본 논문에서는 CAD 시스템에서 사용하는 NURBS 기저함수를 사용하는 아이소-지오메트릭 해석(Isogeometric analysis) 방법과 기 하학적으로 엄밀한 빔 모델링(geometrically exact beam model)을 활용하여 회전과 병진 운동이 결합된 새로운 형태의 메타물질 (metamaterial)에 대한 해석을 진행하였다. 이차원 셀 구조는 자유형상변환(Free-form deformation) 법과 적절한 내삽법(Interpolation) 을 통해 원통 위에 입혀졌다. 원통의 치수와 셀 개수가 비틀림 각도에 미치는 영향이 매개변수 연구(parametric study)를 통해 확인되었 다. 비틀림과 병진 운동이 결합된 구조의 메커니즘에 대해 수치 예제를 통해 알아보았다.

A diverse group of plant-growth promoting bacteria were isolated in button mushroom (Agaricus bisporus) media to investigate the plant-growth promoting traits of compounds including indole acetic acid (IAA), ammonia, 1-aminocyclopropane-1- carboxylic acid deaminase, siderophore, and hydrogen cyanide. Twenty-one bacterial strains showing positive effects for all the test traits were selected and classified to confirm bacterial diversity in the media habitat. Plant-growth promoting traits of the isolates were also assessed. All strains produced IAA ranging from 20 μg/mL to 250 μg/mL. Most of the isolates produced more than 80% siderophore. Four strains (Pantoea sp., PSB-08, Bacillus sp., PSB-13, Pseudomonas sp., PSB-17, and Enterobacter sp., PSB-21) showed outstanding performances for all the tested traits. In a bioassay of these four strains using mung bean plant, the best growth performances (23.16 cm, 22.98 cm, 2.27 g/plant, and 1.83 g/plant for shoot length, root length, shoot dry weight, and root dry weight, respectively) were obtained from the plants co-inoculated with Bacillus sp., PSB-13. The resultant data indicate that button mushroom media have got a diverse group of bacteria with plant growth promoting abilities. Thus, the media could be a good recycling resource for using to an effective bio-fertilizer.

양송이배지로부터 분리한 인산가용화균 Burkholderia contaminans PSB-A와 Burkholderia ambifaria PSB-B의 단일접종 및 동시접종에 따른 인산가용화 능력의 시너지 효과 및 상추생육효과를 조사하였다. 인산캄슘이 함유된 NBRIP 액체배지에 분리균을 접종하고 해리된 가용인산 (soluble phosphorus)함량을 HPLC에 의해 분석하여 인산 가용화능을 측정한 결과, 배양 3일차에 동시접종구 166.3 μg mL -1 , B. contaminans 143.7 μg mL -1 , B. ambifaria 127.1 μg mL -1의 순으로 나타나 두 종의 인산가용화세균 간의 동시접종에 의한 시너지효과가 다소 관찰되었다. 배지 내 pH 와 잔류 glucose 함량 변화도 모든 접종구에서 배양 1 - 3일 후 pH 7.0에서 pH 4.0 수준으로 감소하였으며, glucose 함량은 초기 10 mg mL -1 에서 4.3 mg mL -1 수준으로 검출되어 인산가용화능과 거의 유사한 경향을 보였다. 배양여액의 유기산 분석결과 gluconic acid 약 12.3 mg mL -1 와 malic acid 약 7.9 mg mL -1 수준으로 가장 높게 검출되었으며, 결과적으로 두 세균이 분비하는 유기산이 배지의 pH를 감소시키고, 인산 가용화를 유도하는 주요 원인임을 확인할 수 있었다. 접종 4주 후 상추 생육차이를 조사한 결과, TCP를 첨가하지 않은 B. contaminans 접종구, B. ambifaria 접종구와 동시 접종구 에 비해 TCA 첨가한 모든 처리구에서 약 7-9% 수준의 생육증진효과가 보였으나, 단일접종과 동시접종구간에 유의수준의 차이를 확인할 수 없었다.

