• Journal of the Korean Wood Science and Technology
• /
• v.43 no.5
• /
• pp.628-640
• /
• 2015

Cellulase is the key enzyme in the use of cellulose-based biomaterials. Because of its structure, cellulose is difficult to be degraded by enzymes. In order to utilize cellulose-based biomaterials efficiently, evolutionary wisdom of how to use enzymes accurately and harmoniously in a biological system is needed, such as the cellulose digestive system in animals. In this study, the symbiotic bacteria from snails, Achatina fulica, were identified and their cellulase activity was evaluated. The 16S rRNA sequence analysis of 100 aerobic bacteria showed that they belonged to 9 genus and almost half of the bacteria were Lactococcus spp. Among 100 identified strains, only two Aeromonas sp. strains showed cellulase activity. Aeromonas sp. KMBS020 had both endo-${\beta}$-glucanase and ${\beta}$-glucosidase activities but Aeromonas sp. KMBS018 had ${\beta}$-glucosidase activity only. None of the 100 bacterial colonies had any cellobiohydrolase activity.

• Journal of Life Science
• /
• v.29 no.2
• /
• pp.158-163
• /
• 2019

The purpose of this study was to isolate a new marine agarase-producing bacterium. Agarase can hydrolyze agar and agarose to produce agarooligosaccharides or neoagarooligosaccharides, which possess many physiological functions. Strain DH-3 was isolated from seawater collected from the coast of Yeosu at Jeollanam province, Korea. A 16S rDNA sequence analysis showed this strain to be Persicobacter sp. DH-3. Extracellular agarase was prepared from culture media of Persicobacter sp. DH-3 and used for characterization. Relative activities at 20, 30, 40, 50, 60, and $70^{\circ}C$ were 50, 55, 70, 100, 90, and 50%, respectively. Relative activities at pH 5, 6, 7, and 8 were 75, 100, 90, and 75%, respectively. The enzyme showed maximum activity at $50^{\circ}C$ in a 20 mM Tris-HCl buffer at pH 6. This enzyme could be useful, as agar is in liquid state at $50^{\circ}C$. Agarase activities were maintained at 80% or more for 2 hr at 20, 30, and $40^{\circ}C$. Thin layer chromatography analysis suggested that Persicobacter sp. DH-3 produced extracellular ${\beta}$-agarases as it hydrolyzed agarose to produce neoagarohexaose and neoagarotetraose. In addition, zymogram analysis confirmed that Persicobacter sp. DH-3 produces at least three agar-degrading enzymes with molecular weights of 45, 70, and 140 kDa. Therefore, it is expected that agarases from Persicobacter sp. DH-3 could be used to produce functional neoagarooligosaccharides.

• Journal of Life Science
• /
• v.31 no.5
• /
• pp.496-501
• /
• 2021

In this study, the marine agar-degrading bacterium Pseudoalteromonas sp. JH-1 was isolated, and its growth and agarase properties were investigated. Seawater was collected from the offshore of the Yonggung Temple in Busan, and agar-degrading bacteria were isolated and cultured with marine agar medium. The bacterium Pseudoalteromonas sp. JH-1 was isolated through 16S rRNA gene sequencing. The extracellularly secreted enzyme was obtained from the culture broth of Pseudoalteromonas sp. JH-1 and was used to characterize its agarase. The extracellular agarase exhibited a maximum activity of 116.6 U/l at 50℃ and pH 6.0 of 20 mM Tris-HCl buffer. Relative activities were 31, 59, 94, 100, 45, and 31% at 20, 30, 40, 50, 60, and 70℃, respectively. Relative activities were 49, 85, 100, 86, 81, and 67% at pH 4, 5, 6, 7, 8, and 9, respectively. Residual activity was more than 85% after exposure at 20, 30, and 40℃ for 2 hr, and more than 82% after exposure at 50℃ for 2 hr. Zymogram analysis confirmed that Pseudoalteromonas sp. JH-1 produced at least two agarases of 55 and 97 kDa. As the products of α-agarase and β-agarase have antioxidation, antitumor, skin-whitening, macrophage activation, and prebiotic effects, further studies are needed on the agarase of Pseudoalteromonas sp. JH-1.

