Maximum Specific Growth Rate Μmax Research Articles

Validation of competition and dynamic models for Shiga toxin-producing Escherichia coli (STEC) growth in raw ground pork during temperature abuse

Epidemiological evidence suggests that pork products may be a vehicle for STEC transmission to humans. This study was conducted to validate competition and dynamic models for the growth of STEC during simulated temperature abuse of raw ground pork. Maximum specific growth rates μmax were modeled as a function of temperature using the Cardinal parameter equation, and a dynamic model was validated using sinusoidal temperature profiles. The Acceptable Prediction Zone (APZ) method was used to evaluate the model's performance. The competition model was well fitted to the experimental data having 93% (1849/1981) residual errors within the desired APZ. Growth rates were not different between STEC O157 and non-O157; however, serogroup O91 showed two to three times lower μmax than other STEC at 10, 25, and 30 °C. The theoretical minimum and optimum growth temperature for all STEC groups ranged from 3.4 to 7.8 °C and 33–35 °C, respectively. The dynamic model showed good prediction performance (pAPZ = 0.98) with the experimental data. These results can be used to inform risk assessment models and to support the implementation of risk mitigation strategies to improve the microbiological safety of raw pork products.

KINETIC MODEL OF COMMERCIAL GLUCOSE-AFFECTED GROWTH AND MICROBIAL OIL PRODUCTION OF OLEAGINOUS YEAST Pseudozyma parantarctica CHC28

This research proposed to study the effect of commercial glucose concentration in a nitrogen-limiting medium on the growth of Pseudozyma parantarctica CHC28 and to estimate the kinetic parameters of fermentation. The biomass, microbial oil, biomass production rate (Qx), and oil production rate (Qp) increased dramatically and reached 22.10±1.95 g/L, 10.99±1.31 g/L, 0.184±0.016 g/L h, and 0.092±0.011 g/L h, respectively, when glucose concentration was increased to 100 g/L (C/N ratio = 333). In contrast, these results showed a decrease when glucose and C/N ratio were higher than 100 g/L and 333, respectively. Concurrently, the oil content showed a continuous rise as the glucose and C/N ratio increased. Furthermore, the maximum specific growth rate (μmax) declined sharply when P. parantarctica was cultivated under high glucose concentration. It was therefore suggested that the glucose concentration could affect the growth of oleaginous yeast because of osmotic pressure and C/N ratio. For the bioreactor scale, biomass, microbial oil, and oil content were enhanced to 29.92 g/L, 15.13 g/L, and 50.57 %w/w, respectively, at 120 hrs of cultivation. The mathematical models could describe the effect of glucose concentration on both yeast growth and microbial oil production. Thus, the kinetic model satisfactorily fitted the experimental data relating to oleaginous growth, microbial oil production, and substrate consumption.

A new predictive model for the description of the growth of Salmonella spp. in Italian fresh ricotta cheese

In this study, cardinal parameter models were developed for the growth of Salmonella spp. in different brands of Italian fresh ricotta cheese. Two models were proposed, including the effect of temperature or the combined effect of temperature, pH, and concentration of lactic, citric and, acetic acid. Validation of the models included an assessment of the ability to predict maximum specific growth rate μmax using two indices: bias-factor (Bf) and accuracy factor (Af), and the acceptable simulation zone (ASZ). The new models for Salmonella spp. showed good performances with Bf of 1.11–1.10 (model with 1 or 5 variables), and an average of 91% and 89% of observations within the ASZ (model with 1 or 5 variables, respectively). Comparing the performances of other existing models when applied to ricotta cheese, a general underprediction of the growth rate was evidenced. The proposed models can be applied by a high number of users with the aim to assess levels of this pathogen in ricotta cheese under both static and dynamic environmental conditions, being useful for the dairy business as the tested conditions cover a wide range of the available brands on the market.

A predictive growth model for Yarrowia lipolytica ATCC 9773 in wastewater

This study focuses on the development of a secondary model for Yarrowia lipolytica in a sewage treatment process. The raw data of Y. lipolytica growth were adjusted to the Buchanan model in order to obtain growth parameters such as initial count cells (Y0), maximum specific growth rate (μmax), latency phase (λ) and maximum cell population (Ymax). The µ values obtained at different pH levels (5.0 to 8.0) were used to build the secondary model based on a linear equation. The results showed a significant effect of pH on µmax values. The validation process of the developed models displays accuracy (Af) and bias factor (Bf) values close to one, while the values of root mean square error (RMSE) were low, confirming that such models can predict the growth of Y. lipolytica in dairy wastewater. This can be interesting to optimize sewage treatments that involve this kind of microorganism. Moreover, the dairy wastewater was a good substrate to support the Yarrowia lipolytica's growth and could be used to produce enzymes.

