• Mycobiology
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• v.39 no.2
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• pp.85-91
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• 2011

We investigated the effect of nutritional and environmental factors on Ophiocordyceps longissima mycelial growth. The longest colony diameter was observed on Schizophyllum (mushroom) genetics complete medium plus yeast extract, Schizophyllum (mushroom) genetics minimal medium, and Sabouraud dextrose agar (SDA); however, malt-extract yeast-extract agar, SDA plus yeast extract, yeast-extract malt-extract peptone dextrose agar, SDA, oatmeal agar, and potato dextrose agar showed higher mycelia density. A temperature of $25^{\circ}C$ was optimum and 7.0 was the optimum pH for mycelial growth. Colony diameter was similar under light and dark conditions. Maltose and yeast extract showed the highest mycelial growth among carbon and nitrogen sources respectively. The effect of mineral salts was less obvious; however, $K_3PO_4$ showed slightly better growth than that of the other mineral salts tested. Among all nutrition sources tested, complex organic nitrogen sources such as yeast extract, peptone, and tryptone were best for mycelial growth of O. longissima. Ophiocordyceps longissima composite medium, formulated by adding maltose (2% w/v), yeast extract (1% w/v), and $K_3PO_4$ (0.05% w/v) resulted in slightly longer colony diameter. In vitro mycelial O. longissima growth was sustainable and the production of fruiting bodies could be used for commercial purposes in the future.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.12
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• pp.1755-1762
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• 2014

The objective of this study was to investigate the effect of maize source and complex enzymes containing amylase, xylanase and protease on performance and nutrient utilization of broilers. The experiment was a $4{\times}3$ factorial design with diets containing four source maize samples (M1, M2, M3, and M4) and without or with two kinds of complex enzyme A (Axtra XAP) and B (Avizyme 1502). Nine hundred and sixty day old Arbor Acres broiler chicks were used in the trial (12 treatments with 8 replicate pens of 10 chicks). Birds fed M1 diet had better body weight gain (BWG) and lower feed/gain ratio compared with those fed M3 diet and M4 diet (p<0.05). Apparent ileal crude protein digestibility coefficient of M2 was higher than that of M3 (p<0.05). Apparent metabolisable energy (AME) and nitrogen corrected AME (AMEn) of M1 were significant higher than those of M4 (p<0.05). Supplementation of the basal diets with enzyme A or B improved the BWG by 8.6% (p<0.05) and 4.1% (p>0.05), respectively. The fresh feces output was significantly decreased by the addition of enzyme B (p<0.05). Maize source affects the nutrients digestibility and performance of broilers, and a combination of amylase, xylanase and protease is effective in improving the growth profiles of broilers fed maize-soybean-rapeseed-cotton mixed diets.

• Korean Journal of Microbiology
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• v.38 no.1
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• pp.50-53
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• 2002

The optimum temperature and pH for mycelial growth of B. bassiana DGUM 34001 were $24^{\circ}C$ and pH 7.0, respectively. Among the complex media used, mushroom complex medium (MCM) was the most favorable for mycelial growth. When Czapek-Dox medium was used as a minimal medium, glucose was an excellent source for carbon and energy. Soytone and sodium phosphate were favorable constituent for culture medium as a source of organic nitrogen and phosphorus, respectively. When the fungus was grown in MCM broth, the specific activity of extracellular enzyme of ${\alpha}$-amylase, lipase, chitinase, CMCase and pretease were 297.0, 0.058, 0.33, 0.21 and 22.8 units/mg protein, respectively. When various sources of organic nitrogen and chitin were supplemented to determine the production of enzymes, casein and soluble chitosan enhanced the production of extracellular protease and chitinase.

• Korean Journal of Microbiology
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• v.36 no.2
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• pp.97-102
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• 2000

In order to use Metarhizizmn~ anisopliae as a biological pesticide, effect of envrionmental factors on nlycelial growth, spore formation, and extracellular enzyme activity in culture broth of M. anisopliae DGUM 35001 was determined. Optimal temperature was 26^{\circ}C.$ and optimal pH ranged from 5 to 9. Among the complex media tested, MCM and SDPY media were the most favorable for mycelial growth. When Czapek-Dox agar was used as a mnimal medium, glucose and sucrose among the saccharides were very excellent source of carbohydrate. Among the biopolyners tested. chitin was the most favorable source for mycelial growth and produced high aerial inycelia. Urea and ammonium phosphate as an inorganic nitrogen source and bacto-peptone and soytone as an organic nitrogen source enhanced the mycelial growth When serine as a source of amino acid was supplemented, excellent mycelial growth was shown. Large amount of spores could be obtained from the aerial mycelia of starch medium. When the culture broth was filtrated and then the concentrate with ammonium sulfate was used as a crnde enzyme solution, high enzyme activities of amylase and protease were shown. However, lipase and chitinase activities were comparatively low.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.1
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• pp.61-65
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• 2005

The objective of this work was to investigate the nutritional requirements for the growth of Actinomyces sp. 9RCC5 isolated from the rumen of a native goat in Korea. The growth of strain 9RCC5 on the basal medium or the medium minus certain ingredients from the basal medium demonstrated that strain 9RCC5 showed absolute requirement of vitamin B complex mixture, while hemin and volatile fatty acids (VFA) were stimulatory to growth to some extent. The 9RCC5 strain grew well with casein hydrolysate as the sole added nitrogen source. However, neither a complex of 18 amino acids nor ammonium sulfate effectively replaced casein hydrolysate. Vitamins such as riboflavin and pantothenate were essential for growth, while thiamin and biotin were stimulatory. With regard to VFA, the growth was stimulated by acetic acid but inhibited by valeric acid. Relatively large quantities of $Na^+$, $K^+$ and $Ca^{2+}$ were absolutely required for growth. Supplementation of clarified rumen fluid to the basal medium in a range of 0-10% (vol/vol) resulted in an increased rate of growth as well as an increased extent of growth.