• Journal of Life Science
• /
• v.32 no.4
• /
• pp.285-289
• /
• 2022

In this study, the growth characteristics of an agar-degrading bacterium isolated from seawater samples collected from Yeongheungdo, Incheon, and the characteristics of its agarase were analyzed. The 16S rRNA gene sequence of the isolated strain was 95% similar to that of the genus Agarivorans, and thus the isolated strain was named Agarivorans sp. HY-1. When Agarivorans sp. HY-1 was cultured in a marine broth 2216 medium at 27℃ and 250 rpm, it showed maximum growth on day 1 and showed maximum enzymatic activity on day 2. A crude enzyme solution was prepared from secreted agarase in the culture medium. The extracellular agarase of the Agarivorans sp. HY-1 strain showed maximal activity at 40℃ and pH 7.0 (20 mM Tris-HCl) with 591.91 U/l. The agarase exhibited relative activities of 64, 91, 100, 97, 89, and 60% at 20, 30, 40, 50, 60, and 70℃, respectively. At pH 5, 6, 7, and 8, the relative activities were 79, 95, 100, and 55%, respectively. Furthermore, the agarase exhibited >86% residual activity at 20, 30, and 40℃ for 2 hr and >44% residual activity at 50℃ after 2 hr. A TLC analysis confirmed that Agarivorans sp. HY-1 produced α-agarase. As the degradation products of α-agarase have anticancer and antioxidant effects, Agarivorans sp. HY-1 and its agarase may well prove useful.

• Korean Journal of Environmental Agriculture
• /
• v.20 no.1
• /
• pp.63-66
• /
• 2001

To investgate growth effect of tomato by Bacillus sp. WRD-1 isolated from soil, the Bacillus sp. WRD-1 cultures were treated into tomato cultivated soil with different dilutions (1:100, 1:300, and 1:500) and autoclaved Bacillus cultures as control. Growth and yeild of tomato enhanced in treatments of the Bacillus cultures compared to control. The populations of native bacteria and actinomyces were increased twice in field treated with Bacillus sp. WRD-1 cultures, but the number of mold was decreased. Since the Bacillus sp. WRD-1 promoted growth of tomato and affected population dynamics of microorganism in field, this strain is prominent candidate as a microbial biocide to improve soil potential.

• Korean Journal of Microbiology
• /
• v.40 no.2
• /
• pp.160-166
• /
• 2004

The optimal conditions for production of Monascus sp. KM100l cell mass on submerged culture and production of monacolin K on rice solid culture were investigated. An overproducing mutant of Monascus pigments, KM 1001 mutant, from Monascus purpureus KCCM60016 was selected by NTG treatment. The optimal medium for the production of KM100l mutant cell mass is instructed to be composed of 3% glucose, 2% yeast extract, 0.1 % KH$_2$PO$_4$, 0.05% The optimal conditions for production of Monascus sp. KM100l cell mass on submerged culture and production of monacolin K on rice solid culture were investigated. An overproducing mutant of Monascus pigments, KM 1001 mutant, from Monascus purpureus KCCM60016 was selected by NTG treatment. The optimal medium for the production of KM100l mutant cell mass is instructed to be composed of 3% glucose, 2% yeast extract, 0.1 % KH$_2$The optimal conditions for production of Monascus sp. KM100l cell mass on submerged culture and production of monacolin K on rice solid culture were investigated. An overproducing mutant of Monascus pigments, KM 1001 mutant, from Monascus purpureus KCCM60016 was selected by NTG treatment. The optimal medium for the production of KM100l mutant cell mass is instructed to be composed of 3% glucose, 2% yeast extract, 0.1 % $(KH_2PO_4$, 0.05% $MgSO_4{\cdot}7H_2O$, 0.2% L-asparagine, pH 4.5, and the optimal inoculum size and shaking speed were $1.5{\times}10^6$ spores/50 m1 medium and 150 rpm, respectively. On optimal conditions, 4.1 g/l of the cell mass was obtained at 28$^{\circ}C$ for 3 days. The mycelium were inoculated on 500 g of steamed rice using vinyl bag ($30.6{\times}44$ cm) and incubated at $30^{\circ}C$, 85% humidity for 21 days. Lactone form monacolin K was rapidly increased for 2 days and reached highest concentration of monacolin K (2,930 mg/kg) for 15 days, and monacolin K was decreased after 15 days.

