• KSBB Journal
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• 제20권6호
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• pp.443-446
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• 2005

음식물 쓰레기로부터의 연속 수소 생성 실험을 다양한 수리학적 체류시간(HRT; 18, 21, 24, 30, 36, 42 h)에서 수행하였다. 음식물쓰레기는 분쇄와 알칼리 처리를 거쳐 27.0 g COD/L(average VS 4.4%)의 농도로 fed-batch 형태로 주입되었으며, 반응조 내의 pH는 $5.3{\pm}0.1$ 이상으로 유지되었다. 126일 간의 운전을 통해 유기성 폐기물로부터의 연속 수소 생성이 안정적으로 진행될 수 있음을 확인하였다. 수소 생성 효율은 HRT에 따라 변하였으며, 30 h에서 가장 높은 수치를(25.8 mL $H_2/g\;VS_{added}$, 0.36 mol $H_2/mol\;hexose_{added}$, 0.91 L $H_2/L/d$) 보였다. 대부분의 조건에서 가장 양이 많은 부산물은 노말부티르산이었으며, 수소생성이 증가함에 따라 노말부티르산의 생성이 증가하였다. 이소프로판을 역시 수소 생성과 관련이 있는 나타났다. 반면, 아세트산의 생성량은 수소생성과 반대되는 경향을 보여 수소 소모 아세트산 생성 경로로 발생되는 양이 많았다고 사료된다. 한편 산발효 효율은 $53.3{\sim}65.7%$인 것으로 나타나 기존 산 발효를 수소발효가 대체할 수 있음을 확인하였다.

• 한국수소및신에너지학회논문집
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• 제25권4호
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• pp.337-343
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• 2014

This study was conducted to evaluate the characteristics of dark fermentative $H_2$ production from microalgae (Chlorella vulgaris) using batch reactors under mesophilic (25, $35^{\circ}C$) and thermophilic (45, $55^{\circ}C$) conditions. The $H_2$ yield and $H_2$ production rate increased with increasing temperature. The maximum $H_2$ yield and $H_2$ production rate were 56.77 mL $H_2/g$ dcw, 3.33 mL $H_2/g\;dcw{\cdot}h$ at $55^{\circ}C$, respectively. The activation energy calculated using Arrhenius equation was 36.24 kcal/mol, which was higher than that of dark $H_2$ fermentation of glucose by anaerobic mixed culture. Although the concentration of butyrate was maintained, the concentrations of lactate and acetate increased with increasing temperature. The $H_2$ yield was linearly proportional to acetate/ butyrate ratio.

• Journal of Microbiology and Biotechnology
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• 제15권5호
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• pp.1115-1119
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• 2005

The photoheterotrophic $H_2$ production of Rhodobacter sphaeroides was significantly increased through disruption of the genes coding for uptake hydrogenase and poly-${\beta}$-hydroxybutyrate (PHB) synthase (Lee et al., Appl. Microbiol. Biotechnol. 60: 147-153, 2002). In this work, we further removed the B800-850 light-harvesting (LH) complex from the strain and found an increase in $H_2$ production at the light-saturating cell growth (${\ge}10$ Watts $[W]/m^2$). Neither the mutant nor the wild-type produced more $H_2$ at the brighter light. Accordingly, light does not appear to be limited for the $H_2$ production by the presence of B800-850. However, increase in the level of the spectral complexes resulted in decrease of $H_2$ production. Thus, although the B875 is essential for light harvesting, the consumption of cellular energy for the synthesis of B800-850 and the surplus LH complexes may reduce the energy flow into the $H_2$ production of R. sphaeroides.

