Microbial lipid produced using yeast fermentation with inexpensive carbon sources such as lignocellulosic hydrolyzate can be an alternative feedstock for biodiesel production. Several inhibitors that can be generated during acid hydrolysis of lignocellulose were added solely or together into the culture medium to study their individual inhibitory actions and their synergistic effects on the growth and lipid accumulation of oleaginous yeast Rhodosporidium toruloides. When the inhibitors were present in isolation in the medium, to obtain a high cell biomass accumulation, the concentrations of formic acid, acetic acid, furfural and vanillin should be lower than 2, 5, 0.5 and 1.5 g/L, respectively. However, the synergistic effects of these compounds could dramatically decrease the minimum critical inhibitory concentrations leading to significant growth and lipid production inhibitions. Unlike the above-cited inhibitors, sodium lignosulphonate had no negative influence on biomass accumulation when its concentration was in the range of 0.5-2.0 g/L; in effect, it was found to facilitate cell growth and sugar-to-lipid conversion. The fatty acid compositional profile of the yeast lipid was in the compositional range of various plant oils and animal tallow. Finally, the crude yeast lipid from bagasse hydrolyzate could be well converted into fatty acid methyl ester (FAME, biodiesel) by enzymatic transesterification in a tert-butanol system with biodiesel yield of 67.2% and lipid-to-biodiesel conversion of 88.4%.
BACKGROUND: The crude glycerol from biodiesel production represents an abundant and inexpensive source which can be used as raw material for lactic acid production. The first aim of this investigation was to select a strain suitable for producing lactic acid from glycerol with a high concentration and productivity. The second aim was to obtain the optimum fermentation conditions, as a basis for large-scale lactate production in the future.
The zinc-bromine redox flow battery (ZBB) is an ideal device of energy storage systems. Nevertheless, its energy density is relatively low compared to those of Li-ion batteries, due to its low output voltage. Herein, a high-voltage aqueous hybrid zincbromine battery system (AHZBBs) was developed, where K + -conducting membrane was used to segregate neutral-alkaline hybrid electrolytes and redox couples of Br 2 /Br À and [Zn(OH) 4 ] 2À / Zn at the positive and negative electrode. Benefited from an efficient and stable cathode catalyst (carbon-manganite nanoflakes), this AHZBB delivered a high average output voltage of 2.15 V and energy density of 276.7 Wh/kg without capacity attenuation after 200 cycles. More importantly, this work provides an efficient avenue to elevating the output voltage and energy density, and will strongly encourage studies on redox flow batteries.[a] Dr.
We report here the preparation of biodiesel by transesterification of rapeseed oil with methanol using calcined K 2 CO 3 /c-Al 2 O 3 as a solid base catalyst. The prepared catalysts were characterized using SEM, IR and BET, and their catalytic activities were evaluated. The reaction conditions were optimized, and in particular, the conversion can be as high as 98.62% under the optimal reaction conditions. In addition, the effect of the presence of water in the reaction system on the catalytic activity was also studied.
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