Modelling and Simulation of Cell Growth Dynamics, Substrate Consumption, and Lactic Acid Production Kinetics of Lactococcus lactis

Myrto-Panagiota Zacharof,Robert W. Lovitt 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.1

Lactococcus lactis species have been and still are extensively investigated due to their significant commercial importance. Current scientific research focuses on strains utilized in food industry, due to their multiple uses in food and beverages fabrication. Biomass of Lactococcus lactis is of great interest as well as the end products of its metabolism such as lactic acid and nisin. However their production is constantly challenged due to end product inhibition occurring during intensive propagation of the coccus in reactor systems. To successfully predict the behavior of the culture, the approach of combining mathematics with biology, ergo the development of an unstructured mathematical model, was taken. Although Luedeking and Piret is the model that has been extensively used to demonstrate growth in end-product inhibition cultures, its applicability is limited due to its dependance on the specific growth and product coefficients, particularly related to the culturing conditions used. To overcome these hurdles, a combination of the non competitive single product end inhibition Taylor and Hinselwood models was used, with the significance of this model laying in the fact that it offers a feasible alternative to the commonly used model of Luedeking and Piret for describing fermentation kinetics governed by end-product inhibitions. The fitting with the experimental values, in batch mode, was tested in terms of the coefficient of determination (R²), having values 0.97 ~ 0.99 and suggesting a very good fitting with the experimental data. The model was further developed to achieve theoretical predictions of volumetric cell productivity in continuous and fed-batch mode of substrate feed in different culturring systems.

Design, synthesis, and structure-activity relationship study of halogen containing 2-benzylidene-1-indanone derivatives for inhibition of LPS-stimulated ROS production in RAW 264.7 macrophages

Shrestha, Aarajana,Jin Oh, Hye,Kim, Mi Jin,Pun, Nirmala Tilija,Magar, Til Bahadur Thapa,Bist, Ganesh,Choi, Hongseok,Park, Pil-Hoon,Lee, Eung-Seok Elsevier 2017 European journal of medicinal chemistry Vol.133 No.-

<P><B>Abstract</B></P> <P>As a continuous effort to discover new potential anti-inflammatory agents, we systematically designed and synthesized sixty-one 2-benzylidene-1-indanone derivatives with structural modification of chalcone, and evaluated their inhibitory activity on LPS-stimulated ROS production in RAW 264.7 macrophages. Systematic structure-activity relationship study revealed that hydroxyl group in C-5, C-6, or C-7 position of indanone moiety, and <I>ortho</I>-, <I>meta</I>-, or <I>para</I>-fluorine, trifluoromethyl, trifluoromethoxy, and bromine functionalities in phenyl ring are important for inhibition of ROS production in LPS-stimulated RAW 264.7 macrophages. Among all the tested compounds, 6-hydroxy-2-(2-(trifluoromethoxy) benzylidene)-2,3-dihydro-1<I>H</I>-inden-1-one (compound <B>44</B>) showed the strongest inhibitory activity of ROS production. Further studies on the mode of action revealed that compound <B>44</B> potently suppressed LPS-stimulated ROS production via modulation of NADPH oxidase. The findings of this work could be useful to design 2-benzylidene-indanone based lead compounds as novel anti-inflammatory agents.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A series of halogen containing 2-benzylidene-indanone derivatives were synthesized. </LI> <LI> Evaluated for inhibition of ROS production in LPS-stimulated RAW 264.7 macrophages. </LI> <LI> Structure-activity relationship study was performed. </LI> <LI> C-5, C-6, and C-7 hydroxy-indanone analogues showed better inhibition than malvidin. </LI> <LI> Compound <B>44</B> suppressed LPS-stimulated NADPH oxidase activity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Simulation study of biobutanol production in a polymer-loaded two-phase partitioning bioreactor (PL_TPPB): Simulation and strategy for biobutanol production

