• KSBB Journal
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• v.31 no.3
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• pp.158-164
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• 2016

Plant growth promoting (PGP) hormones, which are produced in a small quantity by bacteria, affect in plant growth and development. PGPs play an important role on the crop productivity in agricultural field. In this study, a photosynthetic bacterial strain producing the PGP was isolated from paddy soil. Bacterial isolate was gram negative, rod-shaped and motility positive. From the 16s rRNA gene sequence analysis, the isolate was identified as Rhodobacter capsulatus PS-2. The mass cultivation of R. capsulatus PS-2 was optimized by considering of the carbon, nitrogen and inorganic salt sources. Optimal medium composition was determined as Na-succinate 4.5 g, yeast extract 5 g, $K_2HPO_4$ 1 g, $MgSO_4$ 5 g, per liter. From the result of 500 L fermentation for 2 days using the optimal medium, the viable cells were $8.7{\times}10^9cfu/mL$. R. capsulatus PS-2 strain produced the carotenoid and indole-3-acetic acid (IAA). The carotenoid extraction and quantitative analysis were performed by HCl-assisting method. Total carotenoid contents from R. capsulatus PS-2 culture broth were measured as $7.02{\pm}0.04$ and $6.93{\pm}0.05mg/L$ under photoheterotrophic and chemoheterotrophic conditions, respectively. To measure the productivity of IAA, colorimetric method was employed using Salkowski reagent at optical density 535 nm. The results showed that the highest content of IAA was $197.44{\pm}5.92mg/L$ in the optimal medium supplemented with 0.3% tryptophan.

• Applied Biological Chemistry
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• v.49 no.2
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• pp.158-162
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• 2006

To determine freshness and quality change of tofu during storage, we manufactured a freshness indicator and monitored the surface pH, volatile basic nitrogen (VBN), thiobarbituric acid reacted substance (TBARS), total bacterial counts, and sensory evaluation. Tofu had a change in color of the freshness indicator after storage of 8 days at $4^{\circ}C$, and its pH and total bacterial counts reached 5.6 and 7.63 log CFU/g, respectively. VBN and TBARS values increased and reached the decay point at the time of color change of the freshness indicator. Sensory evaluation also indicated that samples were unacceptable by off-odor and decrease of firmness at day 8 of storage. These results suggest that a freshness indicator should be useful in determining expiration date of tofu products during marketing by indicating the microbial safety as well as sensory change.

• Food Science of Animal Resources
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• v.23 no.4
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• pp.285-291
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• 2003

The effects of carcass grade(B and E) and containing mugwort powder(0.3％) on the pH, volatile basic nitrogen(VBN), thiobarbituric acid reactive substances(TBARS), bacterial count and residual nitrite of the pork sausage were investigated during storage at 4$^{\circ}C$${\pm}$1 for 8 weeks. The pH value and VBN content of sausage containing mugwort powder were not significant different(p＞0.05) depending on the carcass grade as compared to sausage free of mugwort powder. The TBARS values of sausage containing mugwort powder were significantly lower than those of sausage free of mugwort powder up to 8 weeks of the chilling process. The sausage containing mugwort powder showed to have lower bacterial counts and residual nitrite contents than those free of mugwort powder depending on the carcass grade. However, those of sausage were not affected by the carcass grade.

• Food Science and Preservation
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• v.10 no.3
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• pp.411-416
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• 2003

An effort was attempted to utilize an under-utilized protein source, rice bran protein, in coating or wrapping food material for the purpose of protection them from oxidation and bacterial infection. However, the utilization of rice bran protein as a food coating material is limited because the rice bran protein coating material itself can be spoiled by a bacterial infection. Therefore, this study was conducted to produce the economical and antibacterial rice bran protein film by utilizing rice bran and bacteriocin-producing microorganism. Bacteriocin produced by Pseudomonas putida 21025 was partially purified after 33h of shaking incubation at 30$^{\circ}C$. The amount of amino-type nitrogen did not increase in the rice bran protein film containing the bacteriocin any more after gradual increase upto the content of 0.22％ for 8 days, while that without the bacteriocin increased continuously, implying that application of the bacteriocin to the rice bran had positive effects on prolonging the shelf-life of not only film itself but also the foods wrapped by this film.

