Effect Of Substrate Concentration Research Articles

Fructooligosaccharides: Production by recombinant fructosyltransferase from Festuca arundinacea in a continuous reactor and kinetic modeling profile

In the quest for maximum conversion of sucrose into 1-kestose using fructosyltransferases in a continuous reactor, consideration of the reversible reactions at competing concentrations of sucrose and 1-kestose is crucial. In this study, a kinetic model based on a combined approach of rapid equilibrium and steady-state kinetics was developed to predict the profile of FOS production using recombinant sucrose: sucrose 1-fructosyltransferase from Festuca arundinacea produced in Pichia pastoris. The purified enzyme selectively converted sucrose into 1-kestose with a final yield of 0.66 g/g sucrose consumed. The reaction rate laws adequately described the kinetic profile of the substrate and the products and accurately predicted the composition of the reaction mixture. The model was fitted to experimental data obtained at three enzyme dosages and three initial sucrose concentrations. The model could predict the effect of substrate concentration on initial rate kinetics, half-saturation constant, and transferase to hydrolase ratio. For the known values of initial sucrose and enzyme concentration, the optimum reaction time and the required dilution rate were predicted for the development of a continuous process to produce 1-kestose-enriched short-chain FOS. A volumetric productivity of ∼110 g/L/h of 1-kestose with 40% carbohydrate composition in the permeate flux was demonstrated.

Effect of substrate concentration on reactive metabolite assessment in drug discovery research

Effect of substrate concentration on reactive metabolite assessment in drug discovery research

Effect of Fruit Waste Substrate Concentration and pH on Biogas Production by Mixed Culture

Effect of Fruit Waste Substrate Concentration and pH on Biogas Production by Mixed Culture

Effect of Substrate Concentration (Glucose) on Ethanol Fermentation Continue with Immobilized Fixed Bed Fermenter for 2/3 Mesh Pumice Anchoring Size

The need for ethanol which is increasing at all times demands development related to ethanol production, especially those produced through the fermentation process both development in terms of raw materials and processes. Ethanol fermentation process continues to have problems one of them is wash out or the carrying of microorganisms into the product stream which causes the number of microorganisms to continue to decrease in the fermenter. One way to solve the problem of wash out is to tether the microorganism first to the anchoring medium (immobilized cell) and choose the suitable type of fermenter. The purpose of this study was to determine the effect of glucose concentration and the best conditions on the ethanol fermentation process continue with immobilized cell fixed bed fermenter to the value of ethanol concentration and yield ethanol produced as well as the percent of microorganisms still carried into the product streams. Based on the results of the study, the best conditions were obtained with a residence time of 2 days with the ethanol concentration of 1.20%v/v, the yield of fermented ethanol was 37.75%w/w, and % number of cells released was 0.45% at a glucose feed concentration of 150g/L. Fermentation is carried out under conditions of immobilized cell using microorganisms from the type of yeast Saccharomyces cerevisiae. In this study the variables that were considered fixed were the expansion ½ height of 1.47m column height, temperature of 25-30°C, and a pH of 5.5.

Biohydrogen production kinetics from cacao pod husk hydrolysate in dark fermentations: Effect of pretreatment, substrate concentration, and inoculum

This study aims to explore the impact of pretreatment on cacao pod husk (CPH) and investigate the kinetics of biohydrogen production in a dark fermentation (DF) batch reactor with consideration for substrate and inoculum concentration. As the first study focused on biohydrogen production from CPH, the Taguchi orthogonal array was utilized to determine the optimal pretreatment condition for powdered CPH. This study examined different substrate concentrations (3–100 g VS/L) and inoculum concentrations (5 and 10 % v/v). The study showed that biohydrogen production was significantly increased by 74.4 ± 0.1 % by pretreatment with 5.5 % HCl compared to the untreated CPH as control. Furthermore, the optimal performance was achieved by 35 g VS/L of CPH in the mixture with inoculated by 10 % v/v inoculum, resulting in a biohydrogen production and concentration of 257.05 ± 7.97 mL/L and 23.87 ± 0.15 %, respectively. The inoculum's microbial community analysis using Illumina 16S sequencing showed a dominance of the Ethanoligenes (30.4 %), which was positively correlated with the profiles of hydrogen production and the proportion of VFAs. The Aiba model with an exponential substrate concentration and inhibitory constant (R2 of 0.93) was statistically the most precise mathematical model to predict the specific growth rate during the fermentative biohydrogen production by CPH substrate.

