• KSBB Journal
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• v.19 no.2
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• pp.143-147
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• 2004

Biodegradation of dimethyl sulfide (DMS) was studied in a batch culture using Gordonia sihwaniensis PKL-1 isolated from a compost biofilter after 100 days of operation for the removal of volatile organic compounds. Optimal pH and temperature for the removal of DMS were 7 and $25^{\circ}C$, respectively. The Michaelis-Menten kinetic constants for DMS removal, $\upsilon_{max}$ and $K_s$, were 0.0016 mg/(mg-protein)ㆍhr, and 8.05 mg/L, respectively.

• Korean Journal of Microbiology
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• v.46 no.4
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• pp.383-388
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• 2010

Alkaline protease-overproducing strains of Vibrio metschnikovii were developed by using the molecular evolution from the classical mutants V. metschnikovii L12-23, N4-8, and KS1. Each vapK (Vibrio alkaline protease K) was obtained from the genomic DNAs of mutants by PCR to carry out the DNA shuffling. The modified vapK-1 obtained by DNA shuffling was used again as a template for the error-prone PCR to make the vapK-2. Both genes were cloned in the plasmid pKF3 to construct the recombinant plasmids which have one or two copies of the modified genes. The recombinant plasmids were back-transformed to V. metschnikovii KS1 to construct recombinant V. metschnikovii that expresses the alkaline protease. About 3.9-fold more protease activity was measured in the strain which has the plasmid containing two copies of vapK-2 when compared to strain KS1. When compared to wild type V. metschnikovii RH530, 43-fold more activity was achieved. Comparison of amino acids among vapK, vapK-1, and vapK-2 revealed that the active sites was highly conserved and not changed. However, many amino acids except the active sites were changed. These results suggested that the changes in amino acids might play an important role in the increase of protease activity by allowing the easy access of substrate to active sites of the protease. The fermentation of alkaline protease from the V. metschnikovii KS1 harboring the plasmid that contains two copies of vapK-1 showed the possibility of this strain to be used as industrial producer.

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.495-501
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• 2011

Bacterial strains were isolated from forest soils of Halla mountain, Jeju island in Korea. The soil samples were collected at each altitude of 100m from 1,000 m above sea level. Total 398 strains were isolated and tested for their physiological characteristics of antagonistic and proteolytic activities, and auxin production. Among the isolates, 172 strains were selected as antifungal strains showing antagonistic activity against at least one of 8 plant fungal pathogens (Alternaria alternata, Botrytis cinerea, Collectotrichum acutatum, Fusarium oxysporum, Phytophthora capsici, Pythium ultimum and Sclerotinia sclerotiorum). In addition 203 strains for proteolytic activity and 26 strains for auxin production were characterized for further study. Je28-4 (Rhodococcus sp.) were showed 80% of control value against tomato gray mold in vivo. Thus, it is suggested that soil bacteria isolated from forest soils of Halla mountain can be important sources of bioactive compounds for improving plant growth or promising biocontrol agents.

• Journal of Soil and Groundwater Environment
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• v.6 no.3
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• pp.31-41
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• 2001

In this study, we have examined the potential degradation of MTBE(methyl tert-butyl ether) by pure culture ENV425 and mixed culture obtained from gasoline contaminated soil using n-butane as the sources of carbon and energy. The results described in this study suggest that MTBE is degraded cometabolically by ENV425 and mixed culture grown on n-butane. Butane and MTBE degradation was completely inhibited by acetylene, which indicated that both substrates were degraded by butane monooxygenase. These cultures grown on n-butane generated TBA (tert-butyl alcohol) as a metabolite of MTBE oxidation. TBA Production was accounted 54.7% and 58.6% for MTBE oxidation by ENV425 and mixed culture, respectively. In resting cell experiments, however, TBA and TBF were detected as the oxidation products of MTBE by ENV425 and mixed culture. The observed maximal MTBE degradation rates were 52.3 and 62.3 (nmol MTBE degraded/hr/mg TSS) by ENV425 and mixed culture, respectively, and the observed maximal transformation yields ($T_y$) were 44.7 and 34.0 (nmol MTBE degraded/$\mu$mol n-butane utilized), and the observed maximal transformation capacities ($T_c$) were 199 and 226 ($\mu$mol MTBE degraded/mg TSS used).

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.86-92
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• 2010

Thirty-one chicken feather-degrading bacteria were isolated from wasted feather, compost and wastewater in a chicken farm. These isolates were categorized as Firmicutes (21 strains), ${\gamma}$-proteobacteria (4 strains), Actinobacteria (4 strains), and Bacteroidetes (2 strains) by 16S rRNA gene sequence analysis. We examined the feather-degrading isolates for degradation in the 2% of chicken feather meal. The strain Chryseobacterium sp. FBF-7, Stenotrophomonas maltophilia FBS-4, and Lysinibacillus sp. FBW-3 were selected as a keratinolytic protein degrading bacteria which showed the highest feather degradation of 75-90%. The characteristics of amino acids extracted from chicken feather meal by using keratinolytic protein degrading isolates and chemical method with $Ca(OH)_2$ were analyzed. Total amino acid content of strain Chryseobacterium sp. FBF-7 was 1,661.6 ${\mu}mol$/ml, which was the highest and it was similar with chemical method. And essential amino acid content of total amino acid was thirty-seven percent (619.3 ${\mu}mol$/ml) and 596.9 ${\mu}mol$/ml for keratinolytic protein degrading isolates and chemical method, respectively. The major amino acids were valine, glutamic acid, aspartic acid, glycine, and proline by the strain Chryseobacterium sp. FBF-7 and especially, higher contents of aspartic acid, threonine, serine, cysteine, and tyrosine were detected compared with chemical method.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.1
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• pp.1-6
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• 1990

