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We introduce a reactive extraction to detoxify hydrolysate before fermentation to biofuels. In the selection of diluents, n-octanol showed the highest removal yield of 5-hydroxymethylfurfural (5-HMF) and levulinic acid. The removal yields of inhibitors were normalized to 30-min reactions. In treatments with pure extractant or diluents, only 2 ∼ 4.1% of the formic acid was removed. Tri- n-octylamine (extractant) removed levulinic acid and acetic acid more efficiently, and furfural was removed more efficiently than formic acid or 5-HMF. n-Octanol (polar diluent) removed levulinic acid and acetic acid, furfural, and 5-HMF at 21.2, 33.7, and 65.7%, respectively. In contrast, kerosene (inert diluent) only removed the furfural by 27.6%. Based on these results, the optimum reactiveextraction system comprised tri- n-octylamine as the extractant, n-octanol as the polar diluent, and kerosene as the inert diluent. The optimal proportion of complex extractant was 20% trialkylamine, 70% n-octanol, and 10% kerosene. By detoxification, 63.9% of acetic acid and levulinic acid, 24.4% of 5-HMF, 63.9% of formic acid, and 64.0% of furfural could be removed. [ABSTRACT FROM AUTHOR]

In this study, sulfamic acid-catalyzed pretreatment and subsequent enzymatic hydrolysis was conducted to produce biosugar from the marine macro-alga Gracilaria verrucosa. Sulfamic acid has dual active sites and is a green catalyst. Optimized sulfamic acid pretreatment at 130°C with 7.5% biomass and 100 mM sulfamic acid for 90 min yielded 39.9% total reducing sugar (TRS). Subsequent enzymatic hydrolysis yielded 69.1% TRS. These results indicate the potential of sulfamic acidcatalyzed pretreatment and subsequent enzymatic hydrolysis in producing biosugars using a biorefinery process. [ABSTRACT FROM AUTHOR]

The waste product from salted Undaria pinnatifida (sea mustard) processing was fermented to produce bioethanol by Saccharomyces cerevisiae KCCM 1129 at laboratory and pilot development unit (PDU) scales. Thermal acidic hydrolysis of salted U. pinnatifida was conducted with 75 mM HSO at 121℃ for 60 min and the addition of 1.4 KNU/mL Termamyl 120L. A total monosaccharide concentration of 19.3 g/L and 32.2% conversion from 59.9 g/L total carbohydrate using 130 g dw/L salted U. pinnatifida were achieved. Ethanol fermentations in 5 and 500 L fermenters were carried out to produce 8.5 g/L of ethanol with an ethanol yield (Y) of 0.44 at 24 h and 7.9 g/L with Y of 0.41 at 18 h, respectively. The fermentation time of the PDU-scale reaction was reduced due to differences in the impeller type and geometry of the fermenters. [ABSTRACT FROM AUTHOR]

Marine microalgae were studied as potential resources for the production of biodiesel. Five marine microalgae, Tetraselmis suecica, Phaeodactylum tricornutum, Chaetoceros calcitrans, Isochrysis galbana, and Nannochloropsis oculata were cultured in f/2 media, 12:12 L:D cycle at 20 ± 1°C with a light intensity of 36.3 μmol/m/sec using a 15-L circular cylindrical photobioreactor. The dry cell weight, specific growth rate, biomass productivity, oil content and fatty acid composition of palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid of microalgae were determined. T. suecica, I. galbana, and N. oculata showed high dry cell weights of 0.58, 0.57, and 0.57 g/L, respectively. The culture period of T. suecica to reach the stationary phase was 9 days. On the other hand, N. oculata showed the longest culture period of 28 days to reach the stationary phase. T. suecica absorbed nitrate at the initial stages of cell growth, decreasing the nitrate concentration to 0.5 mg/L on day-7 of the culture. The highest oil contents were observed in P. tricornutum with a 25.31% dry cell weight and I. galbana with a 23.15% dry cell weight on day-9 after the stationary phase. I. galbana showed 417.33 mg of palmitic acid per g oil and T. suecica showed 235.61 mg of oleic acid per g oil. Stearic acid, linoleic acid, and linolenic acid did not exceed 30.02 mg/g oil in any of the microalgae. T. suecica showed the shortest culture period of 9 days to reach the stationary phase. Therefore, the highest biomass production of 0.58 g/L was obtained and I. galbana showed high biomass production of 0.57 g/ L and oil content of 23.15% of dry cell weight. Therefore, T. suecica and I. galbana can be selected as a potential candidate for the production of biodiesel. [ABSTRACT FROM AUTHOR]