• Journal of Microbiology and Biotechnology
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• v.21 no.6
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• pp.545-555
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• 2011

The diversity elucidation by amplified ribosomal DNA restriction analysis and 16S rDNA sequencing of 96 associative diazotrophs, isolated from the feeder roots of tea on enriched nitrogen-free semisolid media, revealed the predominance of Gram-positive over Gram-negative bacteria within the Kangra valley in Himachal Pradesh, India. The Gram-positive bacteria observed belong to two taxonomic groupings; Firmicutes, including the genera Bacillus and Paenibacillus; and Actinobacteria, represented by the genus Microbacterium. The Gram-negative bacteria included ${\alpha}$-Proteobacteria genera Brevundimonas, Rhizobium, and Mesorhizobium; ${\gamma}$-Proteobacteria genera Pseudomonas and Stenotrophomonas; and ${\beta}$-Proteobacteria genera Azospira, Burkholderia, Delftia, Herbaspirillum and Ralstonia. The low level of similarity of two isolates, with the type strains Paenibacillus xinjiangensis and Mesorhizobium albiziae, suggests the possibility of raising species novum. The bacterial strains of different phylogenetic groups exhibited distinct carbon-source utilization patterns and fatty acid methyl ester profiles. The strains differed in their nitrogenase activities with relatively high activity seen in the Gramnegative strains exhibiting the highest similarity to Azospira oryzae, Delftia lacustris and Herbaspirillum huttiense.

• The Plant Pathology Journal
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• v.25 no.1
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• pp.62-69
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• 2009

In this study, we characterized the bacterial strain KJ2C12 in relation with its biocontrol activity against Phytophthora capsici on pepper, and identified this strain using morphological, physiological, biochemical, fatty acid methyl ester, and 16S rRNA gene sequence analyses. Strain KJ2C12 significantly (P=0.05) reduced both final disease severity and areas under the disease progress curves of 5-week-old pepper plants inoculated with P. capsici compared to buffer-treated controls. As for the production of antibiotics, biofilms, biosurfactant, extracellular enzyme, HCN, and swarming activity, strain KJ2C12 produced an extracellular enzyme with protease activity, but no other productions or swarming activity. However, Escherichia coli produced weak biofilm only. Strain KJ2C12 could colonize pepper roots more effectively in a gnotobiotic system using sterile quartz sand compared to E. coli over 4 weeks after treatments. However, no bacterial populations were detected in 10 mM $MgSO_4$ buffer-treated controls. Strain KJ2C12 produced significantly higher microbial activity than the $MgSO_4$-treated control or E. coli over 4 weeks after treatments. Bacterial strain KJ2C12 was identified as Bacillus luciferensis based on morphological, physiological, and biochemical characteristics as well as FAME and 16S rRNA gene sequence analyses. In addition, these results suggested that B. luciferensis strain KJ2C12 could reduce Phytophthora blight of pepper by protecting infection courts through enhanced effective root colonization with protease production and an increase of soil microbial activity.

• Journal of Microbiology and Biotechnology
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• v.24 no.8
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• pp.1123-1132
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• 2014

This study evaluated the growth and nutrient removal ability of an indigenous algal consortium on real untreated municipal wastewater in a high rate algal pond (HRAP). The HRAP was operated semicontinuously under different hydraulic retention times (HRT: 2, 4, 6, and 8 days). The average removal efficiencies of chemical oxygen demand, and total nitrogen and phosphate of real municipal wastewater were maintained at $85.44{\pm}5.10%$, $92.74{\pm}5.82%$, and $82.85{\pm}8.63%$, respectively, in 2 day HRT. Algae dominated the consortium and showed high settling efficiency (99%), and biomass and lipid productivity of $0.50{\pm}0.03g/l/day$ and $0.103{\pm}0.0083g/l/day$ (2day HRT), respectively. Fatty acid methyl ester analysis revealed a predominance of palmitate (C16:0), palmitoleate (C16:1), linoleate (C18:2), and linolenate (C18:3). Microalgal diversity analyses determined the presence of Chlorella, Scenedesmus, and Stigeoclonium as the dominant microalgae. The algal consortium provides significant value not only in terms of energy savings and nutrient removal but also because of its bioenergy potential as indicated by the lipid content (20-23%) and FAME profiling.

• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.303-309
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• 2012

Keratinases are of particular interest because of their action on insoluble keratins and generally on a broad range of protein substrates. Alkalophilic and neutrophilic actinomycete strains isolated from different soil samples, rich in keratinaceous substances were screened for keratinolytic activity. An alkalophilic isolate, TBG-S13A5, was found to possess good keratinolytic activity and was able to utilize feather as the sole carbon and nitrogen source. TBG-S13A5 exhibited an off-white aerial mass color with a rectus-flexibilis type of spore chain. The morphological, microscopical and biochemical characters were comparable with that of Streptomyces albidoflavus. Fatty acid methyl ester profiling (FAME) and 16S rDNA sequence analysis confirmed its identity as a strain of S. albidoflavus. Under submerged fermentation conditions, maximum protease production was recorded on the $5^{th}$ day of incubation at $30^{\circ}C$, using basal broth of pH 9.0 with 0.25% (w/v) white chicken feather. This strain could affect feather degradation when the initial pH was 8 and above and maximum protease production was recorded when the initial pH was around 10.5. The effectiveness of the crude enzyme in destaining and leather dehairing were also demonstrated.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.480-488
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• 2016

