile, content and productivity. The marine strain Chlorella sp. showed, at 0.20 1/day dilution rate, lipid and biomass productivities of 35.10 mg/L day and 0.2 g/L day, respectively. Moreover, data from chlorophyll fluorescence measurements demonstrated the robustness of this strain as it tolerated extreme outdoor conditions including high (38 °C) and low (10 °C) temperature, and high irradiance (1600 µmol/m² s).

CONCLUSIONS

Selection of native microalgae allows identifying potential strains suitable for use in the production of biofuels. The selected strain Chlorella sp. demonstrated adequate performance to be scaled up to outdoor conditions. Although experiments were performed at laboratory conditions, the methodology used in this paper allows a robust evaluation of microalgae strains for potential market applications.

The Effect of Percutaneous Laser Disc Decompression on Reducing Pain and Disability in Patients With Lumbar Disc Herniation

Introduction: As low back pain incidence is increasing, noninvasive modalities are gaining attention for their ability to achieve the best possible outcome with the least complications. Percutaneous laser disc decompression (PLDD) is currently popular for this purpose. This study aims to evaluate the effect of PLDD on disability and pain reduction in patients with lumbar disc herniation. Methods: Thirty patients were enrolled in this study. Spinal nerve blocks were conducted by laser discectomy single stage injection of a needle into the disc space. The nucleus pulposus of herniated discs were irradiated with laser in order to vaporize a small part of the nucleus pulposus of the intervertebral discs and reduce the voluminosity of diseased discs. Patients were treated with 1000 J of 980 nm diode laser with 5 W energy. In order to measure the severity of pain, visual analog scale (VAS) and also ODI (Oswestry Disability Index) were used. Data were analyzed using SPSS version 12. Results: Thirty patients participated in this trial including 11 men and 19 women with a mean age (SD) of 40.8 (10.8) years. The mean patients VAS score and ODI level before and after discectomy showed statistically significant differences. The mean VAS and ODI scores showed no statistical difference between males and females (P<0.05) and percutaneous laser discectomy decreased the VAS and ODI at both groups of patients similarly. Conclusion: We found the use of PLDD reduces pain and disability in patients as a noninvasive procedure.

Selection of native Tunisian microalgae for simultaneous wastewater treatment and biofuel production

This paper focuses on the selection of native microalgae strains suitable for wastewater treatment and biofuel production. Four Chlorophyceae strains were isolated from North-eastern Tunisia. Their performances were compared in continuous mode at a 0.3 1/day dilution rate. The biomass productivity and nutrient removal capacity of each microalgae strain were studied. The most efficient strain was identified as Scenedesmus sp. and experiments at different dilution rates from 0.2 to 0.8 1/day were carried out. Maximal biomass productivity of 0.9 g/L day was obtained at 0.6 1/day. The removal of chemical oxygen demand (COD), ammonium and phosphorus was in the range of 92-94%, 61-99% and 93-99%, respectively. Carbohydrates were the major biomass fraction followed by lipids and then proteins. The saponifiable fatty acid content was in the 4.9-13.2% dry biomass range, with more than 50% of total fatty acids being composed of saturated and monosaturated fatty acids.

Halanaerobacter jeridensis sp. nov., isolated from a hypersaline lake

An obligatory anaerobic, moderately halophilic bacterium, designated strain CEJFG43T, was isolated from a sample of sediment collected below the salt crust on the hypersaline El Jerid lake, in southern Tunisia. The cells of this novel strain were Gram-staining-negative, non-sporulating, motile, short rods. They grew in media with 6–30 % (w/v) NaCl (optimum 15 %), at 20–60 °C (optimum 45 °C) and at pH 5.5–9.5 (optimum pH 8.3). The micro-organism fermented glucose, fructose, ribose, raffinose, galactose, mannose, sucrose, maltose, xylose, mannitol, pyruvate and glycerol. The products of glucose fermentation were lactate, ethanol, acetate, H2 and CO2. The genomic G+C DNA content of strain CEJFG43T was 33.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain CEJFG43T belonged in the genus Halanaerobacter and was most closely related to Halanaerobacter lacunarum DSM 6640T (95.3 % gene sequence similarity) and Halanaerobacter chitinivorans DSM 9569T (95.3 %). The predominant cellular fatty acids were non-branched (C16 : 0 and C16 : 1). Based on the phylogenetic and phenotypic evidence, strain CEJFG43T represents a novel species in the genus Halanaerobacter for which the name Halanaerobacter jeridensis sp. nov. is proposed. The type strain is CEJFG43T ( = DSM 23230T = JCM 16696T).

