• 한국미생물·생명공학회지
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• 제49권1호
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• pp.45-56
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• 2021

Improved amylases were developed from protoplast fusants of two amylase-producing Aspergillus species. Twenty regenerated fusants were screened for amylase production using Remazol Brilliant Blue agar. Crude enzyme extracts produced by solid state fermentation of rice bran were assayed for activity. Three variable factors (temperature, pH and enzyme type) were optimized to increase the amylase activity of the parents and selected fusants using rice bran medium and solid state fermentation. Analysis of this optimization was completed using the Central Composite Design (CCD) of the Response Surface Methodology (RSM). Amylase activity assays conducted at room temperature and 80℃ demonstrated that Aspergillus designates, T5 (920.21 U/ml, 966.67 U/ml), T13 (430 U/ml, 1011.11 U/ml) and T14 (500.63 U/ml, 1012.00 U/ml) all exhibited improved function making them the preferred fusants. Amylases produced from these fusants were observed to be active over the entire pH range evaluated in this study. Fusants T5 and T14 demonstrated optimal activity under acidic and alkaline conditions, respectively. Fusants T13 and T14 produced the most amylase at 72 h while parents TA, TC and fusant T5 produced the most amylase after 96 h of incubation. Response surface methodology examinations revealed that the enzyme from fusant T5 was the optimal enzyme demonstrating the highest activity (1055.17 U/ml) at pH 4 and a temperature of 40℃. This enzyme lost activity with further increases in temperature. Starch hydrolysis using fusant T5 gave the highest yield of glucose (1.6158 g/100 ml). The significant activities of the selected fusants at 28 ± 2℃ and 80℃ and the higher sugar yields from cassava starch hydrolysis over their parental strains indicate that it is possible to improve amylase activity using the protoplast fusion technique.

• 한국축산식품학회지
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• 제30권2호
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• pp.236-242
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• 2010

The objective of this study was to investigate the potential of the application of kimchi LAB as starter culture in the production of fermented sausages. For this, the solid-state model media composed to simulate the substantial conditions of meat mixtures were fermented for 120 h after the treatment with different concentrations of kimchi (0.5, 1.0, 1.5, 3.0, and 5.0%) and lyophilized kimchi-powder (0.2 % and 0.5%). During the fermentation period, the growth of total viable cells and LAB, and the changes of pH and titratable acidity were investigated. The initial LAB counts ranged from 7.18 to 8.34 Log CFU/ mL for kimchi media and from 6.93 to 6.94 Log CFU/mL for kimchi-powder media depending on the added concentrations. The kimchi LAB in this study were not influenced by the immobilized condition for their adaptation and growth by showing no lag phase and thus acted similar as in the submerged medium. The initially increased counts reached around 9 Log CFU/ mL in 12 h independent of the concentrations of a ded kimchi. However, the growth and metabolic activity of kimchi-powder LAB were influenced by the immobilized condition. Supposedly, as the nutrient supply in solid-state depended solely on diffusion, these differences in the souring properties were caused by the LAB topography in the medium matrix. Nevertheless, the differences in the numbers of LAB between two media were less than 0.5 Log units and the pH drop in the solidstate batches was quite rapid and reached low values. Therefore, it can be assumed that kimchi and kimchi-powder LAB showed the utility as the substitute of commercial starter culture even without a rehydrating pretreatment.

• Korean Chemical Engineering Research
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• 제52권3호
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• pp.402-406
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• 2014

본 실험에서는 농부산물인 밀짚을 고체배지로 사용하여 Aspergillus niger NRRL 567에서 구연산 생산 시, 발효조건과 첨가제가 구연산 생산에 미치는 영향을 단일변수(one-factor-at-a-time) 최적화를 이용하여 주요 인자의 순차적 최적화를 수행하였다. 발효 72시간에서 온도, 수분함량, 입자크기, pH와 첨가제 농도를 최적화했을 때, 각각 $30^{\circ}C$, 70%, 0.5~1.0 mm, pH 5.5와 4% 메탄올 첨가조건에서 최대 구연산 생산인 206.0 g/kg 건조중량 (DM)을 확인할 수 있었다. 이는 최적화 이전 구연산 최고 생산인 74.5 g/kg DM 대비 177% 증가한 결과이다. 최적화 실험에서 도출된 조건을 밀짚, 옥수수대와 피트모스(peat moss)에 적용하여 고체발효를 수행하였을 때, 발효 120시간에서 각각 231.8, 213.8, 240.2 g/kg DM 구연산 생산을 확보하였다. 본 실험 결과는 밀짚과 옥수수대 등의 목질계 농부산물을 이용한 구연산 생산 시, 고체발효법이 기존의 액체발효법의 대체가 가능함을 시사하였다.