• Journal of Microbiology and Biotechnology
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• v.6 no.6
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• pp.451-455
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• 1996

Physiological studies on the expression of Bacillus thuringiensis subsp. tenebrionis (Btt) gene coding for insecticidal protein in recombinant Escherichia coli 537 were carried out to identify optimal culture condition. It was necessary to shift culture temperature from 30 to $42^{\circ}C$ to express the gene. Expression of the Btt toxin gene by recombinant E. coli 537 began within one hour after induction. Complex nitrogen sources increased production of the insecticidal protein. The total insecticidal protein was 0.5 g/I when using yeast extract as a complex nitrogen source. Soybean hydrolysate showed apparently the highest induction efficiency. After induction, the cellular content of the insecticidal protein was 5.4 times higher than it had been before induction. The optimal cultivation strategy was found to grow cells for 7hours at $30^{\circ}C$ and then 5-8 hours at $42^{\circ}C$. The optimal cultivation pH for the production of insecticidal protein was 6.5. The Btt toxin produced by the recombinant E. coli 537 was found to have the same level of potency against Colorado potato beetle as the original toxin.

• Korean Journal of Ecology and Environment
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• v.53 no.2
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• pp.138-147
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• 2020

The Singil Stream, flowing into an artificial lake, Lake Shihwa (South Korea), experiences a strong anthropogenic pressure with continuous organic matter (OM) inputs from rural, urban, and industrial areas. In this study, we investigated suspended particulate matter (SPM) and streambed sediments collected along the Singil Stream in 2014 and 2016, by applying a dual element approach (δ¹³C and δ¹⁵N) to identify OM sources. The SPM and streambed sediment samples from the indusrial area showed higher organic carbon and nitrogen concentrations (or contents) than those from the other areas, with distinctively lower δ¹⁵N values. Accordingly, our dual element approach indicates that the industrial area was the predominant OM source influencing OM quality and thus water quality of the Singil Stream flowing into Lake Shihwa during the study periods. However, further studies are necessary to better constrain OM sources in the Singil Stream since OM sources from the industrial area appear to be complex.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.5
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• pp.379-381
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• 2000

Anaerobiospirillum succiniciproducens requires expensive complex nitrogen sources such as yeast extract and polypeptone for its growth and succinic acid production. It was found that A. succiniciproducens was able to grow in a minimal medium containing glucose when supplemented with corn steep liquor (CSL) as the sole complex nitrogen source. The concentration of CSL had a significant effect on the glucose consumption by A. succiniciproducent. When 10-15 g/L of CSL was supplemented, cells were grown to an OD(sub)600 of 3.5 and produced 17.8 g/L succinic acid with 20 g/L glucose. These results are similar to those obtained by supplementing yeast extract and polypeptone, thereby suggesting that succinic acid can be produced more economically using glucose and CSL.

• Journal of the Korean Ceramic Society
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• v.39 no.3
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• pp.272-277
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• 2002

Aluminum nitride (AlN) powders and whiskers were synthesized by a modified carbothermal reduction and nitridation where a ($NH_4)[Al(ethylenediaminetetraacetate)]{\cdot}2H_2O$ complex is used as precursor. The AlN powders were obtained by calcining the complex without mixing any carbon source under a flow of nitrogen in the temperature range 1200∼1500$^{\circ}$C and then burning out the residual carbon. The nitridation process was investigated by $^{27}Al$ magic-angle spinning (MAS) unclear magnetic resonance, infrared spectroscopy and X-ray diffraction. The complex is pyrolyzed, converted to ${\rho}$- and ${\gamma}$- alumina and then nitridated to AlN without ${\gamma}-{\alpha}$ alumina transition. The morphology of ${\gamma}$-alumina, when it was converted to AlN, was retained, strongly indicating that ${\gamma}$-alumina is converted to AlN through solid-state $AlO_xN_y$, not through gaseous intermediates such as aluminum and aluminaum suboxides. AlN whiskers were obtained, when a (0001) sapphire was used as a catalyst.

• Journal of the Korean Ceramic Society
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• v.33 no.4
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• pp.455-463
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• 1996

Aluminium nitride (AlN) powder was prepared by using aluminium (III) complexes with dibasic carboxylate ligands(adipato)(hydroxo) aluminium(III) and (hydroxo)(succinato)aluminium (III) as a precursor. The AlN pow-der was obtained by calcining the complexes without mixing any carbon source under a flow of ammonia at 120$0^{\circ}C$ Contary to the conventional carbothermal reduction and nitridiation the process of decarboniza-tion of the residual carbon was not required because of the reaction of ammonia with carbon at temperature >100$0^{\circ}C$. Fine AlN powder was also prepared by calcining a mixture of an (adipato)(hydroxo)aluminium(III) complex and carbon under a flow of nitrogen at 140$0^{\circ}C$ The AlN powders prepared were ultrafine and their morphology was almost the same as that of powders of two precursors.