• 생명과학회지
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• 제29권1호
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• pp.135-145
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• 2019

자이모모나스 모빌리스(Zymomonas mobilis)는 수십 년 동안 생화학적 발효 기술을 통한 수송용 에탄올을 생산하기에 적합한 산업용 미생물로 각광을 받아왔다. 최근 이 균주의 포스트 게놈 시대 도래 및 미국 듀폰사(DuPont, USA)의 세계 최대 산업용 목질계 에탄올 생산 시설 완료 등은, 이 미생물을 이용한 산업적 에탄올 생산 공정 가시화를 위한 다양한 연구들을 파생시키고 있다. 특히, 산업용 셀룰로오스 에탄올 발효공정에 이용되는 미생물은 다양한 독성 발효 저해물질 및 물리적 스트레스에 보다 쉽게 노출 될 수 있다. 따라서 본 논문은 이 미생물이 보유한 최신 생리학적 이해와 관련 된 정보와 다양한 환경적 스트레스에 견딜 수 있는 산업적 강건성 및 산업용 균주 개발 방법에 대한 사례 및 이 균주를 이용한 가격 경쟁적인 목질계 에탄올 생산 공정 개발에 필요한 균주 개발에 대한 미래 지향적 연구 방향에 대하여 기술하였다.

• Journal of Microbiology and Biotechnology
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• 제31권5호
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• pp.756-763
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• 2021

Agarose is a linear polysaccharide composed of ᴅ-galactose and 3,6-anhydro-ʟ-galactose (AHG). It is a major component of the red algal cell wall and is gaining attention as an abundant marine biomass. However, the inability to ferment AHG is considered an obstacle in the large-scale use of agarose and could be addressed by understanding AHG catabolism in agarolytic microorganisms. Since AHG catabolism was uniquely confirmed in Vibrio sp. EJY3, a gram-negative marine bacterial species, we investigated AHG metabolism in Streptomyces coelicolor A3(2), an agarolytic gram-positive soil bacterium. Based on genomic data, the SCO3486 protein (492 amino acids) and the SCO3480 protein (361 amino acids) of S. coelicolor A3(2) showed identity with H2IFE7.1 (40% identity) encoding AHG dehydrogenase and H2IFX0.1 (42% identity) encoding 3,6-anhydro-ʟ-galactonate cycloisomerase, respectively, which are involved in the initial catabolism of AHG in Vibrio sp. EJY3. Thin layer chromatography and mass spectrometry of the bioconversion products catalyzed by recombinant SCO3486 and SCO3480 proteins, revealed that SCO3486 is an AHG dehydrogenase that oxidizes AHG to 3,6-anhydro-ʟ-galactonate, and SCO3480 is a 3,6-anhydro-ʟ-galactonate cycloisomerase that converts 3,6-anhydro-ʟ-galactonate to 2-keto-3-deoxygalactonate. SCO3486 showed maximum activity at pH 6.0 at 50℃, increased activity in the presence of iron ions, and activity against various aldehyde substrates, which is quite distinct from AHG-specific H2IFE7.1 in Vibrio sp. EJY3. Therefore, the catabolic pathway of AHG seems to be similar in most agar-degrading microorganisms, but the enzymes involved appear to be very diverse.

• Journal of Microbiology and Biotechnology
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• 제31권2호
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• pp.290-297
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• 2021

