The production of synthetic glycerol from petrochemical feedstocks has been decreasing in recent years. This is largely due to increasing supplies of crude glycerol derived as a co-product from the oleochemical industry, especially biodiesel production. The price of glycerol is at historic lows, and the supply of crude glycerol is projected to grow faster than its industrial uses. This oversupply is driving the transition from glycerol as a product to glycerol as a precursor for new industrial applications, including its use as a substrate for bioconversion. This article reviews the use of fungi for the bioconversion of crude glycerol to the value-added products 1,2-propanediol, ethanol, single cell oil, specialty polyunsaturated fatty acids, biosurfactants, and organic acids. Information on the impurities of crude glycerol from different industrial processes is also included.
American ginseng (Panax quinquefolius L.) produces a number of saponins (ginsenosides). The ability of saponins from cultivated American ginseng to inhibit fungal growth in vitro was evaluated. Fungi exhibited a range of sensitivity to ginsenosides extracted from roots collected in two growing seasons. Important root pathogens (Cylindrocarpon destructans, Fusarium solani, and Fusarium oxysporum) were unaffected by these phytochemicals at a concentration of 1 mg·mL -1 , whereas the growth of Alternaria panax and nonpathogenic Trichoderma spp. was inhibited. The same trend emerged when a range of ginsenoside concentrations was used on a subset of fungi. Hyphal growth of C. destructans was unaffected up to a level of ginsenosides approaching that found in roots (i.e.,~3% dry weight). The growth of F. solani was significantly less than that of the control at saponin concentrations of 0.1 to 3.0% (w/v), but was relatively unaffected in comparison to growth of Trichoderma hamatum and A. panax.Résumé : Le ginseng américain (Panax quinquefolius L.) produit des saponines (ginsenosides). Les auteurs ont évalué la capacité des saponines du ginseng américain cultivé à inhiber la croissance fongique in vitro. Les champignons montrent une gamme de sensibilités aux ginsenosides extraits de racines récoltées sur deux saisons de croissance. D'important pathogènes racinaires (Cylindrocarpon destructans, Fusarium solani et Fusarium oxysporum) ne sont pas affectés par ces substances phytochimiques à la concentration de 1,0 mg·mL -1 , alors que la croissance de l'Alternaria panax et des Trichoderma spp. nonpathogènes est inhibée. La même tendance s'est manifestée lorsqu'une gamme de concentrations de ginsenosides a été utilisée sur un sous-ensemble de champignons. La croissance des hyphes du C. destructans n'est pas affectée jusqu'à des concentrations qui approchent les teneurs observées dans les racines (c.-à-d~3% en poids sec). La croissance du F. solani est significativement plus faible que celles des témoins avec des concentrations de 0,1 à 3,0% (p/v), mais est relativement peu affectée comparativement à la croissance du Trichoderma hamatum et de l'A. panax.
The production of the aluminum metal from bauxite ore and bio-diesel from triglyceride oils both generate large waste streams, and their management and valuation is therefore of great interest in Brazil and any other country with established or developing bio-fuel and aluminum industries. The integration of these two waste streams into the development of alternative technologies that utilize wastes as low-cost materials could potentially contribute to economic development as well as chemical sustainability and minimize the environmental and ecological impact of these industries. In this study, a crude untreated bio-diesel plant waste stream consisting of glycerol, methanol, free fatty acid salts and water was coprocessed with Red Mud, the highly alkaline by-product of bauxite refining through the Bayer Process, at elevated temperature and pressure (350 to 400 °C; 0-500 psi hydrogen gas) in an attempt to synergistically produce value-added products from these two waste streams. Comparative analysis between untreated and upgraded materials was performed by CHN EA, TGA, TPR, SEM, MS, FT-IR, Karl-Fischer-Titration, and 1 H/ 13 C NMR. The products obtained showed an increase in carbon and hydrogen content in both the organic product phase and the Red Mud catalyst recovered. Also observed in the organic phases was an increase in the paraffin content relative to starting material as determined by NMR with a concomitant reduction of the alcohol content confirming glycerol and methanol conversion. The Red Mud recovered after every upgrading reaction showed a change of color to dark gray to black, magnetic and amphiphilic properties, as well as a substantial decrease in its alkalinity and an increase in its carbon content. Catalyst recycling reactions were performed highlighting the possibility that the Red Mud could be reused as a catalyst promoting an increase in the observed crude glycerol conversion to paraffins potentially usable as a low-grade heavy fuel oil.Brazilian aluminum industry. According to ABAL (Brazilian Association of Aluminum), Brazil is the sixth largest primary aluminum producer in the world, exceeded only by China, Russia, Canada, United States and Australia. By extension, Brazil possesses the fifth largest bauxite deposits on the planet, is the fourth largest alumina producer and ranks fifth in exports of primary aluminum and its alloys. 1 Both the biodiesel and the aluminum industry generate a large amount of waste giving rise to increasing concerns over environmental impacts. In the production of aluminum, Red Mud is generated from the caustic soda digestion of bauxite ore to create pure alumina via the Bayer process. 2 The alumina production process used today is essentially the same as invented by Karl Bayer in 1887. Exploiting the amphoteric nature of Al 2 O 3 , it uses sodium hydroxide to selectively dissolve this oxide component of the bauxite ore as Na[Al(OH) 4 ]. This solution is then filtered. Concentrating it and adding lime (CaO) leads to the
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