Investigation on the effect of several parameters involved in the biodegradation of polyethylene (PE) and low-density polyethylene (LDPE) under various seawater environments.

This work investigates the biodegradation of polyethylene (PE) and low-density polyethylene (LDPE) and the leaching of their harmful additives. Micro/macro-plastics of both types were subjected to different laboratory-controlled conditions for 3 months. Gas Chromatography-Mass Spectroscopy (GC-MS) results revealed that leachate concentrations ranged from 0.40 ± 0.07 µg/L to 96.36 ± 0.11 µg/L. It was concluded that the additives' leaching process was promoted by light. However, light was not the only factor examined; microorganisms, pH, salinity, aeration/mixing and temperature influenced the biodegradation process, too. GC-MS results showed a prodigious impact on the biodegradation process when Pseudomonas aeruginosa was added to the artificial seawater compared to plastics exposed to light/air only. Scanning Electron Microscopy (SEM) micrographs demonstrated a significant alteration in the plastics' morphologies. Similarly, Fourier-Transform Infrared Spectroscopy (FTIR) spectra showed obvious changes in plastics characteristic peaks, especially microplastics. Furthermore, it was shown that PE was more susceptible to degradation/biodegradation than LDPE. Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) findings showed that some toxic metals were present in water samples after experiments, with concentrations above the permissible limits. For instance, bio-augmentation/bio-stimulation experiments showed that the concentrations of Pb, Sr, and Zn were 0.59 mg/L, 70.09 mg/L, and 0.17 mg/L, respectively; values above the permissible limits. It is crucial to emphasise that plastics must be meticulously engineered to avoid environmental and human impacts, originated from their degradation by-products. Furthermore, a holistic approach engaging stakeholders, researchers, policymakers, industries and consumers, is essential to effectively tackle the global challenge of marine plastic pollution.

Microbiological and physicochemical quality enhancement of treated wastewater using raw and chemically modified clays from Sidi Bouzid region, Tunisia.

Environmental discharge of wastewater represents a source of chemical and biological pollutants. This study firstly evaluates the microbiological and physicochemical quality of treated wastewaters collected from two wastewater treatment plants (WWTPs) located in two different Tunisian cities namely Sidi Bouzid (SB) and Gafsa (G). Then, the capacity of three raw and acid/base-activated local clays to enhance the quality of wastewaters was assessed. The results indicate that the quantities of enteric bacteria (oscillating from 1.381 × 103 to 1.4 × 108 CFU/100 mL), fungi (between 1.331 × 103 and 1.781 × 104 CFU/100 mL), as well as SARS-CoV-2 (between 4.25 × 103 and 5.05 × 105 CFU/100 mL) and Hepatitis A virus RNA (form 4.25 × 103 to 7.4 × 104 CFU/100 mL) detected in effluent wastewaters were not in compliance with the Tunisian standards for both studied WWTPs. Likewise for other indicators such as electrical conductivity (ranging 4.9-5.4 mS/cm), suspended matter (145-160 g l-1), chemical oxygen demand (123-160 mg l-1), biological oxygen demand 5 (172-195 mg l-1), chloride, Total Kjeldahl nitrogen (TKN) and phosphorus contents (710, 58-66 and 9.47-10.83 mg l-1 respectively), the registered values do not agree with the set standards established for wastewater treatment. On the other hand, the pH values fitted (oscillating from 6.86 (at G) to 7.24 (at SB) with the Tunisian standards for both WWTPs. After treatment, wastewaters showed better values for the microbiological parameters, especially for the clays designed as AM and HJ1, which eliminated 100% of viruses. In addition, when acid-activated AM clays were applied, a marked improvement in the quality of physicochemical parameters was obtained, especially for suspended matter (2 and 4 g l-1 for SB and G, respectively), TKN (5.2 (SB) and 6.40 (G) mg/l), phosphorus (1.01 (SB) and 0.81 (G) mg/l). Our results open perspectives for the possibility of efficiently using these specific clays in the enhancement of the quality of treated wastewaters.

Comparative study of the effect of oleuropein and hydroxytyrosol rich extracts on the reproductive toxicity induced by bisphenol A in male rats: biochemical, histopathological, and molecular analyses.