Leptolyngbya sp. KIOST-1 (LK1) is a newly isolated cyanobacterium that shows no obvious cytotoxicity and contains high protein content for both human and animal diets. However, only limited information is available on its toxic effects. The purpose of this study was to validate the safety of LK1 powder. Following Organisation for Economic Co-operation and Development (OECD) guidelines, a single-dose oral toxicity test in Sprague Dawley rats was performed. Genotoxicity was assessed using a bacterial reverse mutation test with Salmonella typhimurium (strains TA98, TA100, TA1535, and TA1537) and Escherichia coli WP2 uvrA, an in vitro mammalian chromosome aberration test using Chinese hamster lung cells, and an in vivo mammalian erythrocyte micronucleus test using Hsd:ICR (CD-1) SPF mouse bone marrow. After LK1 administration (2,500 mg/kg), there were no LK1-related body weight changes or necropsy findings. The reverse mutation test showed no increased reverse mutation upon exposure to 5,000 ㎍/plate of the LK1 powder, the maximum tested amount. The chromosome aberration test and micronucleus assay demonstrated no chromosomal abnormalities and genotoxicity, respectively, in the presence of the LK1 powder. The absence of physiological findings and genetic abnormalities suggests that LK1 powder is appropriate as a candidate biomass to be used as a safe food ingredient.

• 대한본초학회지
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• 제32권6호
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• pp.1-7
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• 2017

Objectives : The heartwood of Sappan Lignum has been used since ancient times as an ingredient in folk medicines against anti-bacterial and anti-anemia purposes. Many bioactive constituents have been derived from this biomass such as chalcones and homoisoflavonoids. In the current investigation, the antioxidant and anti-diabetic properties using DPPH and $ABTS^+$ radicals scavenging, ${\alpha}-glucosidase$, and advanced glycation end products (AGEs) inhibition assays were evaluated by different extraction methods of Sappan Lignum. Methods : In our continuing investigation for bioactive natural ingredients, the antioxidant and ${\alpha}-glucosidase$ inhibitory properties of Sappan Lignum extracts were prepared from different extraction methods and the biological efficacies were investigated in vitro. The antioxidant properties were evaluated employing radical scavenging assays using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) ($ABTS^+$) radicals. In addition, the anti-diabetic effects of Sappan Lignum extracts were tested via ${\alpha}-glucosidase$ and AGEs formation inhibitory assay. The total phenolic contents were determined using a spectrophotometric method. Results : All the tested samples showed dose-dependent radical scavenging and ${\alpha}-glucosidase$ inhibitory activities. Among the tested extracts, the 80% methanolic extract of Sappan Lignum was showed the most potent activity with an $IC_{50}$ value of $82.3{\pm}1.7{\mu}g/m{\ell}$ against DPPH radical scavenging assay. While, $ABTS^+$ radical scavenging activity of 80% methanolic extract was higher than those of other extracts. Also, ${\alpha}-glucosidase$ inhibitory and AGEs formation effects of each extacts and total phenolic contents were evaluated. Conclusions : These results suggested that Sappan Lignum can be considered as a new effective source of natural antioxidant and anti-diabetic materials.

• Membrane and Water Treatment
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• 제14권1호
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• pp.35-45
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• 2023

Biofilms significantly affect the performance of wastewater treatment processes in which biodegradability of numerous microorganisms are actively involved, and various technologies have been applied to secure microbial biofilms. Understanding changes in biofilm characteristics by regulating expression of signaling molecules is important to control and regulate biofilms in membrane bioreactor, i.e., biofouling. This study investigated effects of addition of acyl-homoserine lactones (AHL) as a controllable factor for the microbial signaling system on biofilm formation of Pseudomonas aeruginosa PAO1 and multiple strains in membrane bioreactor. The addition of three AHL, i.e., C4-, C6-, and C8-HSL, at a concentration of 200 ㎍/L, enhanced the formation of the PAO1 biofilm and the degree of increases in the biofilm formation of PAO1 were 70.2%, 76.6%, and 72.9%, respectively. The improvement of biofilm formation of individual strains by C4-HSL was an average of 68%, and the microbial consortia increased by approximately 52.1% in the presence of 200 ㎍/L C4-HSL. CLSM images showed that more bacterial cells were present on the membrane surface after the AHL application. In the COMSTAT results, biomass and thickness were increased up to 2.2 times (PAO1) and 1.6 times (multi-strains) by C4-HSL. This study clearly showed that biofilm formation was increased by the application of AHL to individual strain groups, including PAO1 and microbial consortia, and significant increases were observed when 50 or 100 ㎍/L AHL was administered. This suggests that AHL application can improve the biofilm formation of microorganisms, which could yield an enhancement in efficiency of biofilm control, such as in various biofilm reactors including membrane bioreactor and bioflocculent systems in water/wastewater treatment processes.

