• Korean Journal of Environmental Agriculture
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• v.34 no.3
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• pp.244-251
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• 2015

BACKGROUND: Recent studies have described the importance of bacteria that can degrade polycyclic aromatic hydrocarbons (PAHs). Here we screened bacterial isolates from commercial gasoline for PAH degraders and characterized their ability to degrade PAHs, lipids and proteins as well as their enantioselective epoxide hydrolase activity, salt tolerance, and seawater survival. METHODS AND RESULTS: One hundred two bacteria isolates from commercial gasoline were screened for PAH degraders by adding selected PAHs on to the surface of agar plates by the sublimation method. A clear zone was found only around the colonies of PAH degraders, which accounted for 13 isolates. These were identified as belonging to Bacillus sp., Brevibacterium sp., Micrococcus sp., Corynebacterium sp., Arthrobacter sp., and Gordonia sp. based on 16S rRNA sequences. Six isolates belonging to Corynebacterium sp., 3 of Micrococcus sp., Arthrobacter sp. S49, and Gordonia sp. H37 were lipid degraders. Arthrobacter sp. S49 was the only isolate showing high proteolytic activity. Among the PAH-degrading bacteria, Arthrobacter sp. S49, Brevibacterium sp. S47, Corynebacterium sp. SK20, and Gordonia sp. H37 showed enantioselective epoxide hydrolase activity with biocatalytic resolution of racemic styrene oxide. Among these, highest enantioselective hydrolysis activity was seen in Gordonia sp. H37. An intrinsic resistance to kanamycin was observed in most of the isolates and Corynebacterium sp. SK20 showed resistance to additional antibiotics such as tetracycline, ampicillin, and penicillin. CONCLUSION: Of the 13 PAH-degraders isolated from commercial gasoline, Arthrobacter sp. S49 showed the highest lipid and protein degrading activity along with high active epoxide hydrolase activity, which was the highest in Gordonia sp. H37. Our results suggest that bacteria from commercial gasoline may have the potential to degrade PAHs, lipids, and proteins, and may possess enantioselective epoxide hydrolase activity, high salt tolerance, and growth potential in seawater.

• Journal of Life Science
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• v.31 no.5
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• pp.496-501
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• 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
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• v.22 no.5
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• pp.627-633
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• 2012

$Microbulbifer$ sp. AJ-3 was used to acquire the degrading products from $Capsosiphon$ $fulvescens$ (DPCF), which were investigated to determine its physiological activities. A crude enzyme extract from $Microbulbifer$ sp. AJ-3 hydrolyzes polysaccharide substrates such as agar, agarose, alginic acid, fucoidan, laminaran, starch, and chitin. Among them, agarose, laminaran, and alginic acid showed higher activities, especially alginic acid. The antioxidant activity of DPCF was measured by using 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and superoxide dismutase (SOD)-like activities and were about 32% and 93% at 2 mg/ml, respectively. In addition, the nitrite-scavenging activity of DPCF was about 82%, 53%, and 12% at pH levels of 1.2, 3.0, and 6.0, respectively. To determine the influence of DPCF on alcohol metabolism, the generating activity of reduced-nicotinamide adenine dinucleotide (NADH) by alcohol dehydrogenase (ADH) was measured. The facilitating rate of ADH activity by DPCF was 130% at 2 mg/ml. The tyrosinase inhibitory activity of DPCF was slightly increased in a dose-dependent manner and was about 28% at 2 mg/ml. These results indicated that the enzymatic products from DPCF have a strong antioxidant, nitrite scavenging, and alcohol metabolizing activity.

• Microbiology and Biotechnology Letters
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• v.22 no.2
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• pp.158-163
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• 1994

Microorganisms capale of utilizing linear alkylbenzene sulfonates(LAS) as sole carbon source were isolated from industrial effluent by using LAS agar plates. The isolated strains were identified as Salmonella sp(BC-2) and Escherichia sp.(BC-3) from the results of morphological, cultural and biochemical tests. The optimal condition for the growth and biodegradation of LAS was the initial pH 7.0 and LAS concentration 0.1%. The isolated BC-2 and BC-3 strains harbored plasmid and LAS-degrading activity was lost when the plasmids were cured by mitomycin C. The plasmids were transformed into E. coli and transformants have the LAS-degrading activity. Isolated strains were examined for primary biodegradation rate of LAS in the medium by methylene blueactive substance(MBAS) method. Of these isolates, BC-2 and BC-3 strains degradated LAS upto 60% and high resistant to CdCl$_{2}$ and HgCl$_{2}$. Isolated strains were sensitive to chloramphenicol, kanamycin, rifampicin, streptomycin and tetracycline but resistant to ampicillin and lincomycin.] Its minimal inhibitory concentration(MIC) for ampicillin was more than 1500 $\mu $g/ml.

