To develop farm-made high effective vinegar, this study prepared apple vinegar using four kinds of acetic acid bacteria isolated from a natural fermentation liquid of ‘Cheongsoo’ grapes and analyzed vinegar samples fermented 93% apple juice and 7% alcohols at 30℃ for 20 days. To accomplish this, quality characteristics such as pH, total acidity, reducing sugar, organic acid, color, total polyphenol contents, and antioxidant activity contents were determined. The pH decreased while total acidity of all samples gradually increased during fermentation period. The vinegar with AP 21 strain tended to increase the total acidity quicker than other stains. Reduced sugar content remained high until the last fermentation day. Furthermore, reduced sugar contents of all vinegars increased as fermentation progressed by decomposing sucrose present in apples. When physiological activities were compared, apple vinegars fermented with AP 21 and 30 strains had higher total polyphenol and flavonoid contents than other samples. However, there was no significant difference in antioxidant activity between samples. These results indicate that strain 21 is the most suitable starter as acetic acid bacteria for producing farm-made vinegar.

This study investigated species identification and labeling compliance of 48 shrimp products sold in the Korean online markets. Species identification was conducted using the standard DNA barcoding method, using the cytochrome c oxidase subunit I gene. The obtained sequences were compared with those deposited in the NCBI GenBank and BOLD Systems databases. Additionally, phylogenetic analysis was performed to further verify the identified shrimp species. Consequently, 16 shrimp species were identified, including Penaeus vannamei, Pandalus borealis, Palaemon gravieri, Leptochela gracilis, Penaeus monodon, Pleoticus muelleri, Metapenaeopsis dalei, Euphausia pacifica, Lebbeus groenlandicus, Trachypenaeus curvirostris, Argis lar, Metanephrops thomsoni, Metapenaeopsis barbata, Alpheus japonicus, Penaeus chinensis, and Mierspenaeopsis hardwickii. The most prevalent species was Penaeus vannamei, found in 45.8% of the analyzed products. A significant mislabeling rate of 72.9% was found; however, upon excluding generic names such as shrimp, the mislabeling rate reduced to 10.4%. The mislabeling rate was higher in highly-processed products (89.3%) compared with that in minimally-processed products (50%). No correlation was found between the country of origin and mislabeling rate. The results of this study provide crucial data for future monitoring of shrimp products and improving the labeling of shrimp species in Korea.

In this study, based on an analysis of two DNA barcode markers (cytochrome c oxidase subunit I and cytochrome b genes), we performed species identification and monitored labeling compliance for 50 commercial pufferfish products sold in on-line markets in Korea. Using these barcode sequences as a query for species identification and phylogenetic analysis, we screened the GenBank database. A total of seven pufferfish species (Takifugu chinensis, T. pseudommus, T. xanthopterus, T. alboplumbeus, T. porphyreus, T. vermicularis, and Lagocephalus cheesemanii) were identified and we detected 35 products (70%) that were non-compliant with the corresponding label information. Moreover, the labels on 12 commercial products contained only the general common name (i.e., pufferfish), although not the scientific or Korean names for the 21 edible pufferfish species. Furthermore, the proportion of mislabeled highly processed products (n = 9, 81.8%) was higher than that of simply processed products (n = 26, 66.7%). With respect to the country of origin, the percentage of mislabeled Chinese products (n = 8, 80%) was higher than that of Korean products (n = 26, 66.7%). In addition, the market and dialect names of different pufferfish species were labeled only as Jolbok or Milbok, whereas two non-edible pufferfish species (T. vermicularis and T. pseudommus) were used in six commercial pufferfish products described as JolboK and Gumbok on their labels, which could be attributable to the complex classification system used for pufferfish. These monitoring results highlight the necessity to develop genetic methods that can be used to identify the 21 edible pufferfish species, as well as the need for regulatory monitoring of commercial pufferfish products.

Freshwater jellyfish, a type of jellyfish exclusively found in freshwater, has a limited number of species but is found globally. However, their ecology and causes of occurrence are largely unknown. Therefore, understanding the distribution of polyps, which produce the larvae of freshwater jellyfish, can provide important data for comprehending their ecology. This study aims to explore the COI gene of freshwater jellyfish using environmental DNA from the microbial film in the Miho River system. Among the 12 survey points in the Miho River watershed, genetic material of freshwater jellyfish was detected in 8 points, mainly located upstream near reservoirs. These genetic materials were identified as genes of the well-known freshwater jellyfish species, Craspedacusta sowerbii. Notably, the C. sowerbii genes found in the Miho River watershed survey points were closely related to a species previously discovered in Italy. Consequently, utilizing environmental DNA to explore the genetic traces of freshwater jellyfish enables rapid screening of areas with a high likelihood of freshwater jellyfish occurrence. This approach is deemed to provide crucial information for understanding the distribution and ecology of freshwater jellyfish in Korea.