Simultaneous hydrocarbon biodegradation and biosurfactant production by oilfield-selected bacteria

AIMS

To study the bacterial diversity associated with hydrocarbon biodegradation potentiality and biosurfactant production of Tunisian oilfields bacteria.

METHODS AND RESULTS

Eight Tunisian hydrocarbonoclastic oilfields bacteria have been isolated and selected for further characterization studies. Phylogenetic analysis revealed that three thermophilic strains belonged to the genera Geobacillus, Bacillus and Brevibacillus, and that five mesophilic strains belonged to the genera Pseudomonas, Lysinibacillus, Achromobacter and Halomonas. The bacterial strains were cultivated on crude oil as sole carbon and energy sources, in the presence of different NaCl concentrations (1, 5 and 10%, w/v), and at 37 or 55°C. The hydrocarbon biodegradation potential of each strain was quantified by GC-MS. Strain C450R, phylogenetically related to the species Pseudomonas aeruginosa, showed the maximum crude oil degradation potentiality. During the growth of strain C450R on crude oil (2%, v/v), the emulsifying activity (E24) and glycoside content increased and reached values of 77 and 1.33 g l(-1), respectively. In addition, the surface tension (ST) decreased from 68 to 35.1 mN m(-1), suggesting the production of a rhamnolipid biosurfactant. Crude biosurfactant had been partially purified and characterized. It showed interest stability against temperature and salinity increasing and important emulsifying activity against oils and hydrocarbons.

CONCLUSIONS

The results of this study showed the presence of diverse aerobic bacteria in Tunisian oilfields including mesophilic, thermophilic and halotolerant strains with interesting aliphatic hydrocarbon degradation potentiality, mainly for the most biosurfactant produced strains.

SIGNIFICANCE AND IMPACT OF THE STUDY

It may be suggested that the bacterial isolates are suitable candidates for practical field application for effective in situ bioremediation of hydrocarbon-contaminated sites.

Roles of Lignin Peroxidase and Manganese Peroxidase from Phanerochaete chrysosporium in the Decolorization of Olive Mill Wastewaters

The relative contributions of lignin peroxidase (LiP) and manganese peroxidase (MnP) to the decolorization of olive mill wastewaters (OMW) by Phanerochaete chrysosporium were investigated. A relatively low level (25%) of OMW decolorization was found with P. chrysosporium which was grown in a medium with a high Mn(II) concentration and in which a high level of MnP (0.65 (mu)M) was produced. In contrast, a high degree of OMW decolorization (more than 70%) was observed with P. chrysosporium which was grown in a medium with a low Mn(II) concentration but which resulted in a high level of LiP activity (0.3 (mu)M). In this culture medium, increasing the Mn(II) concentration resulted in decreased levels of OMW decolorization and LiP activity. Decolorization by reconstituted cultures of P. chrysosporium was found to be more enhanced by the addition of isolated LiP than by the addition of isolated MnP. The highest OMW decolorization levels were obtained at low initial chemical oxygen demands combined with high levels of extracellular LiP. These data, plus the positive effect of veratryl alcohol on OMW decolorization and LiP activity, indicate that culture conditions which yield high levels of LiP activity lead to high levels of OMW decolorization.