Bisphenol A, or BPA, goes into the composition of a large number of products including sunglasses, infant's feeding bottles, receipts, or food packaging. Nowadays, there is a growing evidence that BPA may be at the origin of several physiological malignancies. Oleuropein and hydroxytyrosol extracted from olive leaves are highly investigated for numerous health benefits. The present work investigates the potential protective proprieties of olive leaf extracts against BPA-induced testicular damage in Wistar rats. Thirty-two animals were randomly divided into 4 groups: control, BPA-treated (10 mg/kg), BPA and oleuropein rich extract (16 mg/kg) treatment, and the last group treated with BPA and hydroxytyrosol rich extract (16 mg/kg). Biochemical parameters and histological and molecular analyses were evaluated. Our data demonstrated that BPA treatment caused significant alteration in biochemical parameters, disorganization of germinal epithelium, an up-regulation of p53 and Bax, and a reduction of Bcl-2 protein levels. The ingestion of oleuropein- and hydroxytyrosol-rich extracts attenuated BPA-induced biochemical and histological changes. In fact, olive leaf extracts enhanced the enzymatic antioxidant system and the level of Bcl-2, and reduced the expression of p53 and Bax. Fairly, our findings propose that olive leaf extracts may compete with BPA-induced reprotoxicity in vivo.

Olive Leaves Extract and Oleuropein Improve Insulin Sensitivity in 3T3-L1 Cells and in High-Fat Diet-Treated Rats via PI3K/AkT Signaling Pathway.

Olive leaves extracts are known to exert potential pharmacological activities especially, antidiabetic and antiobesity. This study explores the anti-insulin resistant effect of olive leaves extracts and oleuropein in 3 T3-L1 cells and in high-fat diet fed rats. Our results showed that ethanol extract (EE) suppressed significantly (P < 0.01) triacylglycerol accumulation. In preadipocytes cells, EE 1/100 decreased cell viability and induced apoptosis. Real-time PCR analysis showed that EE reduced the mRNA levels of adipogenesis (CEBP-α, PPARγ, SREBP-1c, and FAS) and proinflammatory (TNF-α and IL-6) genes. Moreover, the cotreatment of EE 1/1000 or oleuropein with insulin increased considerably the expression of p-IRS, p85-pI3K, and p-AKT. In vivo model, the oral administration of oleuropein at 50 mg/kg in rats fed with high fat diet for 8 weeks reduced inflammation in liver and adipose tissues (WAT), improved glucose intolerance, and decreased hyperinsulinemia. Furthermore, the immunohistochemistry revealed that the expression level of p-Akt, IRS1, and Glut-4 were significantly enhanced in liver and WAT tissues after oleuropein supplementation comparing with that in HFD group. Additionally, the expression of IRS1 was markedly ameliorated in pancreas. Our obtained results can be adopted as an approach to used olive leaves as complement to prevent insulin-resistance disease.

A jojoba (Simmondsia chinensis) seed cake extracts express hepatoprotective activity against paracetamol-induced toxicity in rats.

This study aimed to investigate the hepatoprotective activity of jojoba seed cake extracts against an acute paracetamol (PC) intoxication. Two aqueous extracts from jojoba (Simmondsia chinensis) seed cake, a simmondsin-rich extract (WE), and a simmondsin-hydrolyzed extract (NE) using Viscozyme L enzyme have been prepared and characterized. After enzyme treatment, simmondsin content decreased from 33.0 % to 3.0 % and glucose content increased from 16.2 % to 27.3 % reflecting simmondsin hydrolysis. Both extracts were administered to different rat groups via gavage (0.6 g/kg b.w.) before PC treatment (2 g/kg b.w.) three times a week for 3 weeks. The PC intoxication altered the serum biomarkers, the oxidative status, and the Tumor necrosis factor alpha (TNF-α), Bax and Bcl-2 protein expressions of tested animals. In addition, the histological analysis of liver tissues proved significant injury and hepatocellular necrosis. WE and NE extract showed a relatively high in vitro radical scavenging (ORAC) and averting activities (HORAC) with a polyphenol content of 3.6 % and 2.9 %, respectively. Both extracts showed a powerful in vivo hepatoprotective activity against PC-induced toxicity by improving the hepatocellular antioxidant status and blocking proteins expression (TNF-α, Bax and Bcl-2), involved in inflammation and liver damage. However, the enzymatic treatment improved the hepatoprotective activity of NE despite its lower simmondsin content and lower in vitro antioxidant capacity. This enhancement could be linked to the synergetic effect between the antioxidant components and the new hydrolytic products as glucose, uronic acids, arabinose and simmondsin-aglycons. These results suggest that jojoba waste could be potentially valorized in developing hepatoprotective drugs.