Experimental and Model-Based Analysis to Optimize Microalgal Biomass Productivity in a Pilot-Scale Tubular Photobioreactor.

A dynamic coarse-grained model of microalgal growth considering light availability and temperature under discontinuous bioprocess operation was parameterized using experimental data from 15 batch cultivations of Nannochloropsis granulata in a pilot-scale tubular photobioreactor. The methodology applied consists of a consecutive two-step model parameter estimation using pooled, clustered and reorganized data to obtain initial estimates and multi-experiment fitting to obtain the final estimates, which are: maximum specific growth rate μmax = 1.56 d−1, specific photon half-saturation constant KS,ph = 1.89 , specific photon maintenance coefficient mph = 0.346 and the cardinal temperatures Tmin = 2.3°C, Topt = 27.93°C and Tmax = 32.59°C. Biomass productivity prediction proved highly accurate, expressed by the mean absolute percent error MAPE = 7.2%. Model-based numerical optimization of biomass productivity for repeated discontinuous operation with respect to the process parameters cultivation cycle time, inoculation biomass concentration and temperature yielded productivity gains of up to 35%. This optimization points to best performance under continuous operation. The approach successfully applied here to small pilot-scale confirms an earlier one to lab-scale, indicating its transferability to larger scale tubular photobioreactors.

Brewers' spent grain liquor as a feedstock for lactate production with Lactobacillusdelbrueckii subsp. lactis.

Brewers’ spent grain (BSG) is a low‐cost by‐product of the brewing process. BSG liquor names the liquid components of BSG, mainly glucose, maltose, and long‐chain α‐1,4‐glycosidic bond glucose oligomers. These substances should be separated in existing BSG biorefineries, as they might lead to an increased formation of microbe‐inhibiting compounds in well‐established hydrothermal/enzymatic saccharification processes. In most cases, this liquid fraction is discarded. The present study presents for the first time an optimized process with BSG liquor for the purpose of producing bulk chemicals (e.g., lactate) in relevant concentrations. The process comprises the application of yeast extract, produced from own brewing processes, as the sole supplemented complex constituent in a simultaneous fermentation and saccharification process. Kinetic parameters for the final optimized process conditions with the organism Lactobacillus delbrueckii subsp. lactis were: maximum specific growth rate µmax = 0.47 h−1, maximum lactate concentration cLac, max = 79.06 g L−1, process yield YPS = 0.89 gLac gSugar −1, lactate production rate qP = 4.18 gLac gCDW −1 h−1, and productivity P 15 h = 4.93 gLac L−1 h−1. BSG liquor, linked with yeast extract from Brewers’ yeast, can be a promising substrate for further bioprocess engineering tasks and contribute to a holistic and sustainable usage of Brewers’ spent grain.

Cultivation of microalgae in fluidized bed bioreactor: impacts of light intensity and CO2 concentration

Harvesting of suspended microalgae biomass will generally incur excessive time and intensive energy due to low biomass density. Microalgae cultivation via fluidized bed bioreactor was introduced to tackle the harvesting process in which the support material was fluidizing within the culture medium, allowing the microalgae to settle onto the surface of fluidized material and grow thereafter. The Central Composite Design (CCD) was adopted to design the experiments for optimization of attached microalgae growth onto the fluidized bioreactor. The optimization condition occurred at 216 μmol/m2 s light intensity and 9% CO2 concentration with maximum biomass concentration (Xmax) and maximum specific growth rate μmax) of attached microalgae obtained at 0.692 g/L and 0.028 1/h, respectively. The Verhulst logistic kinetic model illustrated the attached microalgae growth from lag to stationary phase, supporting the use of this model to represent the kinetic of attached microalgae growth onto the fluidized bed bioreactor under various condition.