본 연구는 까마귀쪽나무 열매 추출물이 대식세포인 RAW264.7세포에서의 면역증가 효능과 조골세포인 MC3T3- E1 세포에서 뼈건강 효능에 미치는 효과를 확인하고자 하였다. 면역증가 효능을 알아보기 위해서 까마귀쪽나무열매 열수추출물(LJF-W)과 70% 에탄올추출물(LJF-70E)을 저농도(10 μg/mL), 중농도(100 μg/mL) 및 고농도(1,000 μg/ mL)로 각각 사용하였고, 양성대조군으로는 홍삼 진세노사이드(Rg1+Rb1+Rg3 5.5 mg/g)를 이용하여 실험을 진행하였다. 실험 결과 열수추출물(LJF-W)과 70%에탄올추출물(LJF- 70E) 처리군에서 NO 생성량이 무처리구 그룹에 비하여 통계적으로 유의하게 증가하였다. 염증성 cytokine인 TNF- α, IL-6, IL-1β의 생성량은 열수추출물(LJF-W)에서 무처리 구에 비해 통계적으로 유의하게 증가하였으나, 70% 에탄올추출물(LJF-70E)에서는 차이가 없음을 관찰할 수 있었다. 또한 뼈건강 효능을 확인하기 위해서 까마귀쪽나무열 매추출물에 의한 조골세포인 MC3T3-E1세포의 세포증식능을 확인한 결과, 열수추출물과 70%에탄올추출물 처리 군에서 조골세포 증식능이 무처리구에 비하여 통계적으로 유의하게 증가하였다. 이 결과를 통해 까마귀쪽나무열매 열수추출물(LJF-W)이 면역증가와 뼈건강에 대한 효능성분으로 가능성이 있음을 확인하였다.

양송이배지로부터 분리한 인산가용화균 Paraburkholderia phenazinium YH3와 Paraburkholderia metrosideri YH4의 단일접종 및 동시접종에 따른 인산가용화 능력의 시너지효과 및 상추생육효과를 조사하였다. 인산캄슘이 함유된 NBRIP 액체배지에 분리균을 접종하고 해리된 가용인산 (soluble phosphorus)함량을 HPLC에 의해 분석하여 인산가용 화능을 측정한 결과, 배양 3일차에 동시접종구 1250 μg mL -1 , P. metrosideri 1196.59 μg mL -1 , P. phenazinium 994.34 μg mL -1 의 순으로 나타나 두 종의 인산가용화 박테리아간의 동시 접종에 의한 시너지효과가 관찰되었다. 배지 내 pH 와 잔류 glucose 함량 변화도 모든 접종구에서 배양 1일 후 대부분의 변화가 이루어져 pH의 경우 초기 pH 7.0에서 pH 4.0 수준으로 감소하였으며, 잔류 glucose 함량은 초기 10 mg mL -1 에서 4.8 mg mL -1 수준으로 검출되어 인산가용 화능과 거의 유사한 경향을 보였다. 배양여액의 유기산 분석결과 gluconic acid 약 11 mg mL -1 와 malic acid 약 4 mg mL -1 수준으로 가장 높게 검출되었으며, Park etal(2016)에 의해 보고된 oxalic acid는 검출되지 않았다. 대부분의 유기산이 배양 1일과 3일 후 생성되는 결과를 보임으로서 유기산이 배지의 pH를 감소시키고 인산 가용화를 유도하는 주요 원인임을 확인할 수 있었다. 접종 4주 후 상추 생육차이를 조사한 결과, TCP를 첨가하지 않은 P. phenazinium 접종구, P. metrosideri 접종구와 동시 접종구에 비해 TCA 첨가한 모든 처리구에서 10 -20% 수준의 생육증진효과가 확인되었으나 단일접종과 동시접종 구간에 유의수준의 차이를 확인할 수 없었다. 결과적으로 인(P) 결핍 토양 및 염류토양에 인산가용화균을 사용하면 식물과 작물 수확량에 의한 P 섭취가 동시에 증가하고 생육이 촉진된다는 다른 연구결과(Rodríguez et al, 1999; Suh et al, 2008; Walpola and Yoon. 2013)와 유사한 경향을 보였다.

