• Biotechnology and Bioprocess Engineering:BBE
• /
• 제10권3호
• /
• pp.270-274
• /
• 2005

A reactor-scale hydrogen (H2) production via the water-gas shift reaction of carbon monoxide (CO) and water was studied using the purple nonsulfur bacterium, Rhodopseudomonas palustris P4. The experiment was conducted in a two-step process: an aerobic/chemoheterotrophic cell growth step and a subsequent anaerobic $H_2$ production step. Important parameters investigated included the agitation speed. inlet CO concentration and gas retention time. P4 showed a stable $H_2$ production capability with a maximum activity of 41 mmol $H_2$ g $cell^{-1}h^{-1}$ during the continuous reactor operation of 400 h. The maximal volumetric H2 production rate was estimated to be 41 mmol $H_2 L^{-1}h^{-1}$, which was about nine-fold and fifteen-fold higher than the rates reported for the photosynthetic bacteria Rhodospirillum rubrum and Rubrivivax gelatinosus, respectively. This is mainly attributed to the ability of P4 to grow to a high cell density with a high specific $H_2$ production activity. This study indicates that P4 has an outstanding potential for a continuous H2 production via the water-gas shift reaction once a proper bioreactor system that provides a high rate of gas-liquid mass transfer is developed.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2003년도 생물공학의 동향(XII)
• /
• pp.327-330
• /
• 2003

본 연구에서는 수질정화능력이 뛰어난 것으로 알려진 D회사의 광합성세균 및 그 겔제품의 탈질특성을 알아 보았고, 실제적용을 위한 해수농도 (3.5% NaCl)에서의 이용 가능성 여부도 알아보았다. 각 염농도별(0, 1, 2, 3.5%) 평균 최대 비증식속도는 각각 0.22, 0.22, 0.20, $0.11\;h^{-1}$ 로 계산되었다. 또한, 낮은 pH에서 배양할 경우 성장에 상당한 영향을 받음을 알 수 있었다. 고정화 비-드의 경우, 최대 $N_2$생성율$(dN_2/dt)$는 각각 0.09-0.10 (직경 0.7cm), 0.09-0.11(직경 1.0cm) ml/h로 계산되었고, 비-드 당 평균 $N_2$생성율$(dN_2/dt)$은 각각 5, $5.5\;{\mu}l$/h/bead이었다. D 광합성세균과 탈질미생물간의 두 균 사이에는 어떠한 길항작용도 없었다.

• 미생물학회지
• /
• 제40권2호
• /
• pp.115-120
• /
• 2004

시안세균(Anabaena cylindrica)의 생장을 효과적으로 억제하는 세균을 분리하여 NG-2로 구분하였다. 이 세균은 그람 음성의 막대형 세균으로서 1.3∼$1.8{\times}0.35{\mu}m$ 정도의 크기를 보였으며, 카탈라제와 옥시다제 양성 반응을 나타내었고, 35∼$40^{\circ}C$아 pH 9.0의 적정생장 조건을 보였다. A.cylindrica의 NG-2를 JM 배지에서 혼합배양할 경우 두 미생물군은 서로 반비례적으로 성장하였으며, 24시간 이내에 A. cylindrica의 영양세포가 거의 완전히 소멸하였다. NG-2는 빛이 있는 조건에서만 효과적으로 A. cylindrica를 분해하였는데, 이는 NG-2의 A. cylindrica 분해활성이 숙주의 광합성 작용에 매우 의존적임을 의미한다. 분리세균의 A. cylindlica 분해작용을 현미경으로 관찰한 결과 NG-2는 숙주세포에 부착하지 않고 배지 내에 산재한 상태에서 영양세포를 분해하였으며, 이형세포는 분해되지 않았다. 또한 영양세포의 세포벽이 분해되면 분해세균들이 filament 주위에 집중적으로 부착하는 콜로니를 형성함으로써 A. cylindrica를 완전히 분해하는 것이 확인되었다. A. cylindrica에 대한 NG-2의 분해활성은 인공배지 뿐만 아니라 강물에서도 유사한 결과를 나타내었다. 또한 발포 polystyrene 재질의 bead에 세균을 부착함으로써 A. cylindrica 분해 효율을 더 상승시킬 수 있었다.