Soil microbes are widely well known to play an important role for sustainable agriculture in terms of crop healthy cultivation and environmental conservation. In this context, the distributional characteristics of soil microbes according to cropping systems were investigated under rice (R)-rice (R), rice (R)-barley (B)-rice (R), and soybean (S)-barley (B)-soybean (S) cropping condition to get basic informations for sustainable agriculture, where barley was grown for winter, in mid-mountainous loam paddy located at the altitude of 285 m above sea level in Sangju area from 2014 to 2015. Estimating from microbial communities by fatty acid methyl ester (FAME) method, a total biomass of bacteria, actinomycetes, and fungi in R-B-R plot was 37% and 40% higher than that in S-B-S and R-R plots, respectively (p < 0.05). In especial, bacteria and fungi were more in R-B-R plot than those in any other ones. B. japonicum, AMF, and mesophilic Bacillus sp. were also greater in S-B-S plot than those. In the community distribution, however, bacteria and actinomycetes showed comparatively high values in S-B-S plot relative to either R-R or R-B-R plot including rice, in which fungi outstanding. In the correlation between microbial biomass and soil properties changed by the cropping, bacteria was positively correlated with C:N ratio; actinomycetes with exchangeable Ca; fungi with available $P_2O_5$ (p < 0.05). While these microbes showed negative response to water stable aggregates of soil.

• Korean Chemical Engineering Research
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• v.53 no.2
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• pp.205-210
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• 2015

In this paper, microalgae lipid extractions were performed using conventional organic solvent and supercritical carbon dioxide (SC-$CO_2$) for biodiesel-convertible lipid fractions. The highest levels (58.31%) of fatty acid methyl ester (FAME) content in the lipid extracted by SC-$CO_2$ was obtained, and 18.0 wt.% crude lipid yield was achieved for Bligh-Dyer method. In the SC-$CO_2$ extraction, methanol as a co-solvent was applied to increase the polarity of extract. The experimental results indicated that crude lipid yield, FAME content and yield extracted by combination of SC-$CO_2$ with methanol were 12.5 wt.%, 56.32% and 7.04 wt.%, respectively, and this method could reduce the extraction time from 2 hour to 30 min when compared to SC-$CO_2$ extraction. Therefore, SC-$CO_2$ extraction is proven to be an environmentally-friendly and an effective method for lipid extraction from microalgae.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1164-1168
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• 2011

This study evaluated the soil microbial communities by fatty acid methyl ester (FAME) method in soils (6 sites for immatured paddy, 9 sites for normal paddy, and 5 sites for sandy paddy) in Gyeongnam Province. The soil microbial biomass carbon content in normal and sandy paddy were 1,235 and $441mg\;kg^{-1}$, respectively, showing the soil microbial biomass carbon content in normal paddy was higher than that in sandy paddy. The soil organic matter contents $33g\;kg^{-1}$ of immatured and normal paddy were higher than sandy paddy $18g\;kg^{-1}$ (p<0.05). The communities of total bacteria and Gram-negative bacteria in normal paddy were significantly higher than those in sandy paddy (p<0.05). Total bacteria communities should be considered as a potential responsible factor for the obvious microbial community differentiation.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.762-767
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• 2009

In this study, the feasibility of using vegetable oil extracted from tropical crop seed as a biodiesel feedstock was investigated by producing biodiesel and analysing the quality parameters as a transport fuel. In order to produce biodiesel efficiently, two step reaction process(pre-treatment and transesterificaion) was required because the tropical crop oil have a high content of free fatty acids. To determine the suitable acid catalyst for the pre-esterification, three kinds of acid catalysts were tested and sulfuric acid was identified as the best catalyst. After constructing the experimental matrix based on RSM and analysing the statistical data, the optimal pre-treatment conditions were determined to be 26.7% of methanol and 0.982% of sulfuric acid. Trans-esterification experiments of the pre-esterified oil based on RSM were carried out, then discovered 1.24% of KOH catalyst and 22.76% of methanol as the optimal trans-esterification conditions. However, the quantity of KOH was higher than the previously established KOH concentration of our team. So, we carried out supplemental experiment to determine the quantity of catalyst and methanol. As a result, the optimal transesterification conditions were determined to be 0.8% of KOH and 16.13% of methanol. After trans-esterification of tropical crop oil, the produced biodiesel could meet the major quality standard specifications; 100.8% of FAME, 0.45 mgKOH/g of acid value, 0.00% of water, 0.04% of total glycerol, $4.041mm^2/s$ of kinematic viscosity(at $40^{\circ}C$).

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.485-491
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• 2011

The present study evaluated the soil microbial communities by fatty acid methyl ester (FAME) in upland soils at 25 sites in Gyeongnam Province. The total bacteria content was $143nmol\;g^{-1}$ for in inclined piedmont, $75nmol\;g^{-1}$ for fan and valley, $49nmol\;g^{-1}$ for hill areas, and $44nmol\;g^{-1}$ for riversider plain. The fungi content was 2.4 times higher in sandy loam than $21nmol\;g^{-1}$ in silt loam (p<0.01). In addition, inclined piedmont soils had a significantly higher ratio of monounsaturated fatty acids to saturated fatty acids compared with fan and valley soils (p<0.05). The communities of total bacteria and arbuscular mycorrhizal fungi in the inclined piedmont soils were significantly higher than those in the fan and valley soils and in the riversider plain soils (p<0.05), whereas the community of fungi was significantly lower (p<0.05). In principal component analyses of soil microbial communities, our findings showed that inclined piedmont was positive relationship with total bacteria and actinomycetes in upland soils.