An auxin-producing bacterium Yangsong-1 was isolated from a button mushroom bed in Chung cheongnam-do. The strain Yangsong-1 was classified as a novel strain of Arthrobacter enclensis based on a chemotaxonomic and phylogenetic analysis. The isolated A. enclensis Yangsong-1 was confirmed to produce indole-3-acetic acid (IAA), which is one of the auxin hormones. When the concentration of IAA was assessed by HPLC quantity analysis, the maximum concentration of IAA, 152.903 mg L-1, was detected from the culture broth incubated in R2A medium containing 0.2% L-tryptophan for 48 h at 35oC. A negative relationship between IAA production and pH was estimated to show that the increase in IAA caused pH acidification of the culture. The effect of the supplement on L-tryptophan, a known precursor of IAA production, appeared to be at maximal production at 0.2% concentration and was rather reduced at concentration above 0.4%. To investigate the growth-promoting effects on the crops, the culture broth of A. enclensis Yangsong-1 was placed in water cultures and seed pots of mung beans and lettuce. In consequence, the adventitious root induction and root growth of mung beans and lettuce were 1.5 and 1.9 times higher, respectively, than those of the control.

충청남도 부여군 석성면 양송이 재배 농가에서 양송이 수확 후 배지로부터 토양을 채취하여 auxin(IAA) 생성능이 뛰어난 세균 Jopap-1 균주를 분리하였다. TLC 및 HPLC 분석을 통해 분리균이 생성한 IAA 농도를 확인한 결과, 0.1% L-tryptophan를 함유한 pH 7.0의 R2A broth 배지에 35℃, 48시간 배양 시 최대 생성농도는 96.05 mg L−1이었다. 생리적 특성 및 계통학적특성 분석을 통해 분리균은 Gram 음성 간균인 Klebsiella michiganensis Jopap-1로 동정되었다. 배양조건별 IAA의 생산능 비교 시, IAA 농도의 증가가 배양액의 pH 산성화에 기인함으로서 IAA 생성량과 pH 변화에는 부의 상관성이 있는 것으로 관측되었다. IAA 생성을 위한 전구물질로 알려진 L-tryptophan의 첨가효과는 0.1% 첨가 시 균의 생육 및 IAA 생성량이 최대이었으며, 0.2% 이상 고농도 첨가 배지에서는 오히려 IAA의 생성이 저해되었다. 또한 분리균에 의한 식물 생육 촉진 효과를 조사하기 위하여 수경재배 및 pot 재배를 통한 녹두발근 생검법과 상추발근 생검법을 수행한 결과, K. michiganensis Jopap-1의 배양액 접종 시 녹두발근 생검법에서는 대조구에 비해 발근수와 뿌리길이에서 약 2.1배의 뿌리 신장 효과를 보였고, 상추발근 생검법에서는 대조구에 비해 뿌리길이와 무게에서 약 1.8배의 뿌리신장효과를 보였다.