• Mycobiology
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• v.47 no.2
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• pp.180-190
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• 2019

In this study, eight-month-old ectomycorrhizae of Tuber borchii with Corylus avellana were synthesized to explore the influence of T. borchii colonization on the soil properties and the microbial communities associated with C. avellana during the early symbiotic stage. The results showed that the bacterial richness and diversity in the ectomycorrhizae were significantly higher than those in the control roots, whereas the fungal diversity was not changed in response to T. borchii colonization. Tuber was the dominant taxon (82.97%) in ectomycorrhizae. Some pathogenic fungi, including Ilyonectria and Podospora, and other competitive mycorrhizal fungi, such as Hymenochaete, had significantly lower abundance in the T. borchii inoculation treatment. It was found that the ectomycorrhizae of C. avellana contained some more abundant bacterial genera (e.g., Rhizobium, Pedomicrobium, Ilumatobacter, Streptomyces, and Geobacillus) and fungal genera (e.g., Trechispora and Humicola) than the control roots. The properties of rhizosphere soils were also changed by T. borchii colonization, like available nitrogen, available phosphorus and exchangeable magnesium, which indicated a feedback effect of mycorrhizal synthesis on soil properties. Overall, this work highlighted the interactions between the symbionts and the microbes present in the host, which shed light on our understanding of the ecological functions of T. borchii and facilitate its commercial cultivation.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.788-794
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• 2009

Both strains of KD-1212 and DAH-1056 were isolated and identified from animal manure-contaminated soil by screening bacterial strains for the removal of sulfur compound-malodor with such substrate as sodium thiosulfate or free sulfur. Then the characteristics on the incubation of these microbes were observed under various incubating-condition such as pH, temperature, aerobic or anaerobic, substrate(sulfur compound) concentration, nitrogen and carbon source and rotating speed for mixing, and the optimum incubating condition was established. The optimum pHs of KD-1212 and DAH-1056 were 7.0 and 4.0, respectively, and their optimum temperatures were in the range of $30{\sim}35^{\circ}C$. Another autotrophic strain, ED-1138, was isolated from contaminated soil. The strain DAH-1056 excelled a strain Thiobacillus sp. IW in eliminating hydrogen sulfide during the process of malodor-biofiltration with a fixed strain. The characteristics on the incubation of strain KD-1212 were observed under various substrate-concentrations, nitrogen and carbon sources. KD-1212 favored glucose and maltose, and yeast extract as carbon sources and nitrogen source, respectively. The optimum concentrations of substrate and nitrogen source were 25 mM of sodium thiosulfate and 0.5% yeast extract, respectively for the growth of strain KD-1212.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1341-1349
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• 2000

The addition of 5% NaCI to standard plate count (SPC) and bromcresol purple (BCP) agar showed the highest viable cell counts for Jeot-kal samples. The use of 15% glycerol as cryoprotectant showed the highest microbial survival rate at both temperatures, $-20^{\circ}C$ and $-170^{\circ}C$, and on both colony count media, SPC and BCP. During the aging, the pH of Bajirak Jogae-Jeot (fermented clam) decreased from 6.8 to 5.0. Crude protein content was 10% for Bajirak Jogae-Jeot and $6{\sim}7%$ for Myeolchi-Jeot (fermented anchovy). Microbial population of Bajirak Jogae-Jeot was $10^9\;CFU/g$ after 4 weeks of aging, but was only $10^{3-5}\;CFU/g$ in the case of Myeolchi-Jeot. The proportion of Gram positive and catalase negative bacteria in Bajirak Jogae-Jeot increased drastically during the 4 weeks of aging, which showed typical lactic bacterial fermentation. After 2 years' storage of Jeot-kal in liquid nitrogen tank, the cell counts of total aerobic or lactic bacteria were decreased, resulting in about 10% survival rate. Microbial floral change of Jeot-kal was also investigated. In the case of Bajirak Jogae-jeot, the ratio of rod to cocci and that of Gram negative to positive increased after liquid nitrogen storage. But, rod to cocci ratio of Myeolchi-jeot decreased after liquid nitrogen storage. The ratio of yeasts decreased in both cases after storage.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.9
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• pp.1248-1254
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• 2012