Cyanobacteria Pseudanabaena strains are known to produce 2-MIB (odorous material) in freshwater systems, thereby causing problems in water use. However, their physiological responses to environmental factors in relation with 2-MIB production is not well explored. This study was conducted to evaluate the effect of temperature on the growth and 2-MIB production of Pseudanabaena redekei. The experimental cyanobacteria strains were separated from the Uiam Reservoir (North Han River) and cultured in the BG-11 medium. Temperature was set to 10, 15, 20, 25, and 30℃ for the experiment, in the reflection of the seasonal water temperature variation in situ. For each temperature treatment, cyanobacterial biomass (Chl-a) and 2-MIB concentration (intra-cellular and extra-cellular fractions) were measured every 2 days for 18 days. Both maximal growth and total 2-MIB production of P. redekei appeared at 30℃. While intra-cellular 2-MIB contents were similar (26~29 ng L-1) regardless of treated temperatures, extra-cellular 2-MIB concentration was higher only in high temperature conditions (25~30℃), indicating that the extents of 2-MIB biosynthesis and release by P. redekei vary with temperature. The 2-MIB productivity of P. redekei was much higher in low-temperature conditions (10~15℃) than high temperature conditions (25~30℃). This study demonstrated that temperature was a critical factor contributing to 2-MIB biosynthesis and its release in cell growth (r=0.605, p<0.01). These results are important to understand the dynamics of 2-MIB in the field and thereby provide basic information for managing odorous material in drinking water resources.

Cyanobacterial resting cells, such as akinetes, are important seed cells for cyanobacteria’s early development and bloom. Due to their importance, various methods have been attempted to isolate resting cells present in the sediment. Ludox is a solution mainly used for cell separation in marine sediments, but finding an accurate method for use in freshwater is difficult. This study compared the two most commonly used Ludox methods (direct sediment treatment and sediment distilled water suspension treatment). Furthermore, we proposed a highly efficient method for isolating cyanobacterial resting cells and eDNA amplification from freshwater sediments. Most of the resting cells found in the sediment were akinete to the Nostocale and were similar to those of Dolichospermum, Cylindrospermum, and Aphanizomenon. Twenty times more akinetes were found in the conical tube column using the sediment that had no treatment than in the sample treated by suspending the sediment in distilled water. Akinete separated through Ludox were mainly spread over the upper and lower layers in the column rather than concentrated at a specific depth in the column layer. The mibC, Geo, and 16S rDNA genes were successfully amplified using the sediment directly in the sample. However, the amplification products of all genes were not found in the sample in which the sediment was suspended in distilled water. Therefore, 5 g to 10 g of sediment is used without pretreatment when isolating cyanobacterial resting cells from freshwater sediment. Cell isolation and gene amplification efficiency are high when four times the volume of Ludox is added. The Ludox treatment method presented in this study isolates cyanobacterial resting cells in freshwater sediment, and the same efficiency may not appear in other biotas. Therefore, to apply Ludox to the separation of other biotas, it is necessary to conduct a pre-experiment to determine the sediment pretreatment method and the water layer where the target organism exists.

Environmental DNA (eDNA) can exist in both intracellular and extracellular forms in natural ecosystems. When targeting harmful cyanobacteria, extracellular eDNA indicates the presence of traces of cyanobacteria, while intracellular eDNA indicates the potential for cyanobacteria to occur. However, identifying the “actual” potential for harmful cyanobacteria to occur is difficult using the existing sediment eDNA analysis method, which uses silica beads and cannot distinguish between these two forms of eDNA. This study analyzes the applicability of a density gradient centrifugation method (Ludox method) that can selectively analyze intracellular eDNA in sediment to overcome the limitations of conventional sediment eDNA analysis. PCR was used to amplify the extracted eDNA based on the two different methods, and the relative amount of gene amplification was compared using electrophoresis and Image J application. While the conventional bead beating method uses sediment as it is to extract eDNA, it is unknown whether the mic gene amplified from eDNA exists in the cyanobacterial cell or only outside of the cell. However, since the Ludox method concentrates the intracellular eDNA of the sediment through filtration and density gradient, only the mic gene present in the cyanobacteria cells could be amplified. Furthermore, the bead beating method can analyze up to 1 g of sediment at a time, whereas the Ludox method can analyze 5 g to 30 g at a time. This gram of sediments makes it possible to search for even a small amount of mic gene that cannot be searched by conventional bead beating method. In this study, the Ludox method secured sufficient intracellular gene concentration and clearly distinguished intracellular and extracellular eDNA, enabling more accurate and detailed potential analysis. By using the Ludox method for environmental RNA expression and next-generation sequencing (NGS) of harmful cyanobacteria in the sediment, it will be possible to analyze the potential more realistically.

