• Korean Chemical Engineering Research
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• v.61 no.2
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• pp.302-311
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• 2023

This study was conducted to evaluate the applicability of castor oil (CSO) as a natural wood preservative. CSO was treated into wood blocks prepared with domestic and imported wood species using a vacuum-pressure method, and then treatability, leachability and decay resistance of the CSO-treated wood blocks were examined. Although CSO was penetrated effectively into wood blocks of all wood species, the CSO-treatability was the highest in Western hemlock, followed by Japanese larch (LA), soft maple and Mongolian oak due to the difference of its anatomical structure. Except for LA, the more retained, the more leached during a saline water-immersing process for 48h. The use of ethanol added to reduce the viscosity of CSO affected negatively the treatability and leachability of wood blocks. Decay resistance, which was evaluated by the weight loss of wood blocks exposed against Fomitopsis palustris (FOP) and Trametes versicolor, of the CSO-treated/leached wood blocks was superior to that of control. Especially, most of wood blocks treated with preserving solution composed of only CSO (CSO-2) did not decayed and showed a very low weight loss against FOP. The decay resistance results from CSO retained in wood blocks after leaching. The retention of CSO could identify using the observation of X-ray microscope. Length of wood strips, which were treated with CSO-2 and then immersed in saline water for 2 weeks, hardly changed in all cutting directions. In addition, weight gain and length-swelling rate of the wood strips were extremely low compared to those of control. These results indicate that moisture resistance of the wood strips was improved by the CSO treatment. It is concluded that the treatment of CSO using a vacuum-pressure method provides the decay resistance and dimensional stability of wood, and thus CSO can be used as a natural wood preservative on various indoor and outdoor circumstances.

• Journal of Life Science
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• v.29 no.1
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• pp.29-36
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• 2019

We investigated the fermentation conditions for extracts of leave/branches and sap from Korean Dendropanax morbifera (D. morbifera) using Lactobacillus plantarum (L. plantarum) ilchiwhangchil 1785 and L. plantarum ilchiwhangchil 2020. Log growth phase cultured L. plantarum ilchiwhangchil 1785 and L. plantarum ilchiwhangchil 2020 were used for fermentation. The pH and growth of the microorganisms in broth were monitored during the fermentation period. The results revealed that the optimum fermentation conditions for 20 wt% of leave/branches extracts and 1 wt% of sap extract was 2 days incubation at $37^{\circ}C$. The minimum inhibitory concentration (MIC) method and a disk diffusion assay were used to evaluate the antimicrobial activity of the fermented extracts of the leave/branches and sap against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The antimicrobial activity increased in all three strains grown on the medium containing fermented extracts of the leave/branches and sap as compared with that of the strains grown on medium containing non fermented extracts. Furthermore, the antimicrobial activity increased in proportion to the contents of the fermented extracts. Our data suggest that fermented extracts of leave/branches and sap of D. morbifera have applications as natural bio functional materials, such as preservatives, cosmetic materials, and natural packaging materials.

• Journal of Life Science
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• v.33 no.1
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• pp.91-101
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• 2023

Bacteriocins are antimicrobial peptides synthesized on ribosomes, produced by bacteria, that inhibit the growth of similar or closely related bacterial strains. Since the discovery of nisin, many bacteriocins with unique structures and various modes of antibacterial activity have been described, and genes encoding production, secretion, and immunity have been reported. Nisin is one of the bacteriocins applied in cheese, liquid eggs, sauces and canned foods. Many of the bacteriocins of the genus Bacillus belong to lantibiotics, which are modified peptides after translation. Other genus Bacillus also produce many non-lantibiotic bacteriocins. Bacteriocins of the genus Bacillus are sometimes becoming more important because of their broader antibacterial spectrum. Bacteriocins are considered attractive compounds in the food and pharmaceutical industries to prevent food spoilage and growth of pathogenic bacteria. Bacteriocins can be used as biological preservatives in a variety of ways in the food system. Biopreservation refers to extending shelf life and improving safety of foods using microorganisms and/or their metabolites. The demand for new antimicrobial compounds has generated great interest in new technologies that can improve food microbiological safety. Applications of bacteriocins are expanding from food to human health. Today, many researchers are shifting their interest in bacteriocins from food preservation to the treatment of bacteria that cause infections and antibiotic-resistant diseases. This exciting new era in bacteriocin research will undoubtedly lead to new inventions and new applications. In this review, we summarize the various properties and applications of bacteriocins produced by the genus Bacillus.