양송이 수확후 배지에서 분리한 Pantoea rodasill LH-1와 Burkholderia stabilis HS-7간의 단일 접종 및 동시접종에 따른 인산가용화능과 상추생육효과를 조사하였다. NBRIP액체 배지에 분리균을 접종하고 배지에 함유된 인산칼슘으로부터 해리된 가용인산(soluble phosphorus)함량을 측정한 결과, P. rodasill LH-1는 736.59 μg mL-1, B. stabilis HS-7은 743.90 μg mL-1, 그리고 B. stabilis HS-7와 P. rodasill LH-1을 동시 접종한 배지는 783.41 μg mL-1로 가장 높았지만 유의수준의시너지 효과는 나타나지 않았다. 배지 내pH는 초기 pH 7.0에서 배양 3일 후 모든 접종구에서 pH 4.3수준으로 감소하였으며, 또한 배지 내잔류 당 감소율은 P. rodasill LH-1 31.7%, B. stabilis HS-7은 53.7%, 동시 접종한 배지에서는 87.1%로 가장 높은 감소율을 나타냈다. 분리균에 의해 생성한 배지 내유기산을 분석한 결과, gluconic acid, lactic acid, malic acid, acetic acid, citric acid 이 검출되었으며, 이 중 citric acid가 주요 유기산으로 동시 접종한 배지에서 0.96 mg mL-1로 가장 높은 함량을 나타내었다. 상추 재배 실험결과 동시 접종구가 대조구에 비해 잎의 길이는 7.7%, 뿌리길이는 15.5% 생육증진효과를 보였다. 이 결과들을 바탕으로 B. stabilis HS-7 와 Pantoea rodasill LH-1이 동시 접종에 의해 유의수준의 인산가용화 시너지 효과는 관찰되지 않았지만, 무 접종구에 비하여 배지 내 인산가용화능과 작물의 생장이 크게 촉진되는 결과를 보임으로서 인산가용화균을 이용한 미생물 비료의 공급으로 염류집적토양의 인산가용화능과 작물의 생육을 향상시킬 수 있다고 생각된다.

This study investigated the synergistic effect of single inoculation and co-inoculation of phosphate-solubilizing bacteria (PSB) Burkholderia metallica JH-7 and Burkholderia contaminans JH-15. Phosphate-solubilizing abilities of these strains were assessed by measuring phosphorus content in culture media that were singly inoculated or co-inoculated with these strains for 7 days. B. metallica JH-7 was found to release the highest content of soluble phosphorus (140.80 μg mL-1) into the medium, followed by single inoculation of B. contaminans JH-15 (135.95 μg mL-1) and co-inoculation of two strains (134.84 μg mL-1). The highest pH reduction, organic acid production, and glucose consumption were observed in the medium inoculated with B. metallica JH-7 alone compared with that in the medium co-inoculated with both the strains. Results of a plant growth promotion bioassay showed 17.4% and 7.48% higher leaf and root growth, respectively, in romaine lettuce inoculated with B. metallica JH-7 alone than in romaine lettuce inoculated with a control strain. However, no significant difference was observed between single inoculation and co-inoculation of these strains with respect to phosphorus release and plant growth. Although the results of the present study did not show the synergistic effect of phosphate solubilization by the PSB strains examined, these results indicate that treatment with PSB exerts a beneficial effect on crop growth.

This study focused on evaluating the phytoextraction of heavy metals (Co, Pb, and Zn) induced by bioaugmentation of button mushroom compost (BMC) in Helianthus annuus (sunflower). When the potential ability of BMC to solubilize heavy metals was assessed in a batch experiment, the inoculation with BMC could increase more the concentrations of water-soluble Co, Pb, and Cd by 35, 25, and 45% respectively, compared to those of non-inoculated soils. BMC-assisted growth promotion and metal uptake in H. annuus was also evaluated in a pot experiment. In comparison with non-inoculated seedlings, the inoculation led to an increase in the growth of H. annuus by 27, 25, and 28% in Co-, Pb-, and Zn-contaminated soils, respectively. Moreover, enhanced accumulation of Co, Pb, and Zn in the shoot and root systems was observed in inoculated plants, where metal the translocation from root to the above-ground tissues was also found to be enhanced by the BMC. Evidently, these results suggest that the BMC could be effectively employed in enhancing the phytoextraction of Co, Pb, and Zn from contaminated soils.