Co-treatment of olive-mill and urban wastewaters by experimental stabilization ponds

Olive oil mill wastewater (OMW) constitutes a source of environmental problems in Morocco due to its significantly high organic load, its phytotoxic properties and its relatively low biodegradability. An effective option for its disposal is its agricultural use after co-treatment with urban wastewater (UWW). The main objective of this investigation was to evaluate the potential of this co-treatment, using experimental waste stabilization ponds, in removing OMW phytotoxicity. We examined the influence of the organic load, at the entry of the treatment system, on the evolution of some physicochemical (chemical oxygen demand and polyphenols) and microbiological (fecal coliforms and fecal streptococci) parameters. The results showed a removal of the organic, phenolic and microbial load throughout the treatment which differed from one system to another according to the OMW load applied to each system. The results concerning the germination assays of Zea mays and Solanum lycopersicum suggested that the co-treatment of OMW with UWW would decrease the phytotoxicity of this waste.

[Treatment of olive mill wastewater by a process combining an intensive treatment (Jet-Loop reactor) followed by an extensive treatment (stabilization ponds)]

Olive oil mill wastewater (OMW) is generally recognized as an environmentally troublesome by-product of the olive oil industry as its disposal without any treatment is known to cause serious environmental problems. However, this effluent has a high fertilizing power and constitutes, with urban wastewater, an important low-cost source. Biological treatment of OMW, with a process combining an aerobic reactor, 'Jet-Loop', and waste stabilization ponds, was investigated for possible agricultural reuse. The focus of the present study was to evaluate the contribution and the complementarity of the two systems in the total OMW treatment. Bio-treatment was performed using a 100-litre Jet-Loop reactor working volume achieving a chemical oxygen demand (COD) and phenolic compounds maximum removal rate of 72% and 68%, respectively, at a hydraulic retention time of 10 days. Co-treatment of OMW and domestic wastewater in waste stabilization ponds, with a hydraulic retention time of 22 days, reached a global removal rate of 66% for COD while no trace of phenolic compounds was detected on this level during the entire treatment period. Dynamics of faecal coliforms in stabilization ponds showed a total removal rate of 99.9% (3 logarithmic units (Log.U)). Preliminary results of agronomic tests on the ray-grass have evaluated the fertilizing effect of the final effluent resulting from the co-treatment.

Mesophilic and thermophilic anaerobic digestion of biologically pretreated abattoir wastewaters in an upflow anaerobic filter

The hydrolysis pretreatment of abattoir wastewaters (AW), rich in organic suspended solids (fats and protein) was studied in static and stirred batch reactors without aeration in the presence of natural microbial population acclimated in a storage tank of AW. Microbial analysis showed that the major populations which contribute to the pretreatment of AW belong to the genera Bacillus. Contrary to the static pretreatment, the stirred conditions favoured the hydrolysis and solubilization of 80% of suspended matter into soluble pollution. The pretreated AW, in continuous stirred tank reactor (CSTR) at a hydraulic retention time (HRT) of 2 days, was fed to an upflow anaerobic filter (UAF) at an HRT of 2 days. The performance of anaerobic digestion of biologically pretreated AW was examined under mesophilic (37 degrees C) and thermophilic (55 degrees C) conditions. The shifting from a mesophilic to a thermophilic environment in the UAF was carried out with a short start-up of thermophilic condition. The UAF ran at organic loading rates (OLRs) ranging from 0.9 to 6g COD/Ld in mesophilic conditions and at OLRs from 0.9 to 9 g COD/Ld in thermophilic conditions. COD removal efficiencies of 80-90% were achieved for OLRs up to 4.5 g COD/Ld in mesophilic conditions, while the highest OLRs i.e. 9 g COD/Ld led to efficiencies of 70-72% in thermophilic conditions. The biogas yield in thermophilic conditions was about 0.32-0.45 L biogas/g of COD removed for OLRs up to 4.5 g COD/Ld. For similar OLR, the UAF in mesophilic conditions showed lower percentage of methanization. Mesophilic anaerobic digestion has been shown to destroy pathogens partially, whereas the thermophilic process was more efficient in the removal of indicator microorganisms and pathogenic bacteria at different organic loading rates.

