scholarly journals Novel denitrifying bacteria Pseudomonas stutzeri strain D1 - from isolation to the biomass production

2019 ◽  
Vol 25 (4) ◽  
pp. 403-415
Author(s):  
Ana Vidakovic ◽  
Olja Sovljanski ◽  
Damjan Vucurovic ◽  
Gordana Racic ◽  
Milan Djilas ◽  
...  

An aerobic denitrifier was newly isolated and identified by VITEK? 2 Compact System and MALDI-TOF MS as P. stutzeri strain D1. Sequence amplification indicates that the denitrification genes napA, nirS, norB and nosZ are present in a novel strain D1, as well as in reference strain ATCC 17588. Strain D1 had capability to fully remove 3 g/L of nitrate (as KNO3) in 48 h, while the reference strain completed this task in 60 h. Single factor experiments indicate that the optimal conditions for biomass production were: temperature of 30?C, pH value of 7 and inoculum volume of 5 vol.%. Scaling up of biomass production of both denitrifiers was successfully performed in 3 and 7 L laboratory bioreactors by reaching 9 log CFU/mL of the viable cells. The results demonstrate the feasibility of using investigated P. stutzeri strains in denitrification processes and the simplicity of the up-scaling of biomass production for the treatment of large areas contaminated with nitrate.

Author(s):  
Suwapha Sawiphak ◽  
Aroon Wongjiratthiti ◽  
Chanankarn Saengprasan

Dioscorea alata (purple yam) is a tuber crop that contains plenty of nutrients. It is widely cultivated in Thailand, but it is underutilized. In this study, the suitability of purple yam to replace potato dextrose media for fungal growth was investigated. Mushrooms and molds were grown on purple yam dextrose agar (PYDA), whereas yeasts were cultured in purple yam dextrose broth (PYDB). Response surface methodology (RSM) with Box-Behnken design (BBD) was used to optimize the culture conditions for Saccharomyces cerevisiae biomass production. The growth profile of S. cerevisiae in PYDB under optimized culture conditions was also studied. All test mushrooms and molds recorded the highest colony diameter and mycelial dry weight on PYDA containing 40% purple yam. Similar to mushrooms and molds, yeasts in PYDB with 40% purple yam showed the highest number of cells. The growth of fungi on purple yam dextrose media was significantly higher than those on potato dextrose media under standard conditions. The optimal conditions from the RSM results for the biomass production of S. cerevisiae in PYDB were purple yam concentration of 49.61%, dextrose concentration of 4.87%, pH value of 5.74, and inoculum size of 7.00%. The biomass of S. cerevisiae in PYDB under the optimal conditions obtained from the results of the optimization by RSM was thirty times higher than S. cerevisiae biomass in potato dextrose broth under standard conditions. Our results suggest that purple yam could be an alternative to potato dextrose media for fungal cultivation.


2017 ◽  
pp. 295-305
Author(s):  
Ana Vidakovic ◽  
Olja Sovljanski ◽  
Aleksandra Ranitovic ◽  
Dragoljub Cvetkovic ◽  
Sinisa Markov

In the recent years, extensive studies have been conducted on the application of bioremediation in order to prevent and solve the global problem of nitrate accumulation especially in water and soil. In the studies related to the biological denitrification, Pseduomonas stutzeri is usually used as a model microorganism due to its ability of performing a complete reduction of nitrate. The aim of this work is to establish a culture medium at a laboratory level for maximizing the biomass production of Pseduomonas stutzeri ATCC 17588 and Pseudomonas stutzeri D1, previously isolated from the Danube (Novi Sad, Serbia) by using a Box-Bhenken experimental design and response surface methodology. The selected independent variables (+, 0, - levels) were: glucose (0, 1 and 2 g/L), KNO3 (1, 2 and 3 g/L), and peptone (0.4, 2 and 4 g/L), while the number of viable cells (log/mL) was chosen as a dependent factor (response). Based on the obtained results, it can be noticed that the maximum number of P. stutzeri ATCC 17588 viable cells is achieved when the initial content of glucose, KNO3 and peptone in the medium are 0 g/L, 2 g/L and 4 g/L, respectively. In the case of P. stutzeri D1, the most appropriate media for enhancing the biomass production consists of glucose (1 g/L), KNO3 (3 g/L) and peptone (4 g/L). ?he obtained results can be used for further technoeconomic analysis and scale up of the P. stutzeri biomass production.


