• KSBB Journal
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• 제14권6호
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• pp.672-676
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• 1999

캡슐고정화 Aspergillus niger를 이용하여 산소공급이 구연산의 생산에 미치는 영향을 조사하였다. 칼슘알지네이트 캡슐에 고정화된 A. niger는 배양중 성장하여 2일 후에는 균사가 캡슐막을 뚫고 나왔으며 배양 8일 후에는 균사가 캡슐전체를 뒤덮었다. 배양액중의 질소원이 충분하거나 산소가 부족한 경우 균사가 느슨해졌다. 일정한 성장용액의 양에 미생물고정화 캡슐의 양이 많이 투입될 수록 구연산의 생산량은 감소하였다. 플라스크 배양의 경우 부피산소전달계수($K_La$)가 1.8 $hr^{-1}$에서 2.55 $hr^{-1}$로 증가하면 미생물의 성장속도는 증가하지만 구연산의 생산량에는 큰 영향이 없었다. 축중심 공기 부양반응기 내에서의 산소전달 속도증가 ($K_La=150hr^{-1}$)는 미생물의 성장속도는 크게 촉진시켰지만 구연산의 생산량은 오히려 감소시켰다. 그러나 중심축 공기 부양반응기내에서 성장배지 중의 질소원 농도를 감소시키면 플라스크 배양의 생산량보다 약 40%이상 증산할 수 있었다. 뿐만 아니라 최대생산량을 얻는 최적 발효기간도 3일 정도 단축시킬 수 있었다. 캡슐고정화 미생물의 성장이나 구연산 생산량은 중심축 공기 부양반응기의 구조변화에 큰 영향을 받지 않았다.

• Mycobiology
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• 제31권2호
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• pp.81-85
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• 2003

Antifungal properties of methyl 2-benzimidazole carbamate(BMC) were investigated using 16 fungi. Cytotoxicity test of BMC revealed that the morphology of HeLa cells was considerably deformed even at the concentrations as low as 0.1 ppm. Minimum inhibitory concentration(MIC) values of BMC for 7 fungi among the 16 tested ones were lower than $1.95{\times}10^{-4}{\mu}g/ml$, while Aspergillus flavus showed an MIC value higher than 1.0 ${\mu}g/ml$. Tolerance induction against BMC was successful only for Paecilomyces farinosus LAR10, contrary to the expectation that tolerance would be induced for the fungi having high MIC values such as Aspergillus niger ATCC 9642 and A. flavus ATCC 9643. Spore germination of A. niger ATCC 9642 was suppressed by BMC. However the mycelial growth of the fungus once germinated was not retarded at all by BMC up to 8 MIC. Addition of lanosterol provided a remedy for the reduced germination rate of A. niger ATCC 9642 spores.

• Journal of Microbiology and Biotechnology
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• 제3권3호
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• pp.204-208
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• 1993

A fully automatic image analysis method was applied to obtain detailed data on morphological parameters of a glucoamylase fermentation broth with Aspergillus niger No. PFST-38. a mutant strain for glucoamylase hyperproducer. In the initial stage of fermentation. there was an increase in hyphal length. whereas at the end of the fermentation a decrease in hyphal length and increase in hyphal thickness were observed. The percentage of clumps declined with dilution and the influence of shear stress upon hyphal length was negligible. It was found that the slower the decrease in the main hyphal length and the number of tips with the fermentation time. the higher the glucoamylase production rate was recorded. The production rate of glucoamylase was closely related to the increase in the hyphal thickness.

• 한국미생물·생명공학회지
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• 제25권1호
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• pp.44-50
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• 1997

$\beta $-Glucosidase (EC 3.2.1.21) was purified from Aspergillus niger SFN-416 by a sequential process of ammonium sulfate precipitation, Sepadex G-100 and DEAE-Sephacel column chromatography. Molecular weight of the enzyme was 46, 000 daltons. The K$_{m}$ and V$_{max}$ values for PNPG were 0.67 mM and 25 moles/ml $\cdot $min., respectively. The optimum pH and temperature of the enzyme activity were 3.5 and 58$\circ $C, respectively. The enzyme activity was decreased by addition of metal ions, and increased by addition of metanol, ethanol, isopropanol and 1-butanol at a concentration of 10% (v/v). Stability of the enzyme was increased by addition of isopropanol and 1-butanol at a concentration of 10% (v/v).

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2005년도 국제학술대회
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• pp.359-364
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• 2005

The possible use of milk factory waste water as fermentation media for the production of citric acid by cells of Aspergillus niger ATCC 9142 has been investigated. The addition of $Mn^{2+}$, $Fe^{2+}$ and $Cu^{2+}$ to a medium promoted the citric acid production steadily, but addition of another metal ion $Mg^{2+}$decreased the citric acid production. The concentrations of citric acid were marked up to 7.2g/1 and 16.5g/l in a batch bioreactor by A. niger ATCC 9142 with 50g/1 and 100g/l of reducing sugar concentration in milk factory waste water, respectively.