Isolation of bacterial strains from compost teas and screening of their PGPR properties on potato plants.

The beneficial effect of compost and compost tea on plant growth and protection is mainly associated with the microbial diversity and the presence of bacteria with plant growth-promoting effect. PGPR are considered as eco-friendly bio-fertilizers that may reduce the use of chemical pesticides and fertilizers. Three composts (AT, A10, and A30) were previously prepared from industrial wastes (olive mill wastewater, olive pomace, coffee ground, and phosphogypsum). In the present study, we isolated three bacterial strains from the compost teas. The phylogenetic identification of these bacterial strains (B.AT, B.A10, and B.A30) showed that they correspond to Serratia liquefaciens (B.AT and B.A10) and Achromobacter spanius (B.A30) species. A further characterization of the PGPR traits of these bacteria showed that they produce siderophore, exopolysaccharides, and IAA. Their effect on potato plant growth, yields, and tuber quality was performed under field culture conditions. Results showed that these strains can be characterized as PGPR, the best effect on potato plant growth was observed with Serratia liquefaciens (B.AT), the best yield and tuber quality was observed with Serratia liquefaciens (B.A10) while bacterial treatment with Achromobacter spanius (B.A30) is a Cd-tolerant PGPR.

Optimizing the Extraction Conditions of Hydroxytyrosol from Olive Leaves Using a Modified Spherical Activated Carbon: A New Experimental Design.

The purification of hydroxytyrosol from olive leaves extract by modified activated carbon was studied experimentally in a batch system and a column by adsorption and desorption processes. The extraction yield reached 90% of hydroxytyrosol, which is the major compound found in the extract. Despite the abundance of research on extracts of hydroxytyrosol from olive leaves, it seems that the applied methods can be further improved. In this study, several approaches were applied to optimize the extraction conditions of this molecule. Hence, the response surface method and the Box-Behnken design (BBD) were used to evaluate the effect of the temperature, time, and adsorbent dose on the hydroxytyrosol recovery. Moreover, adsorption isotherm, kinetics, and thermodynamic studies were also performed to clarify the nature of the process. The main finding was the obtainment of a maximum adsorption yield of 97.5% at an adsorbent/adsorbate ratio of 1 : 20, after a 6 h cycle and at a temperature of 30°C. Furthermore, adsorption process seemed to fit best with Freundlich model. In addition, the thermodynamic study describes a spontaneous and endothermic process. Desorption assay using ethanol helped to recover 73% of hydroxytyrosol. Furthermore, the HPLC analysis of fractions after column adsorption showed a simple peak of hydroxytyrosol with purity higher than 97% and a flavonoids-rich fraction. These findings would indicate that this separation method for the recovery of phenolic compounds with high antioxidant activity can be a very promising one.

Wound healing potential of quercetin-3-O-rhamnoside and myricetin-3-O-rhamnoside isolated from Pistacia lentiscus distilled leaves in rats model.

The development of bioproducts able to accelerate wound healing is an important topic in biomedicine. In the current study, Pistacia lentiscus distilled leaves (PDL) extract and its two isolated glycosylated flavonoids, myricetin-3-O-rhamnoside (MM) and quercetin-3-O-rhamnoside (QM), were evaluated for their wound healing activity, including evaluation of wound closure, revascularization, wound re-epithelialization, fibroblast proliferation, and collagen deposition on rat skin samples. Moreover, hydroxyproline content, C-reactive protein (CRP) level, and immunohistochemistry study were evaluated on blood and tissues collected from rats on day 14 post-wounding. Results showed that the topical application of PDL (at a concentration of 20 mg/ml) (PDL 20), MM, and QM increased wound healing and decreased inflammatory cells infiltration compared to the negative control group. Moreover, the cutaneous wound tissues treated with PDL 20, MM, and QM exhibited significantly higher hydroxyproline content than the negative control group, which means a high collagen biosynthesis in wound tissues. Indeed, the level of the inflammatory protein CRP is significantly lower in groups treated with MM and QM than in the negative control group. Also, the expression of the pro-inflammatory factor TNF-α and the angiogenesis marker CD-31 in PDL 20, MM, and QM treated groups is lower than in the negative control group. Moreover, MM, and QM induced a good elastase inhibition at 100 µg/ml compared to the standard epigallocatechin gallate. Therefore, PDL 20, MM, and QM could be used as effective cutaneous wound healing agents.