Targeting Microcystin (MC), which is most abundantly detected in the North-Han River water area, we analyzed the relationship between the MC biosynthesis gene (mcyA gene), cyanobacteria cell density, and MC concentration, derived an RNA-MC conversion formula, and derived the cyanobacteria. The concentration of MC present in cells was predicted. In the North-Han River waters, the mcyA gene was found mainly at downstream sites of the North-Han River after Muk-Hyeon Stream junction, and higher copy numbers were found on average than other sites. In the Uiam Lake waters upstream of the North-Han River, the mcyA gene copy number increased at the Kong-Ji Stream point, and after September, the mcyA gene copy number decreased throughout the North-Han River waters. The expression of the mcyA gene was concentrated in the short period of summer due to the spatio-temporal difference between upstream and downstream water bodies. The mcyA gene expression level was not only highly correlated with MC concentration, but also correlated with the cell density of Microcystis aeruginosa and Dolichospermum circinale, which are known to biosynthesize MC. Six conversion formulas derived based on the RNA-MC relationship showed statistical significance (p<0.05) and exhibited high correlation coefficients (r) of 0.9 or higher. The expression level of MC biosynthesis gene present in eRNA determines the synthesis of cyanotoxin substances in water, quickly quantifies gene activity, and can be fully utilized for early warning of MC development.

The Bayesian algorithm model is a model algorithm that calculates probabilities based on input data and is mainly used for complex disasters, water quality management, the ecological structure between living things or living-non-living factors. In this study, we analyzed the main factors affected Korean Estuary Trophic Diatom Index (KETDI) change based on the Bayesian network analysis using the diatom community and physicochemical factors in the domestic estuarine aquatic ecosystem. For Bayesian analysis, estuarine diatom habitat data and estuarine aquatic diatom health (2008~2019) data were used. Data were classified into habitat, physical, chemical, and biological factors. Each data was input to the Bayesian network model (GeNIE model) and performed estuary aquatic network analysis along with the nationwide and each coast. From 2008 to 2019, a total of 625 taxa of diatoms were identified, consisting of 2 orders, 5 suborders, 18 families, 141 genera, 595 species, 29 varieties, and 1 species. Nitzschia inconspicua had the highest cumulative cell density, followed by Nitzschia palea, Pseudostaurosira elliptica and Achnanthidium minutissimum. As a result of analyzing the ecological network of diatom health assessment in the estuary ecosystem using the Bayesian network model, the biological factor was the most sensitive factor influencing the health assessment score was. In contrast, the habitat and physicochemical factors had relatively low sensitivity. The most sensitive taxa of diatoms to the assessment of estuarine aquatic health were Nitzschia inconspicua, N. fonticola, Achnanthes convergens, and Pseudostaurosira elliptica. In addition, the ratio of industrial area and cattle shed near the habitat was sensitively linked to the health assessment. The major taxa sensitive to diatom health evaluation differed according to coast. Bayesian network analysis was useful to identify major variables including diatom taxa affecting aquatic health even in complex ecological structures such as estuary ecosystems. In addition, it is possible to identify the restoration target accurately when restoring the consequently damaged estuary aquatic ecosystem.