The effect of silage additives on ensiling characteristics and nutritive value of Napier grass (Pennisetum purpureum) silages was studied. Napier grass silages were made with no additive, fermented juice of epiphytic lactic acid bacteria (FJLB), molasses or cassava meal. The ensiling characteristics were determined by ensiling Napier grass silages in airtight plastic pouches for 2, 4, 7, 14, 21 and 45 d. The effect of Napier grass silages treated with these additives on voluntary feed intake, digestibility, rumen fermentation and microbial rumen fermentation was determined in 4 fistulated cows using $4{\times}4$ Latin square design. The pH value of the treated silages rapidly decreased, and reached to the lowest value within 7 d of the start of fermentation, as compared to the control. Lactic acid content of silages treated with FJLB was stable at 14 d of fermentation and constant until 45 d of ensiling. At 45 d of ensiling, neutral detergent fiber (NDF) and acid detergent fiber (ADF) of silage treated with cassava meal were significantly lower (p<0.05) than the others. In the feeding trial, the intake of silage increased (p<0.05) in the cow fed with the treated silage. Among the treatments, dry matter intake was the lowest in the silage treated with cassava meal. The organic matter, crude protein and NDF digestibility of the silage treated with molasses was higher than the silage without additive and the silage treated with FJLB. The rumen parameters: ruminal pH, ammonia-nitrogen ($NH_3$-N), volatile fatty acid (VFA), blood urea nitrogen (BUN) and bacterial populations were not significantly different among the treatments. In conclusion, these studies confirmed that the applying of molasses improved fermentative quality, feed intake and digestibility of Napier grass.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.6
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• pp.810-817
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• 2011

A feeding trial was conducted to study the effect of tannin rich Pakar (Ficus infectoria) leaves on microbial profile, rumen fermentation and nutrient utilization in goats. Eight goats divided in two groups were fed pakar leaves (experimental group) and green oats (control group) as sole roughage source along with a fixed quantity of concentrate mixture for a period of 3 months. Two metabolic trials of six days duration were conducted after 30 and 90 days of experimental feeding. The dry matter intake was significantly higher (p<0.05) and digestibility's of DM, OM, CP, EE, NDF and ADF were reduced in experimental as compared with the control group. The TDN intake was similar (236.52 vs. 240.39 g/d) in both the groups. All the animals were in positive nitrogen balance. The concentration of ammonia nitrogen, TVFA, lactic acid and activities of xylanase and protease were reduced in pakar leaves fed goats. The rumen microbial profile as obtained by MPN technique showed no change in total bacterial population but total fungi and cellulolytic bacteria were reduced (p<0.05), whereas, tannin degrading/tolerant bacteria increased with the feeding of pakar leaves. Real time PCR data revealed a decrease in Ruminococcus flavefaciens, an increase in methanogens and no change in the Fibrobacter succinogenes population by feeding of pakar leaves.

• Journal of Korean Society on Water Environment
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• v.36 no.3
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• pp.220-228
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• 2020

Anaerobic ammonium oxidation (AMX) is a cost-efficient biological nitrogen removal process. The coexistence of ammonia-oxidizing bacteria (AOB) in an AMX reactor is an interesting research topic as a nitrogen-related bacterial consortium. In this study, a sequencing batch reactor for AMX (AMX-SBR) was operated with a conventional activated sludge. The AOB in an AMX bioreactor were identified and quantified using terminal restriction fragment length polymorphism (T-RFLP) and real-time qPCR. A T-RFLP assay based on the ammonia monooxygenase subunit A (amoA) gene sequences showed the presence of Nitrosomonas europaea-like AOB in the AMX-SBR. A phylogenetic tree based on the sequenced amoA gene showed that AOB were affiliated with the Nitrosomonas europaea/mobilis cluster. Throughout the enrichment period, the AOB population was stable with predominant Nitrosomonas europaea-like AOB. Two OTUs of amoA_SBR_JJY_20 (FJ577843) and amoA_SBR_JJY_9 (FJ577849) are similar to the clones from AMX-related environments. Real-time qPCR was used to quantify AOB populations over time. Interestingly, the exponential growth of AOB populations was observed during the substrate inhibition of the AMX bacteria. The specific growth rate of AOB under anaerobic conditions was only 0.111 d^-1. The growth property of Nitrosomonas europaea-like AOB may provide fundamental information about the metabolic relationship between the AMX bacteria and AOB.