Browsing by Author "Anjali Srivastava"

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Bioremediation of chromium (VI) from mining-contaminated soil using Klebsiella sp. (BH-A1): environmental implications
(Springer, 2025) Anjali Srivastava; Asha Lata Singh; Aniruddha Kumar; Alok Kumar
The present investigation aimed to isolate and identify a novel bacterium from chromium (VI)-contaminated soil samples collected from the Gorbi mine area, Singrauli coalfield, evaluates its potential for Cr(VI) reduction to Cr(III) and enhances environmental and operational conditions to apply this in bioremediation of Cr-contaminated soils. A bacterium was newly isolated from contaminated soils of coal mines for chromium (VI) reduction and identified as Klebsiella sp. (BH-A1) using 16S rRNA gene sequencing. Calcium chloride and sodium alginate solutions were used to immobilize the bacterial cells of isolated Klebsiella sp. Bacteria beads (Klebsiella sp. BH-A1) were tailored to reduce 10 µg/g Cr(VI)-contaminated soil under varied environmental factors such as bead biomass (200–1000 mg), pH (5–8), temperature (25–35 °C), and nutrient sources. Beads of Klebsiella sp. (BH-A1) (1000 mg/g) were efficient for 87% reduction of 10 µg/g Cr(VI) present in the soil at pH 7, 30 °C, within a six-hour contact period. Fourier transform infrared spectroscopy analyses reveal varied functional groups like –OH, –NH, and –COOH in Cr-treated bacterial beads. Functional groups corroborate their involvement in Cr(VI) and Cr(III) absorption on the cell surface of bacteria. Chromium-treated Klebsiella sp. (BH-A1) cell size was wider due to chromium absorption than the non-treated bacterial cells after SEM analyses. The energy dispersive X-ray plot has proven the 0.41 weight percent chromium accumulation inside the bacterial cells. Moreover, XPS analyses of Cr-treated bacterial cells indicate reduced Cr(VI) into Cr(III). The finding further suggests that Klebsiella sp. (BH-A1) might be a new prospect for potential application in Cr detoxification from Cr-contaminated soil. The limitations of this research include the accumulation of hazardous metabolic products due to low diffusion rates, the formation of thick biofilms blocking bead pores, and interrupted substrate transport from the bulk liquid to immobilized cells. © The Author(s), under exclusive licence to Springer Nature B.V. 2025.
Bioremediation of Chromium-contaminated Agricultural Soil Using Alginate-Encapsulated Bacterial Beads
(Springer Nature, 2025) Anjali Srivastava; Asha Lata Singh; Monika Yadav; Mayur B. Kurade; Ramesh Kumar; Moonis Ali Khan; Byong-hun Jeon
In this study, the efficacy of indigenous bacteria present in Cr-contaminated soil was tested for soil decontamination. Potential bacterial strains were screened and selected from soil samples and immobilized on sodium alginate beads. The most effective Cr(VI) reducing strain identified using 16S rRNA genome sequencing was Enterococcus italicus. Bacterial beads of E. italicus were optimized for Cr(VI) reduction under various exploratory conditions, such as temperature, pH, biomass, contact period, and different nutritional sources. Beads containing 1000 mg/g of E. italicus biomass reduced up to 91% of Cr(VI) (from an initial 5.4 mg/g in the soil) at pH 7 and 35 ℃ within 2 h. Glucose was found to be a good source of electron contributors that can reduce up to 94% of Cr(VI). FTIR analysis of the Cr(VI)-treated bacterial beads showed amines, -COO−, -CH3, C–O–C, and PO2 as new functional groups, revealing absorption and reduction of Cr(VI) from contaminated soil. The cell size of E. italicus after Cr-contaminated soil treatment was larger than that of untreated bacterial cells. The elemental analyses of treated and untreated bacterial cells revealed the presence of Cr inside the treated cells of E. italicus, which were transported from the soil during its treatment. Further, the XPS analysis confirmed the reduction of Cr(VI) to Cr(III) in the treated bacterial beads of E. italicus. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.
