• Applied Biological Chemistry
• /
• 제27권
• /
• pp.56-67
• /
• 1984

As in many other country, the use of organic matter in Korea has long history. Farmers understand the value of organic matter as the source of plant nutrient and soil improving agent in general. Since 50 years ago, the sources of organic matter in paddy soils were compost, rice and barly straw, green manure, animal waste, fish and beancake, etc.. Application of green manures such as vetch and chinese milk vetch showed no significant effect on the yield of brown rice in paddy soil. On the other hand, the effects of compost and rice straw showed more significant on the yield of brown rice in paddy soil. Application of rice straw in rice cultivation is commonly made at different times between harvest, early spring and several weeks before transplanting. Considering the suitable paddy soil for application of rice straw under well to moderately well drained soil, the yield was pronounced more than poorly drained soil. Based on laboratory and field experimants, application of rice straw promoted the decrease of oxidation-reduction potential in well to moderately well drained soil. This results to be enhanced the release of some mineral nutrients,. such as potassium, calcium, silicon, and increase of availability of soil phosphorus. In the field experiments, results obtained from nitrogen fraction on the immobilization-mineralization of the tracer nitrogen applied in paddy soil,the amount and index of organic nitrogen incoporated in soil was more pronounced in rice straw application than control. Rice straw and its transformation products incoporated in the soil, provided the inflow of energy necessary to maintain heterotrophic microbes activities. Rice straw and its transformation products, especially soluble carbohydrate, enhanced the population of free-living heterotrophic $N_2$ - fixing microbes. Moreover, rice straw and its transformation products in paddy soil, enhanced the activities of soil enzymes such as dehydrogenase and urease.

• Mycobiology
• /
• 제47권2호
• /
• pp.230-241
• /
• 2019

The Great Sebkha of Oran is a closed depression located in northwestern of Algeria. Despite the ranking of this sebkha among the wetlands of global importance by Ramsar Convention in 2002, no studies on the fungal community in this area have been carried out. In our study, samples were collected from two different regions. The first region is characterized by halophilic vegetation and cereal crops and the second by a total absence of vegetation. The isolated strains were identified morphologically then by molecular analysis. The biotechnological interest of the strains was evaluated by testing their ability to grow at different concentration of NaCl and to produce extracellular enzymes (i.e., lipase, amylase, protease, and cellulase) on solid medium. The results showed that the soil of sebkha is alkaline, with the exception of the soil of cereal crops that is neutral, and extremely saline. In this work, the species Gymnoascus halophilus, Trichoderma gamsii, the two phytopathogenic fungi, Fusarium brachygibbosum and Penicillium allii, and the teleomorphic form of P. longicatenatum observed for the first time in this species, were isolated for the first time in Algeria. The halotolerance test revealed that the majority of the isolated are halotolerant. Wallemia sp. and two strains of G. halophilus are the only obligate halophilic strains. All strains are capable to secrete at least one of the four tested enzymes. The most interesting species presenting the highest enzymatic index were Aspergillus sp. strain A4, Chaetomium sp. strain H1, P. vinaceum, G. halophilus, Wallemia sp. and Ustilago cynodontis.

• 한국연초학회지
• /
• 제27권1호
• /
• pp.75-82
• /
• 2005

This work investigated biodegradability for the cellulose acetate, carbon dual, paper and web used to cigarette filter materials by soil test. Also, because of demanded a lot of the time and effort in case of soil test, the possibility of biodegradation by enzyme was studied. The evaluation of degradation for the filter materials by soil test was examined with the naked eye, electron microscopy and weight loss. The biodegradability according to the filter materials was represented in the order of paper > web > carbon dual > cellulose acetate without relating to the evaluation methods. Experiment of biodegradability by the cellulase(E C 3.2.1.4, Trichoderma viride) among the several biodegradability enzymes was demanded reaction time of the $5\~10$ hours and represented the same result with that of soil test.

