• Journal of Microbiology and Biotechnology
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• v.7 no.6
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• pp.417-422
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• 1997

Recombinant Bacillus subtilis LKS88[pASA240] containing the amylase gene from Streptomyces albus KSM-35 was exploited in fed-batch cultivation for mass production of maltotetraose-producing amylase. The effects of dissolved oxygen, additional organic nutrients (peptone and yeast extract) and mixed carbon sources (glucose plus soluble starch) on amylase production were examined in fed-batch operations in an effort to determine the optimum conditions for a maximum amylase productivity. Under the optimum conditions, maximum amylase activity was about 4.2 times higher than that obtained in batch cultivations, indicating that mass production of maltotetraose-producing amylase could be accomplished in fed-batch cultivation of the recombinant B. subtilis strain.

• Current Research on Agriculture and Life Sciences
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• v.33 no.2
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• pp.37-40
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• 2015

Poria cocos is an edible and pharmaceutical mushroom with a long history of medicinal use in Korea. For the last 30 years, the domestic cultivated supply of Poria cocos has been unable to meet consumer demand, so Poria cocos is collected in mountainous areas and also imported from China. Thus, to increase the supply of Poria cocos, many artificial cultivation methods have been studied. In this study, Poria cocos is cultivated under different environmental conditions using plastic bags and the results compared. When cultivating Poria cocos at different temperatures (20, 25, 30 and $35^{\circ}C$) and using different numbers of plastic bag layers (1, 2), the most efficient cultivation conditions were a temperature of $25-30^{\circ}C$ and 2 plastic bag layers. The fastest growth was at $25-30^{\circ}C$, and the Poria cocos exhibited no weight change when cultivated using layers of plastic bags (1, 2).

• Journal of Applied Biological Chemistry
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• v.65 no.2
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• pp.89-92
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• 2022

In this study, the effects of soil conditions on antioxidant activities of the aerial and underground parts of rosemary were assessed to determine the most effective soil conditions for cultivation. The antioxidant activity was the highest (51.58±2.93 ㎍/mL) when cultivated in the mixture of gardening soil and vermiculite using DPPH assay. The antioxidant activity of underground parts the highest (127.48±12.38 ㎍/mL) when cultivated in the mixture of soil, vermiculite, and perlite. ABTS assay showed that the antioxidant activity of aerial parts was 230.34±57.93 ㎍·mL^-1 when cultivated in the mixture of gardening soil and vermiculite and that of underground parts was 320.98±16.04 ㎍·mL^-1 when cultivated in the mixture of gardening soil, vermiculite, and perlite. The total phenolic content of aerial parts was the highest (155.25±2.96 mg GAE/g) when cultivated in the mixture of gardening soil. The total flavonoid content of aerial parts was the highest (67.32±5.27 mg QE/g) when cultivated in the mixture of gardening soil. Therefore, the mixture of gardening soil, vermiculite, and perlite is superior to gardening soil alone for cultivation of rosemary to increase its antioxidant activity as well as total phenolic and flavonoid content.

• Applied Chemistry for Engineering
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• v.33 no.2
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• pp.222-228
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• 2022

As a possible feedstock for biodiesel, the marine green alga Tetraselmis sp. was cultivated under different conditions of phototrophic, mixotrophic and heterotrophic cultures. Glycerol, a byproduct from biodiesel production process, was used as the carbon source of mixotrophic and heterotrophic culture. The effects of glycerol supply and nitrate-repletion were compared for different trophic conditions. Mixotrophic cultivation exhibited higher biomass productivity than that of phototrophic and heterotrophic cultivation. Maximum lipid productivity of 55.5 mg L^-1 d^-1 was obtained in the mixotrophic culture with 5 g L^-1 of glycerol and 8.8 mM of nitrate due to the enhancement of both biomass and lipid accumulation. The major fatty acid methyl esters (FAME) in the produced biodiesel were palmitic acid (C16:0), oleic acid (C18:1), linoleic acid (C18:2), and linolenic acid (C18:3). The degree of unsaturation was affected by different culture conditions. The biodiesel properties predicted by correlation equations based on the FAME profiles mostly complied with the specifications from the US, Europe and Korea, with the exception of the cold-filter plugging point (CFPP) criterion of Korea.

• Journal of Applied Biological Chemistry
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• v.58 no.3
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• pp.209-218
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• 2015

Fructooligosaccharides have been mainly produced by microbial fructosyltransferases (FTase) enzymes. The present work focuses on the optimization of medium composition and cultivation parameters affecting FTase produced by Penicillium aurantiogriseum AUMC 5605 in shake flask cultivation. FTase production was optimized in two steps using DeMeo's fractional factorial design. A 1.46-fold increase in FTase production (105.4 U/mL) was achieved using the optimized culture medium consisting of (g/L): sucrose, 600; yeast extract, 10; $K_2HPO_4$, 5; $MgSO_4{\cdot}7H_2O$, 0.5; $(NH_4)_2SO_4$, 1.0 and KCl, 0.5. The obtained results showed that the maximum FTase enzyme activity was produced at initial cultivation pH values ranging from 6.0-6.5, at agitation speed of 200 rpm and using vegetative fungal cells as inoculum. Moreover, results showed that optimization of medium composition and some cultivation parameters resulted in an increase of about 93.7% in the enzyme activity than the nonoptimized cultivation conditions after 96 h of cultivation. Additionally, maximum production and specific production rates recorded 2340 U/L/h and 102 U/L/h/g cells, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.294-302
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• 2020