염승호 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.10

A simulation study was performed for a two-phase partitioning bioreactor (TPPB) with polymer beads,Dowex Optipore L_493, as a second phase. When the initial glucose concentration is less than 30 g/L, a single-phase bioreactor is preferred, because it consumed all the glucose with 40% of biobutanol yield. Any glucose over the concentration remained in the single-phase bioreactor because cells were completely inhibited by products, mainly biobutanol,and thus glucose availability became less than 100%. The TPPB with 10% polymer beads completely consumed up to 120 g/L glucose and more polymer beads were required for the higher glucose concentration. Instead of increasing the proportion of polymer beads, 2 vvm of nitrogen gas was introduced continuously into the TPPB for the stripping of products, reducing product inhibitions. By applying gas stripping to the TPPB containing 10% polymer beads, 150 g/L of glucose was completely consumed and 99.7% acetone, 46.8% butanol and 82.5% ethanol was stripped out of the TPPB. Finally, on the basis of these estimations, a novel strategy based on the initial glucose concentration was suggested for high biobutanol production.

Sodium inhibition of fermentative hydrogen production

Kim, Dong-Hoon,Kim, Sang-Hyoun,Shin, Hang-Sik Elsevier 2009 International journal of hydrogen energy Vol.34 No.8

<P><B>Abstract</B></P><P>A continuous-stirred-tank reactor (CSTR) was fed with low-sodium influent containing 0.27g of Na<SUP>+</SUP>/L for 70 days (Phase I), and then subjected to higher concentrations of Na<SUP>+</SUP>/L, i.e. 2.41 (Phase II), 5.36 (Phase III), and 10.14g (Phase IV-1). At the quasi-steady state of each phase, biomass was sampled for an acute sodium toxicity assay. Unlike the control biomass, which exhibited a monotonic decrease of specific H<SUB>2</SUB> production activity (SHPA) with increasing sodium concentration from 0.27 to 21.00g Na<SUP>+</SUP>/L, the acclimated biomass maintained their activity up to 6.00g Na<SUP>+</SUP>/L. Soluble microbial product analysis revealed that a sudden increase of the exterior sodium concentration changed the metabolic pathway such that it became favorable to lactate production while depressing butyrate production. Meanwhile, when the biomass was allowed for sufficient time to adapt to the chronic toxicity condition, the volumetric H<SUB>2</SUB> production rate (VHPR) was maintained above 4.05L H<SUB>2</SUB>/L/d at up to Phase III. However, an irrecoverable H<SUB>2</SUB> production drop was observed at Phase IV-1 with a significant increase of lactate and propionate production. Although the sodium concentration decreased to 8.12 (Phase IV-2), 6.61 (Phase IV-3), and 5.36g Na<SUP>+</SUP>/L (Phase V) at further operation, the performance was never recovered. A PCR-DGGE analysis revealed that lactic acid bacteria (LAB) and propionic acid bacteria (PAB) were only detected at Phases IV and V, which are not capable of producing H<SUB>2</SUB>.</P>

31P Nuclear Magnetic Resonance Studies of Acetic Acid Inhibition of Ethanol Production by Strains of Zymomonas mobilis

( In Seop Kim ),( Kevin D. Barrow ),( Peter L. Rogers ) 한국미생물생명공학회 2003 Journal of microbiology and biotechnology Vol.13 No.1

Modeling methane production in anaerobic forward osmosis bioreactor using a modified anaerobic digestion model No. 1

Song, Young-Chae,Kim, Minseok,Shon, Hokyong,Jegatheesan, Veeriah,Kim, Suhan Elsevier 2018 Bioresource Technology Vol.264 No.-

