• Korean Chemical Engineering Research
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• v.53 no.4
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• pp.478-481
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• 2015

In this study, the hydrolysis of green macro-algae Enteromorpha intestinalis using solid acid catalyst was conducted to obtain total reducing sugar. The hydrolysis was optimized with four reaction parameters of liquid-to-solid (L/S) ratio, catalyst amount, reaction temperature, and reaction time. As a optimized result, the highest TRS of 7.74 g/L was obtained under condition of 7.5 L/S ratio, $140^{\circ}C$, 15% catalyst amount and 2 hr. By the way, at this condition, only 0.13 g/L 5-HMF was detected. The solid acid-catalyzed hydrolysis of marine resources had the potential in the field of bioenergy.

• Bulletin of the Korean Chemical Society
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• v.22 no.7
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• pp.716-720
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• 2001

To test the metal ion effect, hydrolysis experiments for two cellobiohydrolases (CBHⅠ and CBH Ⅱ) from Trichoderma reesei have been carried out in the presence of 10 mM metal ions, such as Cu++, Mn++, Ca++, Hg++, Ba++, Pb++, and Cd++. The addition of Mn++, Ba++, and Ca++(10 mM) during the hydrolysis of Avicel PH 101 caused an increase in the total reducing sugar (TRS) for CBH Ⅰ by 142, 135, and 114 percent, respectively. Those for CBH Ⅱ increased by 177, 175, and 115 percent, respectively. The Mn++ was the most stimulatory metal ion, whereas Hg++ was the most inhibitory metal ion. The adsorption experiments were performed to investigate how the influence of Mn++ and Hg++ on the hydrolysis is related to the adsorption of cellobiohydrolases on cellulose. The increase in TRS during hydrolysis by adding Mn++ caused an increase in adsorption affinity (Kad) and tightness (ΔHa). While, the decrease of TRS during hydrolysis by adding Hg++ caused a decrease in the adsorption affinity (Kad) and tightness (ΔHa). These results indicate the changes in the tightness and affinity of adsorption by adding metal ions play a crucial role in the degradation of the microcrystalline cellulose.

• Korean Chemical Engineering Research
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• v.54 no.1
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• pp.70-74
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• 2016

In this study, the effects of citrate buffer pretreatment conditions (solid-to-liquid ratio, reaction temperature, pH and concentration of buffer) on enzymatic hydrolysis of E. intestinalis for total reducing sugar (TRS) production were investigated. As a results of the citrate buffer pretreatment, a 5.40% hydrolysis yield was obtained under conditions including 1:10 solid-to-liquid ratio, 0.25 M citrate buffer (pH 3.5) at $140^{\circ}C$ for 60 min. The maximum hydrolysis yield of 18.68% was obtained to enzymatic hydrolysis after pretreatment. This result is 1.81 times higher than that of control.

• KSBB Journal
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• v.17 no.6
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• pp.549-554
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• 2002

The hydrolysis of old book(Hanji) was performed using endoglucanase Ⅰ(endo Ⅰ), and exoglucanase II(exe II) and their mixtures purified from Trichoderma viride cellulase. The optimum degradation of old book(Hanji) with endo Ⅰ, exo II and endo-exo mixture(Ⅰ：Ⅰ) were exhibited at pH 4.5, 5.5, 5.0, respectively. Maximum degradations using endo Ⅰ, exo II and endo-exo mixture(Ⅰ：Ⅰ) occurred at 50$\^{C}$. The yield decreased an increasing the enzyme concentration. Especially, the yield was lowest for treatment with the endo Ⅰ-exo II mixture(Ⅰ：Ⅰ), which may be regarded as being due to a synergistic action of the cellulase components. Physical strength increased with increasing exo II concentration, and decreased with increasing concentration of endoglucanase Ⅰ. These results indicated that the degradation of old book(Hanji) depends largely upon the action of endoglucanase. Therefore, the most effective method of conserving paper cultural properties is to repress the action of endoglucanase.

• Microbiology and Biotechnology Letters
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• v.51 no.3
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• pp.257-267
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• 2023

The potential polyhydroxyalkanoates (PHA)-producing bacteria, Bacillus megaterium PP-10, was successfully isolated and studied its feasibility for utilization of pineapple peel waste (PPW) as a cheap carbon substrate. The PPW was pretreated with 1% (v/v) H₂SO₄ under steam sterilization and about 26.4 g/l of total reducing sugar (TRS) in pineapple peel hydrolysate (PPH) was generated and main fermentable sugars were glucose and fructose. A maximum cell growth and PHA concentration of 3.63 ± 0.07 g/l and 1.98 ± 0.09 g/l (about 54.58 ± 2.39%DCW) were received in only 12 h when grown in PPH. Interestingly, PHA productivity and biomass yield (Y_x/s) in PPH was about 4 times and 1.5 times higher than in glucose. To achieve the highest DCW and PHA production, the optimal culture conditions e.g. carbon to nitrogen ratios of 40 mole/mole, incubation temperature at 35℃ and shaking speed of 200 rpm were performed and a maximum DCW up to 4.24 ± 0.04 g/l and PHA concentration of 2.68 ± 0.02 g/l (61% DCW) were obtained. The produced PHA was further examined its monomer composition and found to contain only 3-hydroxybutyrate (3HB). This finding corresponded with the presence of class IV PHA synthase gene. Finally, certain thermal properties of the produced PHA i.e. the melting temperature (T_m) and the glass transition temperature (T_g) were about 176℃ and -4℃, respectively whereas the M_w was about 1.07 KDa ; therefore, the newly isolated B. megaterium PP-10 is a promising bacterial candidate for the efficient conversion of low-cost PPH to PHA.