• 한국버섯학회지
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• 제20권3호
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• pp.163-167
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• 2022

본 연구에서는 균막 형성을 위해 기존에 활용하고 있는 버섯 종과 다른 말굽버섯을 활용하였으며, 다양한 조건으로 감마선 조사를 진행하여 독립성이 검증된 변이균주를 획득하였다. 확보된 균주들의 톱밥배지 및 액체배지에서의 균막 형성을 관찰하고 각 균막의 특성을 조사한 결과 장수버섯, 시루송편버섯의 균막과 비교하여 비슷하거나 더 좋은 결과를 보인 균주를 확인할 수 있었다. 또한 톱밥배지보다는 액체배지에서 배양 했을 때 균막의 활용도 및 경제성이 더 높은 것으로 판단된다. 본 결과는 버섯 균사체를 이용한 대체육, 바이오소재 발굴을 위한 연구에 활용할 수 있을 것으로 여겨진다.

• 한국미생물·생명공학회지
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• 제51권3호
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• pp.257-267
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• 2023

The potential polyhydroxyalkanoates (PHA)-producing bacteria, Bacillus megaterium PP-10, was successfully isolated and studied its feasibility for utilization of pineapple peel waste (PPW) as a cheap carbon substrate. The PPW was pretreated with 1% (v/v) H₂SO₄ under steam sterilization and about 26.4 g/l of total reducing sugar (TRS) in pineapple peel hydrolysate (PPH) was generated and main fermentable sugars were glucose and fructose. A maximum cell growth and PHA concentration of 3.63 ± 0.07 g/l and 1.98 ± 0.09 g/l (about 54.58 ± 2.39%DCW) were received in only 12 h when grown in PPH. Interestingly, PHA productivity and biomass yield (Y_x/s) in PPH was about 4 times and 1.5 times higher than in glucose. To achieve the highest DCW and PHA production, the optimal culture conditions e.g. carbon to nitrogen ratios of 40 mole/mole, incubation temperature at 35℃ and shaking speed of 200 rpm were performed and a maximum DCW up to 4.24 ± 0.04 g/l and PHA concentration of 2.68 ± 0.02 g/l (61% DCW) were obtained. The produced PHA was further examined its monomer composition and found to contain only 3-hydroxybutyrate (3HB). This finding corresponded with the presence of class IV PHA synthase gene. Finally, certain thermal properties of the produced PHA i.e. the melting temperature (T_m) and the glass transition temperature (T_g) were about 176℃ and -4℃, respectively whereas the M_w was about 1.07 KDa ; therefore, the newly isolated B. megaterium PP-10 is a promising bacterial candidate for the efficient conversion of low-cost PPH to PHA.

• 한국육종학회지
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• 제43권6호
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• pp.519-523
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• 2011