Decolorization and biodegradation of RR-195 dye using papaya peels: a green technology
(Taylor and Francis Ltd., 2025) Monika Yadav; Asha Lata Singh; Anjali Srivastava
Reactive Red-195 (RR-195) synthetic dye is aromatic in nature and it is commercially used in the textile industry owing to its good binding ability with fibers. During its processing as a coloring agent, the unfixed RR-195 dye remains in water, which leads to water pollution. In the present investigation papaya peel biomass in the form of granules (Ppbgra), ground (Ppbgri), and extracts (Ppbe) were used for decolorization and degradation of RR-195 dye. The experiments were performed under varying pH, biomass, temperature, shaking, and static conditions to ascertain the most favorable state for optimal degradation and decolorization. The experiments revealed that 3 g of Ppbgra, Ppbe, and Ppbgri Papaya peels were individually efficient to decolorize 83%, 92%, and 96% RR-195 (100 ppm), respectively, at 30 °C and pH 7.0, at a 24 h of incubation period under static conditions. Papain enzyme was found to play a central role in RR-195 dye degradation as determined through HPLC analysis. FTIR results of RR-195 dye treated with Ppbgra and Ppbgri revealed the presence of a peak at 2988 cm−1, which denotes stretching of the = C-H bond in the benzene ring, while the peak at 1737 cm−1 represents = C-C bonds of aromatic compounds and the peak at 1372 cm−1 shows CH3 stretching. Peaks at 941 cm−1 and 841 cm−1 are of N-H and = C-H bonds, respectively. These new functional groups indicate the formation of oximes and nitrous compounds due to dye degradation. Formation of RR-195 biodegraded metabolites was identified through GC-MS analysis. This comprises benzene, acetic acid, 2-Methoxy-4-vinyl phenol, and 3, 5-bis (1, 1-Dimethyl ethyl) phenol. BET result showed that the average pore diameter, pore volume, and surface area of papaya peel biomass (absorbents of unripened papaya peel) are 2.526 nm, 0.008 cm3/g, and 6.066 m2/g, respectively. Field Emission Scanning Electron Microscopy (FE-SEM) and EDS analysis (ZEISS GEMINI SEM-560) revealed that Ppbgri has a high ability to trap more dye particles because of its larger surface area as compared to Ppbgra. COD and TOC of 100 ppm treated dye were reduced up to 80% and 98%, respectively. Phytotoxicity study shows that treated dye is nontoxic for T. aestivum seed germination. Thus, papaya peels have a potential solution for dye effluent treatment. © 2025 Taylor & Francis Group, LLC.
Direct detection of resistance to fluoroquinolones/SLIDs in sputum specimen by GenoType MTBDRsl v.2.0 assay A study from Eastern Uttar Pradesh, India
(BioMed Central Ltd, 2021) Kamal Singh; Richa Kumari; Smita Gupta; Rajneesh Tripathi; Anjali Srivastava; Vidisha Shakya; Ankush Gupta; Shampa Anupurba
Background: According to World Health Organization (WHO), drug-resistant tuberculosis (DR-TB) is a major contributor to antimicrobial resistance globally and continues to be a public health threat. Annually, about half a million people fall ill with DR-TB globally. The gradual increase in resistance to fluoroquinolones (FQs) and second-line injectable drugs (SLIDs), poses a serious threat to effective TB control and adequate patient management. Therefore, WHO suggests the use of GenoType MTBDRsl v.2.0 assay for detection of multiple mutations associated with FQs and SLIDs. Hence, the study was conducted to determine the prevalence of resistance to FQs and SLIDs by comparing direct GenoType MTBDRsl v.2.0 assay with phenotypic drug susceptibility testing (DST). Methods: The study was conducted on 1320 smear positive sputum samples from a total of 2536 RR-TB, confirmed by GeneXpert MTB/RIF. The smear positive specimens were decontaminated, and DNA extraction was performed. Furthermore, the extracted DNA was used for GenoType MTBDRsl v.2.0 assay. While 20% of the decontaminated specimens were inoculated in Mycobacterium growth indicator tube (MGIT) for drug susceptibility testing (DST). Results: Out of 1320 smear positive sputum samples, 1178 were identified as Mycobacterium tuberculosis complex (MTBC) and remaining were negative by GenoType MTBDRsl v.2.0 assay. Of the 1178 MTBC positive, 26.6% were sensitive to both FQs and SLIDs, whereas 57.3% were only FQs resistant and 15.9% were resistant to both FQs and SLIDs. Further DST of 225 isolates by liquid culture showed that 17% were sensitive to both FQs and SLIDs, 61.3% were only FQs resistant and 21.3% were resistant to both. The specificity for FQs and SLIDs was 92.31% and 100% whereas sensitivity was 100% respectively by GenoType MTBDRsl v.2.0 assay in direct sputum samples. Conclusions: Our study clearly suggests that GenoType MTBDRsl v.2.0 assay is a reliable test for the rapid detection of resistance to second-line drugs after confirmation by GeneXpert MTB/RIF assay for RR-TB. Though, high rate FQ (ofloxacin) resistance was seen in our setting, moxifloxacin could be used as treatment option owing to very low resistance. © 2021, The Author(s).