Gold Nanoparticles Based Enzyme Biosensor for the Detection of Chloramphenicol

Chronic use of chloramphenicol (CAM) antibiotic leads to anaemia and bone marrow suppression resulting in 40 – 50% mortality. Hence, there is a need to develop an economical, fast and convenient method to detect CAM in milk, honey, shrimp and other aquaculture products. In the current method, coenzyme A was used to indirectly quantify CAM (since it is the cofactor product of the acetylation reaction of CAM). Coenzyme A (CoASH) was used to stabilize gold nanoparticles which were characterized by studying their extinction spectra. The reductant concentration and synthesis time were optimized. With optimized parameters the proposed system could detect CoASH up to 0.1 nM in buffer, with a linear range of detection from 0.1 μM to 1 mM

Fluorescent aptaswitch for chloramphenicol detection – Quantification enabled by immobilization of aptamer

Chloramphenicol is a potent drug used to treat a variety of bacterial infections. However, due to its toxic effects on human health, use of chloramphenicol is banned in food-producing animals, emphasizing the necessity for its ultrasensitive detection. A molecular beacon-based fluorescent sensing method was developed for the purpose. Fluorophore- and quencher-tagged oligonucleotides complementary to aptamer recognising chloramphenicol were hybridized to construct an aptaswitch sensor complex. On analyte binding the fluorescence was turned on, due to desorption of quencher-oligonucleotide from the complex. With optimized concentrations, the linear range of detection was observed to be from 10 pg mL−1 to 107 pg mL-1 of CAP and LOD in buffer was estimated to be 0.987 pg mL−1. In a modified fluorescence turn-off approach, the aptamers were immobilized through maleimide chemistry on microplates to improve detection limit and resolution. In this format, only fluorophore-oligonucleotide was hybridized to the aptamer which could be detached in presence of chloramphenicol, turning the aptaswitch off. This oligonucleotide was removed to avoid background interference leading to higher resolution and sensitive detection (detection limit 0.039 pg mL−1), with a linear range from 1 pg mL-1 to 104 pg mL−1 and regression coefficient 0.99. The performance of the aptaswitch sensor was tested in real honey samples where it showed excellent reproducibility, selectivity, accuracy and a detection limit of 0.285 pg mL−1, which is considerably lower than previously reported biosensors

Omniphobic membranes in membrane distillation for desalination applications: A mini-review

Membrane processes are extensively used to provide purified water from various saline water bodies. Membrane distillation (MD), one such membrane process, is mainly used for desalinating highly saline feed waters and to provide clean water. The design of robust membranes recently received considerable attention to address wetting, scaling, and fouling issues that hampered performance in long-term MD process. The current review discusses the omniphobic membranes employed in MD process for desalinating highly saline feedwaters containing diverse low surface tension substances. Also, it summarizes the basic concepts, fabrication and modification methods involved in designing omniphobic membranes. The developed omniphobic membranes have re-entrant structures and low surface energy which effectively provided anti-wetting and anti-fouling ability against saline feedwaters containing various low-surface tension substances. Further, the review focused on future research directions for developing omniphobic membranes for MD desalination applications

Spray drying as effective encapsulation method for phenol degrading bacteria

485-492Encapsulated microorganisms are potential candidates for treatment of recalcitrant and persistent toxic compounds in wastewater and agriculture. Though extensive investigations have been done on bacteria with ability to degrade toxic phenolics, there is no product available for efficient removal of phenolic compounds from waste effluents. The present study aims at preparation of encapsulated microorganisms for the treatment of waste water containing phenol. Acinetobacter seifertii and Bacillus pumilus were the organisms used for effective degradation of phenol. Various encapsulation methods have been tried. Among the different carrier materials used, corn starch was found to be the best material with long shelf life. Spray drying and freeze drying were the two methods adopted for encapsulation. Based on cell viability, spray drying was found to be an effective method compared to freeze drying. A. seifertii could degrade phenol completely with in 12 h while B. pumilus degraded phenol completely within 24 h

Spray drying as effective encapsulation method for phenol degrading bacteria

485-492Encapsulated microorganisms are potential candidates for treatment of recalcitrant and persistent toxic compounds in wastewater and agriculture. Though extensive investigations have been done on bacteria with ability to degrade toxic phenolics, there is no product available for efficient removal of phenolic compounds from waste effluents. The present study aims at preparation of encapsulated microorganisms for the treatment of waste water containing phenol. Acinetobacter seifertii and Bacillus pumilus were the organisms used for effective degradation of phenol. Various encapsulation methods have been tried. Among the different carrier materials used, corn starch was found to be the best material with long shelf life. Spray drying and freeze drying were the two methods adopted for encapsulation. Based on cell viability, spray drying was found to be an effective method compared to freeze drying. A. seifertii could degrade phenol completely with in 12 h while B. pumilus degraded phenol completely within 24 h