Isolating the effect of fat content on Listeria monocytogenes growth dynamics in fish-based emulsion and gelled emulsion systems

The influence of food matrix fat content on growth kinetics of bacteria is quite complex and, thus far, not fully elucidated, with different studies reporting contradictory results. Since results in studies involving real food products are possibly influenced by variations in compositional and physicochemical properties, there is a need for systematic studies in artificial food model systems among which the influence of fat content is effectively isolated. In this study, the isolated effect of a gradual increase in fat content, in the range of 1–20% (w/w), on the growth dynamics of Listeria monocytogenes in fish-based emulsion and gelled emulsion model systems was investigated at 4, 7 and 10 °C. Growth parameters estimated by the Baranyi and Roberts model were compared among the different model systems. Overall, an increase from 1 to 5% fat resulted in a significant reduction of the lag phase duration λ in both model systems at all studied temperatures, while a further increase in fat content did not significantly affect λ. The relationship between the fat content (%) and the maximum specific growth rate μmax was more complex, following the same trends for both emulsions and gelled emulsions and tested temperatures, i.e., (i) μmax was higher at 5% than at 1% fat, (ii) μmax was lower at 10% than at 5% fat, (iii) μmax at 20% fat was higher than or equal to μmax at 10% fat, and (iv) μmax was the highest at 5% fat. Based on these experiments, fundamental knowledge was provided which could lead to the development of food matrix-related factors describing the influence of fat content in future predictive modeling tools which include food microstructural elements. Such models could increase the accuracy of the shelf-life estimation for fat-containing foods, in turn resulting in improved food safety.

Interaction of 4-ethylphenol, pH, sucrose and ethanol on the growth and fermentation capacity of the industrial strain of Saccharomyces cerevisiae PE-2.

Volatile phenols such as 4-ethylphenol are produced from hydroxycinnamic acids by Dekkera bruxellensis, an important yeast contaminating alcoholic fermentations. 4-ethylphenol results from the decarboxylation and reduction of p-coumaric acid, a compound found in sugarcane musts. In wine, volatile phenols are responsible by sensorial alterations whereas in the context of bioethanol fermentation, little is known about their effects on the main yeast, Saccharomyces cerevisiae. Here we evaluated the interaction of 4-ethylphenol and pH, sucrose and ethanol on the growth and fermentation capacity of the industrial strain of S. cerevisiae PE-2. A central compound rotational design was utilized to evaluate the effect of 4-ethylphenol, pH, ethanol and sucrose concentration on the yeast maximum specific growth rate (µmax) in microplate experiments in YPS medium (Yeast extract-Peptone-Sucrose), at 30°C. Following, single-cycle fermentations in YPS medium, pH 4.5, 17% sucrose, at 30°C, with 4-ethylphenol in concentrations of 10 and 20mgL-1 being added at the start or after 4h of fermentation, were carried out. 4-ethylphenol affected µmax of S. cerevisiae in situations that resemble the conditions of industrial bioethanol production, especially the low pH of the fermentation medium and the high ethanol concentration because of the anaerobic sucrose uptake. The addition of 4-ethylphenol on fermentation resulted in significant effect on the cell yeast concentration, pH and alcohol production, with significant decrease from 86% to the range of 65-74% in the fermentative efficiency. The industrial yeast S. cerevisiae PE-2 growth and fermentative capacity were affected by the presence of 4-ethylphenol, a metabolite produced by D. bruxellensis, which may contribute to explain the impact of this yeast on bioethanol industrial production.

APPLICATION OF A TWO-STAGE AGITATION SPEED CONTROL STRATEGY TO ENHANCE YELLOW PIGMENTS PRODUCTION BY MONASCUS ANKA MUTANT

Monascus anka mutant strain was isolated using conventional mutation techniques in our laboratory. In our previous study, strain Monascus anka mutant showed high yield of yellow pigments with the characteristics of high protein adhesion, thermal stability, and wide-pH stability. This work focused on the agitation optimization in a 5 L fermentor of strain Monascus anka mutant and two stage agitation speed control strategy was operated as follows: the agitation speed was 400 r/min to improve the Monascus growth and yellow pigments production before culturing 96 hour and then 300 r/min was carried out to extend the time of yellow pigment production with efficient using substrate. The yield of monascus yellow pigments reached 149.43 OD, which was 49.37%，49.25%，35.56%，18.73%, and 41.01% higher than that of 250 r/min, 300 r/min, 350 r/min, 400 r/min, and 450 r/min fermentation, respectively. The maximum specific growth rate (µmax) and the maximum specific production rate of yellow pigments (qy) reached 0.0528 h-1 and 0.2177 OD.g-1.h-1, respectively. Specific growth rate (µ) maintained higher than 0.01 h-1 from 6 hours to 54 hours, and qy could maintain at 0.10 OD.g-1.h-1 from 24 hour to 66 hour, which could not be obtained by single agitation control. The data of this work could contribute to making the industrial production of Monascus yellow pigments feasible.

