Screening of Bacillus subtilis strains capable of producing extracellular hydrolases, including lipolytic enzyme was carried out. Within the scope of this study, total 61 strains were isolated from various domestic specific environmental samples such as seawater, soil, Jeju ranch, hot spring, salt farm, and fermented food and identified as Bacillus subtilis based on 16S rRNA sequences. Among the isolates, 4 strains had extracellular lipase activity. The growth profile of the strains revealed that 4 strains showed well growth at 50℃, 3 strains at 55℃, and pH 7.0. All strains could tolerate salinity up to 5%(w/v), 3 strains up to 10%(w/v), and only one strain showed growth at 15%(w/v). Additionally, amylolytic and proteolytic activities were detected in these strains. The highest lipolytic, amylolytic, and proteolytic activity was detected in Bacillus subtilis YS-YR 5A. These results demonstrate the potential application of extracellular hydrolase-producing Bacillus subtilis strains, especially strain YS-YR 5A, as fermentation starter to enhance the functionality and multiplication of functional natural products in the food/medicine/cosmetics/bio industries.

During the decommissioning of a nuclear power plant, the structures must be dismantled to a disposal size. Thermal cutting methods are used to reduce metal structures to a disposal size. When metal is cut using thermal cutting methods, aerosols of 1 μm or less are generated. To protect workers from aerosols in the work environment during cutting, it is necessary to understand the characteristics of the aerosols generated during the cutting process. In this study, changes in aerosol characteristics in the working environment were observed during metal thermal cutting. The cutting was done using the plasma arc cutting method. To simulate the aerosols generated during metal cutting in the decommissioning of a nuclear power plant, a non-radioactive stainless steel plate with a thickness of 20 mm was cut. The cutting condition was set to plasma current: 80 A cutting speed: 100 mm/min. The aerosols generated during cutting were measured using a highresolution aerosol measurement device called HR-ELPI+ (Dekati®). The HR-ELPI+ is an instrument that can measure the range of aerodynamic diameter from 0.006 μm to 10 μm divided into 500 channels. Using the HR-ELPI+, the number concentration of aerosols generated during the cutting process was measured in real-time. We measured the aerosols generated during cutting at regular intervals from the beginning of cutting. The analyzed aerosol concentration increased almost 10 times, from 5.22×106 [1/cm3] at the start of cutting to 6.03×107 [1/cm3] at the end. To investigate the characteristics of the distribution, we calculated the Count Median Aerodynamic Diameter (CMAD), which showed that the overall diameter of the aerosol increased from 0.0848 μm at the start of cutting to 0.1247 μm at the end of the cutting. The calculation results were compared with the concentration by diameter over time. During the cutting process, particles with a diameter of 0.06 μm or smaller were continuously measured. In comparison, particles with a diameter of 0.2 μm or larger were found to increase in concentration after a certain time following the start of cutting. In addition, when the aerosol was measured after the cutting process had ended, particles with a diameter of 0.06 μm or less, which were measured during cutting, were hardly detected. These results show that the nucleation-sized aerosols are generated during the cutting process, which can explain the measurement of small particles at the beginning of cutting. In addition, it can be speculated that the generated aerosols undergo a process of growth by contact with the atmosphere. This study presents the results of real-time aerosol analysis during the plasma arc cutting of stainless steel. This study shows the generation of nucleation-sized particles at the beginning of the cutting process and the subsequent increase in the aerosol particle size over time at the worksite. The analysis results can characterize the size of aerosol particles that workers may inhale during the dismantling of nuclear power plants.

Allomyrina dichotoma is a typical pet beetles in Korea. From 2010, similar symptoms of milky spore disease were found collectively in grubs of the species reared in insect farms. They shared a specific symptom that the skin of last instar larvae was changed softer with opaque white and infested grubs eventually died. To clarify the cause of the symptom, we collected the larvae of A. dichotoma from five farms and examined intestinal bacterial florae of them using pyrosequencing technique. From those results, a member of Paenibacillus was found only in the larvae showing the symptom of disease. Through PCR analysis using a Paenibacillus specific primer set, we obtained the partial 16S rRNA gene sequence and confirmed the microbe as Paenibacillus sp. For detailed characterizing, a whole guts was extracted from each larva showing the sign of the disease and incubated at 70℃ for 15 min to isolate spore forming bacteria. After then, each content of guts was cultured on MYPGPNAL agar medium (12.5 μg/ml of nalidixic acid) at 30℃. The 16S rRNA gene sequence analysis for six isolate showed that they were closely related to P. rigui (97.5~98.0% similarity) and to P. chinjuensis (95.9~96.6% similarity). Additional tests including API test and cellular fatty acid composition analysis were performed, but the strain couldn’t be identified at species level, suggesting it may represent novel species of the genus Paenibacillus.

We tested the identification ability of DNA barcodes comparing with morphological data using the Korean butterflies. The 921 samples (4.6 samples per species) for 202 resident Korean species except migratory species were used. The obtained samples were morphologically identified based on wing patterns. In a result, genetic divergence to the nearest-neighbouring taxon varied from 0 to 28.2%, with an average of 13.4 per cent. The neighbour joining (NJ) tree profile showed that sequence data for 185 of the 202 species formed distinct barcode clusters. Thus, our results indicated that 91.6 percent of the species were possible to allow the reliable identification using DNA barcoding. The rest 17 species (8.4%) consist of following four cases: clustering separated from each species by less than 1% branch length (two species pairs), paraphyletic clustering (two species pairs and one triple species pair), polyphyletic clustering with sharing barcodes (three species pairs), and clustering separated from existing species by the deep branch divergence (four clusters). However, it was not easy to interpret these ambiguous cases only using our current taxonomic evidences. Therefore, we are performing integrative taxonomy on these cases using other additional evidences such as examination on male genitalia and analysis of other gene regions.