An auxin-producing bacterial strain, designated 4-3, was isolated from waste button mushroom compost in Boryeong-si, Chungnam. The strain 4-3 was classified as a novel strain of Leucobacter tardus, based on chemotaxonomic and phylogenetic analyses. TLC and HPLC the isolated L. tardus strain 4-3 produced indole-3-acetic acid (IAA), the auxin. Maximum IAA productionof 94.3 mg L-1 was detected for bacteria cultured in R2A medium with 0.1% l-tryptophan, incubated for 24 h at 35oC. Negative correlationwas observed between IAA production and pH of the culture medium, indicating that the increase inIAA caused acidification ofthe medium. The effect of supplementation with varying concentrations of l-tryptophan, a known precursor of IAA, was also assessed. production was maximal at 0.1% l, but decreased at lconcentrations above 0.2%. To investigate the plant growth-promoting effects of the bacterium, L. tardus strain 4-3 culture broth was used to inoculate water cultures and seed pots of mung bean. We found thatadventitious root induction and root growth were 2.2-times higher in thethan in the non-inoculated plants.

Button mushroom(Agaricus bisporus) are cultivated on wheat straw or rice straw based compost. In this study different compost formular, sawdust as carbon source and chicken manure as nitrogen source were used for button mushroom cultivation. Two steps of sufficient composting process was required to be successful in the cultivation. 1) the substrates are needed to be mixed periodically under the aerobic condition in the phase I process. 2) the temperature is need to be maintained between 55 and 65? for more than three days in the phase II process. Results showed that button mushroom was possible to grow normally with sawdust based compost. However the mushroom yield was less than that of the conventional compost formular(rice straw or wheat straw). The new compost formular developed from this study may be useful but further research may need to improve button mushroom cultivation more efficiently.

Lactic acid bacteria (LAB) producing phenyllactic acid (PLA), which is known as antimicrobial compound, was isolated from button mushroom bed and the isolated LAB was identified to Lactobacillus casei by 16 rRNA gene sequence analysis. Cell-free supernatant (CFS) from L. casei was assessed for both the capability to produce the antimicrobial compound PLA and the antifungal activity against three fungal pathogens (Rhizoctonia solani, Botrytis cinerea, and Collectotricum aculatum). PLA concentration was investigated to be 3.23 mM in CFS when L. casei was grown in MRS broth containing 5 mM phenylpyruvic acid as precursor for 16 h. Antifungal activity demonstrated that all fungal pathogens were sensitive to 5% CFS (v/v) of L. casei with average growth inhibitions ranging from 34.58% to 65.15% (p < 0.005), in which R. solani was the most sensitive to 65.15% and followed by C. aculatum, and B. cinerea. The minimum inhibitory concentration (MIC) for commercial PLA was also investigated to show the same trend in the range of 0.35 mg mL-1 (2.11 mM) to 0.7 mg mL-1 (4.21 mM) at pH 4.0. The inhibition ability of CFS against the pathogens were not affected by the heating or protease treatment. However, pH modification in CFS to 6.5 resulted in an extreme reduction in their antifungal activity. These results may indicate that antifungal activities in CFS was caused by acidic compounds like PLA or organic acids rather than protein or peptide molecules.

참몰개(Squalidus chankaensis tsuchigae)의 개체군 생태 특성을 연구하기 위해 2013년 3월부터 11월까지 금강에서 조사하였다. 본 종은 하천 중류에 분포하며 하상구조는 주로 큰 돌과 모래로 이루어져 있었다. 서식지 수심은 30~60 ㎝ 이었고 유속은 2.27~4.88 ㎝/sec 상태를 유지하고 있었다. 암수의 성비는 1 : 0.86 이었고 산란시기는 6~7월로 수온은 25~26°C 이었다. 만 2년생 이상부터 성적 성숙이 이루어지기 시작했다. 전장이 40~69㎜의 집단은 만 1년생, 71~89㎜ 의 집단은 만 2년생, 90㎜ 이상은 만 3년생으로 추정되었다. 포란수는 평균 2,219개 이었고 성숙란의 직경은 0.64∼0.98(평균 0.85±0.042)㎜ 이었다. 전장과 체중 관계식은 BW=0.0002TL2.81로 상수 a는 0.0002을, 매개변수 b는 2.81 이었고, 건강도는 평균 1.06 이었다. 먹이생물은 남조류(Cyanophyta), 녹조류(Chlorophyta), 규조류(Bacillariophyta), 갑각류(Crustaceae), 요각류(Copepoda), 선충류(Nematota), 구두동물(Actithocephala), 수서곤충(Aquatic insect)에 속 하는 하루살이목(Ephemeroptera), 노린재목(Hemiptera), 파리목(Diptera), 날도래목(Trichoptera), 태형동물(Brtozoa) 피후강(Phylactolaemata)에 속하는 큰빛이끼벌레(Pectinatella) 등 이었다. 식성은 잡식성이었으며 식물성은 부착성이며 사상체를 형성하는 조류(Algae)가 대부분을 차지하였고 동물성은 깔다구(Chironomidae) 유충을 주로 섭식하였다.