• Asian-Australasian Journal of Animal Sciences
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• 제28권8호
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• pp.1202-1208
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• 2015

The effects of daily dietary Bacillus subtilis (Bs), and adding L-tryptophan, fructan, or casein to fecal fermentation broths were investigated as means to reduce the production of noxious gas during manure fermentation caused by ammonia, hydrogen sulfide ($H_2S$), and 3-methylindole (skatole). Eighty swine ($50.0{\pm}0.5kg$) were equally apportioned to an experimental group given Bs in daily feed, or a control group without Bs. After 6 weeks, fresh manure was collected from both groups for fermentation studies using a $3{\times}3$ orthogonal array, in which tryptophan, casein, and fructan were added at various concentrations. After fermentation, the ammonia, $H_2S$, L-tryptophan, skatole, and microflora were measured. In both groups, L-tryptophan was the principle additive increasing skatole production, with significant correlation (r = 0.9992). L-tryptophan had no effect on the production of ammonia, $H_2S$, or skatole in animals fed Bs. In both groups, fructan was the principle additive that reduced $H_2S$ production (r = 0.9981). Fructan and Bs significantly interacted in $H_2S$ production (p = 0.014). Casein was the principle additive affecting the concentration of ammonia, only in the control group. Casein and Bs significantly interacted in ammonia production (p = 0.039). The predominant bacteria were Bacillus spp. CWBI B1434 (26%) in the control group, and Streptococcus alactolyticus AF201899 (36%) in the experimental group. In summary, daily dietary Bs reduced ammonia production during fecal fermentation. Lessening L-tryptophan and increasing fructan in the fermentation broth reduced skatole and $H_2S$.

• Asian-Australasian Journal of Animal Sciences
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• 제29권4호
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• pp.487-499
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• 2016

The aim of the present study was to examine the effects of testosterone (T) and estradiol-$17{\beta}$ ($E_2$) on the production of progesterone ($P_4$) by granulosa cells, and of the $E_2$ on the production of $P_4$ and T by theca internal cells. In the first experiment, granulosa cells isolated from the largest ($F_1$) and third largest ($F_3$) preovulatory follicle were incubated for 4 h in short-term culture system, $P_4$ production by granulosa cells of both $F_1$ and $F_3$ was increased in a dose-dependent manner by ovine luteinizing hormone (oLH), but not T or $E_2$. In the second experiment, $F_1$ and $F_3$ granulosa cells cultured for 48 h in the developed monolayer culture system were recultured for an additional 48 h with increasing doses of various physiological active substances existing in the ovary, including T and $E_2$. Basal $P_4$ production for 48 h during 48 to 96 h of the cultured was about nine fold greater by $F_1$ granulosa cells than by $F_3$ granulosa cells. In substances examined oLH, chicken vasoactive intestinal polypeptide (cVIP) and T, but not $E_2$, stimulated in a dose-dependent manner $P_4$ production in both $F_1$ and $F_3$ granulosa cells. In addition, when the time course of $P_4$ production by $F_1$ granulosa cells in response to oLH, cVIP, T and $E_2$ was examined for 48 h during 48 to 96 h of culture, although $E_2$ had no effect on $P_4$ production by granulosa cells of $F_1$ during the period from 48 to 96 h of culture, $P_4$ production with oLH was found to be increased at 4 h of the culture, with a maximal 9.14 fold level at 6 h. By contrast, $P_4$ production with cVIP and T increased significantly (p<0.05) from 8 and 12 h of the culture, respectively, with maximal 6.50 fold response at 12 h and 6, 48 fold responses at 36 h. Furthermore, when $F_1$ granulosa cells were precultured with $E_2$ for various times before 4 h culture with oLH at 96 h of culture, the increase in $P_4$ production in response to oLH with a dose-related manner was only found at a pretreatment time of more than 12 h. In the third experiment, theca internal cells of $F_1$, $F_2$ and the largest third to fifth preovulatory follicles ($F_{3-5}$) were incubated for 4 h in short-term culture system with increasing doses of $E_2$. The production of $P_4$ and T by theca internal cells were increased with the addition of $E_2$ of $10^{-6}M$. These increases were greater in smaller follicles. These results indicate that, in granulosa cells of the hen, T may have a direct stimulatory action in the long term on $P_4$ production, and on $E_2$ in long-term action which may enhance the sensitivity to LH for $P_4$ production, and thus, in theca internal cells, $E_2$ in short term action may stimulate the production of $P_4$ and T.