Low cost biosorbent "banana peel" for the removal of phenolic compounds from olive mill wastewater: kinetic and equilibrium studies

The aim of this work is to determine the potential of application of banana peel as a biosorbent for removing phenolic compounds from olive mill wastewaters. The effect of adsorbent dosage, pH and contact time were investigated. The results showed that the increase in the banana peel dosage from 10 to 30 g/L significantly increased the phenolic compounds adsorption rates from 60 to 88%. Increase in the pH to above neutrality resulted in the increase in the phenolic compounds adsorption capacity. The adsorption process was fast, and it reached equilibrium in 3-h contact time. The Freundlich and Langmuir adsorption models were used for mathematical description of the adsorption equilibrium and it was found that experimental data fitted very well to both Freundlich and Langmuir models. Batch adsorption models, based on the assumption of the pseudo-first-order, pseudo-second-order and intraparticle diffusion mechanism, showed that kinetic data follow closely the pseudo-second-order than the pseudo-first-order and intraparticle diffusion. Desorption studies showed that low pH value was efficient for desorption of phenolic compounds. These results indicate clearly the efficiency of banana peel as a low-cost solution for olive mill wastewaters treatment and give some preliminary elements for the comprehension of the interactions between banana peel as a bioadsorbent and the very polluting compounds from the olive oil industry.

Performance of biological treatment of high-level ammonia landfill leachate

The biological treatment efficiency of landfill leachate (LFL) from a Tunisian site collection was investigated in this study. The raw effluent was highly charged with organic matter (more than 25 g l(-1) of chemical oxygen demand (COD)), ammonia (1.7 g l(-1) and salts (20 g l(-1)). With the presence of heavy metals, phenols and hydrocarbons, LFL exhibited high toxicity to organisms since it totally inhibited the bioluminescence of Vibrio fischeri and the germination of Lepidium sativum seeds. The biological oxygen demand (BOD5)/COD ratio of 0.5 indicates that the effluent can be biologically treated. Sludge from a wastewater treatment plant was acclimatized to the effluent in continuous batches. During the acclimatization phase, the consortia demonstrated a good ability to remove organic matter and toxicity in spite of an increase of introduced load reaching 3.2 g of COD 1.d. Consequently, the biodegradation experiments were carried out in a stirred tank reactor (STR) at organic loading rate (OLR) ranging from 0.5 to 5.4 g l(-1) per day. The hydraulic retention time was decreased from 50 days to 4.6 days. The process seemed to be efficient to eliminate organics and ammonia. The COD removal efficiency reached a maximum of 80% for a loading rate of 5.4 g l(-1) per day. The values of N-NH4+ became less than those recommended by standards requested for rejection in public canalizations. During the treatment process, the biomass was increased from 0.8 g l(-1) at the start-up of the process to 3 g l(-1). On the other hand, results of toxicity examinations showed that the treatment was efficient to provide detoxification of the effluent indicating a good adaptability of the consortia in spite of the presence of problematic compounds. The increase of the loading rate up to 6 g l(-1) was responsible for the perturbation of the system and caused an accumulation of residual COD and toxicity.

Purification and characterization of the laccase secreted by the white rot fungus Perenniporia tephropora and its role in the decolourization of synthetic dyes

AIMS

To characterize the white rot fungus Perenniporia tephropora with respect to its laccase and to test its ability to decolourize synthetic dyes.