Microalgal-based feed: promising alternative feedstocks for livestock and poultry production.

There is an immediate need to identify alternative sources of high-nutrient feedstocks for domestic livestock production and poultry, not only to support growing food demands but also to produce microalgae-source functional foods with multiple health benefits. Various species of microalgae and cyanobacteria are used to supplement existing feedstocks. In this review, microalgae have been defined as a potential feedstock for domestic animals due to their abundance of proteins, carbohydrates, lipids, minerals, vitamins, and other high-value products. Additionally, the positive physiological effects on products of animals fed with microalgal biomass have been compiled and recommendations are listed to enhance the assimilation of biomolecules in ruminant and nonruminant animals, which possess differing digestive systems. Furthermore, the role of microalgae as prebiotics is also discussed. With regards to large scale cultivation of microalgae for use as feed, many economic trade-offs must be considered such as the selection of strains with desired nutritional properties, cultivation systems, and steps for downstream processing. These factors are highlighted with further investigations needed to reduce the overall costs of cultivation. Finally, this review outlines the pros and cons of utilizing microalgae as a supplementary feedstock for poultry and cattle, existing cultivation strategies, and the economics of large-scale microalgal production.

Optimization of microwave assisted extraction of simmondsins and polyphenols from Jojoba (Simmondsia chinensis) seed cake using Box-Behnken statistical design.

A closed-vessel microwave-assisted extraction (MAE) of simmondsins and polyphenols from defatted Jojoba cake using Box-Benkhen design with four independent variables (solvent/cake ratio, ethanol concentration, extraction time and microwave power) was investigated. ANOVA results showed that the obtained models were significant at 95% confidence level. Optimal extraction conditions were found for highest values of microwave power (500 W) and extraction time (15 min) and for moderate values of solvent to cake ratio (41 - 45 mL/g). Optimum simmondsins yield (23.35%) was obtained with pure water as solvent. However, optimum polyphenols yield (2.33%) and ORAC antioxidant activity (656 µmol TE/g) were obtained with 46.79% and 42.04% ethanol in water, respectively. ORAC antioxidant activity was found to be well correlated to polyphenol and simmondsin contents. These results indicate that MAE is an effective technique for recovery of bioactive compounds for food and pharmaceutical industries from Jojoba by-products.

Investigation of halotolerant marine Staphylococcus sp. CO100, as a promising hydrocarbon-degrading and biosurfactant-producing bacterium, under saline conditions.

A halotolerant strain CO100 of Staphylococcus sp. was isolated from contaminated sediments taken from the fishing harbour of Sfax, Tunisia, as an efficient hydrocarbonoclastic candidate. Strain CO100 exhibited a high capacity to break down almost 72% of the aliphatic hydrocarbons contained in crude oil (1%, v/v), used as the sole carbon and energy source, after 20 days of culture, at 100 g/l NaCl, 37 °C and 180 rpm. The isolate CO100 displayed also its ability to grow on phenanthrene, fluoranthene and pyrene (100 mg/l), at 100 g/l NaCl. Moreover, the isolate CO100 showed a notable aptitude to synthesize an efficient tensioactive agent namely BS-CO100, on low-value substrates including residual frying oil and expired milk powder, thus reducing the high cost of biosurfactant production. The ESI/MS analysis designated that BS-CO100 belonged to lipopeptide class, in particular lichenysin and iturine members. Critical micelle concentrations of BS-CO100 were varying between 65 and 750 mg/l, depending on of the purity of the biosurfactant and the used carbon sources. BS-CO100 showed a high steadiness against a wide spectrum of pH (4.3-12), temperature (4-121 °C) and salinity (0-300 g/l NaCl), supporting its powerful tensioactive properties under various environmental conditions. Likewise, BS-CO100 exhibited no cytotoxic effect toward human HEK293 cells, at concentrations within 125 and 1000 µg/ml. Furthermore, the biosurfactant BS-CO100 exhibited remarkable anti-adhesive and anti-biofilm activities, being able to avoid and disrupt the biofilm formation by certain pathogenic microorganisms. In addition, BS-CO100 was found to have more potential to remove hydrocarbons from contaminated soils, compared to some chemical surfactants. In light of these promising findings, strain CO100, as well as its biosurfactant, could be successfully used in different biotechnological applications including the bioremediation of oil-polluted areas, even under saline conditions.