<P><B>Abstract</B></P> <P>Anaerobic membrane bioreactor (AnMBR) using microfiltration (MF) or ultrafiltration (UF) membranes was introduced to enhance poor biomass retention of conventional anaerobic digestion (CAD). Recently, forward osmosis (FO) membrane have been applied to AnMBR, which is called AnFOMBR. FO membrane assures not only high biomass retention but also high removal efficiency for low molecular weight (LMW) matters. Methane production rates in CAD, AnMBR, and AnFOMBR were compared using a modified IWA anaerobic digestion model No. 1 (ADM1) in this work. Accumulation of biomass in AnMBR/AnFOMBR results in enhanced biochemical reaction and gains more methane production. AnFOMBR may experience a significant inhibition by accumulated free ammonia and cations, although concentrated soluble substrates rejected by FO membrane are favorable for more methane production. Rejection rate of inorganic nitrogen is a key parameter to determine the inhibition in methane production of AnFOMBR.</P> <P><B>Highlights</B></P> <P> <UL> <LI> ADM1 is modified to compare the performance of CAD, AnMBR and AnFOMBR. </LI> <LI> Membranes integrated into anaerobic digester can increase SRT. </LI> <LI> Increased SRT in AnMBR enhances methane production up to 0.387 l/gCOD. </LI> <LI> Accumulated free ammonia possibly inhibits methane production in AnFOMBR. </LI> <LI> FO membranes with perfect nitrogen removal are not suitable for AnFOMBR. </LI> </UL> </P>

Enhanced Hexanoic Acid Production of Clostridium sp. JS66 Using in situ Removal of Hexanoic Acid and High CO Pressure through Mixotrophic Fermentation

Deurim YUN,Young Soon UM,Sung Ok HAN 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10

Hexanoic acid (HA) is a useful chemical as a precursor of food additive, perfume, and hexanol, an alternative for gasoline. Clostridium sp. JS66 produces HA using syngas as carbon and energy sources. In this study, we conducted mixotrophic fermentation by supplying glucose and syngas together to increase HA production. During the mixotrophic fermentation, produced HA was removed by adsorbent resin to prevent HA inhibition. As a result, gas consumption and HA production increased 6.1 and 3 fold, respectively, under mixotrophic fermentation comparing to no resin mixotrophic fermentation. This result indicates in situ removal of HA is necessary for high production of HA by mixotrophic fermentation. To improve HA production further, high CO pressure was applied during mixotrophic fermentation with absorbent resin. Notably, the final HA concentration under high CO pressure was 5.5 g/L, which was 2.4 times higher than under low CO conditions. This result demonstrates that mixotrophic fermentation under high CO pressure with in-situ removal HA system is effective for high HA production by providing sufficient reducing power for chain elongation and preventing HA inhibition.

Prevention of methane hydrate re-formation in transport pipeline using thermodynamic and kinetic hydrate inhibitors

Kim, Jakyung,Kim, Hyunho,Sohn, Young hoon,Chang, Daejun,Seo, Yutaek,Kang, Seong-Pil Elsevier 2017 Journal of petroleum science & engineering Vol.154 No.-

<P><B>Abstract</B></P> <P>Methane gas produced from marine hydrate deposits will flow together with dissociated water in two phases, and the risk of hydrate reformation must be managed. This study used the OLGA multiphase flow simulation software to simulate methane transportation with dissociated water through a vertical 2160m pipeline in order to determine the amount of monoethylene glycol (MEG) as a thermodynamic hydrate inhibitor. When the hydrate saturation ratio in hydrate deposits varies, a large amount of MEG becomes inevitable. Moreover, when undesired water breakthrough occurs, the MEG concentration would decrease to where hydrates may re-form before responding in the offshore platform. A risk management strategy for hydrate reformation is investigated by adopting under-inhibition with MEG and the addition of PVCap as a kinetic hydrate inhibitor (KHI). The experimental results in high pressure autoclave showed that PVCap exhibited a limited performance in delaying the hydrate formation in a high subcooling condition. Considering the vertical flowline of 2160m, the delay time was not sufficient to prevent the hydrate re-formation in the transport pipeline. Complete prevention of hydrate re-formation can be avoided with 35wt% MEG concentration, however decreasing the MEG concentration to 20wt% was also feasible in order to avoid hydrate formation since it was not observed for more than 960min. In the presence of 0.1wt% of PVCap and 10wt% MEG, the hydrate delay time was of about 311.5min. This delay time is 76% longer than the residence time of methane and water mixture in the transport pipeline, thus this synergistic inhibition can significantly reduce the injection rate of MEG while preventing hydrate formation. This is the first work suggesting a risk management strategy for hydrate reformation in hydrate production system, and thus will provide insights to develop advanced hydrate production technologies.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Multiphase flow simulation was performed for methane hydrate production. </LI> <LI> Hydrate reformation risk was managed by under-inhibition with MEG. </LI> <LI> Synergistic inhibition with MEG and KHI increased onset time significantly. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Hydroxyl- and Halogen-containing Chalcones for the Inhibition of LPS-stimulated ROS Production in RAW 264.7 Macrophages: Design, Synthesis and Structure–Activity Relationship Study

