• Journal of Microbiology and Biotechnology
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• v.30 no.8
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• pp.1252-1260
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• 2020

(R)-2-(4-hydroxyphenoxy)propionic acid (HPOPA) is a key intermediate for the preparation of aryloxyphenoxypropionic acid herbicides (R-isomer). In order to improve the HPOPA production from the substrate (R)-2-phenoxypropionic acid (POPA) with Beauveria bassiana CCN-A7, static cultivation and H₂O₂ addition were attempted and found to be conducive to the task at hand. This is the first report on HPOPA production under static cultivation and reactive oxygen species (ROS) induction. On this premise, the cultivation conditions and fermentation medium compositions were optimized. As a result, the optimal carbon source, organic nitrogen source, and inorganic nitrogen source were determined to be glucose, peptone, and ammonium sulfate, respectively. The optimal inoculum size and fermentation temperature were 13.3% and 28℃, respectively. The significant factors including glucose, peptone, and H₂O₂, identified based on Plackett-Burman design, were further optimized through Central Composite Design (CCD). The optimal concentrations were as follows: glucose 38.81 g/l, peptone 7.28 g/l, and H₂O₂ 1.08 g/l/100 ml. Under the optimized conditions, HPOPA titer was improved from 9.60 g/l to 19.53 g/l, representing an increase of 2.03-fold. The results obtained in this work will provide novel strategies for improving the biosynthesis of hydroxy aromatics.

• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.424-429
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• 2012

The intention of this research was to investigate the solubilization of primary sewage sludge using lactic acid bacteria cultured in a glucose and yeast extract medium. Glucose as the carbon source and yeast extract as the source of nitrogen were chosen as an economic medium with the potential for the mass production of lactic acid bacteria. The optimal concentrations of the medium were 3% (w/v) glucose and 2% (w/v) yeast extract. In this study, in order to improve field applications for the solubilization of sludge at sewage treatment plants, a powdered form of lactic acid bacteria was produced. The optimal inoculum of the powder for the maximum efficiency of solubilization was 1% (w/v). In that condition, the SCOD value increased from 8600 (mg/L) at the beginning of experiment to 10290 (mg/L) at 96 h, with the highest solubilization rate (20.6% DDCOD) and 11.2% (SCOD). Also, the TVFAs of the lactic acid bacteria inoculation group were produced more than that of the control group. In particular, acetic acid was produced 5 times more in the experimental group than in the control group. In this research, the potential of lactic acid bacteria in the pretreatment of primary sewage sludge as a solubilizer, and as an energy source producer for microbial fuel cells was revealed.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.90.2-91
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• 2003

In commercial greenhouses, senescent flower petals or flowers of vegetables such as tomato, strawberry, hot pepper and zucchini squash were blighted to be removed from fruits within five days after spraying of Trichoderma harzianum YC459 (TORY), a biocontrol agent for the gray mold rot of vegetables caused by B. cinerea The mechanism for selective colonization of senescent floral tissues by T. harzianum YC459 was elucidated using fresh and senescent (Hays and 14days after flowering, respectively) floral tissues of zucchini squash (Cucurbita moschata Duchesne). The spores of T. hrzianum YC459 were produced more on agar and liquid culture media supplemented with 5％ dry powder of senescent floral tissues than fresh tissues during 15days. Mycelial growth was also much better in the media with senescent tissues than with fresh tissues. Enzyme activities of amylase, polygalacturonase and cellulase in the liquid media which might be involved in the colonization of tissues by T. harzianum YC459 were compared. The activities of three enzymes were much higher in the media with senescent floral tissues than with fresh floral tissues reaching to the maximum during 9 to 12days of incubation. Based on the results, the removal of senescent floral tissues, a possible inoculum source of the pathogen, may be another mechanism for biocontrol of gray mold rot of vegetables by T. harzianum YC459.

• The Plant Pathology Journal
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• v.20 no.4
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• pp.289-292
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• 2004

The population of Ralstonia solanacearum (Rs) in soil is very important as a primary inoculum source of bacterial wilt in tobacco fields. To investigate the population of Rs, physical properties and chemical components during the tobacco growing season, soil samples were taken from the fifteen fields which were located in the flue-cured tobacco growing area, Ansung, Kyunggi province and Wonju, Kangwon province. Two fields of the fifteen were bacterial wilt free. Six fields had less than 10% plants being diseased and seven over 10%. The Rs population level determined by using SMSA medium generally showed an up-and-down pattern being low in May, high in Jun and July and low in August. The soil population in May and June showed a positive correlation with the incidence of bacterial wilt (r=0.571$^*$, r=0.688$^{**}$), but P$_2O_5$, content of soil was negatively correlated with the disease incidence (r=-0.539$^*$). These results suggest that Rs population in soil examined in May or in June, and the P$_2O_5$ content in soil should be key factors to determine the bacterial wilt potential of tobacco fields.