• Journal of Microbiology and Biotechnology
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• 제34권5호
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• pp.1017-1028
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• 2024

Lignocellulolytic enzymes play a crucial role in efficiently converting lignocellulose into valuable platform molecules in various industries. However, they are limited by their production yields, costs, and stability. Consequently, their production by producers adapted to local environments and the choice of low-cost raw materials can address these limitations. Due to the large amounts of olive stones (OS) generated in Morocco which are still undervalued, Penicillium crustosum, Fusarium nygamai, Trichoderma capillare, and Aspergillus calidoustus, are cultivated under different fermentation techniques using this by-product as a local lignocellulosic substrate. Based on a multilevel factorial design, their potential to produce lignocellulolytic enzymes during 15 days of dark incubation was evaluated. The results revealed that P. crustosum expressed a maximum total cellulase activity of 10.9 IU/ml under sequential fermentation (SF) and 3.6 IU/ml of β-glucosidase activity under submerged fermentation (SmF). F. nygamai recorded the best laccase activity of 9 IU/ml under solid-state fermentation (SSF). Unlike T. capillare, SF was the inducive culture for the former activity with 7.6 IU/ml. A. calidoustus produced, respectively, 1,009 ㎍/ml of proteins and 11.5 IU/ml of endoglucanase activity as the best results achieved. Optimum cellulase production took place after the 5th day under SF, while ligninases occurred between the 9th and the 11th days under SSF. This study reports for the first time the lignocellulolytic activities of F. nygamai and A. calidoustus. Furthermore, it underlines the potential of the four fungi as biomass decomposers for environmentally-friendly applications, emphasizing the efficiency of OS as an inducing substrate for enzyme production.

• Korean Chemical Engineering Research
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• 제52권3호
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• pp.302-306
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• 2014

목질계 분해효소 활성 증대를 위해 밀짚을 이용한 고체발효에서 주요 발효인자의 최적화를 수행하였다. Trichoderma reesei와 Aspergillus niger를 이용한 혼합배양에서 고체발효에 주요한 영향을 미친다고 알려진 배양온도, pH, 수분함량과 고체기질 크기를 순차적 최적화를 진행하였다. 실험에 적용 된 인자 모두 목질계 분해효소 활성에 유의한 효과를 주었으며, 발효온도 $40^{\circ}C$, pH 7, 수분함량 75%와 고체기질 크기 0.25~0.5 mm가 목질계 분해효소 생산을 위한 최적 조건임을 알 수 있었다. 최적조건 하에서 밀짚을 이용한 고체발효를 수행하였을 때, 효소활성 기준 cellulase 10.3 IU, endoglucanase 100.3 IU, ${\beta}$-glucosidase 22.9 IU와 xylanase 2261.7 IU/g dry material을 배양 96시간에 확인할 수 있었다. 본 결과는 기존 효소활성 대비 각각 72.6, 48.7, 55.2와 51.9% 증가한 수치로 혼합배양과 순차적 최적화를 적용하여 효과적인 목질계 분해효소 활성 증대가 가능함을 확인하였다.

• KSBB Journal
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• 제20권1호
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• pp.60-65
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• 2005

본 연구의 목적은 최근 DHA와 더불어 분유첨가제 등 기능성 신소재로서 수요가 증가되고 있는 arachidonic acid (AA)를 곰팡이 Mortierella alpina ATCC 32222를 이용하여 실질적으로 값싸게 생산할 수 있는 고체발효공정을 개발하기 위한 것이다. 본 연구에서는 회분식 심부 및 고체발효연구를 통하여 균체성장과 AA 생성에 대한 패턴을 조사하였는데, 심부발효에서는 포도당과 효모추출물을 그리고 고체발효에서는 농산 부산물인 저렴한 쌀겨를 원료로 하여 실험하였다. 심부발효 및 고체발효의 속도론적 관점에서 두 공정 모두 균체성장과 AA 생성간에 전형적인 mixed-growth associated pattern이 얻어졌다. 고체발효 배지의 최적화를 위하여 carbon to nitrogen (C/N) ratio를 6.5-20 범위로 조절하여 실험해 본 결과 쌀겨에 탄소원인 포도당을 첨가해 주지 않은 경우 즉, 6.5에서 가장 좋은 결과가 얻어졌다. 또한 sodium glutamate를 쌀겨에 소량 $(0-4\%,\;w/w)$ 첨가했을 때 보고된 문헌과는 달리 균체성장은 오히려 감소되는 경향을 보였으며, 고온에서 볶은 참깨로부터 얻어진 sesame oil $(7.5\%,\;w/w)$을 첨가했을 경우 AA 생산성은 약 1.2배가 향상되었다.