Hepatoprotective Effect of Oleuropein-Rich Extract from Olive Leaves against Cadmium-Induced Toxicity in Mice.

Cadmium (Cd) is a harmful pollutant which mainly affects the liver and kidney. In this work, we investigated the hepatoprotective effects of olive leaf extract based on oleuropein against hepatic cadmium toxicity in mice. Three groups of animals were used: the first one served as the control (C); the second one received intraperitoneal injection of cadmium 2 mg/kg b.w. (CD), administered five times during two weeks; and the third group received the same doses of Cd and simultaneously 16 mg/kg b.w. of oleuropein. Results showed that Cd induced a significant increase in liver injury biomarkers coupled with enhanced lipid peroxidation (MDA) and significant depletion of antioxidants (CAT and SOD). Histological and immunohistochemical analysis confirmed these findings. In fact, we observed a severe central lobular apoptosis and inflammation around central veins. Cotreatment with oleuropein significantly reduced the oxidative damage induced by cadmium. Our findings suggest that oleuropein could be used in the prevention of Cd hepatotoxicity.

Comparative Study on Beneficial Effects of Hydroxytyrosol- and Oleuropein-Rich Olive Leaf Extracts on High-Fat Diet-Induced Lipid Metabolism Disturbance and Liver Injury in Rats.

Oleuropein and hydroxytyrosol, as major compounds of olive leaves, have been reported to exert numerous pharmacological properties, including anticancer, antidiabetic, and anti-inflammatory activities. The purpose of this study is to evaluate and compare the protective effect of oleuropein- and hydroxytyrosol-rich extracts, derived from olive leaves, on high-fat diet-induced lipid metabolism disturbance and liver injury in rats. In this respect, four groups of male rats (8 per group) were used: control group (Control), group treated with high-fat diet (HFD), group treated with HFD and oleuropein (HFD + OLE), and group treated with HFD and hydroxytyrosol (HFD + HYD). The current research showed that the treatment with the HFD increased the body weight and adipose tissue mass in male rats. Moreover, the plasma levels of triglycerides, total cholesterol, LDL-cholesterol, AST, ALT, LDH, and TNF-α were also raised. The hepatic immunohistochemical analysis revealed a significant increase in the expression of inflammatory genes (COX-2, NF-κB, and TNF-α). Equally, it showed a rise of the apoptotic markers (a decrease in the expression of the Bcl-2 and an increase of the P53). In addition, the oral administration of oleuropein- and hydroxytyrosol-rich olive leaf extracts at 16 mg/kg similarly reduced the body weight and adipose tissue mass and improved the lipid profile. Moreover, these extracts, mainly the hydroxytyrosol-rich extract, reduced the elevated liver enzymes, enhanced the antioxidant status, and attenuated the liver inflammation and apoptosis. These findings suggest that the oleuropein- and hydroxytyrosol-rich olive leaf extracts possessed hypolipidemic and hepatoprotective effects against the HFD-induced metabolic disorders by enhancing the antioxidative defense system and blocking the expression of the proteins involved in inflammation and liver damage.

Effect of phosphogypsum addition in the composting process on the physico-chemical proprieties and the microbial diversity of the resulting compost tea.

Phosphoric acid production and olive oil production are among the most important economical sectors in Tunisia. However, they generate huge amounts of wastes (phosphogypsum, olive mill waste water, and olive pomace). In a previous study, we used phosphogypsum (PG), in co-composting with organic wastes. Three composts were produced; their PG content was of 0 (AT), 10 (A10), and 30% (A30). In the present study, we focused on their derived compost teas. The physico-chemical characterization of the different compost teas showed that those from A10 and A30 composts presented higher P and Ca contents than that from control one (AT). The microbial characterization using DGGE showed a noticeable microbial diversity in the different compost teas and that the addition of 10% and 30% PG in the compost had different effects on the compost tea microbial diversity. The identification results showed that the addition of 10 and 30% of PG did not affect the presence of PGPR (plant growth-promoting rhizobacteria) and fungal soil antagonists in the compost teas. Two PGPRs were isolated from AT and A30 compost teas, and their effect on the growth of potato plants in vitro was evaluated.