2019 ◽  
Vol 42 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Sadia Qayyum ◽  
Ke Meng ◽  
Sidra Pervez ◽  
Faiza Nawaz ◽  
Changsheng Peng

Abstract Soil contamination with heavy metal content is a growing concern throughout the world as a result of industrial, mining, agricultural and domestic activities. Fungi are the most common and efficient group of heavy metal resistant microbe family which have potential for metal bioleaching. The use of filamentous fungi in bioleaching of heavy metals from contaminated soil has been developed recently. The current study intends to isolate a strain with the ability to degrade the pH value of the liquid medium. Identification results based on morphological and molecular biological analysis gave a 98% match to Aspergillus flavus. Batch experiments were conducted to select the optimal conditions for bioleaching process which indicated that 130 mg/ L sucrose, neutral pH and temperature of 30°C were more suitable during 15-day bioleaching experiments using A. flavus. In one-step bioleaching, the bioleaching efficiencies were 18.16% for Pb, 39.77% for Cd and 58.22% for Zn+2, while two-step bioleaching showed efficiencies of 16.91% for Pb, 49.66% for Cd and 65.73% for Zn+2. Overall, this study indicates that bioleaching of heavy metals in contaminated soil using A. flavus has the potential for contaminated soil remediation.


2021 ◽  
Vol 12 (5) ◽  
pp. 6393-6414

A scaling-up study integrating experimental and field experiments was managed to explore the most appropriate catalysis method to assist industries in getting rid of the Congo Red (CR) dye from industrial wastewater. The adsorption potential of kaolinite (K) modified by Ulva Lactuca (UL) was evaluated to eliminate CR dye from aqueous solutions. The novel kaolinite/alga nanocomposite (KUL) was synthesized following steps of the wet impregnation method and then subjected to characterization using different techniques. The newly reported KUL nanocomposite shows a significant increase in adsorption ability higher than that of K and UL. To research different experimental factors' effects, batch experiments were evaluated, and each of the kinetics/isotherms of CR adsorption were explored either. The CR removal% is clearly affected by catalyst dose, working temperature, and pH value with high percentage. The best temperature for CR adsorption onto KUL is 400C at pH>7. CR adsorption on KUL following the first-order diffusion model, while K and UL appeared to follow two different kinetic adsorption models depending on the CR concentration. Moreover, the field tests (scaling-up experiments) revealed optimistic results with 91% efficiency for KUL nano-adsorbents in eliminating mixed dyes from industrial wastewater, which means the foundation of novel environmentally benign nano-adsorbents to help in industrial wastewater recycling.


2010 ◽  
Vol 28 (No. 4) ◽  
pp. 326-332 ◽  
Author(s):  
S. Purkrtová ◽  
H. Turoňová ◽  
T. Pilchová ◽  
K. Demnerová ◽  
J. Pazlarová

We studied the optimal conditions for the biofilm development by Listeria monocytogenes on a model system represented by microtiter plates, and also for determined some effective disinfectant agents. Listeria monocytogenes ATCC 13932 and an industrial isolate of Listeria monocytogenes Lm-24 were compared as to their abilities to form biofilms. The starting concentration of the cells leading to the most reproducible results was 0.5 McFarland. The temperatures tested ranged between 8°C to 37°C, the optimal values to form biofilm in buffered peptone water (BPW) with 0.05% glucose were 25°C and 30°C. Under comparable conditions the persistent strain L. monocytogenes Lm-24 constituted more massive biofilm than did the reference strain. The following disinfectants were applied: Savo, Merades Alco, benzalalkonium chloride. A persistent industry in isolate Listeria monocytogenes Lm-24 was used as the model organism for these tests. Benzalalkonium chloride treatment was found to be the most efficient way to damage the biofilm. One minute treatment with 500 mg/l was lethal for the biofilm cells, and that with 125 mg/l for planctonic cells. Savo suppresed the viability of the biofilm cells only by about 20% on average while being lethal for planctonic cells. Merades Alco exhibited only a weak effect on both the biofilm and planctonic cells.


2014 ◽  
Vol 675-677 ◽  
pp. 733-737 ◽  
Author(s):  
Hai Feng Lu ◽  
Guang Ming Zhang ◽  
Jing Jing Zhou

Soybean wastewater is a kind of nutrients wastewater. Using yeast to treat this kind of wastewater can not only degrade high concentration organic pollutants, but the yeast cell itself also can be harvest and realize the resources recycling. In this work, the feasibility and the optimal conditions of using yeast to treat soybean wastewater were investigated. Results showed that the initial COD and hydraulic retention time were the critical factors influencing COD degradation. Under 28 °C and with the initial soybean wastewater of 4800 mg/L, usingCandida utiliswith 20% of inoculums dosage could realize the higher reduction of the concentration of COD. And after 18 h’s treatment with rotating speed of 160 rpm, the COD removal could reach to 90%. The yeast wastewater treatment technology has the prospect of resources recycling. Besides, the pH value is very important for yeast to treat soybean wastewater.


