Mixed-culture H₂ fermentation performance and the relation between microbial community composition and hydraulic retention times for a fixed bed reactor fed with galactose/glucose mixtures

Anburajan, P.,Park, J.H.,Sivagurunathan, P.,Pugazhendhi, A.,Kumar, G.,Choi, C.S.,Kim, S.H. Society for Bioscience and Bioengineering, Japan ; 2017 Journal of bioscience and bioengineering Vol.124 No.3

<P>This study examined the mesophilic continuous biohydrogen fermentation from galactose and glucose mixture with an initial substrate concentration of 15 g/L (galactose 12 g/L and glucose 3 g/L) as a resembling carbon source of pre-treated red algal hydrolyzate. A fixed bed reactor was fed with the sugar mixture at various hydraulic retention times (HRTs) ranging 12 to 1.5 h. The maximum hydrogen production rate of 52.6 L/L-d was found at 2 h HRT, while the maximum hydrogen yield of 2.3 +/- 0.1 mol/mol hexose(added), was achieved at 3 h HRT. Microbial communities and species distribution were analyzed via quantitative polymerase chain reaction (qPCR) and the dominant bacterial population was found as Clostridia followed by Lactobacillus sp. Packing material retained higher 16S rRNA gene copy numbers of total bacteria and Clostridium butyricum fraction compared to fermentation liquor. The finding of the study has demonstrated that H-2 production from galactose and glucose mixture could be a viable approach for hydrogen production. (C) 2017, The Society for Biotechnology, Japan. All rights reserved.</P>

Effect of hydraulic retention time (HRT) on biohydrogen production from galactose in an up-flow anaerobic sludge blanket reactor

Sivagurunathan, P.,Anburajan, P.,Kumar, G.,Kim, S.H. Pergamon Press 2016 International journal of hydrogen energy Vol.41 No.46

<P>This study investigated the hydrogen fermentation from galactose in up-flow anaerobic sludge blanket (UASB) reactor under mesophilic temperature of 37 degrees C. The maximum hydrogen production rate (HPR) and hydrogen yield (HY) of 56.8 L/L/d and 2.25 mol/mol galactose added were achieved at a hydraulic retention time (HRT) of 2 h. Further shortening the HRT to 1.5 h, led to the significant drop in the HPR and HY with a value of 48.3 L/L/d and 1.44 mol/mol galactose added, respectively. During the reactor operation, neither external pH adjustment nor recirculation was required, while the pH was maintained in the range of 5.5-6.2 by the carbonate buffer in the nutrient medium. Acetate and butyrate were the major soluble metabolic products (SMPs) formed during the hydrogen fermentation with fewer amounts of lactate and propionate during the peak hydrogen production performances. The results showed that controlling appropriate HRT is prerequisite for the enhancement of hydrogen production performances. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.</P>

Improvement of hydrogen fermentation of galactose by combined inoculation strategy

Sivagurunathan, P.,Anburajan, P.,Kumar, G.,Arivalagan, P.,Bakonyi, P.,Kim, S.H. Society for Bioscience and Bioengineering, Japan ; 2017 Journal of bioscience and bioengineering Vol.123 No.3

<P>This study evaluated the feasibility of anaerobic hydrogen fermentation of galactose, a red algal biomass sugar, using individual and combined mixed culture inocula. Heat-treated (90 degrees C, 30 min) samples of granular sludge (GS) and suspended digester sludge (SDS) were used as inoculum sources. The type of mixed culture inoculum played an important role in hydrogen production from galactose. Between two inocula, granular sludge showed higher hydrogen production rate (HPR) and hydrogen yield (HY) of 2.2 L H2/L-d and 1.09 mol H2/mol galactoseadded, respectively. Combined inoculation (GS + SDS) led to an elevated HPR and HY of 3.1 L H2/L-d and 1.28 mol H2/mol galactoseadded, respectively. Acetic and butyric acids are the major organic acids during fermentation. Quantitative polymerase chain reaction (qPCR) revealed that the mixed culture generated using the combined inoculation contained a higher cluster I Clostridium abundance than the culture produced using the single inoculum. (C) 2016, The Society for Biotechnology, Japan. All rights reserved.</P>

Mesophilic biogenic H₂ production using galactose in a fixed bed reactor

Sivagurunathan, P.,Anburajan, P.,Park, J.H.,Kumar, G.,Park, H.D.,Kim, S.H. Pergamon Press 2017 International journal of hydrogen energy Vol.42 No.6

