Isolation and characterization of nitrogen-fixing bacteria from soil sample in Dhaka, Bangladesh

Biological nitrogen (N2) fixation is very essential for limiting the growth of plants and agricultural crops. The present study was conducted to potentially isolate N2-fixing bacteria from garden soil sample at Stamford University Bangladesh, Siddeswari, Dhaka. Here, we used culture-dependent method to perform this experiment. Firstly, we collected garden soil sample, diluted and inoculated in N2-free Jensen’s media by maintaining the aseptic procedure. We obtained 5 different colonies from soil samples. We cultured the isolates in N2-free Jensen’s media containing bromothymol blue (BMB) and also, in Yeast Extract Mannitol Agar (YEMA) media containing congo red to confirm nitrogen fixation capacity. We collected the colony characteristics of all the isolates. Only 1A isolate showed good growth after 24 h of incubation among all the isolates. We performed ammonification test with Nessler reagent to confirm N2-fixing ability for our selected isolates. The 1A isolate was positive in ammonification test. Culture, microscopy and biochemical tests were performed to identify isolate 1A. This isolate was presumptively identified as Azotobacter sp. In the present study, Azotobacter sp. that was isolated from the soil sample was found to be a potential N2-fixing bacterium. Isolate 1A can be used for N2-fixation to boost production of crops. Stamford Journal of Microbiology, Vol.11 (1) 2021: 11-13

Development of a paper-based microfluidic device for the quantification of ammonia in industrial wastewater

Ammonia is a toxic pollutant increasingly found in urban and industrial wastewater and unprotected surface water. Industry discharges and fertilizer run-off release ammonia into sewers and streams, overloading wastewater treatment plants and causing fish deaths in surface water such as rivers, sea and lakes. The purpose of this study was to develop and evaluate the effectiveness of the microfluidic paper-based device (µPAD) for the quantification of ammonia in wastewater. The µPAD fabricated had an oval-shaped pattern which was designed using CorelDraw software. The hydrophilic zones were created by printing a chromatographic paper with a Xerox wax printer (Xerox colorqube 8570). The modified version of the colorimetric method using Nessler reagent was combined with microfluidic technologies to create a low-cost monitoring system for detection of ammonia in wastewater. The method allows for ammonia determination in the range of 0–5 ppm (mg/L) with a limit of detection of 3.34 ppm. This study indicated that a µPAD was successfully used to quantify the concentration of ammonia in wastewater.

Determination of Nitrogen Losses in the Sulfuric Acid Solution, Waste of the 15N Separation Plant

The most used method for production of stable isotope 15N is based on the isotopic exchange 15N/14N in the nitrogen oxides-nitric acid solution system, known as Nitrox system. At the bottom of the packed separation column, the reflux is provided by total conversion of nitric acid into nitrogen oxides by reaction with sulfur dioxide, in a packed column type refluxer. The waste of HNO3-SO2 reaction is sulfuric acid, solution of 65-70%, which is evacuated at the bottom of the nitrogen oxides refluxer. The magnitude of the nitrogen losses, as NOx and/or HNO3 in the waste sulfuric acid, were determined by analysing the effluent sulfuric acid by spectrofotometric method with Nessler reagent.