Development of an interspecies interaction model: An experiment on Clostridium cadaveris and Clostridium sporogenes under anaerobic condition

The specific primer and probe sets for quantifying Clostridium cadaveris and Clostridium sporogenes using a quantitative real-time PCR were designed. Each primer and probe set detected only the target species very specifically. The two species were cultivated in pure and mixed culture in batch mode with glucose as the only carbon source. The designed QPCR sets were used successfully to estimate the biokinetic parameters of each species in pure culture: i.e., maximum specific growth rate μmax, half saturation concentration Ks, growth yield Y, and decay coefficient Kd. of C. cadaveris and C. sporogenes were 0.311 ± 0.020 and 0.360 ± 0.019 h-1, 4.241 ± 1.653 and 5.171 ± 1.097 g/L, 0.301 ± 0.065 and 0.199 ± 0.037 1011 copies/g, 0.005 ± 0.043 and 0.009 ± 0.025 h-1, respectively. The effect of interspecific interaction of on substrate consumption rate and microbial growth was evaluated using mixed culture; curve fitting and comparison of coefficients detected increase in substrate consumption rate but decrease in microbial growth rate; these results imply interspecific interaction effect. A new model was of the interspecific interaction was developed, with focus on accuracy, realism, simplicity and biological significance. This interspecific interaction model may be extended to more-complex bioprocesses such as biological wastewater treatment systems and anaerobic digestion.

Prediction of breakthrough behaviors using logistic, hyperbolic tangent and double exponential models in the fixed-bed column

In this work, the logistic, hyperbolic tangent and double exponential models were proposed to describe the breakthrough behaviors in the fixed-bed column. Introduction of the parameter n into the above three models resulted in the corresponding modified breakthrough models. The physical meanings of the parameters in these models were explicated. The maximum specific growth rate μmax, lag time λ, inflection point ti and half-operating time t50 were defined to better reflect symmetry and curvature of the breakthrough curve. The breakthrough models established using μmax and λ mainly focused on the adsorption rate instead of adsorption capacity. Many attempts were made to reveal the mathematical relationships between the logistic, hyperbolic tangent and double exponential models. The obtained results indicated that the new breakthrough models could describe the two different adsorption systems very well. These empirical models provided an alternative method for the description of the breakthrough curve.

A review of anaerobic digestion bio-kinetics

Anaerobic digestion is the key to sustainable wastewater management and bioenergy production. Kinetics plays an important role in the design of bioreactors, processes, and process scale-up in anaerobic digestion. This article focuses on a state-of-the-art literature review on the experimental kinetic studies of conventional anaerobic bioreactors and anaerobic membrane bioreactors. Various kinetic models that were used to fit the experimental data and derive the kinetic parameters are summarized and discussed in the literature. The values of the maximum specific growth rate µmax, half saturation constant Ks, decay co-efficient kd, sludge yield Y, and methane yield YCH4 from experimental studies are summarized for each model. This paper can serve as an updated comprehensive source of anaerobic bio-kinetic studies and digester design.

Influence of luminosity, carbon source and concentration of salts in the physiology of Chlorella sorokiniana

ABSTRACTGrowth studies are important to increase the knowledge about the physiology of microalgae. The development of suitable culture media allows optimum growth to each species. The genus Chlorella has the ability to adapt to various environmental and nutritional conditions. Thus, the aim of this work was to evaluate the physiology of Chlorella sorokiniana CTT 7727 at different growth conditions with Basal Bold (BB) medium. For that, heterotrophic, autotrophic and mixotrophic cultures were carried out. The maximum specific growth rates (µmax), the maximum biomass concentrations (Xmax) and cell productivities (PX) were calculated for each experiment. Among all the treatments evaluated, that with 24 h light, 3x BB (g L-1) and CO2 presented a higher µmax (0.40 day-1) and maximum cell concentration due the increased concentration of nutrients. Replacement of dark to light has increased Xmax from 2.3 × 105 to 9.3 × 106 cells mL-1 in regular BB medium and 3.6 × 105 to 2.1 × 107 cells mL-1 in 3x BB medium in autotrophic cultivations. The PX increased from 2.4 × 104 cells mL-1 h-1 (1x BB (g L-1)) to 3.6 × 104 cells mL-1 h-1 (3x BB (g L-1)), in the presence of 24 light and CO2. However, the same behaviour was not observed when BB concentration was increased 6, 8 or 10 times the initial concentration of BB medium. Experiments with pulses of concentrated nutrients showed that declining cells can resume their growth after nutrient depletion, but the viability is decreased after successive pulses.