METHODS AND RESULTS

Under the culture conditions utilized, P. tephropora produced one laccase isozyme, which was purified to electrophoretic homogeneity by ammonium sulfate precipitation, size-exclusion chromatography and anion-exchange chromatography. The protein was monomeric with a molecular mass of 63 kDa (SDS-PAGE) and had an isoelectric point of 3.3. The N-terminal amino acid sequence was SIGPVADLTVTNANI and the highest similarity value was found to the laccase from Lentinus tigrinus (86.6%). The optimum pH of the enzyme varied and was substrate dependent. It was 4.0 and 5.0 for 2,6-dimethoxyphenol (DMP) and 2,2'-azino-di(3-ethyl-benzthiazoline-6-sulfonate) (ABTS), respectively. Under standard assay conditions, K(m) values of the enzyme were 7.3 and 0.4 mmol l(-1) towards DMP and ABTS, respectively. The laccase was inhibited by NaN(3), EDTA and p-coumarate but not by SDS and NaBr. Laccase was stable in the presence of some metal ions such as Cu(2+), Co(2+), Ca(2+), Cd(2+), Mg(2+), Mn(2+), Mo(2+), Ni(2+), Li(+) and Al(3+). The crude enzyme as well as the purified laccase was able to decolourize dyes from the textile industries, including remazol brilliant blue R, neolane blue and neolane pink. However, several other dyes were partially or not decolourized. In the presence of 1-hydroxybenzotriazole as mediator, only the decolourization of neolane yellow was achieved, while the decolourization of most of the dyes was just slightly improved.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study is the first report on the purification and the characterization of the laccase from the white rot fungus P. tephropora. The high levels of laccase secreted by this fungal strain as well as its stability suggest that it could be a useful tool for environmental applications.

Involvement of microbial populations during the composting of olive mill wastewater sludge

Olive mill waste water sludge obtained by the electro-Fenton oxidation of olive mill waste water was composted in a bench scale reactor. The evolution of microbial species within the composter was investigated using a respirometric test and by means of both cultivation-dependent and independent approaches (Polymerase Chain Reaction-Single Strand Conformation Polymorphism, PCR SSCP). During the period of high respiration rate (7-24 days), cultivation method showed that thermophilic bacteria as well as actinomycetes dominated over eumycetes. During the composting process, the PCR-SSCP method showed a higher diversity of the bacterial community than the eukaryotic one. After 60 days of composting, the compost exhibited a microbial stability and a clear absence of phytotoxicity.

Pilot-plant results of the electro-Fenton treatment of olive mill wastewaters followed by anaerobic digestion

In this work, we investigated an integrated technology for the treatment of the recalcitrant contaminants of olive mill wastewaters (OMW), allowing water recovery and reuse for agricultural purposes. The method involves an electrochemical pre-treatment step of the wastewater using the electro-Fenton reaction followed by an anaerobic bio-treatment. The electro-Fenton pre-treatment process removed 66% of the total polyphenolic compounds and subsequently decreased the OMW toxicity from 100 to 66.9%, which resulted in improving the performance of the anaerobic digestion. A continuous laboratory-scale methanogenic reactor was operated at a loading rate of 10g COD/L per day without any apparent toxicity. Furthermore, in the combined process, a high overall reduction in COD, suspended solids, polyphenols and lipids content was achieved by the two successive stages. Moreover, this combined process which was experimented at a real scale (25 m3 digester) demonstrated its technical feasibility and opens promising perspectives for industrial application in the Mediterranean countries because of its easy conception and high energy (methane) production.

Pilot-plant results of the electro-Fenton treatment of olive mill wastewaters followed by anaerobic digestion

In this work, we investigated an integrated technology for the treatment of the recalcitrant contaminants of olive mill wastewaters (OMW), allowing water recovery and reuse for agricultural purposes. The method involves an electrochemical pre-treatment step of the wastewater using the electro-Fenton reaction followed by an anaerobic bio-treatment. The electro-Fenton pre-treatment process removed 66% of the total polyphenolic compounds and subsequently decreased the OMW toxicity from 100 to 66.9% which resulted in improving the performance of the anaerobic digestion. A continuous lab-scale methanogenic reactor was operated at a loading rate of 10 g COD/L day without any apparent toxicity. Furthermore, in the combined process, a high overall reduction in COD, suspended solids, polyphenols and lipids content was achieved by the two successive stages. Moreover, this combined process which was experimented at a real scale (25 m3 digester), demonstrated its technical feasibility and opens promising perspectives for industrial application in the Mediterranean countries due to its easy conception and its high energy (methane) production.