Contribution of Major Polyphenols to the Antioxidant Profile and Cytotoxic Activity of Olive Leaves.

AIMS: This study was designed to investigate the phytochemical profile and the cytotoxic activities of the eco-friendly extracts of olive leaves from Chemlali cultivar. MATERIALS AND METHODS: The Phenolic composition of olive leaves extracts, the antioxidant activity and the cytotoxic effects against MCF-7 and HepG2 cells were determined. RESULTS: Olive leaves extracts showed relevant total polyphenols contents. Oleuropein was the major detected phenolic compound reaching a concentration of 16.9 mg/ml. The antioxidant potential of the studied extracts varied from 23.7 to 46.5mM Trolox equivalents as revealed by DPPH and ABTS assays. Cytotoxicity experiments showed similar trends for both HepG2 and MCF-7 cells with the infusion extract being the most active. CONCLUSION: This study denotes that olive leaves may have great potential as endless bioresource of valuable bioactive compounds which may have a wide application.

Production, characterization and biotechnological potential of lipopeptide biosurfactants from a novel marine Bacillus stratosphericus strain FLU5.

This work aimed at studying the potential of a new hydrocarbonoclastic marine bacterium, Bacillus stratosphericus FLU5, to produce an efficient surface-active agent BS-FLU5. Biosurfactant production was examined on different carbon sources; using the surface tension measurement and the oil displacement test. Strain FLU5 showed its capacity to produce biosurfactants from all tested substrates, in particular the residual frying oil, which is a cheap renewable carbon source alternative, thus minimizing the high cost of producing those surfactants. MALDI-TOF MS/MS analysis confirmed the presence of lipopeptides, which are identified as members of surfactin and pumilacidin series. The critical micelle concentration (CMC) of the purified lipopeptides produced by strain FLU5 was 50 mg/l. At this concentration, the surface tension of the water was reduced from 72 to 28 mN/m. Furthermore, the crude lipopeptides showed an interesting stability against a broad range of pH, temperature and salinity. In addition, the application of BS-FLU5 in oil recovery from hydrocarbons-contaminated soil (used motor oil) showed that it was more effective on the hydrocarbon-remobilization than some tested synthetic surfactants. Interestingly, the biosurfactant BS-FLU5 showed a negligible cytotoxic effect against the mammalian cells HEK293. These results highlight the applicability of the lipopeptides BS-FLU5 in different fields, especially in environmental remediation processes.

Oleuropein and hydroxytyrosol rich extracts from olive leaves attenuate liver injury and lipid metabolism disturbance in bisphenol A-treated rats.

In the present study, we investigated the protective effects of oleuropein- and hydroxytyrosol-rich extracts obtained from olive leaves against bisphenol A (BPA)-induced hyperlipidemia and liver injury in male rats. For this purpose, four groups of male rats (8 per group) were used: control group (Control), rats treated with BPA, rats treated with both BPA and oleuropein (OLE-BPA), and rats treated with both BPA and hydroxytyrosol (HYT-BPA). After 60 days of treatment, the results obtained using the DXA technique showed that treatment with BPA (10 mg per kg b.w.) increased the body weight and adipose tissue mass in male rats. Moreover, plasma levels of triglycerides, total cholesterol, LDL-cholesterol, AST, ALT, LDH, and TNF-α increased. The immunohistochemical analysis revealed a significant increase in the expression of COX-2 and p53 and a decrease in the expression of Bcl-2 related to liver inflammation. Oral administration of oleuropein and hydroxytyrosol-rich extracts obtained from olive leaves at 16 mg kg-1 reduced both the body weight and adipose tissue mass. These extracts were able to ameliorate liver damage and improve the elevated levels of TG and liver enzymes of BPA-treated rats possibly through enhancing CAT and SOD activities. Western blot results revealed that administration of the abovementioned extracts decreased the protein expression of NF-κB and TNF-α through the p38 signaling pathway. Overall, the findings suggest that the olive leaf extracts possess hypolipidemic and hepatoprotective effects against BPA-induced metabolic disorders through enhancing the antioxidative defense system and regulating the important signaling pathway activities.