• Journal of Microbiology and Biotechnology
• /
• 제25권2호
• /
• pp.162-173
• /
• 2015

The cellular fatty acid composition is important for metabolic plasticity in Rhodobacter sphaeroides. We explored the effects of changing the cellular ratio of unsaturated fatty acids (UFAs) to saturated fatty acids (SFAs) in R. sphaeroides by overexpressing several key fatty acid biosynthetic enzymes through the use of expression plasmid pRK415. Bacteria containing the plasmid pRKfabI₁ with the fabI₁ gene that encodes enoyl-acyl carrier protein (ACP) reductase showed a reduction in the cellular UFA to SFA ratio from 4 (80% UFA) to 2 (65% UFA) and had decreased membrane fluidity and reduced cell growth. Additionally, the ratio of UFA to SFA of the chromatophore vesicles from pRKfabI₁-containing cells was similarly lowered, and the cell had decreased levels of light-harvesting complexes, but no change in intracytoplasmic membrane (ICM) content or photosynthetic (PS) gene expression. Both inhibition of enoyl-ACP reductase with diazaborine and addition of exogenous UFA restored membrane fluidity, cell growth, and the UFA to SFA ratio to wild-type levels in this strain. R. sphaeroides containing the pRKfabB plasmid with the fabB gene that encodes the enzyme β-ketoacyl-ACP synthase I exhibited an increased UFA to SFA ratio from 4 (80% UFA) to 9 (90% UFA), but showed no change in membrane fluidity or growth rate relative to control cells. Thus, membrane fluidity in R. sphaeroides remains fairly unchanged when membrane UFA levels are between 80% and 90%, whereas membrane fluidity, cell growth, and cellular composition are affected when UFA levels are below 80%.

• Asian-Australasian Journal of Animal Sciences
• /
• 제31권4호
• /
• pp.556-563
• /
• 2018

Objective: Spirulina has been recognized formerly as a filamentous spiral-shaped blue- green algae but more recently as a genus of photosynthetic bacteria (Arthrospira). This microorganism is considered as a rich source of essential nutrients for human and animals. The present study was conducted to determine potential application of Spirulina for heat- exposed broilers. Methods: Two hundred and fifty Cobb 500 chicks with male to female in equal ratio with average initial weight of 615.6 g at 17 days of age were divided into 5 treatments with 5 replicates of 10 chicks. Treatment groups were as follows: positive and negative controls with 0% Spirulina supplement and three Spirulina receiving groups with 5 g/kg (0.5%), 10 g/kg (1%), and 20 g/kg (2%) supplementation. Spirulina receiving groups as well as positive control were exposed to high ambient temperature at $36^{\circ}C$ for 6 h/d from 38 to 44 days of age. Biochemical variables were measured in serum samples at 35, 38, 42, and 45 days of broiler chickens age. Results: The results showed that supplementation of the diet with Spirulina decreased concentration of stress hormone and some serum lipid parameters while enhanced humoral immunity response and elevated antioxidant status whereas it didn't meaningfully affect performance characteristics. Nevertheless, feed conversion ratio was improved numerically but not statistically in broilers fed with 1% Spirulina under high ambient temperature. Conclusion: Overall, the present study suggests that alleviation of adverse impacts due to high ambient temperature at biochemical level including impaired enzymatic antioxidant system, elevated stress hormone and lipid profile can be approached in broiler chickens through supplementation of the diet with Spirulina platensis.

• KSBB Journal
• /
• 제8권3호
• /
• pp.256-265
• /
• 1993

본 연구는 광합성 미생물 R. rubrum KS-301을 이용한 연속 반응기인 고정층 반응기와 연속 교반탱크 반응기에서 실험을 수행하여 도입 포도당 농도, 희석속도에 대한 수소 생산성과 고정화 담체에 의해서 형성되는 내부, 외부 및 총괄 물질전달 저항, 반응 속도식 변수 등을 평가한 후 비교하였다. 고정층 반응기에서의 겉보기 $K_m$은 희석속도의 증가에 따라 감소하며, 연속 교반탱크 반응기의 경우는 희석속도 $0.4h^{-1}$ 이상에서는 거의 일정한 값을 나타내었다. 고정층 반응기에서의 수소 생산성과 물질전달 실험결과는 연속 교반탱크 반응기에서와 비슷한 경향을 보이나 두 반응기를 비교하면 수소 생산성과 외부 효율인자는 교반탱크 반응기일 때가 크고, 내부 효율인자는 고정층 반응기일 때가 컸다. 그러나 총괄 효율인자는 두 반응기가 도입 포도당 농도에 따라서는 비슷한 수치를 나타내었다.

• 원예과학기술지
• /
• 제16권2호
• /
• pp.233-235
• /
• 1998

Energized 기능수는 미약 에너지 발생 신소재로서 다음과 같은 공정을 거쳐서 경원생명과학연구소에서 제조되었다; 지하수 순수화 처리촉매제 첨가 에너지 imprinting in platinum column 재료혼합 energized water + 특수처리된 zeolite + 광합성 세균균주 발효 (25C) 여과 최종산물 energized 기능수 (여과액) + energized powder (잔유물), 후지사과 나무가 발아하기 전에 주당 3kg의 energized power를 수관하부에 살포하여 토양과 혼합하고 energized 기능수를 생육기 동안 3회에 걸쳐 토양관주한 결과 수확된 과실의 과피와 과육에 Ca 함량이 증가된 반면 잎과 신초 수피조직중의 Ca 및 N함량은 감소되었다. Energized 기능수 처리는 사과나무 잎의 순광합성율과 뿌리활성을 촉진시켰다. 또한 과실특성에 있어서 가용성 고형물과 안토시아닌 함량이 현저히 증가되었고, 과실의 저온저장중 과실경도가 높게 유지되었으며 과심부 갈변현상이 감소되었다. 과실의 유기산 함량은 처리간에 차이가 없었다.

