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Classic (polybromodiphenyl ethers, PBDEs) and emerging halogenated flame retardants (HFRs) such as hexabromobenzenze (HBB), pentabromoetilbenzene (PBEB), decabromodiphenyl ethane (DBDPE) and halogenated norbornenes (HNs), as well as naturally produced methoxylated-PBDEs (MeO-PBDEs), were analyzed in 12 sediment and 30 urchin (Paracentrotus lividus) samples collected from Bizerte Lagoon in northern Tunisia. Levels of HFRs in the sediments ranged from nd to 51.8 ng/g dry weight (dw), while MeO-PBDEs were not detected. As regards levels in urchins, concentrations of PBDEs, HNs and MeO-PBDEs ranged from 3.67 to 56.9, 4.52 to 116 and nd to 364 ng/g lipid weight (lw), respectively. Thus, levels of naturally occurring compounds were higher than those of an anthropogenic origin. As regards HFRs, the highest contribution comes from HNs with levels ranging between 9.98 and 143 ng/g lw. HN and PBDE concentrations in sea urchin are similar or slightly lower than other reports for other species, while total MeO-PBDE concentrations are higher. The comsumption of sea urchins in Bizerte city is not a threat to public health concerning PBDE intakes. © 2018 Elsevier B.V., This work has been funded by the Generalitat de Catalunya (Consolidated Research Group Water and Soil Quality Unit 2017 SGR 01404) and the Tunisian Ministry of Higher Education and Scientific Research. Biotage is acknowledged for providing SPE cartridges.

Contamination by classic (polybromodiphenyl ethers, PBDEs) and emerging halogenated flame retardants (HFRs) like pentabromobenzene (PBEB), hexabromobenzene (HBB), decabromodiphenyl ethane (DBDPE), and halogenated norbornenes (HNs), as well as organophosphate flame retardants (OPFRs) were investigated in sediment and eel (Anguilla Anguilla) samples from Bizerte Lagoon, northern Tunisia. For sediment samples, HFR levels ranged from 3.30 to 28.5 ng/g dry weight (dw), with a mean value of 10.6 ± 4.36 ng/g dw, while OPFR levels ranged between 9.77 and 164 ng/g dw, with a mean value of 53.6 ± 10.5 ng/g dw. As regards levels in fish, concentration of HFRs ranged between 4.72 and 151 ng/g lipid weight (lw) (mean value of 36.5 ± 28.5 ng/g lw), and OPFR levels ranged between 19.7 and 2,154 ng/g lw (mean value of 404 ± 367 ng/g lw). This is the first time that OPFR levels have been reporting in this area, being higher than those for HFRs. Statistical analysis of the relationship between OPFR and HFR concentrations in sediment and total organic carbon (TOC) was examined. Results suggested that OPFR levels were significantly correlated with TOC, whereas no correlation was found for HFRs and TOC. The health risk associated by the consumption of eel in Bizerte city was assessed and posed no threat to public health concerning PBDE and OPFR intakes., This study was supported by the Spanish Ministry of Science and Innovation (Project CEX2018- 000794-S), by the Generalitat de Catalunya (Consolidated Research Group Water and Soil Quality Unit 2017 SGR 01404), and by the Tunisian Ministry of Higher Education and Scientific Research.

The main drivers to develop biorefineries are the energetic and environmental crisis. Consequently, bioenergies have become a scientific and industrial trend. In North Africa, especially in Tunisia, Luffa cylindrica (LC) is a promising energy crop providing lignocellulosic biomass for biofuels production. Three principal fractions compose LC biomass, viz.: α-cellulose (45.8 ± 1.3)%, hemicellulose (20.76 ± 0.3)% and lignins (13.15 ± 0.6)%. The hydrothermal pretreatment of LC fibers was carried out at 96 °C for 54 min. After pretreatment, the reducing sugars amount reached 33.55 g/kg. The subsequent enzymatic saccharification was performed during 1 h at a temperature of 60 °C, by means of two commercial enzymes AP2 and SPC. The enzyme AP2 seemed to be more suitable for the enzymatic hydrolysis of pretreated LC fibers by allowing the release of 59.4 g/kg of reducing sugars, which correspond to a reducing sugars recovery about 93.29%. After that, the liquid state fermentation (LSF) was achieved with Saccharomyces cerevisiae strain during 24 h, in sterile and non-sterile conditions at 30 °C, pH 4.8 ± 0.2 and stirring 250 rpm, in order to conclude about the influence of contamination microflora on fermentation efficiency. After the LSF step, 88.66% of reducing sugars were transformed into alcohol with a conversion rate of 1.58% and a volumetric yield about 70% in sterile conditions. Thus, this work confirms that the potential conversion yield of cellulosic bioethanol is 1 Ton (dry matter) of LC fibers to 13.8545 kg (= 3.6599 Gallon) of biofuel.

This paper opens up a new issue dealing with Luffa cylindrica (LC) lignocellulosic biomass recovery in order to produce 2G bioethanol. LC fibers are composed of three principal fractions, namely, α-cellulose (45.80% ± 1.3), hemicelluloses (20.76% ± 0.3), and lignins (13.15% ± 0.6). The optimization of LC fibers hydrothermal and diluted acid pretreatments duration and temperature were achieved through the cubic central composite experimental design CCD. The pretreatments optimization was monitored via the determination of reducing sugars. Then, the 2G bioethanol process feasibility was tested by means of three successive steps, namely, LC fibers hydrothermal pretreatment performed at 96°C during 54 minutes, enzymatic saccharification carried out by means of a commercial enzyme AP2, and the alcoholic fermentation fulfilled with Saccharomyces cerevisiae. LC fibers hydrothermal pretreatment liberated 33.55 g/kg of reducing sugars. Enzymatic hydrolysis allowed achieving 59.4 g/kg of reducing sugars. The conversion yield of reducing sugar to ethanol was 88.66%. After the distillation step, concentration of ethanol was 1.58% with a volumetric yield about 70%.