• Journal of Microbiology and Biotechnology
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• 제30권12호
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• pp.1937-1943
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• 2020

Although classical metabolic engineering strategies have succeeded in developing microbial strains capable of producing desired bioproducts, metabolic imbalance resulting from extensive genetic manipulation often leads to decreased productivity. Thus, abiotic strategies for improving microbial production performance can be an alternative to overcome drawbacks arising from intensive metabolic engineering. Herein, we report a promising abiotic method for enhancing lycopene production by UV-C irradiation using a radiation-resistant ΔcrtLm/crtB+dxs+ Deinococcus radiodurans R1 strain. First, the onset of UV irradiation was determined through analysis of the expression of 11 genes mainly involved in the carotenoid biosynthetic pathway in the ΔcrtLm/crtB+dxs+ D. radiodurans R1 strain. Second, the effects of different UV wavelengths (UV-A, UV-B, and UV-C) on lycopene production were investigated. UV-C irradiation induced the highest production, resulting in a 69.9% increase in lycopene content [64.2 ± 3.2 mg/g dry cell weight (DCW)]. Extended UV-C irradiation further enhanced lycopene content up to 73.9 ± 2.3 mg/g DCW, a 95.5% increase compared to production without UV-C irradiation (37.8 ± 0.7 mg/g DCW).

• Fisheries and Aquatic Sciences
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• 제11권4호
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• pp.219-223
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• 2008

To increase the level of $CoQ_{10}$ production in mass culture, the effects of pH and light irradiation on $CoQ_{10}$ production by Rhodobacter sphaeroides were investigated in a 1-L bioreactor. $CoQ_{10}$ production was growth-associated, and the highest production of $CoQ_{10}$ (1.69 mg/g dry cell) was obtained under uncontrolled pH: this production was 1.7 times higher than that obtained at controlled pH 7. Therefore, pH was a key factor affecting $CoQ_{10}$ production. The effect of light irradiation on $CoQ_{10}$ production was negligible. This result offers an advantage for mass production of $CoQ_{10}$.

• Preventive Nutrition and Food Science
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• 제4권3호
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• pp.175-179
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• 1999

To develop a production method for modified starches with less pollution, pH adjustment and gamma irradiation were applied to commerical corn starch. Blue values were significantly decreased , while alkali number, optical transmittance and solubility markedly increased when gamma irradiation was applied to pH 2 adjusted corn starch. Water binding capacity and swelling power at pH 5 were the highest among the samples. Gelatinization viscosity was considerably affected by gamma irradiation and pH of the starch. Gamma irradiation of pH 2 adjusted starch showed the lowest peak viscosity and the best cooling stability among the tested samples . Therefore, the production of modified starch with low viscosity as well as with sufficient viscosity stability seems feasible by controlling the pH of the starch and gamma irrdiation.

• Natural Product Sciences
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• 제2권2호
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• pp.90-95
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• 1996

When reserpine-producing cell strains of Rauwolfia serpentina were transferred from the dark to the light irradiation, the production of reserpine was extremely enhanced whereas the cell growth was suppressed. In an incubation period of 20 days, the most effective culture condition for reserpine production was the combination of 8 days of dark culture and following 12 days of light culture. The time courses of both cell growth and reserpine production were measured in vitro in order to clarify the effect of wave length range of light on the biosynthesis of reserpine. Although the growth of cultured cells which had been incubated under continuous red, yellow, and green lights, respectively, was similar to that of the cultured cells subcultured in the dark. The cells cultured under red light irradiation produced less reserpine than dark-grown cultures. Both blue and near-ultraviolet light inhibited the growth of cultured cells. The production of reserpine was strikingly enhanced by blue light, but was strongly inhibited by near-ultraviolet light.

• Journal of Microbiology and Biotechnology
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• 제24권2호
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• pp.209-216
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• 2014

The efficiency of gamma irradiation (0, 1, 5, 10, 15, 20, and 30 kGy) as a sterilization method of corn samples (30 g) artificially contaminated with Fusarium moniliforme stored at normal condition ($25^{\circ}C$ with approximate relative humidity (RH) of 55%) and optimal condition ($25^{\circ}C$ with a controlled RH of 97%) was studied. The results showed that the fungal growth and the amount of fumonisin were decreased as the dose of gamma irradiation increased. Gamma irradiation at 1-5 kGy treatment significantly inhibited the growth of F. moniliforme by 1-2 log reduction on corn samples (P < 0.05). Sublethal effect of gamma irradiation was observed at 10-20 kGy doses after storage, and a complete inactivation required 30 kGy. Fungal growth and fumonisin production increased with higher humidity and longer storage time in all corn samples. This study also demonstrated that there was no strict correlation between fungal growth and fumonisin production. Storage at normal condition significantly resulted in lower growth and fumonisin production of F. moniliforme as compared with those stored at optimal condition (P < 0.05). Gamma irradiation with the dose of ${\geq}5$ kGy followed by storage at normal condition successfully prolonged the shelf life of irradiated corns, intended for human and animal consumptions, up to 7 weeks.

