A new Bacillus subtilis isolate showed high anti-fungal activities (more than 80% control efficacy) against several plant diseases such as rice blast (Magnaporthe grisea), tomato gray mold (Botrytis cinerea), tomato late blight (Phytophthora infestans) and wheat leaf rust (Puccinia recondita). We tried to confer an insecticidal activity to this B. subtilis isolate for constructing a recombinant strain which has dual functions, anti-fungal and insecticidal activity. The insecticidal cry1Ac gene of B. thuringiensis was constructed under its own promoter in a minimal E. coli-B. thuringiensis shuttle vector (pHT1K-1Ac). The plasmid, pHT1K-1Ac was introduced into B. subtilis isolate by electroporation and the transformant was confirmed by PCR with cry1Ac specific primers. B. subtilis transformant produced a parasporal inclusion in the cells as in B. thuringiensis and the size of that protein was appox. 130 kDa. The insecticidal activity of the transformant was checked against lepidopteran pest, Plutella xylostella. This result suggests that this recombinant B. subtilis strain shows the possibility of controlling harmful insect pests as well as plant fungal diseases simultaneously at one crop, and both culture broth and harvested cells of this strain can be used as individual biological control agents separately for integrated crop protection.

To investigate the antifungal activity related protein in pesticidal bacteria, a bacterial strain LTD was isolated from soil collected at Gimje in Jeonbuk province, Korea, and identified as Bacillus subtilis LTD based on a API50 CHB kit and 168 rDNA seque

아플라톡신 생성균의 생육을 억제할 수 있는 미생물을 분리동정하고 진공동결 건조한 대사산물로부터 길항물질을 분리하였다. 대두로부터 아플라톡신 생육을 저해하는 길항균을 분리하였으며, 그 균은 Bacillus subtilis로 동정되었다. Bacillus subtilis는 아플라톡신 생성균에 대한 길항물질을 생산하였으며 MeOH추출, 실리카겔 흡착 크로마토그래피법, Sephadex LH-20 크로마토그래피법으로 길항물질을 분리하였다. 아플라톡신 생성균인 Asp. flavus와 Asp. parasiticus의 생육은 길항미생물인 Bacillus subtilis가 생산하는 길항물질에 의해 강하게 저해되었으며 이는 아플라톡신 오염방지를 위하여 효과적인 생물학적 방법일 것이라 기대된다.

고추의 뿌리에 서식하고 있는 근권미생물을 30여종 분리하여 고추 검은 곰팡이병원균 A. alteranta에 길항하는 미생물을 분리한 결과 분리주 No. J-24 균주가 가장 길항력이 우수하였으며 Bacillus subtilis로 동정되었다. B. subtilis J-24는 검은곰팡이병균(Alternaria alternata)에 대해서는 생육저지 효과가 99%로 나타났으며, 그외 갯빛곰팡이병균(Botrytis cinerea), 역병균(Phytophthora capsici), 잘록병균(Pythium ultimum), 탄저병균(Colletotrichum gloeosporioides), 겹무늬병균(Stemphylium botryosum)에도 생육저지효과를 강하게 나타내었다. 고추 유묘의 생장활력은 미생물제제가 첨가된 상토가 일반 상토 보다 엽면적이 15%, 줄기길이가 12%, 뿌리길이가 12% 증가하였고 전체 건물중이 약 13% 증가하여 고추유묘의 생장활력이 증가되었다.

치자에서 황색색소를 제조한 후 생기는 부산물을 Bacillus를 이용하여 청색색소로의 전환실험을 한 결과, 색소생성의 최적조건은 온도 30℃, pH 6.0, 최적 탄소원인 glucose의 농도는 3%, 최적질소원인 yeast extract의 농도는 0.4%였다. 발효조내에서 청색색소로의 전환을 위한 최적반응 조건은 교반속도 400rpm, 최적통기량은 2vvm, 최적 종균 접종량은 5%, 최적 종균 배양시간은 20시간으로 나타났다.

This study was performed to investigate the possible effect of Bacillus subtilis which is the predominant species of bacteria in Korean soy sauce, soy paste, and Meju (soybean cake) on the growth and aflatoxin production of Aspergillus parasiticus ATCC 15517. The microorganisms were grown in a modified APT broth and incubated at 30℃ for 12 days. Aflatoxins were determined using high performance liquid chromatography (HPLC). A remarkable inhibition of the growth of Aspergillus parasiticus was observed during the incubation period when in the presence of B. subtilis (mixed culture). Dry mycelial weight in the mixed culture was significantly reduced by 85.3% in comparison to the control at the end of the incubation period (p$lt;0.01). Lower levels of aflatoxins were found in the mixed culture than in the monoculture. At the end of the incubation period aflatoxin production was significantly inhibited by more than 50% (p$lt;0.05). These results indicate that B. subtilis mainly inhibites the growth and aflatoxin production of toxigenic Aspergillus in Meju, soy sauce and soy paste. Although its effect on aflatoxin production was less pronounced, we . could expect more inhibition by another bacteria related with fermentation in Meju.

This study was designed to investigate the effects of antagonistic microorganism, Bacillus subtilis, on the growth of forage seedlings in repeated cultivation soils and unrepeated cultivation soils. The field experiment was wnducted in pots in a vinyl hou

This study was conducted to investigate the effect of antagonistic bacteria and pathogenic fungi on growth and yields of white clover(Trifo1iurn repens L.) in continuous cropping soil(CCS) and non-continuous cropping soil(NCCS). The gowth experiment of wh

Streptomyces albus KSM-35의 amylase의 유전자를 Bacillus subtilis LKS88에서 발현시킨 균주를 사용하여 amylase의 생산에 미치는 몇가지 요인들을 조사하였다. 본 실험에 사용한 탄소원들중에서 sodium citrate와 왕겨의 효소 생산량이 가장 높았고, 이들을 1:1의 비율로 혼합하여 첨가하였을 때 효소의 생산량은 대조군으로 사용한 가용성 전분에 비하여 20배 이상 증가하였다. 질소원으로 대두박을 사용하였을 경우 yeast extract의 첨가량을 줄이면서 효소의 생산량을 증가시켰다. 배양을 위한 초기 pH를 60으로 조절하고 SDS를 0.01%첨가하였을 때 대조구조보다 높은 효소 생산량을 나타내었다. Bacillus subtilis LKS88 (pASA240)을 sodium citrate와 왕겨 각각 1.5%, K_2HPO_4 0.66%, yeast extract 0.3%, 대두박 0.7%, SDS 0.01% 및 초기 pH를 6.0으로 조절한 배지에서 37℃에서 배양시 최대 효소 활성은 배양 후 36시간에서 나타났으며 이때 효소 활성은 56.6 U/ml이었다.

This study was conducted to investigate the effects of antagonistic microorganisms, Bacillus spp., on growth of alfalfa(Medicag0 sativa L.) in repeated cultivation soil(RCS) and unrepeated cultivation soil(URCS). Alfalfa was established by seeding into po

Bacillus subtilis SH-1 have been isolated and identified from coastal sea, in Pusan. The optimal cultural characterization of Bacillus subtilis SH-1 for the production of bacteriolytic enzyme was determined. Bacillus subtilis SH-1 produced the bacteriolytic enzyme well in the medium consist of 1.0% glucose, 1.0% yeast extract, 1.0% NaCl, 0.02% K₂HPO₄, 0.002% MgSO₄, 7H₂O, 0.001% MnSO₄, 5H₂O, and 0.0001% FeSO₄, 7H₂O. The optimal medium pH, incubation temperature, and shaking time for the highest production of the enzyme were 8.0, 30℃ and 28 hours respectively.