Studies on the occurrence of rice preharvest sprouting (PHS) have primarily focused on temperature and rainfall duration at the time of PHS induction, but average temperature during grain filling can have a great influence on PHS. This study analyzed the effect of average temperature during grain filling on PHS occurrence and subsequent changes in grain quality after PHS. For two consecutive years, average temperature differences during grain filling were produced by varying the transplanting date. Artificial rainfall was treated under identical accumulated temperatures of 1200℃ after heading. It was confirmed that the occurrence of PHS was higher under high average temperature conditions during grain filling. In addition, the degree of grain quality reduction caused by PHS occurred more severely under high temperature conditions during grain filling. In order to reduce the risk of PHS occurrence and subsequent quality damage, it is important to control the planting date to avoid high-temperature conditions during grain filling.

• Journal of Environmental Science International
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• v.30 no.5
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• pp.379-389
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• 2021

Soil microorganism activity in an agricultural field is affected by various factors including climate conditions, soil chemical properties, and crop cultivation. In this study, we elucidate the correlation between microorganism activity and agricultural environment factors using the dehydrogenase activity (DHA) value, which is one of the indicators of soil microbial activity. As a result, the various factors noted above were related to the DHA value. Annual rainfall, soil Mg2+, bacterial and fungal diversities, types of crops, developmental stages, seasons, and cultivation status were highly correlated with the DHA value. Furthermore, next-generation sequencing (NGS) analysis was used to identify that the type of crop affected soil microbial compositions of both bacteria and fungi. Soil used for soybean cultivation showed the highest relative abundance for Verrucomicrobia, Planctomycetes, and Acidobacteria but Actinobacteria and Firmicutes had the lowest relative abundance. In the case of soil used for potato cultivation, Actinobacteria had the highest relative abundance but Proteobacteria had the lowest relative abundance. Armatimonadetes showed the highest relative abundance in soil used for cabbage cultivation. Among the fungal communities, Mortierellomycota had the highest relative abundance for soybean cultivation but the lowest relative abundance for cabbage cultivation; further, Rozellomycota, Chytridiomycota, and Cercozoa had the highest relative abundance for cabbage cultivation. Basidiomycota had the highest relative abundance for potato cultivation but the lowest relative abundance for soybean cultivation.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.2
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• pp.75-87
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• 2023

This research was conducted to analyze the cultivation performance and meteorological data of winter rye in Suwon, Gyeonggi Province, and Daegu for 11 years. The objective was to compare the growth and yield of domestically cultivated Korean rye cultivar "Gogu" and identify the factors influencing them, to determine suitable cultivation areas for Korean rye cultivar in the country. The results of the study showed that both Daegu and Suwon regions possess favorable climatic conditions for winter rye cultivation, with Suwon exhibiting a superior moisture supply compared to Daegu. Furthermore, the analysis of climate suitability revealed that rainfall days and precipitation were significant factors affecting rye cultivation. Through correlation and principal component analysis, the research evaluated the interrelationship between climate, cultivation factors, and winter rye crop performance, as well as identified variations among winter rye cultivation regions. This study provides valuable insights and information for winter rye cultivation in the country, thereby assisting in the decision-making process for selecting optimal cultivation areas.

• Journal of the Korea Society of Computer and Information
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• v.29 no.4
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• pp.55-62
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• 2024

In this paper, we propose a thin-film hydroponic plant cultivator using HMI display and IoT technology. Existing plant cultivators were difficult to manage due to soil-based cultivation, and it was difficult to optimize environmental conditions due to the open cultivation environment. In addition, there are problems with plant cultivation as immediate control is difficult and growth of plants is delayed. To solve this problem, a cultivation environment was established by connecting the MCU and sensors, and the environment information could be checked and quickly controlled by linking with the HMI display. Additionally, a case was applied to minimize changes in environmental information. Implementation of a thin-film hydroponic cultivation system made soil management easier, improved functionality through operation and control, and made it easy to understand environmental information through the display. The effectiveness of rapid growth was confirmed through crop cultivation experiments in existing growers and hydroponic growers. Future research directions will include optimizing growth information by transmitting and storing cultivation environment information and linking and comparing growth information using vision cameras. It is expected that this will enable efficient and stable plant cultivation.

• Journal of Microbiology and Biotechnology
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• v.4 no.4
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• pp.327-332
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• 1994

Optimum conditions for the production of acetoin and ammonia as the precursors of tetramethylpyrazine(TMP) were determined using Lactococcus lactis subsp. lactis biovar. diacetylactis FC1 in a modified Lactose-citrate broth containing galactose, citrate, and arginine. The cell growth and the productivity of acetoin and ammonia were remarkably increased in an aerobic culture with 10 $\mu M$ of hematin. For the optimum conditions of acetoin and ammonia production, the concentration of citrate and arginine were adjusted to 156 mM and 50 mM after 18 hr cultivation, and citrate and galactose to 156 mM and 50 mM after 36 hr cultivation, respectively. In these conditions, acetoin and ammonia were produced to the final concentration of 127 mM and 195 mM, which were the highest concentations, respectively. The optimum conditions of the TMP production were also determined as follows; 4 hours at 121, pH 8.3, and the maximal yield of TMP under these conditions was 0.81 g/l.