• Journal of Microbiology and Biotechnology
• /
• 제31권4호
• /
• pp.601-609
• /
• 2021

Erythrobacter species are extensively studied marine bacteria that produce various carotenoids. Due to their photoheterotrophic ability, it has been suggested that they play a crucial role in marine ecosystems. It is essential to identify the genome sequence and the genes of the species to predict their role in the marine ecosystem. In this study, we report the complete genome sequence of the marine bacterium Erythrobacter sp. 3-20A1M. The genome size was 3.1 Mbp and its GC content was 64.8%. In total, 2998 genetic features were annotated, of which 2882 were annotated as functional coding genes. Using the genetic information of Erythrobacter sp. 3-20A1M, we performed pan-genome analysis with other Erythrobacter species. This revealed highly conserved secondary metabolite biosynthesis-related COG functions across Erythrobacter species. Through subsequent secondary metabolite biosynthetic gene cluster prediction and KEGG analysis, the carotenoid biosynthetic pathway was proven conserved in all Erythrobacter species, except for the spheroidene and spirilloxanthin pathways, which are only found in photosynthetic Erythrobacter species. The presence of virulence genes, especially the plant-algae cell wall degrading genes, revealed that Erythrobacter sp. 3-20A1M is a potential marine plant-algae scavenger.

• 한국물환경학회지
• /
• 제38권6호
• /
• pp.282-291
• /
• 2022

Since the efficiency of wastewater treatment using microalgae differs depending on the metabolic characteristics of the species, it is important to understand the characteristics of target algae prior to the application in wastewater treatment. In this study, for the application of Arthrospira platensis to wastewater treatment, which is a filamentous alkaliphilic cyanobacteria, basic species specificity was identified and the possibility of application to wastewater treatment was investigated. As a result of the species specificity investigation, the specific growth rate between pH 7.0 and 11.0 showed the highest value near pH 9 at 0.25/day. The reason for the relatively low growth(0.08/day) at pH 11 was thought to be the CA(carbonic anhydrase) enzyme that is involved in carbon fixation during photosynthesis has the highest activity at pH 8.0 to 9.0, and at pH 11, CA activity was relatively low. In addition, A. platensis showed optimal growth at 400 PPFD(photosynthetic photon flux density) and 30℃, and this means that cyanobacteria such as A. platensis have a larger number of PS-I(photosystem I) than that of PS-II(photosystem II). It was speculated that it was because higher light intensity and temperature were required to sufficiently generate electrons to transfer to PS-I. Regarding the applicability of A. platensis, it was suggested that if a system using the synergistic effect of co-culture of A. platensis and bacteria was developed, a more efficient system would be possible. And different from single cocci, filamentous A. platensis expected to have a positive impact on harvesting, which is very important in the latter part of the wastewater treatment process.

• 한국양식학회지
• /
• 제17권2호
• /
• pp.109-114
• /
• 2004

유용 미생물과 한약재가 포함된 새로운 사료첨가제의 다양한 농도(0.3, 0.6 및 0.9%)에 따른 넙치의 간기능의 활성에 미치는 영향 및 사료첨가제의 특성에 대해서도 조사하였다. 첨가제에 포함된 유용미생물(유산균, 바실러스균, 효모 및 광합성균)의 총수는 한방천이 5.6${\times}$$10^{8}$ CFU/g이었으며, 어력천은 3.0${\times}$$10^{8}$ CFU/g 이었다. 앙식에 일반적으로 사용되는 습사료의 병원미생물(Edwardsiella tarda, Vibrio anguillarum and Streptorwccus sp.)은 모든 첨가군에 있어서 첨가제의 농도의존적으로 유의한 감소를 나타내었다. 간중량 지수는 0.3%의 첨가군에서 유의하게 증가하였다. 혈중의 단백질량은 모든 첨가군이 유의한 증가를 나타내었으나. 간장내의 단백질량은 대조군이 높은 수치를 나타내었다. 생체방어기작을 하는 catalase 및 superoxide dismutase는 0.3% 및 0.6% 첨가군에서 각각 높은 활성을 나타내었다. 이상의 결과로 한약재와 유용미생물 혼합 사료첨가제의 사용으로 넙치의 항산화효소의 활성을 증대시켜 어류스트레스의 면역증대를 기대할 수 있을 것으로 여겨진다.