Batch bioethanol production via the biological and chemical saccharification of some Egyptian marine macroalgae.

AIMS: Marine seaweeds (macroalgae) cause an eutrophication problem and affects the touristic activities. The success of the production of the third-generation bioethanol from marine macroalgae depends mainly on the development of an ecofriendly and eco-feasible pretreatment (i.e. hydrolysis) technique, a highly effective saccharification step and finally an efficient bioethanol fermentation step. Therefore, this study aimed to investigate the potentiality of different marine macroalgal strains, collected from Egyptian coasts, for bioethanol production via different saccharification processes. METHODS AND RESULTS: Different marine macroalgal strains, red Jania rubens, green Ulva lactuca and brown Sargassum latifolium, have been collected from Egyptian Mediterranean and Red Sea shores. Different hydrolysis processes were evaluated to maximize the extraction of fermentable sugars; thermochemical hydrolysis with diluted acids (HCl and H2 SO4 ) and base (NaOH), hydrothermal hydrolysis followed by saccharification with different fungal strains and finally, thermochemical hydrolysis with diluted HCl, followed by fungal saccharification. The hydrothermal hydrolysis of S. latifolium followed by biological saccharification using Trichoderma asperellum RM1 produced maximum total sugars of 510 mg g-1 macroalgal biomass. The integration of the hydrothermal and fungal hydrolyses of the macroalgal biomass with a separate batch fermentation of the produced sugars using two Saccharomyces cerevisiae strains, produced approximately 0·29 g bioethanol g-1 total reducing sugars. A simulated regression modelling for the batch bioethanol fermentation was also performed. CONCLUSIONS: This study supported the possibility of using seaweeds as a renewable source of bioethanol throughout a suggested integration of macroalgal biomass hydrothermal and fungal hydrolyses with a separate batch bioethanol fermentation process of the produced sugars. SIGNIFICANCE AND IMPACT OF THE STUDY: The usage of marine macroalgae (i.e. seaweeds) as feedstock for bioethanol; an alternative and/or complimentary to petro-fuel, would act as triple fact solution; bioremediation process for ecosystem, renewable energy source and economy savings.

The naturally occurring steroid solasodine induces neurogenesis in vitro and in vivo.

In this study, we explored the capacity of the naturally occurring compound solasodine to promote neurogenesis in vitro and in vivo. Mouse embryonic teratocarcinoma P19 cells exposed to solasodine for 2 days followed by a 5-day washout differentiated into cholinergic neurons that expressed specific neuronal markers and displayed important axonal formation that continued growing even 30 days after treatment. In vivo, a 2-week infusion of solasodine into the left ventricle of the rat brain followed by a 3-week washout resulted in a significant increase in bromodeoxyuridine uptake by cells of the ependymal layer, subventricular zone, and cortex that co-localized with doublecortin immunostaining, demonstrating the proliferative and differentiating properties of solasodine on neuronal progenitors. In addition, these data demonstrate that under our experimental conditions adult ependymal cells retrieved their proliferative and differentiating abilities. The GAP-43/HuD pathway was activated both in vitro and in vivo, suggesting a role in the differentiating process triggered by solasodine. Solasodine treatment in rats resulted in a dramatic increase in expression of the cholesterol- and drug-binding translocator protein in ependymal cells, suggesting a possible role played by neurosteroid production in solasodine-induced neurogenesis. In GAD65-GFP mice that express the green fluorescent protein under the control of the glutamic acid decarboxylase 65-kDa promoter, solasodine treatment increased the number of GABAergic progenitors and neuroblasts generated in the subventricular zone and present in the olfactory migratory tract. Taken together, these results suggest that solasodine offers an interesting approach to stimulate in situ neurogenesis from resident neuronal progenitors as part of neuron replacement therapy.