A species of facultative photo-organotrophic, purple, non-sulfur bacterium was isolated from the 47 point at west and south coast of Korea in September 2001. Separated 13 samples of changes with red color under 28～32 ℃, 3000 lux, anaerobe conditions for 7 days cultivated in basal medium. For pure isolation from 13 samples, we used agar-shake tube method (0.4 % agar) and separated 5 strains through 13-repetition test. EGH-24 and EGH-30 was identified as the same strain through the RAPD(Random Amplified Polymorphic DNA)-PCR of strain EGH-9, EGH-13, EGH-23, EGH-24, EGH-30. Four isolates cultivated in synthesis wastewater for wastewater biodegradation test. EGH-24 was selected with efficient wastwater treating strain. Based on the results obtained from morphology, nutrient requirements, major bacteriochlorophyll content, 16S-rDNA phylogenetic analysis, EGH-24 strain may be identified as a new strain of the genus Rhodobacter and named Rhodobacter sp. EGH-24.

The isolated strain, Rhodococcus sp. EL-GT was able to degrade high phenol concentrations up to 10 mM within 24 hours in the medium consisting of 5.3 mM KH2PO4, 95 mM Na2HPO4, 18mM NH4NO3, 1mM MgSO4·7H2O, 50μM CaCl2, 0.5μM FeCl3, initial pH8.0, temperature 30℃ in rotary shaker at 200rpm. This strain was good cell growth and phenol degradation in the alkaline pH range range, and the highest in the pH range of 7 to 9. The microorganism was able to grow at the various chlorinated phenols, benzene, toluene, and bunker-C oil. As Rhodococcus sp. EL-GT was good capable of attachment on the acryl media, it would be used as microorganism to consist of biofilm in wastewater treatment.

The research was performed to compare to the biofilm characteristics and phenol removal efficiency in RBCs(Rotating Biological Contactor) using Rhodococcus sp. EL-GT(single population) and activated sludge(mixed population) as inoculum. Both reactors showed similar tendency on variations of dry weight, thickness and dry density of biofilm. However, the growth of biofilm thickness in 3 and 4 stage of single population reactor has sustained longer than that of the mixed population reactor. Unlike the mixed population reactor, the dry density of biofilm in the single population reactor had a difference between 1, 2 stage and 3, 4 stage. The single population reactor was stably operated without the decrease of phenol removal efficiency in the range of pH 6～9 and 15mM phenol was completely degraded in these pH ranges. But in case of the mixed population reactor, the phenol degradability was dramatically decreased at over 5mM phenol concentration because of the overgrowth and detachment of its biofilm.

An antimicrobial substance-producing microorganism was isolated from soil samples. Based of the taxonomic characteristics of its morphological, cultural, physiological properties and 16s rRNA sequence alignment, this microorganism was identified as Pseudomonas aeruginosa, and we named Pseudomonas aeruginosa EL-KM. The optimal culture condition for production of antimicrobial substance was 1% mannitol, 0.4% yeast extract, 0.5% Nacl, 0.2% K₂SO₄, 100μM MgSO₄.7H2O, 10μM CaCl2.$2H_2O$, 1μM $FeSO_4$.7H2O, 1μM MnSO4.$4-5H_2O$, initial pH 7 and 200 rpm at 30℃. The purification of the antimicrbial substance was performed by silica gel column chromatographys, and fraction with TLC $R_f$ 0.77 value represented good antimicrobial activity. The crude antimicrbial substance was stable within a pH range of 3-10 and temperature range of 4°C-121°C autoclaving. This crude antibacterial substance acted as bacteriolytic agent against Vibrio cholerae non-Ol ATCC 25872, and also exhibited excellent properties, when the substance was demonstrated against many other gram-positive, gram-negative bacteria, yeast and fungi.

The bacterial strain JE-1 degrading and utilizing Congo Red as a sole carbon source was isolated from dye-contaminated soil and identified as Enterobacter species. Enterobacter sp. JE-1 had the highest decolorization ability when it was cultured in the medium containing 0.05% NH_4NO_3, 0.05% K_2HPO_4 0.03% MgSO_4·7H_2O, 0.025% Congo Red, initial pH 7.0 at 30℃, respectively. Enterobacter sp. JE-1 had the relatively high substrate specificity. The dye decolorizing activity was exclusively extracellular. The expected metabolic intermediates of Congo Red by Enterobacter sp. JE-1 were analyzed by GC/MS. As a result, metabolic products like hexadecanoic acid, 1,2,3-triphenylcyclopropene, aliphatic hydrocarbons such as hexadecane, heptadecane, octadecane, hexacosane etc., and 1,2-benzenedicarboxylic acid, dibutyl ester were detected. Benzidine did not detected.

