• Food Science and Industry
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• v.52 no.2
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• pp.171-187
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• 2019

Novel food materials can be produced based on biotechnology such as genetic recombination, microbial fermentation, and enzymatic engineering by utilizing living organisms such as animal, plant, and microorganism or by applying the enzymes isolated from them. Especially, exploration and development of novel prebiotics and probiotics attracted great attention worldwide in the food industry, of which the research and industrial trends in food biotechnology field are promoting the production of next generation sweeteners and proliferation of beneficial bacteria in gastrointestinal tract. Development and commercialization of novel food materials by domestic bioprocessing technology have been sluggish due to the GMO/LMO food safety issues. Meanwhile, the US and EU do not perceive badly about gene manipulation technology, and the research is most active in the fields of crops and GMMs, respectively. Genetic scissors, which are considered as next generation technology, are notable since foreign genes do not remain in final products.

• Journal of Microbiology and Biotechnology
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• v.16 no.12
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• pp.1868-1873
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• 2006

A novel microorganism that could degrade high molecular weight gellan was screened and isolated from soil. On gellan plate, the microorganism grew well and completely liquefied the plate. The gellan-degrading microorganism was isolated by pure culture on glucose and nutrient agar medium afterwards. The 16S rDNA sequence analysis and biochemical tests using an API 50CHB/20E kit revealed that the strain belonged to Bacillus sp. The isolate, named as Bacillus sp. YJ-1, showed optimum gellan-degrading activity in 0.5% gellan medium at pH 7.5 and 37$^{\circ}C$. The activity was measured and evaluated by the thiobarbituric acid and thin-layer chromatography method. Mass spectrometry revealed that the major gellan.. depolymerized product was an unsaturated tetrasaccharide consisting of $\Delta$4,5-glucuronic acid-(1$\rightarrow$4 )-$\beta$-D-glucose-(1$\rightarrow$4)- $\alpha$-L-rhamnose-(1$\rightarrow$3)-$\beta$-D-glucose, which is a dehydrated repeating unit of gellan, thus the enzyme was identified as gellan lyase. When the gellan was present in the medium, the gellan-degrading activity was much higher than that in glucose-grown cells. These results indicate that in the presence of gellan, Bacillus sp. YJ-1 is able to metabolize the gellan by inducing gellan-degrading enzymes that can degrade gellan into small molecular weight oligosaccharides, and then the gellan. depolymerized products are taken up by the cells and utilized by intracellular enzymes.

• Preventive Nutrition and Food Science
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• v.4 no.1
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• pp.28-32
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• 1999

A novel antimicrbial peptide , named HFS-I, was isolated and characterized from the skin of the hagfish, Eptatretus bugeri. The decapeptide with a molecular mass of 1279.5 Da was purified to homogeneity using a gel-filtration column, ion-exchange and C18 reverse-phase high performance liquid chromatograpy . The complete amino acid sequence of HFS-I, which was determined by a combination of an automated amino acid sequencing and FAB-MS, was F-P-W-W-L-S-G-K-Y-P-NH2. Comparison of the amino acid sequence with those of other known antimicrobial peptides revealed that HFS-I was a novel antimicrobial peptide. HFS-I showed a weak antimicrobial activity in vitro aganinst a broad spectrum of microorganism without hemolytic acitivity.

• Korean Journal of Food Science and Technology
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• v.52 no.1
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• pp.11-18
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• 2020

Bacteria of the genus Enterococcus are of importance in food fermentations as well as their use as probiotics in humans and livestock. However, they are also important nosocomial pathogens that cause infections. Some strains are resistant to multiple antibiotics and possess virulence factors. The role of Enterococcus species in disease has raised issues on their safety for use in foods or as probiotics. First, this review summarized the positive and negative traits of Enterococcus spp. to illustrate the controversial nature of this bacterial genus and discussed the current genomic approaches can eliminate pathogenic strains. Then, this review examined the current status of starter development for traditional food fermentations and the regulation on the approval of novel food microorganisms in Korea to point out problems in the regulation. Based on the conclusions from the studies on Enterococcus spp., we suggested the direction of safety assessment of novel food microorganisms in Korea.

• Food Science and Industry
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• v.52 no.2
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• pp.153-170
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• 2019

With the breathtaking stride beingmade in the field of biotechnology, biocatalyst research using genetically modified microorganism (GMM) is actively being pursued in food industry. However, domestic food and food additive regulation standards and the number of examination management examples currently used in industry is lacking significantly. Up till now, there are only 6 examples of domestic GMM examination and approval cases for food production purposes and furthermore they are limited to the production of functional sweeteners. Domestically, although GMM is developed as a processing aid (contained use), if they are used in the production of food, the safety of GMM, including environmental safety, is evaluated. Also the produced food or food additives using GMM need to be separately examined and approved as a novel food. On the other hand, imported products produced using GMM need to gain approval for the final product only. Thus the expense and the time to obtain regulatory approval is advantageous for imported products versus domestically produced products. This commentary is written to create the opportunity to reform the current domestic food GMM regulation by comparing and discussing domestic and foreign case analyses of safety evaluation of GMM and related regulations.