2017년 즈음부터, 야구경기장에서 야구경기 관람객 즉, 스포츠팬들에 의하여 불리워지는 소위 ‘응원가’를 어느날 갑자기 스포츠팬들은 부를 수 없게 되었다. 야구장 응원가는 보통 기존의 음악을 응원의 가사와 악곡 으로 변경하여 만들어진다. 기존 음악은 저작권 보호 기간이 끝난, 그래 서 공유(Public Domain)의 영역으로 들어간 음악과 저작권 보호 기간이 존속 중인 음악으로 나눌 수 있겠다. 기존 음악의 저작자들은 응원가로 서의 변형이 본인들의 저작권을 침해했다며 문제를 제기하였다. 작곡/작 사가 20여명이 프로야구 구단 삼성라이온즈가 동의 없이 곡을 변형해 응 원가로 사용했다며 삼성라이온즈를 상대로 낸 손해배상청구 소송을 제기 한 것이다. 대상 사건에서 문제가 되었던 것은 저작권 보호 기간 존속 중인 기존 음악을 응원가로 이용하는 과정에서 변형이 이루어졌는데, 그 변형이 기존 음악 저작권자의 저작재산권인 2차적저작물작성권, 저작인 격권인 동일성유지권, 성명표시권을 침해하였는지 여부이다. 1심에서는 동의 없이 곡을 변경해 응원가로 사용했다는 이유로 프로야 구구단을 상대로 응원가 저작권 소송을 제기한 작곡/작사가들이 패소하 였다. 구단들은 저작물 사용료를 지급하며 상당 기간 노래를 응원가로 사용했고, 구단들이 노래를 일부 변경해 응원가로 사용한 것이 원고들이 주장하는 권리를 침해한 것으로 인정하기 어렵다고 판단하였다. 2심에서 는 원고 패소로 판결한 1심을 깨고 원고 일부 승소로 판결했다. 그러나 항소심에서 성명표시권 침해만 인정되어 청구액의 10%에도 못 미치는 배상액을 인정받아 원고들의 실익은 크지 않은 것으로 보인다. 대상 판결에서 문제가 되었던 스포츠와 음악 영역은 문화 산업에서 차 지하는 비중이 높은 분야로 이 분야에서 파생되는 여러 지적재산 이용자 들을 고려하지 않을 수 없다. 재판부의 판단은 야구장을 찾은 관람객들 의 응원 문화를 고려한 관점에서의 결론이라고 생각된다. 저작권법의 목 적에서 저작물을 이용하는 자들의 권리를 고려하여 스포츠 산업 향상발 전에 이바지하는 것을 염두해 둔 판결로 보인다. 결국 ‘저작물의 이용 목 적에 부합한 저작권의 행사와 저작물의 공정한 이용’이라는 저작권법의 목적을 재고함과 동시에 사전에 분쟁을 예방할 수 있는 명확한 계약 체 결의 중요성에 대하여 확인하게 해주는 의미 있는 판결이다.

환경유전자 (eDNA)는 다양한 환경 (수중, 토양, 대기)에 존재하는 생물체로부터 유래된 유전물질을 의미한다. eDNA는 높은 민감도, 짧은 조사시간 등 많은 장점들이 존재하며 이로 인해 생물 모니터링 및 유해생물과 멸종위기 생물을 탐색하는 분야에 다양하게 활용되고 있다. 이러한 eDNA 를 채집하기 위해서는 대상생물 및 대상유전자뿐만 아니라 현장 여과방법 및 eDNA 보존방법과 같이 매우 다양한 항목들을 고려해야 한다. 특히 환경에서 eDNA를 채집하는 방법은 eDNA 농도와 직결되는 항목으로서 적절한 채집방법을 사용하여 eDNA를 채집할 때 정확한 분석결과를 얻을 수 있다. 또한 현장에서 채집한 eDNA를 보존하고 추출하는 과정에서도 정확한 방법을 사용하였을 때 현장에 분포하는 eDNA의 농도를 정확하게 파악할 수 있다. 특히 eDNA 연구를 시작하는 연구자들에게 eDNA 분야는 초기 진입 장벽이 매우 높은 기술로서 이를 위한 기초 자료가 매우 절실하다. 본 연구에서는 본 연구는 eDNA가 수생태계를 연구하기 위한 도구로서 보다 널리 이용되며, eDNA를 이용하기 시작하는 연구자들에게 도움을 주고자 수생태계에서 eDNA를 채집하고 및 운반하는 방법과 실험실에서 eDNA를 추출하는 방법을 소개하고, 보다 간편하고 효율적인 eDNA 채집 도구와 방법을 제시하였다.