<P>This study investigated hydrogen fermentation from galactose in a fixed bed reactor (FBR) under a mesophilic temperature of 37 degrees C. The fixed bed reactor was packed with Lantec HD-Q-PAC material to support biomass growth and microbial assisted granule formation over the time course of the reactor operation. Hydraulic retention times (HRT) of 1.5-12 h over 79 days of bioreactor operation were assessed to determine the optimal hydrogen production efficiency of the system. The maximum hydrogen production rate and hydrogen yield of 65.5 L/L/d and 2.60 mol/mol hexoseadaed were achieved at a hydraulic retention time (HRT) of 2 h, which is higher than the reported maximum hydrogen production performance of reactors fed with galactose using other reactor configuration. The major volatile fatty acids formed were butyric and acetic acids. Microbial community analysis by quantitative real time polymerase chain reaction revealed that population changes greatly affected hydrogen production performance. The increase in the bacterial fraction of Lactobacillus spp. over 21.5% at a 1.5 h HRT led to increased lactic acid production up to 1865 mg/L, which deteriorated the reactor performances. Conversely, a bacterial fraction of Clostridium butyricum over 98% was observed when the H-2 production performance and organic acid distribution were recovered using a 2 h HRT. FBR would be a promising reactor configuration to achieve high hydrogen productivity while preventing the wash out of active biomass. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.</P>

Optimal Gene Pathway Prediction to Detect Progeria Syndrome using Mathematical Graph Theory

N. Senthilkumaran,S. Sivagurunathan 한국디지털융합학회 2022 IJICTDC Vol.7 No.1

Network analysis is one of the hottest areas of research in biotechnology and biomedical research. It is a straight forward method of representing local and global characteristics of biological nodes representing the various biological elements. In network analysis, we use mathematical graph theory to show the interaction among the genes and its product. This represents the various biological activities in the cell. In order to predict the certain activity and interaction among the biological elements, it is necessary to find the optimal path in the network. This optimal path is usually the shortest path, which clearly depicts the key elements involved for the particular reaction. It is also necessary to count the number of shortest paths between the given pairs of genes in the network. This paper describes the need for finding shortest path in the biological network and illustrate the usage of Bellman-Ford algorithm to find the shortest path in Hutchinson-Gilford Progeria Syndrome (HGPS) data sets.

Optimal Gene Pathway Prediction to Detect Progeria Syndrome using Mathematical Graph Theory

N. Senthilkumaran,S. Sivagurunathan 한국디지털융합학회 2022 IJICTDC Vol.7 No.1

Network analysis is one of the hottest areas of research in biotechnology and biomedical research. It is a straight forward method of representing local and global characteristics of biological nodes representing the various biological elements. In network analysis, we use mathematical graph theory to show the interaction among the genes and its product. This represents the various biological activities in the cell. In order to predict the certain activity and interaction among the biological elements, it is necessary to find the optimal path in the network. This optimal path is usually the shortest path, which clearly depicts the key elements involved for the particular reaction. It is also necessary to count the number of shortest paths between the given pairs of genes in the network. This paper describes the need for finding shortest path in the biological network and illustrate the usage of Bellman-Ford algorithm to find the shortest path in Hutchinson-Gilford Progeria Syndrome (HGPS) data sets.

Evaluation of different pretreatments on organic matter solubilization and hydrogen fermentation of mixed microalgae consortia

Kumar, G.,Sivagurunathan, P.,Thi, N.B.D.,Zhen, G.,Kobayashi, T.,Kim, S.H.,Xu, K. Pergamon Press 2016 International journal of hydrogen energy Vol.41 No.46

<P>This study investigated the effects of pretreatment methods (such as autoclave, ultra-sonication and electrolysis) of mixed microalgae consortia (predominantly composed of Scenedesmus followed by Chlorella species) from natural ecological niche. In addition, the cultivated biomass (wet) was subsequently utilized for fermentative H-2 production in mesophilic regime. The results showed that peak hydrogen production rate (HPR) and hydrogen yield (HY) were achieved from electrolysis pretreated algal consortia as 236 +/- 14 mL/L-d and 37.7 +/- 0.4 mL/g (volatile solids) VSadded, whereas the untreated algal consortia resulted in the turnout as 64 +/- 5 mL/L-d and 9.5 +/- 0.0 mL/g VSadded, respectively. The significant increment observed in HPR and HY values were nearly 4 times higher. The solubilization of organic matter during the pretreatment showed positive correlation with the H-2 production. The energy generation rate and yield of the corresponding pretreatment methods were as follows, 1.44, 1.79 and 2.65 kJ/L-d for autoclave, ultra-sonication and electrolysis, the corresponding yields also fell in the range of 0.32, 0.41 and 0.43 kJ/g VSadded, respectively. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.</P>