• Journal of Life Science
• /
• v.26 no.4
• /
• pp.453-459
• /
• 2016

Agarases are classified into α-agarase and β-agarase that produce agarooligosaccharides and neoagarooligosaccharides, respectively. Neoagarooligosaccharides have whitening effect of skin, delay of starch degradation, and inhibition of bacterial growth etc. Hence, the object of this study was to isolate a novel agarase producing marine bacterium and characterization of its β-agarase. A novel agar-degrading bacterium was isolated from seashore of Namhae at Gyeongnamprovine, Korea and purely cultured with Marine agar 2216 media. The isolated bacterium was identified as Simiduia sp. SH-4 after 16S rRNA gene sequencing. The enzymatic sample was obtained from culture media of Simiduia sp. SH-4. Enzymatic activity was highly increased from 20(30% relative activity) to 30℃ (100%) and decreased from 30 to 40℃(75%) and so more. Relative activity was 100% at pH 6 while those were about 91% and 59% at pH 5.0 and 7.0, respectively, meaning the enzyme possesses narrow optimal pH range. Hence, the enzyme exhibited the maximal activity with 120.4 units/l at pH 6.0 and 30℃ in 20 mM Tris-HCl buffer. Thin layer chromatography (TLC) analysis showed that Simiduia sp. SH-4 produces β-agarase, which hydrolyze agarose to produce biofunctional neoagarooligosaccharides such as neoagarotetraose and neoagarobiose. Hence, broad applications would be possible using Simiduia sp. SH-4 and its enzyme in the food industry, cosmetics and medical fields.

• Microbiology and Biotechnology Letters
• /
• v.44 no.2
• /
• pp.156-162
• /
• 2016

In this study, we isolated a new agar-degrading marine bacterium and characterized its agarase. An agardegrading marine bacterium SH-1 was isolated from seawater, collected from the seashore of Namhae in Gyeongnam province, Korea, and cultured in marine agar 2216 media. It was identified as Maribacter. sp. SH-1 by phylogenetic analyses, based on 16S rRNA gene sequence. The extracellular agarase was extracted from culture media of Maribacter sp. SH-1 and characterized. Its relative activities were 56, 62, 94, 100, and 8% at 20, 30, 40, 50, and 60℃, respectively, whereas 15, 100, 60, and 21% relative activities were observed at pH 5, 6, 7, and 8, respectively. Its extracellular agarase exhibited maximum activity (231 units/l) at pH 6.0 and 50℃, in 20 mM Tris-HCl buffer. Therefore, this agarase would be applicable as it showed the maximum activity at the temperature at which the agar is in a sol state. Furthermore, the agarase activities remained over 90% at 20, 30, and 40℃ after 0.5 h exposure at these temperatures. Thin layer chromatography analysis suggested that Maribacter sp. SH-1 produces extracellular β-agarase, as it hydrolyzes agarose to produce neoagarooligosaccharides, such as neoagarohexaose (34.8%), neoagarotetraose (52.2%), and neoagarobiose (13.0%). Maribacter sp. SH-1 and its β-agarase would be useful for the production of neoagarooligosaccharides, which shows functional properties, like skin moisturizing, skin whitening, inhibition of bacterial growth, and delay in starch degradation.

• Korean Journal of Organic Agriculture
• /
• v.27 no.1
• /
• pp.57-63
• /
• 2019

Ricania sp. is a pest to many crops in Korea. This pest prefers fruit crops especially, blueberry and apple trees. We tested the possibility of Ricania sp. control using of methylcinnamate. In the laboratory bioassay, the mortality of methylcinnamate against Ricania sp. adult with 100 and 250 time diluted solution was 36.6% and 13.3% respectively. While repellent that the use of methylcinnamate resulted rate of 43.3% with 100 time diluted solution and 40.0% in 250 time diluted solution. Insecticidal and repellent effect in semifield bioassay were higher than those in laboratory bioassay. From this result, methylcinnamate might have synergic effect for Ricania sp. management. The result of this study showed a possibility of Ricania. sp. control using methylcinnamate.

• Microbiology and Biotechnology Letters
• /
• v.26 no.5
• /
• pp.413-419
• /
• 1998

Aryl acylamidase [EC 3.5.1.13] present in an acetaminophen-assimilating Pseudomonas sp. has been purified to a homogeneity using series of ammonium sulfate fractionation, DEAE-Sephacel anion exchange, Phenyl-Sepharose CL-4B hydrophobic, and Sephadex G-100 gel-permeation chromatography. The molecular weight, which was estimated by gel-permeation filtration and sodium dodecyl sulfate polyacylamide gel electrophoresis, was about 57 kDa and 56 kDa, respectively, indicating that this enzyme is a monomeric protein. The optimum pH was 10.5 and the optimum temperature was 40$^{\circ}C$. After incubation of the enzyme at 50$^{\circ}C$ for 30 min, residual activity of the enzyme was 34% compared to its original activity. The Km values for acetaminophen and 4'-nitroactanilide were 0.10 mM and 0.11 mM, respectively.