• Mycobiology
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• 제32권2호
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• pp.74-78
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• 2004

An alkaline protease produced by Aspergillus niger C-15 was purified and characterized. The enzyme was purified 19.41-fold with a specific activity of 74150 U/mg and a recovery of 34.4% by gel filtration and ion exchange chromatography. The molecular weight of the enzyme was estimated to be 34 kDa. The optimum pH and temperature for the protease activity were pH 8.0 and $60^{\circ}C$, respectively. The enzyme activity inhibited by EDTA suggests that the preparation contains a metalloprotease. The enzyme activity of the metalloprotease was completely inhibited by 5 mM $HgCl_2$ and $FeCl_3$, while partially inhibited by $CuSO_4$, and $MnCl_2$. When polyols such as glycerol, mannitol, sorbitol and xylitol, were added to the reaction medium, most polyols tested enhanced protease activity. Especially, glycerol showed the highest effect. The alkaline metalloprotease was stable at high temperature and retained more than 90% of the initial activity at $60^{\circ}C$ and 86.4% under addition of glycerol.

• Journal of Microbiology and Biotechnology
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• 제5권3호
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• pp.172-176
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• 1995

Citrate is mainly produced from fungi and oxygen transfer has been known as one of the important factors in citric acid production. A bubble column bioreactor was used for citrate production after pellet was initially made using a stirred bioreactor for the inoculation. The relationship between the pellet size of Aspergillus niger and the oxygen transfer was elucidated by considering morphological characteristics of the pellet. The pellet size was determined by adjusting the impeller speed in the stirred bioreactor and the optimum diameter of the pellet was observed to be 2.2 mm under the experimental conditions. Pellet was maintained quite stable in the bubble column bioreactor and production of citric acid was significantly improved by maintaining optimal pellet conditions in the bubble column bioreactor.

• Mycobiology
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• 제36권3호
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• pp.167-172
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• 2008

Beef luncheon meat is one of the most popular meals in several countries in the world including Egypt. Thirty one fungal species and 3 species varieties were recovered from 30 samples of beef luncheon meat collected from different supermarkets in Qena. Alternaria, Aspergillus, Emericella, Mucor, Mycosphaerella, Penicillium and Rhizopus were the most common genera on the two types of media. From the above genera, the most prevalent species were Alternaria alternate, Aspergillus flavus, A. fumigatus, A. niger, A. terreus, Emericella nidulans, Mucor racemosus, Mycosphaerella tassiana, Penicillium chrysogenum and Rhizopus stolonifer. Screening of fungi for their abilities to produce lipase enzyme showed that, ten isolates represented 32.26% of total isolates appeared high lipase production, while sixteen isolates (51.61%) were moderate and 5 isolates (16.13%) were low producers. Aspergillus niger, Fusarium oxysporum and Nectria haematococca produced the highest amount of lipase enzyme, so these fungi were used in further studies. The incorporation of five food preservatives (Disodium phosphate, sodium benzoate, citric acid, potassium sorbate and sodium citrate) individually in the culture medium of lipase production exhibited an inhibitive effect on the mycelial growth and enzyme production by Aspergillus niger, Fusarium oxysporum and Nectria haematococca.

• 한국식품과학회지
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• 제28권2호
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• pp.273-278
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• 1996

올리고당중에서 ${\alpha}$-1, 6-결합을 가진 isomaltose, isomaltotriose, panose 등을 주성분으로 하는 이소말토올리고당의 생산을 위해 A. niger 유래의 transglucosidase　（TG)의 효소학적 특성을 살펴보았다. TG는 maltose를 포도당으로 가수분해하여 panose와 포도당을 생성하였다. panose가 초기기질일 때 TG는 panose를 maltose와 포도당으로 가수분해하였다. ${\alpha}$-1, 6-결합을 가진 isomaltose나 isomaltotriose, isomaltotetraose를 기질로 하였을 때 반응산물의 생성은 ${\alpha}$-1,4-결합을 가진 maltose가 기질일 경우와는 다른 양상을 보였다. 반면 maltotriose를 기질로 한 경우에는 maltose와 유사한 양상을 보였다. TG는 maltotetraose(G4)에서 maltodecaose (G10)가 주성분인 말토올리고당을 기질로 한 경우에도 이소말토올리고당을 생성하였다. 기질인 maltose로부터 TG에 의해 panose가 생성되는 반응은 Michaelos-Menten 식으로 표현되었으며 최대속도, $V_{max}$와 Michaelis 상수, $K_m$은 각각 400 ${\mu}M/min$과 21.4${\mu}M$이었다.

• 한국응용곤충학회지
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• 제13권2호
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• pp.71-75
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• 1974

1. 쌀바구미류는 성충>유충>용의 순으로 체내에 곰팡이를 많이 갖고 있었다. 2. 무균소맥에서 사육하면서 체내 균류의 잔존상황을 조사한 바 10일후에는 완전히 제거할 수 있었고, 가장 오래 잔류하는 것은 A. candidus였다. 3. 곰팡이류의 산난수에 미치는 영향은 A. candidus 구가 가장 많았고 A. ruber 그리고 대조구의 순이고 A. niger구가 가장 적었다. 4. 유충의 생육은 A. candidus>A. ruber>대조구의 순으로 양호하였고 A. niger구에서는 2-3령까지 밖에 발육을 하지 못하였다. 5. 생육이 가장 빠른 것은 A. candidus구로 제3주에용화개체를 볼 수 있었고 제4편에 성충 우화를 볼 수 있었다. 대조구에서도 동일한 경향을 볼 수 있었으나 생육은 약간 늦었다. 6. A. niger구에서 생육이 불량한 것은 왕성한 균생장으로 쌀바구미의 활동이 저해되는 것과 동시에 불명의 원인이 있는 듯 하였다. 7. 저곡중의 쌀바구미와 곰팡이류간에는 진화과정을 통하여 원시적 협동작용이 있었다.