Optimization of substrate concentration of dilute acid hydrolyzate of lignocellulosic biomass in batch hydrogen production

Gonzales, R.R.,Sivagurunathan, P.,Parthiban, A.,Kim, S.H. Elsevier Applied Science 2016 INTERNATIONAL BIODETERIORATION AND BIODEGRADATION Vol.113 No.-

Lignocellulosic biomass is a promising alternative source for biohydrogen production. Its recalcitrant structure requires physicochemical pretreatment methods, such as dilute acid pretreatment, to utilize the carbohydrates in the biomass for fermentation. This study was aimed to investigate the optimum substrate concentration of dilute acid lignocellulosic hydrolyzate for dark hydrogen fermentation processes. Empty palm fruit bunch, rice husk, and pine tree wood were used as the substrates. The lignocellulosic biomass samples were hydrolyzed and fed to batch hydrogen fermentation after adjustment of substrate concentration of the hydrolyzate solutions to 5, 10, 15, and 20 g/L. The maximum hydrogen production rates were 1510 +/- 96 mL H<SUB>2</SUB> L<SUP>-1</SUP> day<SUP>-1</SUP>, 1860 +/- 245 mL H<SUB>2</SUB> L<SUP>-1</SUP> day<SUP>-1</SUP>, and 1629 +/- 170 mL H<SUB>2</SUB> L<SUP>-1</SUP> day<SUP>-1</SUP> at 10 g L<SUP>-1</SUP> substrate concentration of empty palm fruit bunch, rice husk, and pine tree wood, respectively. These correspond to hydrogen yields of 0.96 +/- 0.04 mol H<SUB>2</SUB> mol<SUP>-1</SUP> sugar, 1.25 +/- 0.15 mL H<SUB>2</SUB> mol<SUP>-1</SUP> sugar, and 0.99 +/- 0.05 mL H<SUB>2</SUB> mol<SUP>-1</SUP> sugar, respectively. The results indicate that dilute acid pretreated lignocellulosic biomass would be a suitable substrate for fermentative hydrogen production.

Dielectric Study of Methyl Acrylate-Alcohol Mixtures Using Time Domain Reflectometry

Dharmalingam, K.,Ramachandran, K.,Sivagurunathan, P.,Prabhakar , B.,Khirade, P.W.,Mehrotra, S.C. Korean Chemical Society 2006 Bulletin of the Korean Chemical Society Vol.27 No.12

Dielectric studies of methyl acrylate with 1-propanol, 1-butanol, 1-heptanol and 1-octanol binary mixtures have been carried out over the frequency range from 10 MHz to 10 GHz at temperatures of 283, 293, 303 and 313 K using Time Domain Reflectometry (TDR) for various concentrations. The Kirkwood correlation factor and excess inverse relaxation time were determined and discussed to yield information on the molecular structure and dynamics of the mixture. The values of the static dielectric constant, relaxation time and the Kirkwood correlation factor decrease with increased concentration of methyl acrylate in alcohol. The Bruggman plot shows a non-linearity of the curves for all the systems studied indicates the heterointeraction which may be due to hydrogen bonding of the OH group of alcohol with C=O of the methyl acrylate. The excess inverse relaxation time values are negative for all the systems at all the temperatures indicates that the solute-solvent interaction hinders the rotation of the dipoles of the system.

Effect of severity on dilute acid pretreatment of lignocellulosic biomass and the following hydrogen fermentation

Gonzales, R.R.,Sivagurunathan, P.,Kim, S.H. Pergamon Press 2016 International journal of hydrogen energy Vol.41 No.46

<P>This study aimed to investigate the relationship of the severity of dilute acid pretreatment and the following dark hydrogen fermentation performance. Empty palm fruit bunch, rice husk, and pine tree wood were hydrolyzed in 5% (v/v) H2SO4 at 10% (w/v) solid/liquid ratio and 121 degrees C for 30, 60, and 90 min, and then used as the substrate of batch hydrogen fermentation. The maximum sugar yield was achieved at pretreatment with 60 min reaction time; however, it did not guarantee the maximum H-2 production. Hydrolyzate obtained from pretreatment where the combined severity factor was at or over 2.01 showed severe 5-hydroxymethylfurfural production and consequent decrease of H-2 production rate. Peak H-2 production rates of 2640, 3340, and 2565 mL H-2 L-1 day(-1) were achieved at the following severity factors: 1.95, 1.86, and 1.83, for empty palm fruit bunch, rice husk, and pine tree wood, respectively. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.</P>