• The Plant Pathology Journal
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• v.25 no.4
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• pp.422-428
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• 2009

Studies were conducted to identify the sources of resistance in mungbean recombinant inbred lines (RILs) in Thailand against mungbean yellow mosaic disease (MYMD). 146 mungbean RILs in $F_8$ series were evaluated in a field including resistant parent NM-10-12-1 and susceptible parent KPS 2 during summer 2008 under high inoculum pressure. The RILs were subsequently scored for disease symptom severity ratings (DSSR) using a new scale. Observations regarding DSSR and % disease index (%DI) showed that the tested RILs responded differently to the disease. A large number of RILs (132) were found highly susceptible, 12 were susceptible, 3 were tolerant and one was resistant. Overall screening results showed that three RILs, viz. line no. 30, 100 and 101 had minimum DSSR and % disease index thus they are good source of resistance to MYMD in spite of high disease pressure and can therefore be used directly as varieties to manage the disease in Thailand.

• Journal of Microbiology and Biotechnology
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• v.28 no.9
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• pp.1493-1501
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• 2018

Wastewater from cider factories (losses during transfers, products discarded due to quality policies, and products returned from the market) exhibits a Chemical Oxygen Demand greater than $170,000mg\;O_2/l$, mainly due to the ethanol content and carbohydrates that are added to obtain the finished product. These effluents can represent up to 10% of the volume of cider produced, and they must be treated to meet environmental regulations. In this work, a process was developed, based on alcoholic fermentation of the available carbohydrates present in ciders. The impact of inhibitors at different pH, size and reuse of inoculums and different nutrient supplementation on the ethanol yield were evaluated. The use of a 0.5 g/l yeast inoculum and corn steep water as the nutrient source allowed for depletion of the sugars in less than 48 h, which increased the content of ethanol to more than 70 g/l.

• Research in Plant Disease
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• v.10 no.2
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• pp.130-134
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• 2004

The pathogenesity of 25 isolates of Colletotrichum gloeosporioides from apple, 42 isolates from pepper, 5 isolates from jujube, 8 isolates from persimmon was evaluated to know transmission to strawberry from other infected plants. Followings are the results. Colony morphology and spore size on potato dextrose agar was similar. When each isolate was inoculated on leaf and petiole of strawberry, isolates from persimmon was the most pathogenic. Five isolates, one pathogenic isolate per each host, were evaluated in simulated field condition under natural rainfall for their natural infectivity. All isolates infected strawberry in field condition, so C. gloeosporioides from other hosts are potential inoculum source of strawberry anthracnose.

• The Plant Pathology Journal
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• v.21 no.1
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• pp.73-76
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• 2005

Oriental melon, Cucumis melo L. cv. Geumssaragieuncheon, grafted on Shintozoa (Cucurbit maxima ${\times}$ Cu. moschata) was planted in a greenhouse infested with Meloidogyne arenaria and root galls were examined five months after planting. A gram of root gall was volumed at ca. 10 cm3 and contained in an average of 363 females (170 developing and 193 matured females), 2,120 secondstage juveniles (J2), and 13,074 eggs. In addition, there was 56 J2 per $cm^3$ soil around the infested plant. An oriental melon had an average of 134.6 g of root gall (70% of total root weight) per 0.72 $m^2$ area. In a conservative estimation, an oriental melon plant could accommodate ca. 1.2 ${\times}$ $10^7$ eggs and J2 per 0.72 $m^2$. The eggs contained in root tissues could be an important inoculum source to the next crop and the fate of these eggs are well worth further investigation.

• Journal of Microbiology and Biotechnology
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• v.23 no.6
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• pp.802-810
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• 2013

This work aims at investigating the production of yellow, orange, and red natural colorants in a submerged culture of Penicillium purpurogenum DPUA 1275. For this purpose, different experimental conditions evaluating the effect of incubation time, type and size of inoculum, and different carbon and nitrogen sources were performed. Furthermore, the growth kinetics were obtained in the conditions of $10^8$ spores/ml and 5 mycelia agar discs during 360 h. These experiments showed that 5 mycelia agar discs and 336 h promoted the highest yellow (3.08 $UA_{400nm}$), orange (1.44 $UA_{470nm}$), and red (2.27 $UA_{490nm}$) colorants production. Moreover, sucrose and yeast extract were the most suitable carbon and nitrogen sources for natural colorants production. Thus, the present study shows a new source of natural colorants, which can be used as an alternative to others available in the market after toxicological studies.

• Journal of the Korean Society of Tobacco Science
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• v.11 no.1
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• pp.41-48
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• 1989

The significance of soil and/or rhisosphere populations of Erwinia carotovora sobsp. carotovora (Ecc) as a source of primary inoculum for tobacco hollow stalk disease has been demonstrated conclusively. The survival of Ecc in field soils fter overwintering was estimated by using the enrichment technique. The population number of pectolytic erwinia (PE) in field soils relatively decreased at the rate of 102-104 colony forming unit(CFU) per g of soil after overwintering. Higher level of PE population overwintered in the rhlzosphere foils of tobacco stubbles and detected more frequently in rhizosphere soils of weed plants than in those of bare fields. All of the tobacco stubbles collected from fields where tobacco had been grown the previous year contained Ecc. The more survived population number of PE at the 30cm depth of artifitiany infested soils than at the upper of those by introducing with diseased tobacco plant tissue after overwintering. Ecc overwintered effectively in rhizosphere soils of tobacco stubbles, overwintered weeds and tobacco debris in field soils.