• Fisheries and Aquatic Sciences
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• v.13 no.1
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• pp.36-48
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• 2010

An agar-degrading Agarivorans sp. AG17 strain was isolated from the red seaweed Grateloupia filicina collected from Jeju Island. A beta-agarase gene from Agarivorans sp. AG17 was cloned and designated as agrA. agrA has a 2,985 bp coding region encoding 995 amino acids and was classified into the glycoside hydrolase family (GHF)-50. Predicted molecular mass of the mature protein was 105 kDa. His-tagged agrA was overexpressed in Escherichia coli and purified as a fusion protein. The enzyme showed 158.8 unit/mg specific activity (optimum temperature at $65^{\circ}C$ and pH 5.5 in acetate buffer) with unique biochemical properties (high thermal and pH stabilities). Enzyme produced neoagarohexaose, neoagarotetraose and neoagarobiose by degrading agar, and hydrolyzed neoagaro-oligosaccharides were biologically active. Hence the purified enzyme has potential for use in industrial applications such as the development of cosmetics and pharmaceuticals.

• 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.

• Journal of Microbiology and Biotechnology
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• v.29 no.2
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• pp.235-243
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• 2019

A special eosinophilic agarase exo-type ${\beta}$-agarase gene, AgaDL6, was cloned from a marine agar-degrading bacterium, Flammeovirga sp. HQM9. The gene comprised 1,383-bp nucleotides encoding a putative agarase AgaDL6 of 461 amino acids with a calculated molecular mass of 52.8 kDa. Sequence analysis revealed a ${\beta}$-agarase domain that belongs to the glycoside hydrolase family (GH) 16 and a carbohydrate-binding module (CBM_4_9) unique to agarases. AgaDL6 was heterologously expressed in Escherichia coli BL21 (DE3). Enzyme activity analysis of the purified protein showed that the optimal temperature and pH of AgaDL6 were $50^{\circ}C$ and 3.0, respectively. AgaDL6 showed thermal stability by retaining more than 98% of activity after incubation for 2 h at $50^{\circ}C$, a feature quite different from other agarases. AgaDL6 also exhibited outstanding acid stability, retaining 100% of activity after incubation for 24 h at pH 2.0 to 5.0, a property distinct from other agarases. This is the first agarase characterized to have such high acid stability. In addition, we observed no obvious stimulation or inhibition of AgaDL6 in the presence of various metal ions and denaturants. AgaDL6 is an exo-type ${\beta}$-1,4 agarase that cleaved agarose into neoagarotetraose and neoagarohexaose as the final products. These characteristics make AgaDL6 a potentially valuable enzyme in the cosmetic, food, and pharmaceutical industries.

• Fisheries and Aquatic Sciences
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• v.14 no.3
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• pp.186-191
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• 2011

An agar-degrading enzyme-producing strain was isolated from seawater. The isolate was identified as Microbulbifer sp. SD-1 by 16S rRNA sequencing analysis. The optimal pH and temperature for growth were 6.0 and $30^{\circ}C$, respectively, and growth was possible at pH 9.0 and $60^{\circ}C$. The isolate required 5% NaCl for optimal growth and showed 45% growth activity without NaCl. Agar concentrations of 0-0.4% in the medium did not affect growth. Thin-layer chromatography analysis revealed that this strain could degrade agar into a monosaccharide and oligosaccharide, which may have industrial applications.

• Journal of Animal Science and Technology
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• v.57 no.7
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• pp.23.1-23.6
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• 2015

Cellulose degrading bacteria from koala faeces were isolated using caboxymethylcellulose-Congo red agar, screened in vitro for different hydrolytic enzyme activities and phylogenetically characterized using molecular tools. Bacillus sp. and Pseudomonas sp. were the most prominent bacteria from koala faeces. The isolates demonstrated good xylanase, amylase, lipase, protease, tannase and lignin peroxidase activities apart from endoglucanase activity. Furthermore many isolates grew in the presence of phenanthrene, indicating their probable application for bioremediation. Potential isolates can be exploited further for industrial enzyme production or in bioremediation of contaminated sites.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.3
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• pp.142-148
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• 2007

An agar-degrading marine bacterium, strain AS-3 was isolated from the seawater. The strain AS-3 was identified as Algibacter lectus AS-3 by 16S rDNA sequence. The optimum medium for agarase activity of the isolated strain was determined to be marine medium, marine broth 2216 containing 0.1% agar as carbon source. An extracellular agarase was purified 6.9-fold from the culture supernatant by ammonium sulfate precipitation, ion exchange chromatography and gel filtration methods. The optimum pH and temperature for this enzyme were 7.0 and $40-50^{\circ}C$, respectively. Antioxidative activity of the strain AS-3 was 62.4% in the supernatant cultured for 12 h.