'녹양'은 초다수 총체사료용 벼 품종을 육성하기 위하여 1996년 하계에 국제미작연구소에서 다수성인 용문벼를 모본으로하고 신초형 IR67396-16-3-3-1을 부본으로 교배하여 계통육종법에 의하여 육성한 품종으로, 2006년 12월에 직무육성신픔종선정위원회에서 국가목록등재품종으로 선정됨과 동시에 '녹양'으로 명명하였으며, 지역적응시험 결과는 다음과 같다. 1. '녹양'의 출수기는 보통기 재배에서 8월16일로 '다산벼' 보다 5일 정도 늦은 중만생종이다. 2. '녹양'은 흰잎마름병, 호엽고병 및 오갈병에 복합 내병성이나 도열별, 벼멸구에는 약한 편이다. 3. '녹양'은 '다산벼'보다 탈립에 강하고, 후기녹체성이 우수하였다. 4. '녹양'은 가소화양분총량(TDN) 함량이 높고 중성세제 불용섬유소(NDF)와 산성세제불용섬유소(ADF)가 낮아 상대적사료가치(RFV)가 높았다. 5. '녹양'의 총체수량은 지역적응시험에서 2004년부터 2006년 평균 16.5 MT/ha로 '다산벼'보다 11% 증수하는 경향을 보였다. 6. '녹양'은 가소화양분총량(TDN)은 9.9 MT/ha이며 ADF와 NDF가 낮아 상대적 사료가치가 '다산벼'에 비해 높은 품종이다. 7. '녹양'의 쌀 수량은 보통기 재배에서 6.93 MT/ha로 '다산벼'의 80% 수준이었다. 8. 재배적지는 중부 및 남부평야지 1모작 지대이다.

• KSBB Journal
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• 제7권4호
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• pp.296-301
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• 1992

버섯 갈변병 유발세균인 Pseudomonas tolaasii와 이에 대해 길항성을 나타내는 세균을 버섯으로부터 각각 분리 하여 Gram staining, gelatin liquefaction, oxidase test 등을 통해 P. fluorescens와 P. tolaasii 를 동정하였으며 , pigment production, tempera t ture sensitivity, salt tolerance, 그리고 rapid pit­ting test 등의 여러가지 실험을 통하여 특정을 알아 보았다. 또한 P. fluorescens를 대량으로 배양하기 위하여 최적 배지조성 및 배양의 최척조건을 확립하였고, 세포농도를 높이기 위하여 유가배양을 시행하였다. 세포성장에 있어서 carbon 및 energy source 인 glucose의 경우 30g/L일 때 세포농도가 가장 높았으며, yeast extract의 농도가 10g/L에서 세포농도가 최적으로 성장하였다. 질소원인 $NH_4Cl$과 ${(NH_4Cl)}_2SO_4$는 각각 1.0g/L와 O.lg/L일 때 세포성장이 가장 좋게 나타났고, sulfur source인 $MgSO_4{\cdot}7H_2O$의 최적농도는 1.0g/L였다. 그리고 $KH_2PO_4$와 $CaCl_2$는 각각 1.0g/L와 O.lg/L일 때 세포농도가 가장 높았으며, 온도 $30^{\circ}C$, pH 6.0 그라고 DO는 40 %로 유지시켰을 때 세포성장이 가장 높았으며, 유가배양에 의해 세포농도를 증가시킬 수 있었다.

• KSBB Journal
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• 제30권6호
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• pp.283-290
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• 2015

In this study was selected the cellulolytic microorganism and investigated optimum condition of cellulase production for the cellulosic bioethanol production. A bacterial strain Paenibacillus jamilae BRC15-1, was isolated from soil of domestic reclaimed land. For optimizing cellulase production from the selected strain, various culture parameters were investigated such as culture medium, pH (pH 4~10), temperature ($25{\sim}50^{\circ}C$) and culture time (2~72 h). As a result, P. jamilae BRC15-1 efficiently produced cellulase from cellulosic biomass under following conditions: 24 h of culture time (pH 7, $40^{\circ}C$) in manufactured media of CMC (carboxymethyl cellulose) with peptone. Optimum saccharifying condition of crude enzyme produced from P. jamilae BRC15-1 was identified on pH 6 and $40^{\circ}C$ of reaction temperature, respectively. This crude enzyme from P. jamilae BRC15-1 was used for saccharification of pretreated sweet sorghum (Sorghum bicolor var. dulciusculum Ohwi) bagasse under the optimal condition. Finally, pretreated sweet sorghum bagasse including 0.1 g of glucan was saccharified by crude enzyme of P. jamilae BRC15-1 into 2.75 mg glucose, 0.79 mg xylose and 1.12 mg arabinose.