Chung-Yeol Lee

Evaluation of cutter orientations in high-speed ball end milling of cantilever-shaped thin plate

Abstract This work was carried out in order to evaluate machinability in high-speed ball end milling of thin cantilever-shaped aluminum plate, and the effect of tool path, tool angle on geometric accuracy and surface integrity. The experiments were performed at tilt angles 0°, 15°, 45° of workpieces using four cutter orientations (horizontal outward, horizontal inward, vertical outward, vertical inward). Workpiece deflection, surface profile and machined surface have been measured. The results show that when machining cantilever-shaped thin plate, the best cutting strategy is vertical outward at a workpiece tilt angle of 45°.

Characteristics of Chungkookjang Produced by Bacillus subtillus MC31

Chungkookjang was fermented by B. subtilis MC31, a -amino butyric acid (GABA) producing microorganism. The characteristics of Chungkookjang were investigated while fermenting. Twenty four amino acids were detected in Chungkookjang, leucine was the highest of them all. Total cell populations of B. subtilis MC31 phase were between log ~ log CFU/g at stationary phase. Contents of moisture, crude ash, crude protein, crude lipid and crude fiber are , , , and 2.61%, respectively. Contents of ammonia type nitrogen, amino type nitrogen and reducing sugar were increased during fermentation at for 72 hr, however those of titratable acidity and total sugar were decreased. pH was slowly alkalized during fermentation. Viscous substance and protease contents in Chungkookjang were and g/l, apiece. When the fibrin plate and Robbin method for fibrinolytic activity were applied, B. subtilis MC31 showed high activity. These results suggested that B. subtilis MC31 is suitable to be used as a starter to enhance the quality of Chungkookjang.

Isolation and Characterization of Feather Keratin-Degrading Bacteria and Plant Growth-Promoting Activity of Feather Hydrolysate

Abstract This study was conducted to isolate and characterize a novel feather-degrading bacterium producing keratinase activity. A strain K9 was isolated from soil at poultry farm and identified as Xanthomonas sp. K9 by phenotypic characters and 16S rRNA gene analysis. The cultural conditions for the keratinase production were 0.3% fructose, 0.1% gelatin, 0.04% K 2 HPO 4 , 0.06% KH 2 PO 4 , 0.05% NaCl and 0.01% FeSO 4 with an initial pH 8.0 at 30 ℃ and 200 rpm. In an optimized medium containing 0.1% chicken feather, production yield of keratinase was approximately 8-fold higher than the yield in basal medium. The strain K9 effectively degraded chicken feather meal (67%) and duck feather (54%), whereas human nail and human hair showed relatively low degradation rates (13-22%). Total free amino acid concentration in the cell-free supernatant was about 25.799 mg/l. Feather hydrolysate produced by the strain K9 stimulated growth of red pepper, indicating Xanthomonas sp. K9 could be not only used to increase the nutritional value of chicken feather but also a potential candidate for the development of natural fertilizer applicable to crop plant soil. Key Words :Feather, Fertilizer, Keratin, Keratinase

Isolation and Application of Feather-Degrading Bacteria for Development of Environment-Friendly Biofertilizer

The aim of this study was to isolate mesophilic chicken feather-degrading bacteria and to evaluate feather hydrolysate as alternative biofertilizer. Isolate RS7 was isolated from compost and identified as Bacillus pumilus according to API analysis and l6S rDNA sequencing analysis. Chicken feathers were completely degraded after 5 days of cultivation at . Feather hydrolysate treated by B. pumilius RS7 positively influenced Helianthus sannuus L. (sunflower) growth (e.g. growth rate, number and dry weight of leave, and flowering rate). These results suggest that feather hydrolysate prepared using B. pumilius RS7 could successfully be used as alternative biofertilizer, thereby reducing the environmental impact of feather waste from the poultry industry.

Conditions for Soluble Phosphate Production by Environment-Friendly Biofertilizer Resources, Pseudomonas fluorescens

【The effects of inorganic salts, inoculum concentration, aeration rate and shaking speed on insoluble phosphate solubilization by Pseudomonas fluorescens RAF15 were investigated. Soluble phosphate production was dependent on the presence of

Nutritional regulation of keratinolytic activity in Bacillus pumilis

MgCl_2{\cdot}6H_2O

Rapid solubilization of insoluble phosphate by a novel environmental stress-tolerant Burkholderia vietnamiensis M6 isolated from ginseng rhizospheric soil

and

Changes in Yeast Cell Number, Total Acid and Organic Acid during Production and Distribution Processes of Makgeolli, Traditional Alcohol of Korea

MgSO_4{\cdot}7H_2O

The optimal cutter orientation in ball end milling of cantilever-shaped thin plate

in the medium. Supplementation of medium with 0.01%

Evaluation of the thermal characteristics in high-speed ball-end milling

CaCl_2{\cdot}2H_2O