• 한국미생물·생명공학회지
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• 제37권2호
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• pp.176-182
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• 2009

안양천 공단 주변 슬러지를 미생물 접종원으로 무기염배지에 10 g/L의 자당을 첨가하여 수소 생산 균주 MeL 6-2을 분리하였다. 분리 균주 MeL 6-2은 호기성조건과 혐기성 조건에서 모두 생장하는 통성 혐기성 균주 Rhodopseudomonas sp.였다. 유기성 폐기물 내에 다량 함유되어있는 포도당과 자당의 농도변화가 수소 생산 속도 및 수소 생성효율에 미치는 영향에 대하여 알아보았다. 포도당을 1~12 g/L의 범위로 첨가할 경우 lag phase 없이 생장하였으며, 첨가량이 증가할수록 단위시간 및 단위부피당 수소 생산성 이 증가하여, 10 g/L에서 최대값인 $4.2\;mmol-H_2{\cdot}L^{-1}{\cdot}h^{-1}$을 보이고 그 이후 다소 감소하는 경향을 보였다. 균체량에 대한 수소생산수율은 $0.76{\sim}2.46\;L-H_2{\cdot}g-DCW^{-1}$의 값을 보였으며, 첨가된 기질인 포도당에 의한 수소생산수율은 $2.6{\sim}3.1\;mol-H_2{\cdot}mol-glucose^{-1}$의 범위였다. 자당을 1~12 g/L의 범위에서 첨가할 경우 약 10시간의 지체기 후 원할한 생장을 보였다. 단위시간 및 단위 세포무게 당 비수소 생산속도는 및 수소 생산수율은 자당의 첨가량이 증가할수록 증가하여 각각 $163\;mmol-H_2{\cdot}mg-DCW^{-1}{\cdot}h^{-1}$ 및 $4.5\;mol-H_2{\cdot}mol-glucose^{-1}$의 최대값을 보였다.

• 유기물자원화
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• 제11권1호
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• pp.70-76
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• 2003

소화슬러지를 열처리한 혼합 배양 미생물을 식종균으로, 자당을 기질로 사용하는 혐기성 수소 생산 공정을 운전하면서 pH 조절, 반복 열처리, 기질 농도 변화 등을 통해 지속적인 수소 생산 방법을 고찰하였다. 유입 기질의 농도가 5g COD/L인 경우 운전 초기에는 $0.5mole\;H_2/mole\;hexose$ 이상의 수소가 발생하지만 9일 이상 지속되지 못하였다. 이러한 현상의 원인은 수소 생성균이 공정 내에서 고농도로 존재하지 못하기 때문인 것으로 판단되며 pH를 5.3으로 유지하는 것만으로는 극복될 수 없었다. 반복 열처리를 적용할 경우 별도의 식종균 재주입 없이 효율이 감소된 수소 생성 공정을 원상태로 복구할 수 있음을 확인할 수 있었으나, 수소 생성 효율이 시간에 따라 감소하므로 열처리를 자주 해야 하는 문제가 발생했다. 유입 기질의 농도가 30g COD/L인 경우에는 24일간 지속적인 수소 생성이 가능하였으며, CSTR의 경우 $1.0-1.4mole\;H_2/mole\;hexose$, ASBR의 경우에는 $0.2-0.3mole\;H_2/mole\;hexose$의 생성 효율을 보였다. 수소 생성 시 유출수 내 용존성 유기물의 90% 이상은 유기산이었으며 그 중 n-butyrate가 가장 많은 양을 차지하였다.