Pilot-scale outdoor production of Scenedesmus sp. in raceways using flue gases and centrate from anaerobic digestion as the sole culture medium.

This work investigated the production of Scenedesmus sp. in semi-continuous mode in three pilot-scale outdoor raceways (7.2 m2) using flue gas for CO2 supply and centrate from the anaerobic digestion of urban wastewater as the sole nutrient source. Experiments were performed at different culture depths, 5, 10 and 15 cm, while evaluating two centrate concentrations (30% and 45%) at dilution rates of 0.2 and 0.3 d-1. Under optimal conditions of 30% centrate, 0.3 d-1 dilution rate and a 15 cm culture depth, a maximum biomass productivity of 22.9 g m-2 d-1 was obtained. The optical properties of the cultures were studied and the results showed a photosynthetic efficiency of up to 2.0% and a quantum yield of 0.3 g biomass E-1. Nitrogen and phosphorus removal rates of 3 g N m-2 d-1 and 0.6 g P m-2 d-1 were recorded, respectively. Lipid productivity of 2.3 g m-2 d-1 was determined possessing a suitable fatty acids profile for biofuel production.

Utilization of centrate from urban wastewater plants for the production of Scenedesmus sp. in a raceway-simulating reactor.

This work investigates the production of the native microalgae strain Scenedesmus sp. in semi-continuous mode at lab scale in open raceway-simulating reactors and using centrate as the culture medium. The biomass productivity and nutrient removal capacity of Scenedesmus sp. at different dilution rates were investigated indoors as well as its tolerance to centrate as the culture medium at different concentrations. A biomass productivity of 7.80 g/m2 day was obtained at 200 µE/m2 s, 5 cm culture depth, 0.30 1/day of dilution rate and 60% centrate while nitrogen and phosphorus removal rates were 1.50 g/m2 day and 0.15 g/m2 day, respectively. The produced biomass characterization under these conditions showed a lipid content of 12.60% d wt. along with a favorable fatty acids profile with 57.70% of total fatty acids composed of saturated and monounsaturated fatty acids. Subsequently, the effect of light intensity and culture depth on biomass productivity and nutrient uptake as well as the biochemical composition and fatty acids profile was studied using two irradiance levels (200 and 1000 µE/m2 s) and four culture depths (5 cm, 10 cm, 15 cm and 20 cm). Under optimal conditions of 1000 µE/m2 s, 60% centrate, 0.30 1/day dilution rate and 15 cm culture depth, a maximum biomass productivity of 22.20 g/m2 day was obtained. Nitrogen and phosphorus removal rates of 2.00 gN/m2 day and 0.40 gP/m2 day, respectively, were recorded. An amount of 11.70% d wt. of lipids was determined along with a suitable fatty acids profile for biofuel production.

A non-toxic microbial surfactant from Marinobacter hydrocarbonoclasticus SdK644 for crude oil solubilization enhancement.

This study aims to investigate the ability of a biosurfactant produced by Marinobacter hydrocarbonoclasticus strain SdK644 isolated from hydrocarbon contaminated sediment to enhance the solubilization rate of crude oil contaminated seawater. Phylogenetic analysis shows that strain SdK644 was very closely related to M. hydrocarbonoclasticus with 16S rRNA gene sequence similarity of 97.44%. Using waste frying oil as inducer carbon source, the producing biosurfactant by strain SdK644 was applied to improve crude oil solubilization in seawater. The preliminary characterization of the produced biosurfactant by FT-IR analysis indicates its possible classification in a glycolipids group. Results from crude oil solubilization assay showed that SdK644 strain biosurfactant was 2-fold greater than Tween 80 surfactant in crude oil solubilization and 12-fold higher than seawater control, as shown by GC-MS analysis of aliphatic compounds. Furthermore, this bioactive compound was shown to be nontoxic against Artemia larvae in short-term acute toxicity bioassay. Generally, the results showed the possible use of M. hydrocarbonoclasticus strain SdK644 biosurfactant in bioremediation processes of the marine environments.