본 연구는 고등학생의 자아존중감, 분노표현, SNS중독경향성의 정도 및 그들 변수 간의 관계와 SNS중독경향성에 미치는 영향 요인을 알아보고자 하는 서술적 조사연구이다. 대상자는 2020년 5월 18일~28일까지 총 10일 간 S시, G도 고등학교에 재학 중이며 SNS을 이용하고 있는 대상자에게 온라인 설문지를 이용하여 총 100부의 자료를 수집하였다. 연구결과, SNS중독경향성과 자아존중감(r=-.385, p<.001), 분노조절(r=-.354, p<.001)과는 보통의 역 상관관계, 분노표출(r=.321, p=.001), 분노억압(r=.308, p=.002)과는 보통의 순 상관관계를 나타냈다. SNS중독경향성에 미치는 영향 요인은 자아존중감(β =-.297, p=.001), 성별(β=.266, p=.003), 분노표출(β=.247, p=.007) 순으로 회귀모형의 설명력은 27.7% 로 나타났다(F=12.279, p<.001). 따라서 SNS중독경향성을 낮추기 위해 고등학생의 자아존중감을 높이고 분노표출을 낮추기 위한 프로그램 개발이 필요하며 특히 성별에서 여자 고등학생의 SNS중독경향성을 낮추기 위한 방안이 모색되어야 할 것이다.

This study examined the antioxidative and lipid accumulation inhibitory effects of 14 plants from Mongolia and Myanmar on 3T3-L1 and HepG2 cells. The total phenolic and flavonoid contents (TPC and TFC) of 14 plant extracts were measured, and the antioxidative activities were analyzed using DPPH, ABTS, FRAP, and ORAC. After measuring the pancreatic lipase levels and performing the thiobarbituric acid assay, the degree of lipid accumulation was determined by lipid (Oil Red O) staining and triglyceride assay in 3T3-L1 and HepG2 cells. M. paniculate (259.43 mgGAE/g) and C. benghalensis (130.78 mgNAE/g) had the highest TPC and TFC, respectively, among the 14 plants. R. acicularis Lindl. had the highest antioxidant activity in DPPH. The ABTS, FRAP, and ORAC results showed that the antioxidant activity of 11 species was higher than that of the positive control. The pancreatic lipase inhibitory effect of C. angustifolium Scop. was reduced to 23.65% at 0.1 mg/mL, and the level of lipid peroxidation of C. abrorescens Lam. was 0.63 nmol/mg. Five selected plants inhibited the lipid accumulation and triglyceride content, respectively, in 3T3-L1 and HepG2 cells. These results provide scientific evidence for developing functional foods using 14 plants from Mongolia and Myanmar, which have antioxidant activities and lipid accumulation reduction effects.

In this study, 11 plant extracts from Bangladesh were used to evaluate the total phenolic and flavonoid content, in vitro antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis-(3-ethylbenzthiazolin-6-sulfonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) assay. Also, the inhibitory effect of nitric oxide (NO) production in RAW 264.7 macrophage cell line and the neuroprotective effect on H2O2-induced PC12 cells were tested. Our results revealed that Piper betle L. showed the highest total phenolic content (162.2 mg GAE/g extract) among the 11 plants from Bangladesh. Most plants showed strong radical scavenging effects and ferric reducing antioxidant power. Besides, Piper betle L. protected PC12 neuronal cells against H2O2 related oxidative stress in LPS-induced PC12 cells. Regarding the antiinflammatory effect, Piper betle L. significantly inhibited NO accumulation in LPS-induced RAW 264.7 cells. Our results provide evidence that Piper betle L. could be useful for the development of functional health foods.

이취미 물질인 2-MIB를 합성하는 원인종에 대한 정보는 담수생태계에서 이와 관련된 환경 및 경제적 문제를 해결하는 데 필수적이다. 본 연구는 북한강 수계에서 출현하는 Pseudanabaena strain을 분리·배양하고, 16S rDNA 염기서열을 이용하여 종 수준의 동정과 2-MIB 합성 유전자 탐색을 통해 이취미 물질 발생 잠재성을 분석하였다. 북한강 본류 지역 (삼봉리, 조암면, 의암호 지역)에서 분리한 Pseudanabaena strain은 총 11개로서 NHUA201911과 NHPD201909 strain을 제외하고 단일세포의 크기는 서로 유사하였다. 그러나 16S rDNA 계통분석을 통한 유전자 염기서 열의 유연관계를 분석한 결과, 분리된 strain들은 총 5개 종 (P. cinerea, P. yagii, P. mucicola, P. galeata, P. redekei)으 로 분류되었다 (40~55% 유사도). 2-MIB를 합성하는 mibC 유전자는 P. cinerea 07 strain (NHUA202007-07)와 P. yagii (NHUA202007-08), P. redekei (NHUA201911)에서만 발견 되었으며, 가스크로마토그래피 분석에 따라 실질적인 2-MIB 합성은 P. cinerea와 P. redekei 종에서 확인되었다. 본 연구 결과는 분자생물학적 수준에서 북한강 수역에서 발생하는 Pseudanabaena속 남조류의 다양도에 대한 증거를 제공하는 연구로서 북한강 수계에서 2-MIB 생산 원인종에 대한 중요한 정보를 제공한다.

