• Journal of Korean Society of Environmental Engineers
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• v.32 no.4
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• pp.325-332
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• 2010

This study was conducted with the experiment of solubilisation of excess sludge by microbubble ozone process. To improve ozone contact efficiency, microbubble ozones which its diameter were the avearge 30 ${\mu}m$, microbubble size less than 40 ${\mu}m$ occupied about over 90% of all. In treating sludge using microbubble ozones, in case microbubble ozones are injected at microbubble ozone dosage of 0.34 g $O_3/g$ SS or less regardless of sludge concentration, microbubble ozone consumption rate was found to be 100% with no emission of waste ozones. In treating sludges by each concentration, in case the initial SS concentration of sludge is set to 6,447 mg/L, 5,557 mg/L, 3,180 mg/L, 1,092 mg/L and 515 mg/L, the amount of removed SS tended to increase with increase in initial SS concentration for the same microbubble ozone dosage, and treatment of sludge with high initial SS concentration was effective in raising the oxidation efficiency of microbubble ozones. On the other hand, as a result of reviewing acid, alkali and microbubble ozone treatment as composite treatment of sludge, use of acid treatment for the pre-treatment of microbubble ozone was more effective than alkali treatment, and in case of treatment at microbubble ozone dosage 0.05g $O_3/g$ SS with the concentration of sulfuric acid infused in the sludge, the amount of removed SS, 153.9 g, was 1.9 times more than 81.2 g the amount of single treatment of microbubble ozone.

• YAKHAK HOEJI
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• v.37 no.6
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• pp.571-576
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• 1993

The substrate specificity of the purified rabbit plasma alkaline phosphatase (ALPase) was determined towards a extended range of potential substrates including relatively simple phosphate derivatives as p-NPP and indolyl phosphate, and several synthetic peptides and phosphoproteins. These results further estabilish the broad substrate specificity of these circulating enzymes. Interestingly, the plasma ALPase preferentially dephosphorylates Thr over Ser residues, as demonstrated with a series of synthetic peptides. The latter result is in contradiction to the behaviour of the tissue ALPase, which is thought to the ultimate source of plasma ALPase, and open therefore new perspectives with respective to the origin and "solubilisation" processes of these enzymes. Dephsphrylation of protein substrates by endogenous and isolated plasma ALPases indicates that ALPase probably displays protein phosphatase activity in vivo.

• BMB Reports
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• v.40 no.2
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• pp.163-171
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• 2007

Functional elements of the conserved helix 7 in the poreforming domain of the Bacillus thuringiensis Cry $\delta$- endotoxins have not yet been clearly identified. Here, we initially performed alanine substitutions of four highly conserved aromatic residues, $Trp^{243}$, $Phe^{246}$, $Tyr^{249}$ and $Phe^{264}$, in helix 7 of the Cry4Ba mosquito-larvicidal protein. All mutant toxins were overexpressed in Escherichia coli as 130-kDa protoxins at levels comparable to the wild-type. Bioassays against Stegomyia aegypti mosquito larvae revealed that only W243A, Y249A or F264A mutant toxins displayed a dramatic decrease in toxicity. Further mutagenic analysis showed that replacements with an aromatic residue particularly at $Tyr^{249}$ and $Phe^{264}$ still retained the high-level toxin activity. In addition, a nearly complete loss in larvicidal activity was found for Y249L/F264L or F264A/ Y249A double mutants, confirming the involvement in toxicity of both aromatic residues which face towards the same direction. Furthermore, the Y249L/F264L mutant was found to be structurally stable upon toxin solubilisation and trypsin digestion, albeit a small change in the circular dichroism spectrum. Altogether, the present study provides for the first time an insight into the highly conserved aromaticity of $Tyr^{249}$ and $Phe^{264}$ within helix 7 playing an important role in larvicidal activity of the Cry4Ba toxin.

• Applied Chemistry for Engineering
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• v.20 no.2
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• pp.126-133
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• 2009

The surfactants applied in household detergents and industrial cleansers should satisfy the requirement of not just the basic function such as emulsification, solubilisation, dispersion, detergency, wetting and foaming, but also the economical efficiency and the safety to human and environment. In the viewpoint of the sustainable development, the surfactants, moreover, have to reduce raw materials and energy consumption and waste disposal when they are being manufactured and also consumed for their purposes. New high-performance surfactants have been extensively studied and developed in order to respond the change in social and economical environment. Noticeable progresses have been achieved so far, which are the significant increase in solubility and surface activity through the minor modification of existing surfactant molecular structure and the synergistic increase in a surface activity shown in the mixed surfactant system of anionic and cationic surfactants. In this review, the important and meaningful progresses achieved recently in technological advance and practical application will be summarized and discussed.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.2
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• pp.113-119
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• 2011

The study purpose was to examine an effect of zero emission of excess sludge on biological reactor and treated water quality within the biological reactor in the process of biological treatment combined with excess sludge reduction system with ozone. Under an ozone injection rate 0.03 g $O_3/g$ SS, Sludge Disintegration Number (SDN) 3 and less than pH 4 as pre-treatment process, it was possible to maintain a stable biological treatment process without sludge disintegration. In the test of $OUR_{max}$, of sludge, its value was hardly under the condition of ozone injection rate 0.03 g $O_3/g$ SS. There were almost no changes of MLVSS/MLSS within biological reactor followed by a solubilization of excess sludge. Accumulation of microorganism within biological reactor was also not observed. After solubilization of excess sludge, an increase for organic matter and SS concentrations of an effluent was not observed and T-N concentration was reduced by increasing nitrification and denitrification rate within biological reactor. Most of T-P was not removed by zero emission of excess sludge and was leaked by being included in effluents.