Study of ethanol fermentation reaction using Saccharomyces diastaticus in a two-tank fermentation system with cell recycling

Abstract Experimental data of ethanol fermentation in a two-tank system with cell recycling using sucrose as a substrate were investigated to establish a kinetic model that described the reaction. Flocculent yeast Saccharomyces diastaticus LORRE-316 was used as the fermenting yeast, and the fermentation medium comprised 80 g/L sucrose, 10 g/L yeast extract, 10 g/L peptone, 2 g/L potassium phosphate monobasic (KH2PO4), and 0.5 g/L magnesium sulfate heptahydrate (MgSO4·7H2O). Three models, the Monod model, the modified Monod model, and the extended-modified Monod model, were used to describe fermentation, and the extended-modified Monod model described the reaction more accurately than the other two models. The model took substrate limitations plus substrate and ethanol inhibitive effects into consideration, and was modified to include assumptions that included terms for substrates (sucrose, glucose and fructose) and product (ethanol). In addition, the ethanol concentration had a significant effect on cell growth. The results of Lineweaver–Burk plots showed that the maximum specific growth rate (μMAX) and the Monod constant (KS) were 0.72/h and 26.77 g/L, respectively. The models were suitable for describing the experimental data.

Performance and Kinetics Evaluation of Integrated Suspended Growth Bioreactor Treating Beverage Industry Wastewater

In this research, feasibility of using a continuous flow integrated suspended growth bioreactor (i-SGBR) pilot plant was explored to treat beverage industry wastewater. The bioreactor treatment units comprise of three sequentially arranged suspended growth bioreactors with anoxic (ANX-C), aerobic (AER-C), and aerobic digester chambers (AD-C). Clarifier (CLR) was installed as last chamber to settle sludge. Parameters such as total chemical oxygen demand (TCOD) were monitored and validated with biochemical oxygen demand (BOD5). Other parameters measured include soluble COD (sCOD), mixed liquor suspended solids (MLSS), mixed liquor volatile suspended solids (MLVSS), total suspended solids (TSS), and pH. Transformational behavior of aerobic metabolic performance for extended aeration process was investigated by operating regimes of variable aerobic hydraulic retention time (HRT) and organic loading rate (OLR) between 20 and 30 h and 0.49–0.79 kg COD/m3 day, respectively. Solids retention time (SRT) between 20 and 40 days was operated. The aim was to generate data for bacterial growth and substrate utilization kinetics from modified Monod’s model. Removal of TCOD, BOD5, and TSS were achieved in the range of 95.2–97.9% (Influent 995 ± 21–1028 ± 25 mg/L and Effluent 21 ± 2–4.9 ± 3 mg/L), 98–98.7% (Influent 489 ± 19–507 ± 7 mg/L and Effluent 27 ± 2–41 ± 1.8 mg/L), and 91.2–94.6% (Influent 500 ± 23–653 ± 11 mg/L and Effluent 6.3 ± 7–41 ± 1.8 mg/L), respectively. The maximum substrate utilization rate (k), half velocity constant (Ks), growth yield co-efficient (Y), and decay coefficients (kd) were determined as 2.81 days−1, 979 mg sCOD/L, 0.72 mg VSS/mg sCOD, and − 0.0172 day−1, respectively. Maximum specific growth rate (μmax) was found as 2.03 days−1. Treatment efficiencies declined with reduction of HRT and with increased OLR applied to the bioreactor. The aerobic digester (AD) achieved between 9.8% (Influent 15,021 mg/L) and 18.6% (10,893 mg/L) MLVSS reduction, where performance decreased with additional solids concentration from influent aerobic digester (IAD). i-SGBR has accomplished effective removal of pollutants and simultaneous sludge degradation of beverage industry wastewater. Kinetic parameters obtained could be useful for design and modeling of aerobic treatment unit to improve effluent quality.

ASSESSMENT OF KINETIC AND METABOLIC FEATURES OF TWO HYBRIDOMAS IN SUSPENSION CULTURE FOR PRODUCTION OF TWO MONOCLONAL ANTIBODIES FOR BLOOD TYPING

Abstract The aim of this study was to analyze kinetic and metabolic features of two hybridomas for monoclonal antibodies (MAbs) production for blood typing. Two lines of hybridomas, ED7 and ED9, were evaluated to produce anti-A and anti-AB, respectively. Experiments with ED7 and ED9 lines were conducted in a 500mL spinner flask and 2L bioreactor, using two different basal culture media, both with 10 % v/v addition of fetal bovine serum. The results revealed the necessity of additional supplementation of the culture media to meet the nutritional demands of the cells. Through nutritional balance and cultivation in better controlled conditions in the bioreactor, it was possible to raise the maximum specific growth rate µmax in 8.2 % and the productivity of anti-A in 148 % with the line ED7. For the ED9 line the µmax decreased 9.5% but the productivity of anti-AB increased 33.3%.

