Validation of a cationic polyacrylamide flocculant for the harvesting fresh and seawater microalgal biomass

© 2019 Elsevier B.V. A simple, efficient, and fast settling flocculation technique to harvest microalgal biomass was demonstrated using a proprietary cationic polyacrylamide flocculant for a freshwater (Chlorella vulgaris) and a marine (Phaeodactylum tricornutum) microalgal culture at their mid-stationary growth phase. The optimal flocculant doses were 18.9 and 13.7 mg/g of dry algal biomass for C. vulgaris and P. tricornutum, respectively (equivalent to 7 g per m3 of algal culture for both species). The obtained optimal dose was well corroborated with changes in cell surface charge, and culture solution optical density and turbidity. At the optimal dose, charge neutralization of 64 and 86% was observed for C. vulgaris and P. tricornutum algal cells, respectively. Algae recovery was independent of the culture solution pH in the range of pH 6 to 9. Algal biomass recovery was achieved of 100 and 90% for C vulgaris and P. tricornutum respectively, and over 98% medium recovery was achievable by simple decanting

Ancient origin of the biosynthesis of lignin precursors

BACKGROUND: Lignin plays an important role in plant structural support and water transport, and is considered one of the hallmarks of land plants. The recent discovery of lignin or its precursors in various algae has raised questions on the evolution of its biosynthetic pathway, which could be much more ancient than previously thought. To determine the taxonomic distribution of the lignin biosynthesis genes, we screened all publicly available genomes of algae and their closest non-photosynthetic relatives, as well as representative land plants. We also performed phylogenetic analysis of these genes to decipher the evolution and origin(s) of lignin biosynthesis. RESULTS: Enzymes involved in making p-coumaryl alcohol, the simplest lignin monomer, are found in a variety of photosynthetic eukaryotes, including diatoms, dinoflagellates, haptophytes, cryptophytes as well as green and red algae. Phylogenetic analysis of these enzymes suggests that they are ancient and spread to some secondarily photosynthetic lineages when they acquired red and/or green algal endosymbionts. In some cases, one or more of these enzymes was likely acquired through lateral gene transfer (LGT) from bacteria. CONCLUSIONS: Genes associated with p-coumaryl alcohol biosynthesis are likely to have evolved long before the transition of photosynthetic eukaryotes to land. The original function of this lignin precursor is therefore unlikely to have been related to water transport. We suggest that it participates in the biological defense of some unicellular and multicellular algae. REVIEWERS: This article was reviewed by Mark Ragan, Uri Gophna, Philippe Deschamps

Estrogen receptor β controls proliferation of enteric glia and differentiation of neurons in the myenteric plexus after damage.

status: accepte

Estrogen receptor β controls proliferation of enteric glia and differentiation of neurons in the myenteric plexus after damage

Injury to the enteric nervous system (ENS) can cause several gastrointestinal (GI) disorders including achalasia, irritable bowel syndrome, and gastroparesis. Recently, a subpopulation of enteric glial cells with neuronal stem/progenitor properties (ENSCs) has been identified in the adult ENS. ENSCs have the ability of reconstituting the enteric neuronal pool after damage of the myenteric plexus. Since the estrogen receptor β (ERβ) is expressed in enteric glial cells and neurons, we investigated whether a selective ERβ agonist, LY3201, can influence neuronal and glial cell differentiation. Myenteric ganglia from the murine muscularis externa were isolated and cultured in either glial cell medium or neuronal medium. In glial cell medium, the number of glial progenitor cells (Sox10+) was increased by fourfold in the presence of LY3201. In the neuronal medium supplemented with an antimitotic agent to block glial cell proliferation, LY3201 elicited a 2.7-fold increase in the number of neurons (neurofilament+ or HuC/D+). In addition, the effect of LY3201 was evaluated in vivo in two murine models of enteric neuronal damage and loss, namely, high-fat diet and topical application of the cationic detergent benzalkonium chloride (BAC) on the intestinal serosa, respectively. In both models, treatment with LY3201 significantly increased the recovery of neurons after damage. Thus, LY3201 was able to stimulate glial-to-neuron cell differentiation in vitro and promoted neurogenesis in the damaged myenteric plexus in vivo. Overall, our study suggests that selective ERβ agonists may represent a therapeutic tool to treat patients suffering from GI disorders, caused by excessive neuronal/glial cell damage

Medical Freezers as Flexible Load for Demand Response in a Business Park Microgrid with Local Solar Power Generation

This work presents a day-ahead demand response (DR) scheduling framework that quantifies the flexibility in non-residential buildings by using thermodynamic modeling, and assesses the benefits of DR in terms of three separate optimization variants: net payment minimization, energy self-sufficiency, and peak power reduction. We test the framework in a case study of a medical research facility located in a business park with local solar power generation. The flexible loads are four groups of independently-controlled medical freezers. Our DR framework generates optimal freezer operation and solar power production/curtailment schedules that are compared against a business-as-usual scenario with no DR. We perform simulations for cases with and without end-of-horizon temperature constraints. Results show that the flexibility harnessed from the freezers’ thermal mass for DR actions improves the price-responsiveness, energy independence, and peak power consumption of the system with respect to the business-as-usual scenario. Furthermore, adding end-of-horizon constraints ensures that the thermal buffer of the flexible load will be full for the next simulation time window

Medical Freezers as Flexible Load for Demand Response in a Business Park Microgrid with Local Solar Power Generation

This work presents a day-ahead demand response (DR) scheduling framework that quantifies the flexibility in non-residential buildings by using thermodynamic modeling, and assesses the benefits of DR in terms of three separate optimization variants: net payment minimization, energy self-sufficiency, and peak power reduction. We test the framework in a case study of a medical research facility located in a business park with local solar power generation. The flexible loads are four groups of independently-controlled medical freezers. Our DR framework generates optimal freezer operation and solar power production/curtailment schedules that are compared against a business-as-usual scenario with no DR. We perform simulations for cases with and without end-of-horizon temperature constraints. Results show that the flexibility harnessed from the freezers’ thermal mass for DR actions improves the price-responsiveness, energy independence, and peak power consumption of the system with respect to the business-as-usual scenario. Furthermore, adding end-of-horizon constraints ensures that the thermal buffer of the flexible load will be full for the next simulation time window

Modified Shapiro reactions with bismesitylmagnesium as an efficient base reagent

Bismesitylmagnesium has been shown to successfully mediate the Shapiro reaction. A range of tosylhydrazones has been subjected to the developed system, which furnishes exceptionally high incorporation of the introduced electrophiles and good yields of the functionalised styrenes. At conveniently accessible temperatures and with a comparably small excess of base reagent, this protocol offers an efficient alternative to the lithium-mediated process. Importantly, 1.05 equiv of Weinreb amides are sufficient to obtain aryl enones in good yields