An auxin-producing bacteria (A-1) was isolated from soils of Oyster mushroom farmhouse in Daejeon city, South Korea. The strain A-1 was classified as a novel strain of Ochrobactrum anthropi based on a chemotaxanomic and phylogenetic analyses. The isolate was confirmed to produce indole-3-acetic acid (IAA), one of auxin hormones, by TLC and HPLC analyses. The maximum concentration of IAA, 5.6 mg L-1 was detected from the culture broth of O. anthropi A-1 incubated for 24 h at 35oC in R2A broth containing 0.1% L-tryptophan. To investigate the growth-promoting effects to the crops, the culture broth of O. anthropi A-1 was inoculated to water cultures and seed pots of mung bean as well as lettuce. In consequence, the adventitious root induction and root growth of mung bean and lettuce were 2.7 and 1.4 times higher than those of the non-inoculated, respectively.

본 논문에서는 아이소-지오메트릭 형상 최적설계 기법에서 얻은 CAD 정보를 직접 활용하여, 3D 프린터를 활용한 실험적 검증을 위한 시편을 제작하였다. 유한요소법에서는 요소망에 내재하는 기하학적인 근사가 응답과 설계민감도 해석에서 정밀도 문제를 발생시킨다. 더욱이 유한요소 기반 형상 최적화 과정에서는 CAD와의 정보교환이 필수적이나 그 과정에서 최적설계 정보의 손실이 발생할 수 있다. 아이소-지오메트릭 기법은 CAD에서 사용된 동일한 NURBS 기저함수와 조정점을 사용하므로 법선벡터와 곡률과 같은 엄밀한 기하학적 정보를 응답해석과 설계민감도 해석에 사용할 수 있다. 또한 최적설계 과정에서 CAD와 정보교환 없이 복잡한 형상을 손쉽게 변경할 수 있다. 그러므로 최적의 설계의 재료량을 실험적 검증을 위한 시편제작에 엄밀하게 반영할 수 있다. 굽힘 하중을 받는 단순지지 구조물에 대한 최적설계 및 실험적 검증을 통해 최적형상이 초기 형상에 비해 더 큰 강성을 가지며 실험결과와 수치 해석결과가 매우 잘 일치함을 보였다. 또한 인장력을 받는 유공판에 대한 형상 최적설계를 수행하였으며, 비접촉식 3차원 변형 측정 장치를 이용하여 초기설계에 비해 최적설계에서 구멍주변에서의 응력집중 현상이 완화됨을 확인하였다. 따라서 수치적인 방법을 활용한 최적설계가 실제 구조물에 대한 실험에서도 유효함을 입증하였다고 할 수 있다. 또한, 아이소-지오메트릭 최적설계 방법론이 기존의 유한요소법에 비해서 최적설계 결과를 제작하여 활용하는데 있어서도 훨씬 효율적이고 엄밀한 방법임을 보였다.

