Enhancing efficacy of microbial bioremediation by intervention of nanotechnology and metabolic engineering: A review

Ever since the start of the Industrial Revolution, environmental pollution has significantly increased. The prominent cause of most diseases in humans, animals, and plants is the presence of toxic materials, pollutants, contaminants, and hazardous compounds released by industries. One of the major factors is the presence of heavy metals in the air, water bodies and soil. Heavy metals have biomagnification and bioaccumulation characteristics, making them hazardous for flora and fauna on a large scale. Recently, biological sources such as bacteria, fungi, algae, etc., have been used to bioabsorb these heavy metals. The microbial properties of these cell walls are utilized for effective and low-cost absorption of metals. Bioaugmentation, biosorption and biostimulation are effective strategies for reducing the toxicity of hazardous contaminants in the soil and facilitating bioremediation. The mechanism of biosorption is mainly based on ions and functional groups present in the microbes. Fungal species are advantageous over bacteria as they are easier to handle, cost-effective and, most importantly, non-pathogenic, making them ideal candidates for biosorption. This review provides a comprehensive overview of various microbial strains utilized in bioremediation. Further, the review highlights the application of nanotechnology and metabolic engineering approaches to improve the efficacy of Biosorption, Biostimulation and Bioaugmentation. It provides insights on the role of microbial nanoparticles in bioremediation and prospects in the forte of microbe-assisted bioremediation.

Diagnosis of pediatric pulmonary tuberculosis with special reference to polymerase chain reaction based nucleic acid amplification test

Objective: To determine the utility of polymerase chain reaction (PCR) for diagnosing pediatric pulmonary tuberculosis (PPTB). Method: A prospective cross-sectional study was carried out on 100 children less than 14 years of age, with strong clinical suspicion and radiological evidence suggestive of pulmonary tuberculosis (TB). Sputum samples/gastric lavage were collected. Direct smears and culture on Lowenstein Jensen (LJ) media were performed. DNA extraction and amplification was performed using Genei™ Amplification Reagent set for Mycobacterium tuberculosis (MTB) (by Genei, Bangalore, India). This test is based on the principle of single-tube nested PCR which amplifies the repetitive insertion sequence IS6110. Results: When compared with culture, sensitivity and specificity of PCR was 93.55% and 92.75%, respectively. The PPV was 85.29% and the NPV was 96.97%. When intention to treat (ITT) was used as the standard, sensitivity, specificity, PPV and NPV of PCR was 47.88%, 93.1%, 94.4%, and 42.19%, respectively, and that of culture was 40.85%, 100%, 100% and 40.85%, respectively. Against response to treatment (RTT), PCR demonstrated sensitivity, specificity, PPV and NPV of 50.9%, 93.1%, 93.33% and 50%, respectively, and for culture it was 43.64%, 100%, 100% and 48.33%, respectively. Conclusion/recommendation: The present study reinforces better case detection rate with PCR-based nucleic acid amplification test as compared with microscopy and culture in pediatric pulmonary TB. PCR showed a higher correlation with clinical diagnosis as compared with microscopy and solid culture. Hence, a molecular platform should be the test of choice for detecting PPTB