Atrazine Degradation by Bacillus safensis Strain BUK_BCH_BTE6 Isolated from Agricultural Land in Northwestern Nigeria

Atrazine herbicide is known to disrupt the endocrine system and is potentially carcinogenic. Consumption of which is devastating. This research aimed to isolate and characterize bacteria with atrazine degrading ability. An enrichment method was adopted to isolate the bacteria on mineral salt media following serial dilution. The isolate was identified molecularly and characterized based on effects of temperature, pH, substrate concentration, incubation time, inoculum size and heavy metals. GC-MS analysis was performed to identify the metabolites and degradation efficiency. The isolate was identified as Bacillus safensis strain BUKˍBCHˍBTE6 based on 16S rRNA gene sequence and molecular phylogenetic analysis. Growth and degradation of atrazine by this bacterium was optimal at 35 °C, pH of 7.5, 400 mgL-1, inoculum size 600 µL after 48 h. The growth of the isolate was inhibited by 2 ppm Hg, Cd, Cr, Pb, Ar and Ni. The degradation efficiency after 120 h was 88.85%. GC-MS analysis detected the formation of Desethyldeisopropylatrazine, Deisopropylatrazine, N-Ethylammelide and Cyanuric acid as metabolites. This isolate can be efficient atrazine degrader, hence may be beneficial for bioremediation of atrazine polluted sites.

Application of OFAT approach for optimizing tannase production under submerged fermentation

Current study reports the optimization of tannase production by Bacillus haynesii SSRY4MN031245 by employing One factor at a Time approach (OFAT). The effects of supplementary carbon sources, nitrogen sources, inoculum size and substrate (Tannic acid) concentration were studied on enzyme production. Tannic acid, when added optimally in the production media along with optimized inoculum size and optimized concentrations of glucose, sodium nitrate resulted in improved tannase production. Optimization of 2.85-fold was achieved by OFAT strategy.

Investigation into Optimal Conditions for Enzymatic Hydrolysis of Cassava Starch to Glucose by Amylase from Rice

The challenge of finding locally available materials in abundance to meet up with the increase in demand for glucose syrup necessitated this study. Enzymatic hydrolysis of cassava starch to glucose using glucose amylase sourced from rice was conducted. A-3 factor with 6 levels factorial viz. substrate concentration (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0% w/v), pH (4, 5, 6, 7, 8 and 9) and temperature (30, 40, 50, 60, 70 and 80 °C) experiment were employed. Rice malt was prepared and enzyme activated. Starch (substrate), buffer solutions, standard glucose solution and its calibration curve were also prepared. Starch was hydrolyzed by α-amylase and tested for presence of reducing sugar using Benedict solution. Time course of the reaction was studied and enzyme activity determined. It was observed that as reaction time increased (t), amount of glucose produced [P] initially increased but soon recorded infinitesimal increase and later assumed constant. The effects of substrate concentration, pH and temperature were found to be essential on glucose production. Statistical analysis on the effect of substrate concentration [S], reaction time and their interactions showed significant impact at probability level of (p) = 0.05.

BIOKINETIC CHARACTERIZATION OF FERROPLASMA ACIDIPHILUM

Abstract. Recently a mixed culture dominated by the iron-oxidizing microorganisms Leptospirillum and Ferroplasma has been used in a large-scale microbial fuel cell for electrical power generation. There are many factors that affect the kinetics of iron oxidation by the mixotroph Ferroplasma acidiphilum. This study investigated the effects of pH, temperature, and substrate and yeast extract concentrations in order to arrive at kinetically favorable operating conditions with minimal jarosite precipitation. Furthermore, F. acidiphilum was cultured with Leptospirillum sp. in order to determine its viability as a species capable of limiting the organic by-products of chemolithotrophic microbial growth. Bacterial characterization in the culture was accomplished using fluorescent in situ hybridization (FISH). It was found that the ferrous iron oxidation was most favorable at yeast extract concentration of 0.02% (w/v), pH of 1.6, temperature of 35 oC and an initial ferrous iron concentration of 1 g/L yielding a maximum specific growth rate of 0.0351-0.042 h-1. Moreover, F. acidiphilum displayed a symbiotic relationship with its chemolithotrophic counterpart, Leptospirillum sp. in that they were able to utilize the metabolic organic products of the chemolithotroph and limit the organic concentration to ~20 ppm total organic carbon (TOC), well below the threshold concentration of 250 ppm for chemolithotroph activity.