Microorganisms capable of degrading trichloroethylene(TCE) using phenol as a induction substrate were isolated from industrial effluents and soil. The strain MS-64K which had the highest biodegradability was identified as the genus Micrococcus. The optimal conditions of medium for the growth and biodegradation of trichloroethylene were observed as follows; the initial pH 7.0, trichloroethylene 1,000ppm as the carbon source, 0.2% (NH_4)_2SO_4 as the nitrogen source, respectively. Lag period and degradation time on optimal medium were shorter than those on isolation medium. Growth on the optimal medium was increased. Addition of 0.1% Triton X-100 increased the growth rate of Micrococcus sp. MS-64K, but degradation was equal to optimal medium. Trichloroethylene degradation by Micrococcus sp. MS-64K was shown to fit logarithmic model when the compound was added at initial concentration of 1,000ppm.

Microorganisms producing bioemulsifier were isolated from the sea water in Pusan coastal area. The isolated strain which had the highest emulsification activity and stability was identified as the genus Acinetobacter from the results of morphological, cultural and biochemical tests and named Acinetobacter sp. EL-C6 for convenience. The compositions of optimum medium for emulsification of crude oil by Actnetobacter sp. EL-C6 were crude oil 2.0%, NH_4NO_3 0.2%, K_2HPO_4 0.01%, MgSO_4·7H_2O 1.0%, CaCl_2·2H_2O 0.1% and NaCl 3.0% at initial pH 7.5 and 30℃, respectively. The cultivation for emulsification of crude oil was carried out in 500㎖ shaking flask containing 100㎖ of the optimum medium at 30℃. The highest emulsification was observed after 5 days. The utilization on the various hydrocarbon of the Acinetobacter sp. EL-C6 showed that utilization of n-alkane compounds were better than that of aromatic compounds. Among the petroleum compounds, crude oil was best utilized by the Actnetobacter sp. EL-C6.

The biodegradable characteristics of poly-β-hydroxybutyrate(PHB) film by fungi and soil burial are investigated. As the results of the American Standards for Testing and Materials(ASTM) method, the growth of Aspergillus niger was apparent on the PHB containing plate. This suggests that PHB was utilized as the sole carbon source by Aspergillus niger and ASTM method may have applications as measuring means of biodegradability of polyhydroxyalkanoic acid(PHA). PHB film was studied by monitoring the time-dependant changes in weight loss of PHB film under 30℃ and relative humidity 80 % during pot-test. As the results of pot-test, PHB film was decomposed about 87 % in 30 days by soil microorganisms. PHB film was more slowly degraded than PHB/HV film.

The bacterial strains, which utilizes 2,4,4`-trichloro-2`-hydroxydiphenyl ether(TCHDPE) as a sole carbon source, were isolated by selective enrichment culture from soil samples of industrial waste deposits. The bacterium that showed the highest biodegradation activity was designated as EL-047R. The isolated strain EL-047R was identified as the genus Pseudomonas from the results of morphological, cultural, and biochemical tests. The optimum conditions of medium for the growth and the degradation of TCHDPE were TCHDPE 500 ppm, (NH_4)_2SO_4 0.1% as the nitrogen source, initial pH 7.0±0.1, and 37℃, respectively. In this conditions, the degradation rate of TCHDPE was about 97%. Pseudomonas sp. EL-047R was tested for resistance to several metal compounds and antibiotics. Pseudomonas sp. EL-047R was moderately grown to Cd(NO_3)_2, ZnCl_2, AgSO_4, CuSO_4 and HgCl_2. This strain was sensitive to rifampicin and kanamycin but resistant to ampicillin, penicillin, tetracyclin and chloramphenicol. Pseudomonas sp. EL-047R was grown structurally related compounds and potential metabolites of TCHDPE, and has the stability on TCHDPE biodegradation.

In order to find the most fitted biodegradation model, biodegradation kinetics model to the initial phenol and p-cresol concentrations were investigated and had been fitted by the linear regression. Bacteria capable of degrading p-cresol were isolated from soil by enrichment culture technique. Among them, strain M1 capable of degrading p-cresol has also degraded phenol and was identified as the genus Micrococcus from the results from of taxonomical studies. The optimal conditions for the biodegradation of phenol and pcresol by Micrococcus sp. M1 were NH_4NO_3 0.05%, pH 7.0, 30℃, respectively, and medium volume 100㎖/250㎖ shaking flask. Micrococcus sp. M1 was able to grow on phenol concentration up to 14mM and p-cresol concentration up to 8mM. With increasing substrate concentration, the lag period increased, but the maximum specific growth rates decreased. The yield coefficient decreased with increasing substrate concentration. The biodegradation kinetics of phenol and p-cresol were best described by Monod with growth model for every experimented concentration. In cultivation of mixed substrate, p-cresol was degraded first and phenol was second. This result implies that p-cresol and phenol was not degraded simultaneously.