아라자나쉬레스타,Aastha Shrestha,박필훈,이응석 대한화학회 2019 Bulletin of the Korean Chemical Society Vol.40 No.7

Oxidative stress due to overproduction of reactive oxygen species (ROS) plays a major role in inflammation, cancer, and neurodegenerative disorders. In this study, 60 chalcone derivatives with fluorine (F), trifluoromethyl (CF3), trifluoromethoxy (OCF3), chlorine (Cl), and bromine (Br) in ring A and with or without hydroxy (OH) in ring B were designed, synthesized, and screened for inhibitory activity against lipopolysaccharide (LPS)-stimulated ROS production in RAW 264.7 macrophages. Structure?activity relationship study revealed the importance of a hydroxyl moiety in ring B for enhancing inhibitory activity of ROS production. Furthermore, a hydroxyl group at the ortho-position is more essential for inhibition of ROS production followed by meta- and para-positions. Among all, compound 27 that contains para-chlorine moiety in ring A and ortho-hydroxy in ring B displayed the strongest inhibitory activity (IC50 = 3.42??M) against LPS-stimulated ROS production in RAW264.7 macrophages.

매몰지 내 유기물 농도가 분해 속도에 미치는 영향

이채영(Chae-Young Lee),최재민(Jae-min Choi),오승준(Seung-Jun Oh_,한선기(Sun-kee Han),박준규(Joon-Kyu Park) 유기성자원학회 2013 유기물자원화 Vol.21 No.1

회분식 실험을 통해 매몰지 내 유기물의 농도가 분해 속도에 미치는 영향을 평가하였다. 기질은 돈 및 우육을 이용하였으며 기질의 농도는 2, 4, 6, 8 및 10 g VS/L로 선정하였다. 기질의 농도가 2 g VS/L 일 경우에 돈 및 우육의 메탄 발생율 각각 46.3 및 48.4 ml CH4/g VS.d 로 가장 높게 나타났으며 기질의 농도가 증가할수록 메탄 발생율은 감소하였다. 비선형 저해 방정식을 이용하여 평가된 저해 상수 값은 돈육의 경우, n 및 m은 각각 4.9 및 0.6으로 나타났으며 우육은 각각 1.1 및 0.4로 나타났다(n: 최대 메탄 발생율 저해 상수, m: 최종 메탄 수율 저해 상수). 기질의 농도가 증가할수록 메탄 발생율은 민감하게 반응하였으나 최종 메탄 수율은 상대적으로 둔감하게 반응하였다. 또한, 돈 및 우육의 n과 m 값 관계를 통해 기질 농도에 따른 저해 특성은 반경쟁적 저해 특성으로 판단된다. The effect of organic substance on its degradation rate in burial site was investigated using batch tests. Substrate were swine and cattle with the initial concentrations of 2, 4, 6, 8, and 10 g VS(volatile solids)/L, respectively. The highest methane production rates of swine and cattle were found at 2 g VS/L as 46.3 and 48.4 ml CH4/g VS.d, respectively. As substrate concentration increased, the methane production rate decreased. The inhibition constants were n and m that were estimated using nonlinear inhibition model. The values of n and m were inhibition constants of methane production rate and ultimate methane yield, respectively. The values of n and m were 4.9 and 0.6 on swine and 1.1 and 0.4 on cattle. The methane production rate was responded sensitively by increase and decrease of substrate concentration, whereas ultimate methane yield do not relatively. From a relation between n and m, inhibitory effect of substrate concentration was confirmed as uncompetitive inhibition.