2018 ◽  
Vol 54 (4A) ◽  
pp. 181
Author(s):  
Nguyen Thi Thanh Ngoc

The yield of proteolylic hydrolysis for spent brewer’s yeast by protease and aminoacid contents of hydrolysates (the main  factors influencing in taste of hydrolysed product) depends on factors influencing in catalytic activities of enzymes as temperature, pH value, type of used  enzymes and ratio enzyme/substrate. With the purpose to hydrolyse the spent brewer’s yeast for food application, bitterness of hydrolysate takes the firth consideration, and than the yield of hydrolysing process plays economic role. In this paper, it is dealt with determination of optimal conditions to obtain the highest yield of hydrolysis process and the lowest bitterness of hydrolysate (the bitterness is determined by sensory evaluation, expressed equivalently with concentration of quinine). Response surface methodology (RSM) was used to determine optimum condition for batch proteolytic hydrolysis of spent brewer’s yeast. The influencing factors were investigated as temperature (X1): 40 oC–60 oC; pH (X2): 6.0–9.0, ratio E (flavourzyme)/S (X3): 5–10 U/g and hydrolysis time (X4): 6–9 hours. The experimental responses including degree of hydrolysis (Y1) (%) and bitterness of hydrolysate (Y2) (μmol quinine/ml) are performed in second-degree model. The optimal conditions for obtaining high degree of hydrolysis and low bitterness are determined: Ratio of enzyme mixture (alcalase 7.5 U/g and flavourzyme 8.5 U/g), pH 7.5, hydrolysis temperature at 52oC and hydrolysis time 9 hours. Under the optimal conditions, the actual values obtained for the yield of hydrolysis was 40.81  ± 0.044 % and the bitterness equivalently with concentration of quinine was 16.37 ± 0.03 μmol quinine/ml.


Author(s):  
Hatungimana Françoise ◽  
Hongjun Wang

Various classical Chinese medicines have shown their efficiency in curing various infectious diseases. Among them, Dahuang Qinyu San (DQS) found in the Chinese Veterinary Pharmacopoeia is composed of three kinds of Chinese herbs: rhubarb, Scutellaria baicalensis, and Outtuynia cordata. Due to its urgent need in human health and its effectiveness, a semi-bionic extract of Dahuang Qinyu San (SEDQS) was studied to evaluate its optimal extraction conditions and investigate its antibacterial activity against Salmonella goose. The U5 (53) uniform design method was used to investigate the effects of three independent variables, including pH value (X1), solid-to-liquid ratio (X2), and extraction time (X3), on the composite score (Y) of the extract rate and the MIC, using the semi-bionic extraction process. The broth microdilution method was also used to determine the minimum inhibitory concentration (MIC) against Salmonella goose. After 30 minutes of extraction, the optimal conditions for SEDQS were found to be pH 8.3 and a solidto-liquid ratio of 1: 40. Under these optimal conditions, the extraction rate was 43.66 % and the MIC was 9.10 mg/ml, which indicates antibacterial efficacy against Salmonella goose.


Author(s):  
Anna Nikolaevna Gneush ◽  
Albina Vladimirovna Luneva ◽  
Nadezhda Leonidovna Machneva ◽  
Yury Andreevich Lysenko ◽  
Maria Vladimirova Aniskina ◽  
...  

The purpose of the research work was to select the optimal conditions for the cultivation of microorganisms. As a result of the conducted research work, the modes of growing a nitrogen-fixing culture and a microorganism with high enzymatic activity were selected and worked out. At the same time, the optimal conditions for the cultivation of Azotobacter sp were determined – the temperature optimum for cell accumulation was 30°C, for increased polysaccharide production 20 °C, aeration within 5-10 l/l/min, agitator speed-150 rpm, pH value within 6.0±0.2 units, which allowed to achieve a cell titer of at least 1.0×109 CFU/ml. A cost-effective nutrient medium was selected for growing Pseudomonas sp. molasses-autolysate medium and optimal conditions for growing the culture: cultivation temperature 30-32 °C, aeration 1.0-1.5 l/l/ min, agitator speed 150-200 rpm, pH 6.8-7.2 units, sub-titration 5.0 % KOH, defoaming with adecanol, cultivation time-72 hours, which allowed to achieve a cell titer of at least 1.0×109 CFU/ml.


Author(s):  
Mahboubeh Kalantarmahdavi ◽  
Saeid Khanzadi ◽  
Amir Salari

Introduction: Due to the advantages of sourdough, its film production for food packaging could be interesting. This study aimed to evaluate the influence of probiotic sourdough based edible film covered on set yogurt and subsequent changes during post fermentation storage. Materials and Methods: The parameters examined included changes to the fermentation characteristics (pH, and viable counts of probiotic bacteria), synersies, and sensory evaluation during 21-d storage at 4°C. lactobacillus plantarum was supplemented with sourdough films and yogurt produced by commercial yogurt starters (Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus) then films placed on yogurt containers, and a panel of parameters reflecting product quality was subsequently monitored along with 21-d post-fermentation storage. Results: Results demonstrated that the pH value of yogurt decreased slowly during the storage and no significant difference was observed between the control and the samples with the films. Although the number of viable cells decreased during storage, it did not lower than the minimum requirement for probiotics (> 107 log CFU / g). The synersies of the film-treated samples were significantly (P ≤ 0.05) lower than the control samples. The yogurt with the film without bacteria had the least synersis. Film-treated yogurts had acceptable sensory properties in comparison with control. Conclusion: Sourdough films can be an optimizing candidate to enter the food industry as a bioactive edible film and also could improve the delivery of probiotic bacteria.


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