• 한국균학회지
• /
• 제21권4호
• /
• pp.293-300
• /
• 1993

Enzyme AAT, GmDH, ME, GPI, LDH 그리고 IDH에 대해 각각 아홉, 일곱. 넷, 아홉, 일곱 그리고 네개의 서로 다른 phenotype이 관찰되었다. Sugarcane field에서 분기한 종명이 밝혀지지 않은 여섯개의 sterile isolate 모두 여섯개의 enzyme에 대해 동일한 위치에 band를 형성하였다. 이 phenotype들은 이미 밝혀진 Pythium species와는 다른 위치에서 band를 형성하였다. 종명이 밝혀지지 않은 Pythium isolate중 isolate 145와 299는 여섯개의 enzyme에 대해서 동일한 위치에서 band가 형성되었고, 다른 isolate들은 다른 위치에서 band를 형성하였다. 다섯개의 Pythium heterothallicum isolate들은 IDH를 제외한 모든 enzyme에 대해서 동일한 위치에서 band를 형성하였다. 두개 그리고 세개의 P. torulosum isolate가 AAT, GmDH 그리고 ME와 GPI,LDH 그리고 IDH 에 대해 각각 동일한 위치에 band를 형성하였다. 한개의 P. spinosum 과 P. irregulare isolate 각각이 enzyme AAT, GmDH 그리고 GPI에 대해 동일한 위치에 band를 형성하였다. 결론적으로, sterile Pythium isolate 들은 intraspecies level에서는 similarity 가 100%였지만, P. heterothallicum 그리고 Pythium spinosum과는 무관함이 밝혀졌고 isolate 306 을 제외한 다른 Pythium species들과는 전반적으로 낮은 상관성을 나타내었다 . 서로 다른 species간의 상관성은 몇몇 경우를 제외하고는 전반적으로 매우 낮았다.

• Mycobiology
• /
• 제38권4호
• /
• pp.238-248
• /
• 2010

This review provides background information on the importance of bioremediation approaches. It describes the roles of fungi, specifically white rot fungi, and their extracellular enzymes, laccases, ligninases, and peroxidises, in the degradation of xenobiotic compounds such as single and mixtures of pesticides. We discuss the importance of abiotic factors such as water potential, temperature, and pH stress when considering an environmental screening approach, and examples are provided of the differential effect of white rot fungi on the degradation of single and mixtures of pesticides using fungi such as Trametes versicolor and Phanerochaete chrysosporium. We also explore the formulation and delivery of fungal bioremedial inoculants to terrestrial ecosystems as well as the use of spent mushroom compost as an approach. Future areas for research and potential exploitation of new techniques are also considered.

• Asian-Australasian Journal of Animal Sciences
• /
• 제17권5호
• /
• pp.608-611
• /
• 2004

The 15 buffaloes were divided into three groups, viz. group 1: normal cyclic buffaloes; group 2: postpartum anoestrus buffaloes and group 3: post partum anoestrus buffaloes supplemented with intramuscular injections of Vit. E.-care Se containing 500 mg $\alpha$-tocopheryl acetate and 15 mg selenium at weekly intervals for two months. The postpartum anoestrus buffaloes had significantly higher levels of erythrocytic lipid peroxidation, superoxide dismutase and glucose-6 phosphate dehydrogenase activities but lower glutathione peroxidase activity as compared to normal cyclic buffaloes. The supplementation of vitamin E and selenium lowered the level of erythrocytic lipid peroxidation, superoxide dismutase and glucose-6 phosphate dehydrogenase activities but it had no effect on whole blood selenium and erythrocytic gluathione peroxidase activity. All the animals in group 3 became cyclic and showed 60% conception rate.

• 한국미생물·생명공학회지
• /
• 제24권2호
• /
• pp.143-148
• /
• 1996

Thousand actinomycetes and 50 soil samples were used for the isolation of microorganisms producing yeast cell wall lytic enzymes. Among 493 strains producing large clear zones on autolysed washed yeast (AWY), 117 strains were selected on living yeast cell agar plates. With the method of lytic activity, one strain (St-1702) was selected, which was temporarily identified as Streptomyces eurythermus. The optimal condition for enzyme production of this strain was partially determined as follows: incubation of the strain for 3 days at 30$\circ$C in the medium containing 2% freeze dried yeast cell, 1% glucose, 1% K$_{2}$HPO$_{4}$, 0.01% MgSO$_{4}$'7H$_{2}$O, 0.5% peptone, and 0.2% (NH$_{4}$)$_{2}$CO$_{3}$ with pH 7.0. The protoplast formation of yeast by using the enzyme produced by this strain was compared with commercial enzymes.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2003년도 International Symposium
• /
• pp.111-124
• /
• 2003