A galactose fermentation bacterium producing lactose from red seaweed, which was known well to com-promise the galactose as main reducing sugar, was isolated from button mushroom bed in Buyeo-Gun, Chungchugnam-do province. The lactic acid bacteria MONGB-2 was identified as Lactobacillus paracasei subsp. tolerans by analysisof 16S rRNA gene sequence. When the production of lactic acid and acetic acid by L. paracasei MONGB-2 was inves-tigated by HPLC analysis with various carbohydrates, the strain MONGB-2 efficiently convert the glucose and galactoseto lactic acid with the yield of 18.86 g/L and 18.23 g/L, respectively and the ratio of lactic acid to total organic acidswas 1.0 and 0.91g/g for both substrates. However, in the case of acetic acid fermentation, other carbohydrates besidesgalactose and red seaweed hydrolysate could not be totally utilized as carbon sources for acetic acid production by thestrain. The lactic acid production from glucose and galactose in the fermentation time courses was gradually enhancedupto 60 h fermentation and the maximal concentration reached to be 16-18 g/L from both substrates after 48 h of fer-mentation. The initial concentration of glucose and galactose were completely consumed within 36 h of fermentation, ofwhich the growth of cell also was maximum level. In addition, the bioconversion of lactic acid from the red seaweedhydrolysate by L. paracasei MONGB-2 appeared to be about 20% levels of the initial substrates concentration and thisresults were entirely lower than those of galactose and glucose showed about 60% of conversion. The apparent resultsshowed that L. paracasei MONGB-2 could produce the lactic acid with glucose as well as galactose by the homof-ermentation through EMP pathway

Y-Aminobutyric acid(GABA) is a four carbon non-protein amino acid that has several well-known phys-iological functions, such as a postsynaptic inhibitory neurotransmitter in the brain and induction of hypotensive and tran-quilizer effects. A lactic acid bacterium was isolated from button mushroom bed, which is showing high GABAproductivity by TLC or HPLC analysis. The strain was identified as Lactobacillus hilgardii by analysis of 16S rDNAgene sequence. When the maximum production of GABA by L. hilgardii was investigated with various concentration ofmonosodium glutamate, the yield of GABA reached to be 53.65mM at 1% mono sodium glutamate (MSG) in flask cul-tivation. A Glutamate decarboxylase (GAD) enzyme, which was known to convert MSG to GABA, was purified froma cell-free extract of L. hilgardii and the molecular weights of purified GAD was estimated to 60,000 by SDS-PAGE.The optimum pH and temperature of GAD were at pH4.6 and at 37°C, respectively. The GAD activity was increasedby the addition of sulfate ions such as ammonium sulfate, sodium sulfate and magnesium sulfate, indicating that theincrease of hydrophobic interaction causes the increase of GAD activity.

A total of 35 phosphate solubilizing bacterial strains were isolated from waste bed of Agaricus bisporus in Buyeo-Gun, Chungchugnam-do province and screened for the production of indole acetic acid(IAA). The best IAA producing strain was identified as Pantoea rodasii using 16S rRNA analysis. In addition to the IAA production, this strain could act as an efficient phosphate solubilizer (1100 μg ml-1 after 5 days of incubation) also. The selected strain was cultured under different conditions in order to assess the optimum conditions for maximum IAA production. The nutrient broth (NB) medium was recorded as the best medium, where the maximum IAA production (229 μg ml-1) was recorded at the start of stationary phase (12 hours after inoculation) of the bacteria growth. The performance of the strain was found to be maximum at the temperature of 30°C followed by 25°C. IAA production was found to be increased with increasing tryptophan concentration (from 0.1 to 0.6%), however beyond this limit, a slight reduction in IAA production was observed. The strains’ ability to produce IAA was further confirmed by extraction of crude IAA and subsequent TLC analysis. A specific spot from the extracted IAA preparation was found corresponding with the standard spot of IAA with same Rf value. The results of HPLC analysis conducted in identifying and quantifying the IAA production more precisely, are in agreement with the results of the assessment done with colorimetric method. As revealed by the results of the pot experiment, the isolated strain could significantly enhance the growth (as measured by shoot and root growth) of mung bean plants compared to that of non-inoculated plants. Therefore it can be concluded that the present strain, Pantoea rodasii has great potential to be used as bio-inoculants.