A comparative study on the anaerobic membrane bioreactor performance during the treatment of domestic wastewaters of various origins

This study examined the practical performance of a cross-flow ultrafiltration membrane coupled to an anaerobic bioreactor, for treatment of raw domestic wastewater (RDW), at a pilot-scale plant. Wastewaters used in this study originated from two different domestic wastewater treatment plans (DWTPs) (Sfax and Ksour Essef). During the treatment in the membrane bioreactor (MBR) of the RDW originating from Sfax DWTP, the bioreactor did not reach its stationary phase because the anaerobic biomass was unable to adapt to the wastewater. This was explained by the considerable fluctuations in the domestic wastewater composition and a possible contamination of Sfax wastewater by industrial discharges. However, the treatment of RDW originating from Ksour Essef (DWTP) was successful. In both cases, the treatment led to a total removal of all tested pathogens. The quality of treated wastewater fits largely with WHO guidelines for unrestricted irrigation. The phytotoxicity and the microtoxicity tests, using Lepidium sativum and Vibrio fischeri respectively, demonstrated that wastewater from Sfax exhibited higher toxicity than that from Ksour Sssef.

Effect of bioaugmentation of activated sludge with white-rot fungi on olive mill wastewater detoxification

AIMS

To test the potential use of Phanerochaete chrysosporium and other white-rot fungi to detoxify olive mill wastewaters (OMW) in the presence of a complex activated sludge. To combine the aerobic with anaerobic treatment to optimize the conversion of OMW in biogas.

METHODS AND RESULTS

A 25-l air lift reactor was used to pretreat OMW by white-rot fungi. Detoxification of the OMW was monitored by size exclusion HPLC analysis, chemical oxygen demand (COD)/biological oxygen demand (BOD(5)) ratio evolution, and bioluminescence toxicity test. Anaerobic treatment of OMW was performed in a 12-l anaerobic filter reactor. Efficiency of the treatment was evaluated by organic matter removal, and biogas production. By comparison with the pretreatment by activated sludge only, the bioaugmentation with Phanerochaete chrysosporium or Trametes versicolor led to high removal of organic matter, decreased the COD/BOD(5) ratio and the toxicity. The subsequent anaerobic digestion of the OMW pretreated with activated sludge-white-rot fungi showed higher biomethanization yields than that pretreated with activated sludge only. Higher loading rates (7 g COD l(-1) day(-1)) were reached without any acidification or inhibition of biomethanization.

CONCLUSIONS

The use of white-rot fungi, even in the presence of complex biological consortia to detoxify OMW, proved to be possible and made the anaerobic digestion of OMW for methane production feasible.

SIGNIFICANCE AND IMPACT OF THE STUDY

The use of fungi for OMW reuse and energy production could be adapted to industrial applications.

Olive mill wastewater sludge from evaporation ponds: evolution of physico-chemical parameters during storage and composting process

The evolution of analytical parameters of olive mill waste water sludge stored in evaporation ponds was investigated after one year and two years of storage. It was observed that some of the phenolic monomer compounds resisted removal and the fraction of water soluble phenols was only slightly polymerised. Co-composting of the sludge was carried out with yard trimming as bulking agent ratio and poultry manure to balance the C/N. Three turned piles with three proportions of 35%, 65% and 80% of olive mill waste water sludge were prepared. Co-composting of the sludge was possible in all the cases. Best results were obtained, however, at a proportion of 35% which permitted a shorter composting time, a higher degree of nitrification and a higher rate of total phenols decreasing. A high polymerisation of the fraction of water soluble phenols was observed at the end of composting in all the piles.

Involvement of lignin peroxidase in the decolourization of black olive mill wastewaters by Geotrichum candidum

AIM

Decolourization of black olive mill wastewaters (OMW) by depolymerization of phenolic compounds by Geotrichum candidum.

METHODS AND RESULTS

Our results show that G. candidum is able to grow on black OMW supplemented with carbon source and nitrogen. The Geotrichum growth decreased the pH and induced a 49% of colour removal when the black OMW was supplemented with glycerol and diammonium tartrate (20 mm ammonium). An improvement of 10% of colour removal was observed when the culture was supplemented with veratryl alcohol. The decolourization was inhibited with glutamate as nitrogen source.