Microbial degradation of N,N-dimethylformamide by Paracoccus sp. strain DMF-3 from activated sludge

N,N-dimethylformamide (DMF) was a typical toxic chemical and existed extensively in industrial wastewater. In this study, a strain of the high-efficient DMF degrading bacteria DMF-3 belonging to Paracoccus sp. was enriched and isolated from activated sludge. The removal rate of DMF by DMF-3 was up to 100% while 1000 mg/L DMF was used as the sole carbon and nitrogen source. Growth kinetics model of DMF-3 was thus established, and the kinetic constants were determined with maximum specific growth rate μmax = 0.22 (h−1), saturation constant Ks = 0.41 (g/L) and inhibition constant Ki = 25.93 (g/L). Based on the analysis of the intermediate products, it was found that DMF was firstly converted into dimethylamine and formic acid, and these intermediates were finally degraded to ammonia and carbon dioxide following the typical metabolic pathway of methylotrophs. In addition, to enhance the degrading capacity of DMF-3 in high DMF concentration, ultraviolet mutagenesis process was applied. Compared with the usage of the original strain of DMF-3, the degradation rate was increased by 14.8% with the usage of obtained mutant strain with applied initial DMF concentration 10,000 mg/L.

Treatment of high-strength purified terephthalic acid (PTA) wastewater using a magnetic porous ceramic support in laboratory-scale anaerobic-aerobic fluidized bed reactors

Laboratory-scale anaerobic-aerobic fluidized-bed bioreactors (FBR) with porous magnetic ceramics as support were successfully applied to treat purified terephthalic acid (PTA) wastewater. After a short 14-day start-up period, the system was stably operating. During the 40 d stable period, the system organic loading rate (OLR) increased from 6.68 to 23.87 kg chemical oxygen demand (COD)/(m3d), the effluent COD and PTA were below 90 and 30 mg/L, respectively. The FBR presented excellent COD and PTA removal efficiency with a low hydraulic retention time (HRT) value of six hours. The growth kinetic parameters suggested that the biomass in FBR possess high maximum specific growth rate (μmax = 2.22 d−1) and good tolerance to varied OLR (Ks = 258.67 mg COD/L).

Isolation, Characterization and Kinetics of Perchlorate Reducing Magnetospirillum Species

ABSTRACTPerchlorate reducing bacteria reduce perchlorate to chlorate (ClO3−), which, in turn, is reduced to chlorite (ClO2−) and ultimately to chloride (Cl−). Magnetospirillum strains are reported to use chlorate/perchlorate as electron acceptors. This study describes the perchlorate reducing property of strain VITRJS5, a Magnetopsirillum isolated from freshwater sediment collected from Chelur freshwater lake, Kerala, India. The strain was microaerophile and was phylogenetically related to a Magnetospirillum sp., a member of the α-subclass of the class Proteobacteria. The placement of the isolate in the genus Magnetospirillum has further confirmed the presence of four key magnetosome membrane genes. PCR amplification and phylogenetic analysis of central metabolic genes such as nifH (nitrogenase) and cbbM (type II RubisCo) displayed the highest similarity (97% and 81%, respectively) with Magnetospirillum sp. BB-1 The growth kinetic parameters of the isolate were studied with acetate as the electron donor in batch experiments. Monod's substrate utilization model has been established with oxygen, nitrate and perchlorate as electron acceptors separately. The maximum specific growth rate (µmax) and half-saturation constant (ksconc) for the bacterium varied while utilizing different electron acceptors. The maximum specific growth rate was 0.226, 0.190 and 0.096 per hour and half-velocity constant Ks was 25.09, 33.36 and 65.37 mg acetate/l for oxygen, nitrate and perchlorate, respectively. The reduction of perchlorate has been analyzed using kinetic studies of the substrate uptake by the bacteria and the half-velocity constant Ks was found to be 52.8 mg/l. The results indicate that the strain VITRJS5 effectively reduces perchlorate by using it as an electron acceptor.