The Impact of Process Parameters on 1,3-Propanediol Production and 3-Hydroxypropionaldehyde Accumulation in Fed-Batch Fermentation of Glycerol with Citrobacter freundii AD119

Microbial production of 1,3-propanediol (1,3-PD) has attracted the interest of scientists for decades. Its product offers an environmentally friendly and sustainable alternative to fossil-based raw materials for chemical synthesis. Citrobacter freundii is one of the natural producers of 1,3-PD known for its ability to yield it in significant titers. An efficient bioprocess requires an in-depth understanding of the factors that influence the performance of its biocatalyst. The effects of pH, temperature, stirring rate, and substrate concentration on glycerol fermentation in fed-batch cultures of C. freundii AD119 were investigated in this study. In addition to monitoring the kinetics of substrate utilization and the formation of the final products, the concentration of 3-hydroxypropionaldehyde (3-HPA), an inhibitory intermediate of glycerol bioconversion, was analyzed. When the optimal working conditions were used (pH 7.0, temperature 30 °C, stirring rate of 80 rpm, and glycerol concentration below 15 g/L during the fed-batch phase), 53.44 g/L of 1,3-PD were obtained. When the process was performed at temperatures of 33 °C or higher or in acidic pH (6.5), an elevated concentration of 3-HPA was observed and the process halted prematurely.

Mathematical modeling of dark fermentative hydrogen and soluble by-products generations from water hyacinth

The production of hydrogen and soluble metabolite products from water hyacinth via dark fermentation was modeled. The model was built on the assumption that the substrate exists in two forms (i.e., soluble and particulate) and undergoes two stages (i.e., hydrolysis and acidogenesis) in the dark fermentation process. The modified Michaelis-Menten and surface-limiting models were applied to describe the hydrolysis of soluble and particulate forms, respectively. Meanwhile, the acidogenesis stage was modeled based on the multi-substrate-single-biomass model. The effects of temperature, pH, and substrate concentration were integrated into the model to increase flexibility. As a result, the model prediction agreed with the experimental and literature data of water hyacinth-fed dark fermentation, with high coefficient of determination values of 0.92 – 0.97 for hydrogen and total soluble metabolite products. These results indicate that the proposed model could be further applied to dark fermentation’s downstream and hybrid processes using water hyacinth and other substrates.

Effect of Fructose and Butyric Acid Addition during Electricity Production in Single Chamber Microbial Fuel Cell

The substrate is an important factor for efficient electricity production in Microbial Fuel Cell systems. The substrate is an organic compound that promotes the growth of active microbes. The goal of this study was to investigate the effect of substrate type and concentration on the bioelectricity produced by a single-chamber MFC. Fructose and butyric acid were used as substrates and carbon felt used as an electrode. Types and variations in substrate concentration were applied to the soil media used in the MFC. After 3 weeks of incubation, the optimum power density value achieved by MFC with 90 g/L fructose substrate was 20.5 mW/m2. Whereas, MFC treated with 800 mg/L butyric acid produced a maximum power density of 19.7 mW/m2.Keywords: Substrate, Fructose, Butyric acid, Power density, Microbial Fuel Cell.

Effect of Substrate Concentration and Temperature for Bio-Enzyme Production Using Enterococcus faecalis Isolated from Waste Dump Soil in Sokoto Metropolis, Nigeria

The study evaluated the effect of substrate concentration and temperature on the production of amylase enzyme by Enterococcus faecalis from the wastes dump soil Sokoto Metropolis, Nigeria. Five bacteria species were isolated and biochemically characterized which include E. coli, B. subtilis, S. aureus, E. faecalis and P. aeroginosa. The screening of identified bacteria for amylase production was carried out and all bacteria produced a wide halo on a starch agar. E. faecalis produced highest zone of clearance with 70mm,B.subtilis 50mm,S.aureus 34mm, E. coli 29mm,thenB.cereus with the least zone of clearance of 24mm. proximate analysis of the potato peels sample shows that the potatoes peels has high carbohydrate content with value of 75.737 recorded. The effect of substrate concentration was studied at 5g,10g,15g and 20g. The highest amylase production was recorded (20g) with value of 1.218 and 15g with the least absorbance value of 0.973.The effect of temperature were studied at 25˚C, 35˚C, 45˚C, and 55˚C. The temperature of 45˚C has the highest absorbance value of 1.691. While the least was recorded at55˚C with value of 0.970.These shows that temperature and substrate concentration has a vital role to play in the production of microbial enzymes. It’s concluded in this study that waste dump site is a reservoir of important microorganisms and potato peels is a good substrate for enzyme production and therefore can be utilized instead of dumping it for natural degradation.