CONCLUSION

Our results suggest the potential use of G. candidum in black OMW decolourization and support the concept that lignin peroxidase (LiP) of G. candidum is involved in the depolymerization of phenolic compounds.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report of LiP production by G. candidum on OMW.

Use of whole cells of Pseudomonas aeruginosa for synthesis of the antioxidant hydroxytyrosol via conversion of tyrosol

For the first time, a soil bacterium, designated Pseudomonas aeruginosa, was isolated based on its ability to grow on tyrosol as a sole source of carbon and energy. During growth on tyrosol, this strain was capable of promoting the formation of a significant amount of hydroxytyrosol and trace quantities of parahydroxyphenyl acetic acid and 3,4-dihydroxyphenyl acetic acid. The products were confirmed by high-performance liquid chromatography and gas chromatography-mass spectrometry analyses. Using an optimized tyrosol concentration of 2 g liter(-1), the maximal hydroxytyrosol yield (80%) was achieved after a 7-h reaction in a growth experiment. To enhance the formation of hydroxytyrosol and prevent its degradation, a resting-cell method using P. aeruginosa was performed. The growth state of the culture utilized for biomass production, the carbon source on which the biomass was grown, the concentration of the biomass, and the amount of tyrosol that was treated were optimized. The optimal yield of hydroxytyrosol (96%) was obtained after a 7-h reaction using 4 g of tyrosol liter(-1) and 5 g of cells liter(-1) pregrown on tyrosol and harvested at the end of the exponential phase. This proposed procedure is an alternative approach to obtain hydroxytyrosol in an environmentally friendly way. In addition, the reaction is easy to perform and can be adapted to a bioreactor for industrial purposes.

Application of electro-Fenton oxidation for the detoxification of olive mill wastewater phenolic compounds

Olive mill wastewaters are powerful pollutants that are difficult to treat as they contain high concentrations of recalcitrant and toxic polyphenolics of different molecular masses. We report in this paper that pre-treatment of phenolic fractions extracted from olive mill wastewaters as well as a synthetic phenolic mixture by the electro-Fenton method is a highly efficient procedure in which low mass phenolics are polymerised to polyphenolics and removed by precipitation. This decreases the toxicity load by 78% and makes the waste amenable to further anaerobic post-treatment.

Cloning and sequencing of a phenol hydroxylase gene of Pseudomonas pseudoalcaligenes strain MH1: a bacterium able to mineralize various aromatic compounds

The phenol-degrading strain Pseudomonas pseudoalcaligenes MH1, identified by the rRNA approach, was isolated from wastewater enrichment culture. It utilized phenol up to 1.5 g/L as the sole source of carbon and energy. In addition, cresols (o-, m-, p-), 4-hydroxybenzoic acid, syringic acid, and vanillic acid were metabolized as sole substrates by phenol-grown cells of strain MH1. Using primers, designed on the basis of the sequence of the dmp operon of P. putida strain CF600, a gene encoding phenol hydroxylase, which catalyzes the hydroxylation of phenol to catechol, was detected in strain MH1. The whole phenol hydroxylase operon of strain MH1 was amplified in a polymerase chain reaction fragment of 5.207 kb that was cloned and sequenced. The total sequence revealed a cluster of six ATG starting open reading frames (ORFs). Analysis of the regulatory signals showed a putative promoter region, 40 bp upstream from the transcriptional start of ORF1, which have a strong homology to a set of positively controlled promoters. Comparison of the MH1 phenol hydroxylase gene sequence with those of other Pseudomonas strains revealed higher homology except in the 5' region. Thus, the deduced amino acid sequence of the first subunit of phenol hydroxylase of P. pseudoalcaligenes strain MH1 exhibited a difference at the N-terminal region (the first 10 amino acids) compared with that of known phenol hydroxylase of Pseudomonas strains.