The degradation of non-volatile-amines by microorganisms were investigated. The degra-ding activity could be noted in four strains isolated from fermented sardine sauce, and those were Pseudomonas aeruginosa, Pseudomonas fluorescens P-2, Pseudomonas fluorescens P-3 and Enterobacter aerogenes. The strongest degrading activity of non-volatile-amines was showed in Pseudomonas fluorescens P-3 among the four strains isolated. The optimum temperature for degradation by Pseudomonas fluorescens P-3 was $35^{\circ}C$, corresponding to the optimum temperature for growth of this strain, pH between 7.0 and 7.5 could gave effective degradation and the optimum concentration of NaCl was 0 and/or $1\%$.

• KSBB Journal
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• v.18 no.6
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• pp.479-484
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• 2003

34 strains were isolated from dyeing wastewater in order to improve treatment efficiency of dyeing wastewater containing PVA. Two strains of them were finally selected through the PVA degrading test, and identified as Microbacterium barkeri LCa and Paenibacillus amylolyticus LCb. As a result, optimal conditions for microbial growth and PVA degradation were 30$^{\circ}C$, neutral pH, starch as a carbon source, and peptone as a nitrogen source. And it was concluded that these two strains have good ability for PVA degradation. And 90% over PVA was degraded by single culture as well as a mixed culture of 2 different strains.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.11a
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• pp.432-435
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• 2006

전 세계적으로 방대하게 배출되는 도축 부산물인 우모는 높은 영양적 가치를 가짐에도 불구하고 현재 사용하는 물리화학적 처리법의 여러 단점으로 효율적으로 이용되지 못하고 있는 실정이다. 그 결과 2차 오염을 발생시키지 않는 경제적 방법인 생물학적 처리에 대한 연구의 필요성이 커지고 있다. 본 연구에서는 그러한 방법 중 대표적인 방법으로 미생물이 생산하는 keratinase를 이용한 생분해에 대해 연구를 하기 위해 경남 일대 퇴비화 볏짚에서 keratinolytic protease 생성능이 우수한 균주인 RS7을 분리하였고 생화학적 동정법과 16S rDNA를 이용한 동정결과 B. pumilus로 동정되었다. 본 실험에서 분리된 B. pumilus는 기존에 활발히 연구되어 있지 않는 균주로써 native feather 분해도가 기존에 알려진 Bacillus 속들이 3일 정도에서 분해 완료되는 것과는 달리 36시간 ${\sim}$48시간 내에 깃대까지 완전히 분해하였다. 또한 분리 균주의 경제적인 분해능을 토대로 분해산물이 식물 생장에 주는 영향과 아미노산 함유량을 검토한 결과 기존의 화학적 분해에 의한 분해산물보다 아미노산 함유량이 4배가량 많았으며 식물 생장에 있어서도 생장율과 개화시점으로 미루어볼 때 비료로써의 역할을 수행할 수 있었다.

• Korean Journal of Microbiology
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• v.46 no.2
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• pp.183-191
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• 2010

In this study, we isolated 179 bacterial strains using benzene, phenol, ethylbenzene, aniline, cumene, toluene as growth substrate from TCE contaminated soils and wastewaters. All the 179 strains were screened for TCE (30 mg/L) removal (growth substrate 0.2 g/L, $30^{\circ}C$, pH 7, cell biomass 1.0 g/L (w/v)) under aerobic condition for 21 days. EK2 strain using aniline showed the highest removal efficiency (74.4%) for TCE degradation. This strain was identified as Delftia acidovorans as the results of API kit, 16S rDNA sequence and fatty acid assay. In the batch culture, D. acidovorans EK2 showed the bio-degradation for TCE in the various TCE concentration (10 mg/L to 200 mg/L). However, D. acidovorans EK2 did not show the bio-degradation in the TCE 250 mg/L. D. acidovorans EK2 also show the removal efficiency (99.9%) for 12 days in the low concentration (1.0 mg/L). Optimal conditions to degrade TCE 200 mg/L were cell biomass 1.0 g/L (w/v), aniline 0.5 g/L, pH 7 and $30^{\circ}C$. Removal efficiency and removal rate by D. acidovorans EK2 strain was 71.0% and 94.7 nmol/h for 21 days under optimal conditions. Conclusion, we expect that D. acidovorans EK2 may contribute on the biological treatment in the contaminated soil or industrio us wastewater.

• Journal of Life Science
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• v.10 no.3
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• pp.300-306
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• 2000

Several bacterial strains utilizing crude oil as their sole carbon and energy source were isolated from polluted marine by crude oil. One of the strains, named KCL-2 showed strong degradation activity for crude oil. This strain was identified as a Klebsiella sp. based on the morphological, biochemical, and physiological characteristics. The optimum cultural conditions were as follows; $27^{\circ}C$~$37^{\circ}C$ for temperature and 7.0 for initial pH. Additionally, the optimal concentration of sodium chloride was 3.0%, confirming indicating that this strain was derived from sea water.The strain KCL-2 could use several kinds of n-alkane hydrocarbones from octadecane to octacosane as a sole carbon source. The emulsifying activity by KCL-2 was the highest after 3 days of cultivation under the condition of 3.0% sodium chloride, pH 7.0 and 32$^{\circ}C$. This strain had several criptic plasmids.