• Elastomers and Composites
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• v.51 no.3
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• pp.175-180
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• 2016

Influence of amino acidic chemical on properties of maleic anhydride-grafted ethylene-propylene-diene terpolymer/zinc oxide (EPDM-g-MAH/ZnO) composites was investigated. 4-Aminosalicylic acid (ASA), 4-amino-2-methoxybenzoic acid (AMBA), 12-aminolauric acid (ALA), and glutamine (Gln) were employed as the amino acidic chemicals. Though small quantity (0.5 phr) of the amino acidic chemical was added to the EPDM-g-MAH/ZnO composite, the properties were notably changed. By adding the amino acidic chemical, the percent crystallinity and apparent crosslink density were reduced. Order of the percent crystallinity was related to that of the $pK_a$ values of amino acidic chemicals. By adding the amino acidic chemical, the basic tensile properties were on the whole improved. The experimental results were explained by the $pK_a$ values of amino acidic chemicals, change of zinc ionomer formation, and interactions between the additive and EPDM-g-MAH chain.

• Analytical Science and Technology
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• v.22 no.4
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• pp.313-318
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• 2009

Liquid chromatographic enantiomer separation of amino alcohols was performed on several chiral columns based on polysaccharide derivatives under the mobile phase conditions containing acid or base additive. The chromatographic parameters were greatly influenced by the nature of the mobile phase containing acid or base additive as well as the used chiral columns. Compared to chromatographic results obtained in the mobile phase containing base additive (0.1% triethylamine), especially, Chiralcel OD showed dramatically enhanced separation factors and resolution factors with reduced capacity factors under the mobile phase condition containing acidic additive (0.1% trifluoroacetic acid). When the mobile phase containing 0.05% trifluoroacetic acid and 0.05% triethylamine was used on Chiralcel OD, the greatest separation factors and resolution factors among all other mobile phase conditions in this study were observed.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.327-333
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• 2014

Two genes encoding the mannanase of Bacillus sp. YB-1401 and B. amyloliquefaciens YB-1402, which had been isolated at acidic pH as mannanase producers, were each cloned into Escherichia coli, and sequenced. Both mannanase genes consisted of 1,080 nucleotides, encoding polypeptides of 360 amino acid residues. The deduced amino acid sequences of the two mannanase genes differed by four amino acid residues different, and were highly homologous to those of mannanases belonging to the glycosyl hydrolase family 26. Comparison of two mannanases produced from recombinant E. coli indicated that His-tagged mannanase of YB-1402 (HtMAN1402) was more stable than that of YB-1401 at acidic pH and high temperature. In particular, HtMAN1402 retained more than 50% of its activity at pH 3.0 after 4 h of pre-incubation, suggesting the enzyme is a valuable candidate for use as a feed additive. In addition, thermostability of the two mannanases was found to be enhanced by $Ca^{2+}$ ions.

• Journal of Aquaculture
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• v.22 no.1
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• pp.105-111
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• 2009

In this study, we carried out an experiment for estimation the larval digestibility in aspects which digestive enzymatic activities and nutrition of the rotifers, Brachionus rotundiformis. Thus we enhanced the digestive enzymatic activity through the addition of starch for the increase of digestibility of rotifer (starch-rotifer), and compared with the feed efficiency through rearing of the olive flounder, Paralichthys olivaceus used rotifer lipid-enriched with Algamac $2000^{(R)}$ (CE-rotifer). The digestive enzyme activities (except for TG-lipase), total protein contents, total essential amino acid, essential amino acids (methionin and phenylalanine) of starch-rotifer (the rotifer used a starch as additive, and enriched not) was assayed significantly higher than CE-rotifer (P<0.05). And total lipid, lipid classes (except for sterol) and fatty acids as DHA and EPA showed higher in CE-rotifer than starch-rotifer (P<0.05). But, sterol contents and ST/TG ratio were shown significantly higher in starch-rotifer (P<0.05). The flounder larvae supplied the two rotifers showed standard length and body weight that not significantly differed with ranges $3.72{\sim}3.79\;mm$ and $32.9{\sim}37.8\;mg$/larva on 6 days after hatching (DAH), respectively (P>0.05). However, these of 12 DAH showed the values of significantly higher to $5.94{\pm}0.249\;mm$, $144.0{\pm}23.86\;mg$/larva and $26.2{\pm}12.13%$ in standard length, body weight and survival in CE-flounder than that of starch-flounder (P<0.05). The hydrolytic enzymatic activities of flounder larvae severally supplied the two rotifers showed the significantly higher activities in acidic -amylase, neutral -amylase, TG-lipase, lysozyme and acidic phosphatase in starch-flounder on 5 DAH (P<0.05). But neutral $\alpha$-amylase, three proteases and two phosphatases of CE-flounder on 11 DAH showed the significantly higher activities than that of starch-flounder (P<0.05). Therefore, for the flounder, Paralichthys olivaceus larvae just depleted yolk was more beneficial to supply the feed, rotifer, enhanced the digestibility than to supply the feed lipid-enriched for aspect of larval digestibility up to 6 DAH, thereafter nutrition of absorption due to the development of digestive organs suggested that enrichment effect appeared with larval somatic growth. Consequently, investigation more detailed about the larval digestive physiological and nutritional requirement variations after 6 DAH will be necessary, thereafter.