• 생명과학회지
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• 제20권6호
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• pp.902-906
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• 2010

고온성 균주로 알려진 Geobacillus 속의 다양한 균주로부터 내열성 extracellular lipase를 생산하는 G. kaustophilus DSM 7263를 선별하였다. 우리는 본 균주로부터 lipase를 대량생산하기 위한 최적 조건을 조사하였다. 배양 배지에 다양한 천연오일을 첨가한 결과, lipase의 최적 생장을 위한 탄소원으로는 0.5% 올리브 오일이 최적 조건으로 확인되었다. 본 균주의 생장을 위한 최적온도와 pH는 각각 $55^{\circ}C$와 8.0인 반면, lipase 생산을 위한 최적 온도와 pH는 각각 $50^{\circ}C$와 6.0을 나타내어 최적생육조건과는 다른 양상을 나타내었다. 금속이온에 대한 영향에 대해서는 배지에 $Mg^{2+}$과 $Mn^{2+}$을 첨가한 경우 각각 247%와 157%의 효소 생산이 증가한 반면, $Co^{2+}$, $Fe^{2+}$, $Ni^{2+}$, $Cu^{2+}$는 효소 생산을 저해 하였다. 또한 0.1% (v/v) triton X-100을 첨가하면 대조구에 비해 효소생산과 균의 생장이 모두 증가하는 것으로 나타났다.

• 한국미생물·생명공학회지
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• 제25권2호
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• pp.212-217
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• 1997

A strain of Bacillus sp. WS-14 was isolated from soil. Medium optimization for ${\beta}-mannanase$ production by Bacillus sp. WS-14 was performed. Effect of various carbon sources on ${\beta}-mannanase$ production was investigated and locust bean gum was the most effective for ${\beta}-mannanase$ production. ${\beta}-mannanase$ activity and cell growth increased with increasing the concentration of locust bean gum, however, the amounts were not significant. Among nitrogen sources, soytone was the most effective for ${\beta}-mannanase$ production. Inorganic compounds such as $KH_2PO_4,\;NaCl\;Na_2CO_3\;and\;MgSO_4{\cdot}7H_2O\;on\;{\beta}-mannanase$ production were optimized for ${\beta}-mannanase$ production. Locust bean gum of 10.0 g/l, soytone of 5.0 g/l, $KH_2PO_4$ of 2.0 g/l, NaCl of 10.0 g/l, $MgSO_4{\cdot}7H_2O\;of\;0.2\;g/l,\;Na_2CO_3$, of 2.0 g/l were selected as optimum content. Production of ${\beta}-mannanase$ by using the optimum medium was carried out. The maximum ${\beta}-mannanase$ activity of 20.8 unit/ml could be obtained after 14 h fermentation which corresponed to the productivity of ${\beta}-mannanase$ of 1.48 unit/ml-h.

• 한국식품위생안전성학회지
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• 제11권4호
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• pp.235-241
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• 1996

The rhamnan sulfate extracted from green algae seaweed, Monostroma nitidum was characterized as activity in vitro culture assay with macrophages from mice. Rhamnan sulfate indicated that F-4-3 fraction enhanced glucose consumption, as well as the production of nitrogen dioxide and tumor necrosis factor(TNF). F-4-3 fraction was also augmented IL-1 secretion from those macrophages. Effects of the pretreatment of peritoneal macrophages with rhamnan sulfate F-4-3 fraction and several polysaccharides as relative standard on the production of H2O2 induced with unopsonized zymosan A were examined. Pretreatment with polysaccharides inhibited the zymosan A mediated H2O2 production by macrophages. The phorbol myristate acetate (PMA) mediated H2O2 production was not affected by the pretreament. These result suggested that pretreatment of rhamnan sulfate interfered with the interaction of macrophages zymosan A. Rhamnan sulfate inhibited zymosan A mediated production of H**O** by macrophages and F-4-3 Fraction was also activator of macrophages.