Decolorization of olive mill waste-waters by free and immobilized Phanerochaete chrysosporium cultures. Effect of the high-molecular-weight polyphenols

This paper describes the decolorization and chemical oxygen demand (COD) removal of olive mill waste-waters (OMW) by Phanerochaete chrysosporium grown in agitated submerged cultures. When P. chrysosporium was cultivated in the form of pellet, no decolorization of crude OMW was observed. Decolorization occurred only after removing by ultrafiltration, the high-mol-wt (HM) polyphenolic fraction (> 60 kDa). The use of high lignin peroxidase (LiP) producing medium yielded the highest levels of OMW decolorization and COD removal. In this case, extensive depolymerization and subsequent accumulation of phenolics with intermediates molecular weight were observed. Furthermore, increasing the concentration of the HM fraction decreased the color and COD removals. The decolorizing activity was lost when the concentration of the HM fraction reached 25% (v/v). Consequently, LiP activity was found to be completely inhibited in the presence of HM fraction, but not with the low-mol-wt (LM) polyphenolic fraction (< 8 kDa). The use of P. chrysosporium immobilized on polyurethane foam resulted in efficient decolorization of crude OMW. Moreover, the addition of an induction medium was shown to perform several repeated batch cultures for OMW decolorization and COD removal.

Immobilized and free cell continuous cultures of a recombinant E. coli producing catechol 2,3-dioxygenase in a two-stage chemostat: improvement of plasmid stability

The immobilization of recombinant strains of E. coli W3110/pTG205 in K-carrageenan gel beads improves the plasmid stability during continuous cultures in the absence of selection pressure. Since, xyl E gene (which encodes catechol 2,3-dioxygenase from Pseudomonas putida) transcription is controlled by the trp promoter, the effects of tryptophan (repressor) and 3 beta-indolyl acrylic acid (derepressor) on pTG 205 stability and enzyme production have been studied in both free and immobilized cell cultures. A two-stage continuous culture system running for 150 h is described. In the first stage an immobilized culture is performed in the presence of tryptophan with a significant plasmid stability. The cells released from the gel beads are continuously transferred in the second stage reactor where expression is induced by 3 beta-indolyl acrylic acid. In these conditions an efficient production of catechol 2,3-dioxygenase is observed.

Stability fluctuations of plasmid-bearing cells: immobilization effects

The maintenance of the plasmid vectors pTG201 and pTG206 (which both carry the Pseudomonas putida xylE gene) and pB lambda H3 in Escherichia coli hosts was studied in free and immobilized continuous cultures. pTG201, containing the strong lambda PR promoter, was more quickly lost than plasmid pTG206, containing the tetracycline resistance gene promoter. The instability of pTG201 seems to be related to high expression of the cloned xylE genet. Fluctuations in the proportion of pTG201-containing cells were observed in the free system, suggesting the appearance of adaptive descendants (with and without plasmid) from the initial strains. The loss of plasmid vectors from E. coli cells and the fluctuations in the proportion of plasmid-containing cells could be prevented by immobilizing plasmid-containing bacteria in carrageenan gel beads.

Effect of temperature on the stability of plasmid pTG201 and productivity of xylE gene product in recombinant Escherichia coli: development of a two-stage chemostat with free and immobilized cells

The effect of temperature on the stability of pTG201, a plasmid carrying the xylE gene (which encodes catechol 2,3-dioxygenase from Pseudomonas putida), and the production of catechol 2,3-dioxygenase in free and immobilized Escherichia coli during continuous culture have been studied at various temperatures. Immobilization of cells increased the stability of pTG201 considerably, even under conditions when expression of the xylE product was enhanced. Since xylE transcription was controlled by the lambda PR promoter and cI857 repressor, increasing derepression temperatures increased catechol 2,3-dioxygenase productivity and decreased pTG201 stability. A two-stage continuous culture system to overcome the impact of the high-level expression of the xylE gene on the stability of pTG201 is described. In the first stage, immobilized cells were grown in the repressed state in order to prevent loss of pTG201, whereas in the second stage, cultures were maintained in the derepressed state.