Volatile fatty acid production in anaerobic fermentation of food waste saccharified residue: Effect of substrate concentration

In this study, food waste saccharified residue was used to produce volatile fatty acids (VFAs), and the effects of substrate concentration on VFA production, VFA composition, acidogenic efficiency, microbial community, and carbon transfer were investigated. Interestingly, chain elongation from acetate to n-butyrate played an important role with a substrate concentration of 200 g/L in the acidogenesis process. Results showed that 200 g/L was a suitable substrate concentration for both VFA and n-butyrate production, the highest VFA production, and n-butyrate composition were 280.87 mg COD/g vS and more than 90.00 %, respectively, and VFA/SCOD reached 82.39 %. Microbial analysis showed that Clostridium_Sensu_Stricto_12 promoted n-butyrate production by chain elongation. Carbon transfer analysis indicated that chain elongation made a contribution of 43.93 % to n-butyrate production. Totally 38.47 % of organic matter in food waste saccharified residue was further utilized. This study provides a new way for n-butyrate production with waste recycling and low cost.

Growth Optimization of Naphthalene-Degrading Pseudomonas Stutzeri Strain BUK_BTEG1 Isolated from Petrochemical Contaminated Soil.

Bioremediation of PAHs such as naphthalene by the activity of microorganisms represents an eco-friendly, economical, and safe decontamination approach compared physical and chemical processes. In this study, the biodegradation conditions for naphthalene by Pseudomonas stutzeri strain BUK_BTEG1 was optimized through onfactor-at-a-time (OFAT). The Characterization was conducted by studying the effect of incubation time, nitrogen source, pH, inoculum size, substrate concentration and temperature in BH media containing naphthalene as sole source of carbon and energy. The growth and degradation of naphthalene by this strain was optimal at 1000 mg/L ammonium Nitrate, substrate concentration of 800mg/L, temperature of 35 °C, pH of 7.0, inoculum size of 4% (v/v) and 72 hours of incubation time. After 72 hours of incubation under optimal conditions, the degradation efficiency of this strain to naphthalene was 72%. The analysis using gas chromatography-mass spectrometry reveals 1,2-naphthalenediol, 1-hydroxy-napthoic acid, 1,4-Napthoquinone, salicylic acid, and catechol as metabolites of naphthalene degradation by comparing the fragmentation pattern and mass spectrum obtained with data available on NIST library. This strain demonstrates promising potential and could be handy for its application in the bioremediation of naphthalene contaminated sites.

Study of enzyme kinetics for urease extracted from Glycine max

Urease is an enzyme that has a key role in nitrogen metabolism in plant germination. Grains are produced more amount of urease than other plants. Glycine max is also called soya bean, a yearly vegetable of the pea family Fabaceae and it’s an eatable seed. Glycine max is mostly used as protein rich legume only, but it has a lot of medical and industrial applications too. Glycine max is used as a source of urease. The goal of this task is to study the kinetic activities of urease enzyme in Glycine max. The first enzyme was extracted from soya beans and partially purified. The enzyme activity was determined in both crude and partially purified using standard procedure. Further, enzyme kinetics (effect of temperature, pH, and substrate concentration) was studied using urease enzyme extracted from soya beans. The purification fold was 1.8 with a yield of 75%. The factors accustomed for its action was pH 8, temperature 50°C, Vmax and Km in Michaelis-Menten plot is 100 units and 8x10-4 moles/litre and LB Plot is 0.25units and 20x10-4 moles/litre.

A Sensitive Amperometric Biosensor Based on Carbon Dot 3-Chloropropyl-trimethoxysilane Modified Electrode for Detection of Neurotransmitter Dopamine