기존의 오염물질을 제거하는 많은 화학적-물리적 정화 방법은 고비용과 오랜 시간을 요구하는 처리 과정 등의 단점을 갖고 있는 경우가 많았다. 따라서 흙과 수(水)환경내로 유입된 오염물질을 빠른 시간 내에 제거 할 수 있는 대안이 요구 되었다. 흙에 유출된 화합 물질 중 상당양은 흙에 의해 격리, 구속되고 이로 인해 일단 구속된 오염물질은 물과 유기 용매에 의해서도 잘 추출되지 않는 것으로 보고 되고 있다. 이러한 흙에 의한 오염물질의 비유동성(immobilization) 과정은 오염물질의 제거 기술의 대안으로 평가 될 수 있다. 기존 연구자들의 연구 결과, 화학적 혹은 물리적 반응 작용을 통해 오염물질을 흙을 구성하는 물질에 구속할 수 있음이 증명되었다. 이러한 과정 중 환경적 측면에서 볼 때, 화학적 반응이 더 우수하다 할 수 있다. 이는 강한 공유결합(covalent bonds)으로 연결될 경우 미생물의 활동이나 화학 처리로도 이를 분리하기 어렵기 때문이다. 리그닌(lignin) 분해에서 발생하는 휴믹(humic) 물질 등이 안정 된 화학적 연결을 통해 흙 매질 내에 오염물질과 결합하는 대표적 물질이다. 인위적으로 제조된 많은 화학물질은 자연적에서 발생하는 휴민산 발생원(humic acid precursors)과 닮았다. 따라서 화학물은 부식 과정(humifications process)동안 부식토(humus) 내로 병합(incorporate)되어 진다. 일단 이렇게 구성된 결합체는 생물체와 오염물질과의 반응을 방지하여 오염물질로 인한 생물체로의 독성을 감소시키는 역할을 하게 된다. 본 논문에서는 이러한 흙의 유기물(organic matter)와 오염물질과의 결합체에 대한 평가로서 다음의 항목에 대한 고찰이 이루어져야 함을 강조하였다. (a)결합체에서 생물체(biota)와의 반응에 의해 오염물질은 감소되는가\ulcorner (b) 모(parent) 화합물과 비교하여 복합체 생성물(complexed products)이 얼마나 덜 유독한가\ulcorner 그리고 (c)지하수 오염이 오염물질의 유동성 구속에 의해 얼마나 감소되는지\ulcorner

• 한국미생물·생명공학회지
• /
• 제49권3호
• /
• pp.391-402
• /
• 2021

Earthworms play an important role in soil fertilization, interacting continually with microorganisms. This study aims to demonstrate the existence of beneficial microorganisms living in the earthworm's immune system, the coelomic fluid. To achieve this goal, a molecular identification technique was performed, using cytochrome c oxidase I (COI) barcoding to identify abundant endogenic earthworms inhabiting the temperate zone of Rabat, Morocco. Then, 16S rDNA and ITS sequencing techniques were adopted for bacteria and fungi, respectively. Biochemical analysis, showed the ability of bacteria to produce characteristic enzymes and utilize substrates. Qualitative screening of plant growth-promoting traits, including nitrogen fixation, phosphate and potassium solubilization, and indole acetic acid (IAA) production, was also performed. The result of mitochondrial COI barcoding allowed the identification of the earthworm species Aporrectodea molleri. Phenotypic and genotypic studies of the sixteen isolated bacteria and the two isolated fungi showed that they belong to the Pseudomonas, Aeromonas, Bacillus, Buttiauxella, Enterobacter, Pantoea, and Raoultella, and the Penicillium genera, respectively. Most of the isolated bacteria in the coelomic fluid showed the ability to produce β-glucosidase, β-glucosaminidase, Glutamyl-β-naphthylamidase, and aminopeptidase enzymes, utilizing substrates like aliphatic thiol, sorbitol, and fatty acid ester. Furthermore, three bacteria were able to fix nitrogen, solubilize phosphate and potassium, and produce IAA. This initial study demonstrated that despite the immune property of earthworms' coelomic fluid, it harbors beneficial microorganisms. Thus, the presence of resistant microorganisms in the earthworm's immune system highlights a possible selection process at the coelomic fluid level.

• 농업과학연구
• /
• 제49권3호
• /
• pp.463-481
• /
• 2022

Phosphorous (P) is considered to be one of the key essential elements demanded by crop plants. Approximately 70 - 90% of phosphatic fertilizers applied to crops are fixed in soil as Ca, Fe, and Al metal cations, which are insoluble and thus not readily available for plant uptake. Therefore, most soils are deficient in plant available P. This is usually rectified by applying phosphate fertilizers continuously, although this is not economically viable or environmentally acceptable. The present paper reviews the mechanisms involved with phosphate solubilization and mineralization by phosphate solubilizing microorganisms (PSMs) with the associated factors that determine the success. PSMs are effectively involved in mediating the bioavailability of soil P. Their contribution includes mineralization of organic P solubilization of inorganic P minerals, and storing sizable amounts of P in biomass through different mechanisms such as the production of organic and inorganic acids, H₂S, siderophores, exopolysaccharides, and production of enzymes such as phosphatases, phytase, and phosphonatases/C-P lyases, which are capable of chelating the metal ions, forming complexes, and making plant available P. PSMs manifest a wide range of metabolic functions in different environments, resulting in significantly higher plant growth, enhanced soil properties, and increased biological activities. Therefore, development of bio-inoculants with efficient novel PSM strains and further investigations on exploring such strains from diverse ecological niches with multifunctional plant-growth-promoting traits are needed.