• Preventive Nutrition and Food Science
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• v.13 no.4
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• pp.354-361
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• 2008

A novel bacterium isolated from Cheonggukjang was identified as a glutamate-dependent Bacillus subtilis HA with 98.3% similarity to Bacillus subtilis Z99104. Optimization of poly-$\gamma$-glutamic acid ($\gamma$-PGA) production by modulating fermentation factors including carbon sources, nitrogen sources, inorganic salts and fermentation time was investigated. Optimum culture broth for $\gamma$-PGA production consisted of 3% glutamate, 3% glucose and various salts, resulting in the PGA production of 22.5 g/L by shaking culture for 72 hr at $37^{\circ}C$. Average molecular weight of $\gamma$-PGA was determined to be 1,220 kDa through MALLS analysis. The $\gamma$-PGA solution showed a typical pseudoplastic flow behavior, and a great decrease in consistency below pH 6.0 regardless of the same molecular weight of $\gamma$-PGA. The molecular weights of isolated $\gamma$-PGA were drastically decreased by heat treatment in various acidic conditions, resulting in different hydrolysis of $\gamma$-PGA. The consistency of $\gamma$-PGA solution was greatly decreased with increase heating time in acidic conditions.

• Mycobiology
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• v.49 no.1
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• pp.46-53
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• 2021

In a study of the fungal diversity on Ulleung Island in Korea, three novel strains of Penicillium were isolated. Different sites on Ulleung Island were selected for collecting endophytic fungi, and three endophytic fungal strains showed unique morphological characteristics. DNA sequence of the internal transcribed spacer, β-tubulin, calmodulin, and RNA polymerase II second largest subunit regions of the strains were analyzed and they showed unique taxonomic position from the other species of Penicillium section Sclerotiora. The new strains were named Penicillium ulleungdoense sp. nov. As the novel endophytic Penicillium taxa were discovered in a unique environment, the data could be meaningful for understanding the geographical distribution of Ascomycetes on Ulleung Island.

• Journal of Microbiology and Biotechnology
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• v.17 no.7
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• pp.1169-1176
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• 2007

Genes encoding proteins responsible for limonene catabolism were cloned from a limonene-degrading microorganism, Enterobacter cowanii 6L, which was isolated from citron (Citrus junos) peel. The 8.6, 4.7, and 7.7 kb fragments (CD3, CD4, and CD6) of E. cowanii 6L chromosomal DNA that confer to E. coli the ability to grow on limonene have been cloned and their corresponding DNA sequences were determined. Nine open reading frames (ORFs) were identified, and the four ORFs (921 bp of CD3-2; 1,515 bp of CD4-1; 1,776 bp of CD6-1; and 1,356 bp of CD6-2) that encode limonene hydroxylase were confirmed by independently expressing these genes in E. coli. FAD and NADH were found to stimulate the hydroxylation reaction if added to cell extracts from E. coli recombinants, and multiple compounds (linalool, dihydrolinalool, perillyl alcohol, (${\alpha}-terpineol$, and ${\gamma}-terpineol$) were the principal products observed. Our results suggest that the isolate E. cowanii 6L has a broad metabolic capability including utilization of limonene. This broad metabolic ability was confirmed by identifying four novel limonene hydroxylase functional ORFs in E. cowanii 6L.

• Microbiology and Biotechnology Letters
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• v.49 no.4
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• pp.510-518
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• 2021

Bacteriophages are considered excellent sensing elements for platforms detecting bacteria. However, their lytic cycle has restricted their efficacy. Here, we used the minor coat protein pIII domain (N1N2) of phage CTXφ to construct a novel surface plasmon resonance (SPR) biosensor that could detect Vibrio cholerae. N1N2 harboring the domains required for phage adsorption and entry was obtained from Escherichia coli using recombinant protein expression and purification. SDS-PAGE revealed an approximate size of 30 kDa for N1N2. Dot blot and transmission electron microscopy analyses revealed that the protein bound to the host V. cholerae but not to non-host E. coli K-12 cells. Next, we used amine-coupling to develop a novel recombinant N1N2 (rN1N2)-functionalized SPR biosensor by immobilizing rN1N2 proteins on gold substrates and using SPR to monitor the binding kinetics of the proteins with target bacteria. We observed rapid detection of V. cholerae in the range of approximately 10³ to 10⁹ CFU/ml but not of E. coli at any tested concentration, thereby confirming that the biosensor exhibited differential recognition and binding. The results indicate that the novel biosensor can rapidly monitor a target pathogenic microorganism in the environment and is very useful for monitoring food safety and facilitating early disease prevention.

• Journal of Dairy Science and Biotechnology
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• v.37 no.3
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• pp.155-166
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• 2019

Bacteria from the genus Lactobacillus are important for the production of fermented food and dairy products, and as symbionts in human and animals. Lactobacillus acidophilus has widely been used in the production of yogurt, health foods, and even medicines. The efficacy of L. acidophilus has been proven with regards to the reduction of cholesterol, prevention and treatment of diarrhea, modulation of the immune system, suppression of cancer, etc. Using molecular biology tools, Lactobacillus acidophilus has now been reclassified into six species: L. acidophilus, L. amylovorus, L. crispatus, L gallinarium, L. gasseri, and L. johnsonii. Thus, since L. acidophilus has now been marked as a newly defined species, caution is advised when reading future publications regarding this bacterium. In this article, the results of the reclassification of L. acidophilus are mentioned after an analysis of its field inheritance was performed by my research team. Especially, L. amylovorus KU4 (formerly named as L. acidophilus KU4; KCCM 10975P) is a novel probiotic strain that is isolated from humans; it has the ability to reduce cholesterol. It has also been reported as a microorganism that effectively inhibits the growth of pathogenic E. coli. However, this Korean patent (No 10-1541280) refers to a strain obtained from calves; the origin of this strain was incorrectly labeled. Furthermore, after the discovery of L. acidophilus in 1900, its role in intestinal microbiological research was described and its utilization as a probiotic was presented.