• 환경위생공학
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• 제14권3호
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• pp.123-129
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• 1999

The utilization methods of algae biomass have been studied constantly in whole world. These are $\circled1$the wastewater treatment if waste stabilization pond and oxidation ditch etc. and $\circled2$the biosorption of heavy metals and recovery of strategic' precious metals and $\circled3$the single-celled protein production and the production of chemicals like coloring agent and $\circled4$the production of electric energy through methane gasification. The culture system also has been developed constantly in relation with such utilization method developments. In the result of experimental operation under continuous and cyclic irradiation of light, using high rate algae biomass culture pond(HRABCP), which had been made so as to be an association system with the various items which had been managed to have high efficiency for algae culture, the algae production of the 12 hours-irradiance pond was 41.48 Chlorophyll-a ${\mu}g/L$ only in spite of having the more chance of $CO_2$ synthesis to algae cell than the 24 hours-irradiance pond. This means that the energy supply required for dark-reaction of photosynthesis is very important like this. The difference of algae production between continuous and cyclc irradiation explains that the dark-reaction of photosynthesis acts on algae production as the biggest primary factor. The continuous irradiance on HRABCP made the good algae-production($1403.97{\;}{\mu}g$ Chlorophyll-a/mg) and the good oxygen-production(5.8 mg $O_2/L$) and the good solid-liquid seperation. especially, DO concentration through the oxygen-production was enough to fishes' survival.

• Preventive Nutrition and Food Science
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• 제19권3호
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• pp.156-163
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• 2014

We investigated the effects of a high-protein diet and resveratrol supplementation on immune cells changes induced by abdominal irradiation in rats. Female Wistar rats were divided into 5 groups: 1) control diet, 2) control diet with irradiation 3) 30% high-protein diet with irradiation, 4) normal diet with resveratrol supplementation and irradiation, and 5) 30% high-protein diet with resveratrol supplementation and irradiation. We measured blood protein and albumin concentrations, lipid profiles, white blood cell (WBC) counts, proinflammatory cytokine production, and splenocyte proliferation in rats that had been treated with a 17.5 Gy dose of radiation 30 days prior. A high-protein diet affected plasma total cholesterol and very low density lipoprotein-cholesterol levels, which were increased by the radiation treatment. In addition, the lymphocyte percentage and immunoglobulin M (IgM) concentration were increased, and the neutrophil percentage was decreased in rats fed a high-protein diet. Resveratrol supplementation decreased the triglyceride (TG) level, but increased the IgM concentration and splenocyte proliferation. Proinflammatory cytokine production was lower in rats fed a high-protein diet supplemented with resveratrol than in rats fed a control diet. The results of the present study indicate that high-protein diets, with or without resveratrol supplementation, might assist with recovery from radiation-induced inflammation by modulating immune cell percentages and cytokine production.

• 한국식물병리학회지
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• 제13권2호
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• pp.105-112
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• 1997

Didymella bryoniae, gummy stem blight fungus of cucurbits, has been known not to produce its pycnidium in vitro without irradiation. Various methods for producing pycnidiospores of the fungus as an inoculum have been used. However, those methods have not been verified in terms of efficiency of the productivity, activity and synchronous maturation of the inoculum. Therefore, a pycnidiospore production method in vitro that is highly reliable and reproducible has to be developed to obtain a large amount of inoculum for screening disease resistant varieties or effective fungicides. Here we standardized a mass-production technique for pycnidiospores of D. bryoniae in vitro by comprehensively finding the optimal conditions such as kinds and thickness of cultural medium, growing temperature, and quality and duration of irradiation as well as examining the activity and pathogenicity of the pycnidiospores reproduced. In brief, mycelial colony on the PDA plate was cultured at 26$^{\circ}C$ for 2 days under the darkness, and then the plate was irradiated under the UV light (12 hr/a day) for 2~3 days at the same temperature(26$^{\circ}C$). Two days after UV irradiation, a great number of pycnidia was simultaneously formed. This plate was subjected to darkness again for 4~5 days to mature pycnidiospores. We could obtain a large amount of inoculum that is synchronously matured in a short period of time through the above procedures.

• Nuclear Engineering and Technology
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• 제55권11호
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• pp.3996-4001
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• 2023

The High-flux Advanced Neutron Application Reactor (HANARO) produces radioisotopes (RIs) (¹³¹I, ¹⁹²Ir, etc.) through neutron irradiation on various RI production targets. Among them, ¹⁷⁷Lu and ¹⁶⁶Ho are particularly promising owing to their theranostic characteristics that facilitate simultaneous diagnosis and treatment. Prior to neutron irradiation, evaluating the nuclear heating of the RI production target is essential for ensuring the thermal-hydraulic safety of HANARO. In this study, the feasibility of producing ¹⁷⁷Lu and ¹⁶⁶Ho using irradiation holes of HANARO was investigated in terms of thermal-hydraulic safety. The nuclear heating rates of the RI production target by prompt and delayed radiation were calculated using MCNP6. The calculated nuclear heating rates were used as an input parameter in COMSOL Multiphysics to obtain the temperature distribution in an irradiation hole. The degree of temperature increase of the ¹⁷⁷Lu and ¹⁶⁶Ho production targets satisfied the safety criteria of HANARO. The nuclear heating rates and temperature distribution obtained through the in silico study are expected to provide valuable insight into the production of ¹⁷⁷Lu and ¹⁶⁶Ho using HANARO.

• Food Science and Biotechnology
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• 제17권4호
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• pp.723-727
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• 2008

The effect of gamma irradiation on the prevention of breeding a patulin-producing mold and reducing patulin content was evaluated in an apple model system. Penicillium griseofulvum, a patulin-producing standard mold strain was artificially inoculated into apples and a gamma irradiation was performed. The $D_{10}$-values of the conidia of P. griseofulvum in an aqueous suspension and the apple model system were calculated at 0.28 and 0.48 kGy, respectively. The viable cell counts of the inoculated conidia in the apples showed 2 decimal point reductions at a dose of 1 kGy. Breeding and growth of the survived conidia was prevented during 10 weeks of post-irradiation storage period, especially at $4^{\circ}C$. The concentration of patulin in the non-irradiated apples was gradually increased and reached about 950 ppm at $25^{\circ}C$ and 410 ppm at $4^{\circ}C$, but the production of patulin was not observed during storage after 1 kGy of gamma irradiation.