Development of paper-based microfluidic strips for quantification of ammonia

Water is one of the most valuable and crucial of life and therefore accurate monitoring and assessment of water resources for sustainability is imperative. Conventional water investigation includes manual gathering of tests, their transportation and resulting examination in the research center. This is time and labour-intensive, costly and requires exceptionally qualified personnel. Sovereign of this procedure empowers more continuous examination, sparing time and cash for analysts, ventures and administering bodies. Consequently, there is requirement for advancement of minimal effort ecological microfluidic paper-based expository gadget that is fundamental for compelling administration of our profitable water assets. This will address the huge and growing demand for low-cost ammonia sensors as legislation becomes more stringent and as more frequent monitoring becomes essential for legislative compliance. Subsequently, this thesis reports on the development of a low-cost, colorimetric, wax- printed microfluidic paper-based analytical device (µPAD) to detect ammonia in industrial wastewaters. Microfluidic innovation was utilized to facilitate the examination of analytes on the colorimetric explanatory techniques onto a convenient detecting gadget. This therefore empowers the blending of little volumes of analytes with synthetic reagents to form a coloured/hued product in the sight of the analyte of interest. The µPAD fabricated was an oval shaped pattern which was designed on Corel draw software. The hydrophilic segments were made by printing a chromatographic paper with hydrophobic paper sizing agents utilizing a standard Xerox wax printer (Xerox colorqube 8570). The quantification of ammonia in wastewater was performed on the µPADs using two typical colorimetric methods namely, Nessler reagent and Salicylate. The reaction of ammonia with the Nessler reagent resulted in a brown or intense yellow colour whereas with the salicylate method, the final colour was green. For both methods, the colour intensity increased proportionally with the analyte concentration, and all images of the μPADs were captured and colorimetrically analyzed with ImageJ software for quantification. The analytical performances of the µPAD were linear from 0 to 5 mg L-1 with a limit of detection of 3.37 mg L-1 and 3.20 mg L-1 for the Nessler vii reagent and salicylate methods respectively. The validity and accuracy of aforementioned methods was supported by the standard UV Visible spectrophotometric method and applied to the measurement of wastewater effluent samples. Wastewater samples were analyzed and the results obtained were similar to those obtained with a spectrophotometric method, demonstrating that the µPAD is suitable to determine ammonia in wastewater.

Ammonia Determination In Bottled Water Using Spectrophotometer : Comparison Between Nessler And Berthelot Methods

Ammonium concentration in bottled drinking water should not exceed 0.15 ppm. National Standardization Agency of Indonesia (BSN) had issued two standard methods for analysis, Nessler (SNI 01-03554-1998) and Berthelot (SNI 01-03554-2006). Both were statistically compared. The first method was much simpler than the second one because the preparation was only by adding the Nessler reagent into the sample. Whereas in the second one, the addition of reagents should be prepared freshly. The variance coefficient of the first method was 3.41% with linearity 0.9995 and recovery was 101.05%. Whereas variance coefficient of second method was 3.64 % with linearity 0.9995 and recovery was 105.62%. Significance test between the methods showed that value of Fexp (1.043) was less than Fcrit (4.284), and value of texp (2.36) was less than tcrit (2.45) in interval of confidence 95%. There was no significant difference between two methods

Design of Optical Sensor Membrane Based on Polymer Poly(methyl methacrylate) for Paracetamol Detection in Traditional Herbal Medicine

Generally, regulation states that herbal medicines are remedies containing plants or preparation of plants as active ingredients only. Paracetamol is one of the drugs that is frequently added in herbal medicine to enhance the effect as an analgesic. The government regulation disallows chemical drugs contained in herbal medicine due to the toxic effect of uncontrolled consumption. On this study, the optical sensor membrane from polymer poly(methyl methacrylate) (PMMA) was synthesized by phase inversion method and was used to detect paracetamol in herbal medicine. PMMA was made in three different concentrations 5%, 7.5%, and 10% and was mixed with ferric chloride (FeCl3), Folin-Ciocalteu, and Nessler reagent as specific colorimetric reagents for paracetamol detection, with a ratio of solvent:reagent was 6:4; 7:3; and 8:2. The result of the experiment shows that PMMA-FeCl3 7.5% (7:3), PMMA-Folin 5% (6:4), and PMMA-Nessler 5% (6:4) give the best performance for paracetamol detection. Real herbal medicine samples were analyzed to confirm the practical application of this sensor, and the result shows good agreement with UV-Vis data. The results show that optical sensor membrane which has been developed can be used as new detection method of paracetamol for community application.