• 한국식품영양과학회지
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• 제39권6호
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• pp.872-879
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• 2010

조직대두단백을 이용하여 B. subtilis HA에 의한 장기간 동안 고체 발효를 통해 얻어진 발효물의 품질, 항산화 활성 및 물성 변화를 평가하였다. 발효시간에 따라 발효물의 색도는 L값은 감소하고 a, b 값은 증가하였으며 수용성 추출물의 갈색도는 발효 48시간까지는 서서히 증가하나 그 후에는 변화가 없는 것으로 나타났다. TVP 발효물의 물과 70% 에탄올 추출물의 DPPH radical 소거 활성 측정 결과 발효 24시간째 70% 에탄올 추출물의 $ IC_{50}$값이 0.99 mg/mL로 가장 활성이 우수하였고 발효시간이 길어져도 활성이 증가하지 않았다. 또한 ABTS radical 소거 활성도 70% 에탄올 추출물이 발효 72시간째 $ IC_{50}$값이 1.68 mg/g으로 가장 높았다. TVP 발효물의 점조도는 발효 48시간째 7.89 $Pa{\cdot}s^n$으로 가장 높았고 그 후에는 감소하는 것으로 나타났으며 점질물 함량은 발효 24시간째 26.49%로 가장 높은 함량을 보인 후 감소하는 것으로 나타났다. 발효물의 점탄성은 발효 48시간째 가장 높았으며 이후 감소하였고 탄성(G')보다 점성(G")이 높은 것으로 나타났다. $\gamma$-PGA 함량은 발효시간이 증가하면서 증가하는 경향을 보이면서 168시간에 37.72% 생산되었고, 분자량은 발효시간이 경과될수록 감소하였다. Levan 함량은 발효 초기인 12시간째 7.83%에서 발효시간이 경과할수록 감소하는 것으로 나타났다.

• 한국미생물·생명공학회지
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• 제17권6호
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• pp.645-654
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• 1989

The historical background of fish fermentation in Asia and other regions of the world is reviewed. The classification of fermented fish products in different regions is attempted with respect to the technology involved. The fermented fish products are largely divided into three groups; (1) high-salt, (2) low-salt, and (3) non-salt fermented. High-salt fermented products contain over 20％ of salt and are represented by fish sauce, cured fish and fish paste. Low-salt fermented products contain 6-18％ salt and are subdivided into lactic fermented products with added carbohydrate and acid pickling associated with low temperature. Non-salt fermented products are represented by the solid state bonito fermentation and some alkaline fermentation of flat fishes. The local names of the products in different regions are compared and classified accordingly. The microbial and biochemical changes during fish fermentation are considered in relation to the quality of the products, and their wholesomeness is reviewed.

• Food Science and Biotechnology
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• 제27권6호
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• pp.1791-1799
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• 2018

In this study, the immunomodulatory activity of oligopeptide (CP) derived from solid-state fermented cottonseed meal were investigated in immunosuppressed BALB/c mice models by treatment with cyclophosphamide (CY). Results indicated that oligopeptide increased the thymus and spleen indices of CY-treated mice. The count of plague forming cells (PFC) and the content of half serum hemolysis ($HC_{50}$) in immunosuppressive mice were restored to the normal level in CP-10 and CP-20 groups while the cytokines interleukin (IL)-2, IL-6, and tumor necrosis factor alpha (TNF-${\alpha}$) were increased significantly in CP-20 group. Similar increasing the immunoglobulin of IgG and IgM content in the serum of CP-10 group were also observed. These findings indicated that oligopeptide derived from solid-state fermented cottonseed meal had a strong immune-enhancing activity as well as a protective effect against immunosuppression induced by cyclophosphamide in mice.

• Mycobiology
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• 제42권4호
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• pp.346-352
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• 2014

Recently, the Q biotype of tobacco whitefly has been recognized as the most hazardous strain of Bemisia tabaci worldwide, because of its increased resistance to some insecticide groups. As an alternative control agent, we selected an Isaria javanica isolate as a candidate for the development of a mycopesticide against the Q biotype of sweet potato whitefly. To select optimal mass production media for solid-state fermentation, we compared the production yield and virulence of conidia between 2 substrates (barley and brown rice), and we also compared the effects of various additives on conidia production and virulence. Barley was a better substrate for conidia production, producing $3.43{\times}10^{10}$ conidia/g, compared with $3.05{\times}10^{10}$ conidia/g for brown rice. The addition of 2% $CaCO_3+2%$ $CaSO_4$ to barley significantly increased conidia production. Addition of yeast extract, casein, or gluten also improved conidia production on barley. Gluten addition (3% and 1.32%) to brown rice improved conidia production by 14 and 6 times, respectively, relative to brown rice without additives. Conidia cultivated on barley produced a mortality rate of 62% in the sweet potato whitefly after 4-day treatment, compared with 53% for conidia cultivated on brown rice. The amendment of solid substrate cultivation with additives changed the virulence of the conidia produced; the median lethal time ($LT_{50}$) was shorter for conidia produced on barley and brown rice with added yeast extract (1.32% and 3%, respectively), $KNO_3$ (0.6% and 1%), or gluten (1.32% and 3%) compared with conidia produced on substrates without additives.