This study aims to classify parents by considering important factors in the management of foodservice for children. An offline survey was conducted by enrolling 583 Korean parents whose children attended public or private kindergartens in Seoul. The important factors required for managing foodservice for children are meal service resources, menu management, and food allergy. Considering these factors, parents were grouped into 3 clusters: the allergy important group, environment important group, and high concern group. Evaluation of the demographic characteristics revealed a significant difference between clusters with respect to type of kindergarten. Parents perceived that a private kitchen is more required than a private dining room, and perceptions about the need for a private kitchen and dining room were significantly different among the clusters. Furthermore, the results reveal significant differences between clusters, when considering the need to support meal service. Therefore, the government needs to consider characteristics of the parent cluster if they plan to support the kindergarten foodservice. We believe that this study can be used as supportive data to establish a working policy.

In this study, we examined antioxidative effects and the anti-adipogenesis effect of different parts of Cudrania tricuspidata (C), and Morus alba (M). Total polyphenol contents were highest in M-root (34.56±0.045 mg GAE/g), and there was no significant difference, between C-root and M-leaf. Total flavonoid contents of C-root were highest (23.07±0.004 mg QE/g). To examine antioxidant activities of C and M extracts, DPPH and ABTS radical scavenging activity, and FRAP assay, was used. Results show that antioxidant activities of C and M extracts increased, in a dose-dependent manner. Adipocytes are generated by preadipocyte differentiation, during adipogenesis. Matured adipocytes accumulate in abnormal and cause obesity. We investigated effects of leaf and root extracts of C and M, on lipid accumulation, in 3T3-L1 adipocytes. Changes in cell morphology, and degrees of lipid accumulation in adipocytes, were evaluated by Oil Red O staining. Root extracts of C and M, reduced lipid content in a dose-dependent manner. Therefore, root extracts of C and M, may be good candidates for managing obesity.

The objective of this study was to evaluate novel usability as natural anti-obesity supplement of Selaginella tamariscina extract. The total phenol contents and total flavonoid contents were 60.29±3.11 GAE mg/g and 14.90±0.34 QE mg/g, respectively. To evaluate anti-obesity activity of Selaginella tamariscina extract, pancreatic lipase inhibition activity as well as its inhibition effect of lipid accumulation in adipocytes were conducted by Oil Red O staining and lipolysis assay. The result of pancreatic lipase inhibition activity of S. tamariscina extract showed a wide range between 40 and 73% dose dependently. While the incubation of 3T3-L1 cells with S. tamariscina extract inhibited differentiation of preadipocytes and reduced lipid accumulation, the level of released free glycerol into culturing medium was increased in multiple concentrations. These results showed that S. tamariscina extract inhibit adipogenesis and pancreatic lipase activity. Thus, S. tamariscina extract can be a candidate for regulating lipid accumulation in obesity.

Additive manufacturing by electron beam melting is an affordable process for fabricating near net shaped parts of titanium and its alloys. 3D additive-manufactured parts have various kinds of voids, lack of fusion, etc., and they may affect crack initiation and propagation. Post process is necessary to eliminate or minimize these defects. Hot isostatic pressing (HIP) is the main method, which is expensive. The objective of this paper is to achieve an optimum and simple post heat treatment process without the HIP process. Various post heat treatments are conducted for the 3Dprinted Ti-6Al-4V specimen below and above the beta transus temperature (996oC). The as-fabricated EBM Ti-6Al-4V alloy has an α‘-martensite structure and transforms into the α+β duplex phase during the post heat treatment. The fatigue strength of the as-fabricated specimen is 400 MPa. The post heat treatment at 1000oC/30 min/AC increases the fatigue strength to 420 MPa. By post heat treatment, the interior pore size and the pore volume fraction are reduced and this can increase the fatigue limit.