Biorefinery potential of sustainable municipal wastewater treatment using fast-growing willow.

The use of willow plantations can be a sustainable approach for treating primary municipal wastewater, potentially reducing both the environmental and economic burdens associated with conventional treatment. However, the impact of wastewater irrigation upon the willow biorefinery potential has not yet been established. To investigate this effect, three-year-old field grown willows were harvested from plots kept as either controls or irrigated with primary municipal wastewater effluent at 29.5 million L ha-1 yr-1. Biomass compositional analysis, ionic liquid pretreatment and enzymatic saccharification were assessed and differential abundance of persistent extractable phytochemicals was evaluated using untargeted metabolite profiling. Glucan significantly increased by 8% in wastewater treated trees, arabinose and galactose were significantly decreased by 8 and 29%, respectively, while xylose, mannose and lignin content were unaltered. Ionic liquid pretreatment and enzymatic saccharification efficiencies did not vary significantly, releasing >95% of the cell wall glucose and recovering 35% of the lignin. From a total of 213 phytochemical features, 83 were significantly depleted and 14 were significantly enriched due to wastewater irrigation, including flavonoids and lignan derivatives. Considered alongside increased biomass yield from wastewater irrigation (+200%), lignocellulosic bioenergy yields increased to 8.87 t glucose ha-1 yr-1 and 1.89 t ha-1 yr-1 recovered lignin, while net extractives yields increased to 1.48 t ha-1 yr-1, including phytochemicals of interest. The maintenance of glucose accessibility after low-cost ionic liquid pretreatment is promising evidence that sustainable lignocellulose bioenergy production can complement wastewater treatment. Untargeted metabolite assessment revealed some of the phytochemical toolkit employed by wastewater irrigated willows, including accumulation of flooding and salinity tolerance associated flavonoids glabraoside A and glabrene. The extractable phytochemicals underpin a novel high biomass phenotype in willow and, alongside lignocellulosic yields, could help enhance the economic feasibility of this clean wastewater treatment biotechnology through integration with sustainable biorefinery.

Effect of estradiol on the induction of porphyria by hexachlorobenzene in the rat.

Hexachlorobenzene (HCB) is porphyrinogenic in adult female but not in male rats. This study aimed to assess the role of 17beta-estradiol in the induction of porphyria by HCB in both sexes by adding or removing the hormone. Groups of intact females, ovariectomized females (Ova), castrated males (Cas), and Cas receiving 17beta-estradiol (4 mg/kg, i.m., once a week beginning 2 weeks prior to HCB) were given five consecutive daily doses of HCB (100 mg/kg in corn oil, p.o.). Porphyria was assessed by urinary uroporphyrin excretion measured at days 16, 31, 38, 45, 52, 59, and 87. The percentage of porphyric rats in intact females increased from day 31 (58%) to day 87 (75%), whereas none of the Ova or Cas rats responded. However, administration of estradiol (days 120-169) and another sequence of HCB doses (days 134-138) to the same Ova rats caused porphyria (50% at day 186). Cas rats given estradiol also developed porphyria (43 and 86% on days 31 and 87, respectively). HCB-treated Ova rats given two doses of estradiol at either days 1 and 8 or days 22 and 29 developed a porphyria of similar magnitude (day 52). The role of estradiol cannot be explained by a reduction of pentachlorothiophenol formation, a putative detoxication pathway. Overall, results show that both sexes have the ability to respond to HCB when 17beta-estradiol is present and suggest that the sexual dimorphism in HCB-induced porphyria in the rat is related to the hormonal status.

Effect of 6-hydroxydopamine on polymerization of tubulin. Protection by superoxide dismutase, catalase, or anaerobic conditions.

Microtubular protein (tubulin) isolated from porcine brain was subjected to selected oxidative stresses, including incubation with the neurotoxin 6-hydroxydopamine (6-OHDA) under aerobic and anaerobic conditions. The functional capacity of the tubulin was determined on the basis of its ability to form microtubules as measured by alterations in the viscosity of the test mixtures, and confirmed by electron microscopy. 6-OHDA completely inhibited formation of microtubules at concentrations as low as 10 mM. Assembled microtubules were half as susceptible to destruction by 6-OHDA as unaggregated tubulin. Anaerobic conditions or the presence of catalase, superoxide dismutase, or a mixture of superoxide dismutase and catalase provided partial protection against 6-OHDA-induced destruction. In control reactions, tubulin-containing solutions incubated for up to 8 hr at ambient oxygen tensions, also showed significant decreases in ability to polymerize. Anaerobic conditions provided partial protection against this loss of function. In contrast, ascorbate accelerated the loss of activity upon standing, while glutathione or dithiothreitol offered no protection.