• Bulletin of the Korean Chemical Society
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• v.25 no.3
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• pp.410-412
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• 2004

• Applied Biological Chemistry
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• v.28 no.1
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• pp.1-7
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• 1985

Exo-maltotetraohydrolase produced by Pseudomonas stutzeri IAM 12097 was characterized with respect to substrate specificity, the reaction products and hydolysis rate on various carbohydrates. Maltopentaose, maltoheptaose, soluble starch, amylose, amylopectin, oyster glycogen and gelatinized starch of corn, potato, glutinous rice, green banana and arrow root were hydolyzed by this enzyme, but ${\alpha},{\beta},{\gamma}-cyclodextin$, sucrose, raffinose, lactose, pullulan, maltose, maltotriose and maltotetraose were not hydrolyzed. Among oligosaccharides, maltohexaose was favorably hydrolyzed by this enzyme and the main reaction product of oligosaccharides and polysaccharides was maltotetraose. Addition of pullulanase to this enzyme increased the hydolysis rate on gelatinized starches. tut it did not on raw starches. Among various starches, corn starch was favorably hydrolyzed by this enzyme, whereas it acted on potato starch, arrow root starch and high amylose corn starch weakly.

• New & Renewable Energy
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• v.7 no.3
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• pp.6-16
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• 2011

In order to study the utilization of seaweeds as an alternative renewable feedstock for bioethanol production, their properties of hydrolysis and fermentation were investigated. The seaweeds were well hydrolyzed with diluted sulfuric acid. The weight loss of seaweeds reached 75-90%, but only 12-51% of them was converted into reducing sugars after the acid-hydrolysis at $130^{\circ}C$ for 4-6h. The yield of reducing sugars increased with increasing the hydrolysis time up to 4h and then decreased thereafter. In contrast, the ethanol yield from the hydrolysates increased with hydrolysis time except for green seaweeds maximizing at 4h. Optimal fermentation time by Saccharomyces cerevisiae (ATCC 24858) varied with seaweeds; 48h for green seaweeds, 96h for brown and red seaweeds. The ethanol yield from the hydrolysate reached 138${\pm}$37mg/g-dry for green seaweeds, 258${\pm}$29mg/g-dry for brown seaweeds, and 343${\pm}$53mg/g-dry for red seaweeds, which correspond to approximately 1.5-4.0 times more than the theoretical yield from total reducing sugars in the hydrolysates. The results obtained indicate clearly that the non-reducing sugars or oligosaccharides dissolved in the hydrolysate played an important role in producing bioethanol. Considering the productivity and production cost of each seaweed, brown seaweeds such as Laminaria japonica and Undaria pinnatifida seem to be a promissing feedstock for bioethanol production.

• New & Renewable Energy
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• v.9 no.2
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• pp.5-14
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• 2013

The efficiency of microwave-assisted acid hydrolysis of seaweeds for the production of ethanol was investigated and its effect on hydrolysis into reducing sugar and fermentation into ethanol evaluated as compared with those by conventional heating. A brown seaweed, Laminaria japonica (10-100g/L) was hydrolysed under dilute acidic condition (0.5N $H_2SO_4$, $100^{\circ}C$) with two sorts of heating: microwave irradiation for ${\leq}10min$ and conventional heating for 10-60min. Microwave-assisted hydrolysis was shown to be more efficient. A similar range of reducing sugar and ethanol yields as with the conventional autoclave heating procedure(${\geq}30min$) was observed, but it was obvious that production of ethanol from microwave-assisted hydrolysis had a 3 times faster reaction rate leading to very short production times, lower energy consumption/loss than from the conventional heating mode, and higher biomass loading without significant reducing ethanol yield, thus microwave-assisted acid hydrolysis is a potential alternative method for more effective hydrolysis of Laminaria japonica.

• Journal of the Korean Chemical Society
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• v.40 no.9
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• pp.599-606
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• 1996

The effects of chemical species in groundwater on the solubility of the uranyl hydrolysis precipitates formed at pH 6.4 and 9.7 were investigated. Based on the chemical composition of the groundwater, the synthetic groundwater was prepared. The colloid-free (separated) groundwater was also prepared by removal of both organic and inorganic colloids from the sampled groundwater. Solubilities of precipitates formed in the hydrolysis of uranyl ion in groundwater, separated groundwater, synthetic groundwater and 0.1 M NaCl solution were measured over neutral to alkaline pH range, and especially, the effect of the anions and cations found in groundwater on the solubility was investigated. Solubility in groundwater was approximately two orders of magnitude greater than that in 0.1 M NaCl solution. Soubililties of uranyl hydrolysis precipitates formed at pH 9.7 and 6.4 were compared in groundwater and synthetic groundwater. Solubilities of the precipitates formed at different pH were found to be in the same order of magnitude in groundwater and synthetic groundwater, however the uranyl hydolysis precipitates formed at higher pH values showed a tendency of higher solubility.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.6
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• pp.1020-1025
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• 1995

A new method was developed to prepare ${\beta}-1$, 4-mannotriose by the enzymatic hydrolysis of white copra meal and the subsequent elimination of monosaccharides and mannobiose from the resulted hydrolysate with a yeast. The optimum pH and temperature for the mannanase were 6 and $50^{\circ}C$, respectively. The mannanase was stable between pH 5.5 and 7 after 2hr treatment at $30^{\circ}C$. White copra meal(70g) was hgydrolyzed with the mannanase(3,450units/500ml) at pH 6 and $50^{\circ}C$ for 24hr. The hydolysis products were monosaccharides, mannobiose and mannotriose. By the elimination of monosaccharides and mannobiose from the hydrolysis products with Candida guilliermondii IFO 0556, 12.1g of mannotriose was obtained without the use of chromatographic techiniques.