Dopamine (DA) is an important electroactive neurotransmitter. The concentration of DA in the body of a healthy person is approximately 1.0 × 10−7−1.0 × 10−3 M. A decrease in dopamine concentration is associated with Parkinson’s disease. Thus, it is important to determine the amount of dopamine in early diagnosis of Parkinson’s disease. Different methods such as immunoassay, flow injection analysis (FIA), high performance liquid chromatography (HPLC) etc could be used for determination of dopamine but they are expensive and have long determination times, and pre analytic processes. In this study, a tyrosinase based amperometric biosensor was developed with carbon paste electrode modified with carbon nano dot 3-Chloropropyl-trimethoxysilane (CDs-CPTMS) for determination of the amount of dopamine. CDs-CPTMS was synthesized for the first time. Determination of dopamine was carried out by the reduction of dopamine-o-quinone at −0.15 V versus Ag/AgCl. The effect of temperature, pH, and substrate concentration on the dopamine response of the prepared biosensor and interference effect were investigated. There was no interference effect of uric acid and ascorbic acid. The designed biosensor has wide working range (0.001–0.01 μM and 0.01−0.1 μM), low limit of detection, very good reproducibility and shelf life. In addition, the preparation of the biosensor is practical and cost-effective.

Ethanolysis of glucose into biofuel 5-ethoxymethyl-furfural catalyzed by NH4H2PO4 modified USY zeolite

5-Ethoxymethylfurfural (EMF) can be considered as a potential biofuel because of its excellent combustion properties, such as high energy density and low carbon smoke emissions. In this study, Ultra-stable Y (USY) zeolite was modified with NH4H2PO4 and then used as an efficient solid catalyst for the catalytic synthesis of EMF via ethanolysis of glucose First, the NH4H2PO4-modified USY was characterized by FT-IR, XRD, BET, and NH3-TPD. The effect of reaction temperature, reaction time, substrate concentration, and catalyst loading on the yield of EMF was investigated. The P0.2-USY optimal EMF yield was 39.6 mol%, which increased by 20.7% compared to USY, and still had better activity after being reused for 5 cycles. Moreover, the pseudo-homogeneous first-order kinetics model was developed to elucidate the kinetics of EMF formation from glucose, and the kinetics results showed that the activation energy of EMF formation (64.2 kJ⋅mol-1) was lower than that of humins formation (73.2 kJ⋅mol-1). Finally, the ethanolysis pathway was proposed based on the product distribution.

Radial flow tubular membrane bioreactor for enhanced enzymatic hydrolysis of lignocellulosic waste biomass

A tubular membrane bioreactor was used for enhanced enzymatic hydrolysis of waste biomass, palm date seeds. The bioreactor successfully handled high solid loadings with effective simultaneous product removal. The effects of substrate concentrations, 14.3, 21.4, and 39.6 g/L, and water flowrates, 0.4, 0.8, and 1.2 mL/min, on the production of total reducing sugars were examined. At substrate concentration of 21.4 g/L, the total reducing sugars yield increased from 28.9 % to 42.7 % after 8 h as the water flowrate increased from 0.4 to 1.2 mL/min. Substrate inhibition was observed at the highest tested substrate concentration of 39.6 g/L. A dynamic model was developed to describe the designed bioreactor, accounting for the simultaneous product separation and the dynamic changes in substrate structure. The nonhydrolyzable substrate fraction parameter was found to significantly affect the model prediction. The novel membrane bioreactor and the developed model enable the industrial valorization of lignocellulosic biomass for bioethanol production.

Lactic acid fermentation of banana peel using Lactobacillus plantarum : Effect of substrate concentration, inoculum concentration, and various nitrogen sources

Semeru Banana peel is an organic waste that is exclusively utilized as animal feed and does not harm the environment. The primary component of banana peels is carbohydrates, which can be used as a substrate during the fermentation process to produce lactic acid. The fermentation of banana peel flour with Lactobacillus plantarum strain FNCC 0020 was the main focus of this investigation. Variations in the concentrations of the substrate and inoculum as well as the impact of the type of nitrogen on lactic acid concentration were investigated. According to research findings, the big banana peel contains 70.52% carbs, 5.68% soluble protein, 3.115% fat, 6.74% water, 2.395% ash, and 13.38% crude fiber. While the inoculum variable was 0.5% v/v and the best substrate concentration variable was 17.5% w/v, the best lactic acid concentrations were 5.401 g/L and 8.586 g/L, respectively, as determined by HPLC (High-Performance Liquid) analysis. Banana peel flour only includes a modest amount of nitrogen (0.8295%), sulfate (0.037 grams), phosphate (1.6105%), and vitamin B1 (0.2315%), so additional nitrogen sources must be added. The production of lactic acid is shown to increase with the addition of various forms of nitrogen, with ammonium sulfate and ammonium phosphate (2:1) producing the greatest yields of 9.781 g/L and 14.255 g/L, respectively, of lactic acid, which is lower than lactic acid from yeast extract.