Department of Biological Sciences
Permanent URI for this collectionhttp://localhost:4000/handle/123456789/1922
Browse
49 results
Search Results
Item Unveiling the potential of Aspergillus terreus SJP02 for zinc remediation and its driving mechanism(Springer Nature, 2025-01) Verma, Sanjay Kumar; Gupta, Suresh; Panwar, JitendraIn present study, 15 morphologically different fungi isolated from rhizopheric soils of an industrial area were screened for their Zn2+ removal efficiency from aqueous solution. Isolate depicting highest potential was molecularly identified as Aspergillus terreus SJP02. Effect of various process parameters viz. biosorbent dose, contact time, temperature, agitation rate, pH and initial Zn2+ concentration on the fungal sorption capacity were studied. The biosorbent exhibited maximum Zn2+ sorption capacity of 10.7 ± 0.2 mg g− 1 in 60 min. Desorption studies showed 71.46% Zn2+ recovery rate in 120 min with 0.01 N HNO3, indicating efficient metal recovery for reuse and subsequent reutilization of spent mycosorbents. Acid digestion study suggested adsorption being the primary mechanism accounting for 87% Zn2+removal. It was further confirmed by the FE-SEM and EDX analysis. FTIR analysis suggested involvement of amino, hydroxyl, carbonyl, and phosphate functional groups of fungal cell wall in adsorption. The experimental results were in accordance with the tested isotherm and kinetic models, and suggested the role of physical adsorption for Zn2+ removal. Noteworthy, the present study showed better sorption capacity in considerably shorter equilibration time compared to previous reports and advocate potential utilization of A. terreus SJP02 for bioremediation of Zn2+ contaminated wastewater at industrial scale.Item Direct saponification of wet microalgae by methanolic potassium hydroxide using acetone as co-solvent(Elsevier, 2019-02) Verma, Sanjay KumarThe fatty acids of microalgae are promising source of biodiesel and omega-3 fatty acids. The objective of this study is extraction of fatty acids from wet Dunaliela salina by direct saponification using methanolic potassium hydroxide and a suitable co-solvent. The study identified acetone as an efficient co-solvent for saponification of wet microalgal biomass by methanolic potassium hydroxide. The presence of acetone in methanolic KOH saponification produced 24% more fatty acid than its absence. Further optimization of concentration of acetone (80% v/v), concentration of potassium hydroxide (0.1% v/v) and solvent-dry biomass ratio (75:1) resulted in a maximum yield of 98% fatty acid. The proposed acetone assisted saponification of wet microalgal biomass could serve as an energy efficient route for fatty acid production since the reaction happens under room temperature and normal atmospheric pressure without any cell lysis or drying the biomass.Item Antimicrobial Haplindole Alkaloids as Chemical Marker for Rapid Identification of Stigonematales (Cyanobacteria)(Taylor & Francis, 2020-12) Verma, Sanjay KumarAntimicrobial Hapalindole alkaloids have been identified in the order Stigonematales. Being exclusively present in a few members of this order, they can easily serve as a good chemical marker for their identification. In the present experiment, some locally isolated cyanobacterial strains were identified on the basis of these chemical compounds. Cyanobacterial strains were isolated from natural samples through standard techniques. Their antimicrobial activity was tested against various fungal and bacterial strains, which include: Psuedomonas syringe, Escherichia coli, Bacillus cereus, Pseudomonas putida, Salmonella sp., Fusarium oxysporum, Cercospora canescens and Colletotricum dematium. Of the several natural isolates, two strains showed strong antimicrobial activity against most of the tested microorganisms. Isolates showing antimicrobial activity were further subjected to DART-MS analysis to identify the chemical compounds. Mass spectra revealed the presence of a range of hapalindole alkaloids, which were confirmed through their exact mass measurement, elemental composition determination, and fragment ion generation in the DART source. Quantitative analysis was conducted by measuring relative abundance.Item Bio-Mitigation of Carbon Dioxide Using Desmodesmus sp. in the Custom-Designed Pilot-Scale Loop Photobioreactor(MDPI, 2021-09) Gupta, Suresh; Raghuvanshi, Smita; Verma, Sanjay KumarToday’s society is faced with many upfront challenges such as the energy crisis, water pollution, air pollution, and global warming. The greenhouse gases (GHGs) responsible for global warming include carbon dioxide (CO2), methane (CH4), nitrous oxide (NOx), water vapor (H2O), and fluorinated gases. A fraction of the increased emissions of CO2 in the atmosphere is due to agricultural and municipal solid waste (MSW) management systems. There is a need for a sustainable solution which can degrade the pollutants and provide a technology-based solution. Hence, the present work deals with the custom design of a loop photobioreactor with 34 L of total volume used to handle different inlet CO2 concentrations (0.03%, 5%, and 10% (v/v)). The obtained values of biomass productivity and CO2 fixation rate include 0.185 ± 0.004 g L−1 d−1 and 0.333 ± 0.004 g L−1 d−1, respectively, at 10% (v/v) CO2 concentration and 0.084 ± 0.003 g L−1 d−1 and 0.155 ± 0.003 g L−1 d−1, respectively, at 5% (v/v) CO2 concentration. The biochemical compositions, such as carbohydrate, proteins, and lipid content, were estimated in the algal biomass produced from CO2 mitigation studies. The maximum carbohydrate, proteins, and lipid content were obtained as 20.7 ± 2.4%, 32.2 ± 2.5%, and 42 ± 1.0%, respectively, at 10% (v/v) CO2 concentration. Chlorophyll (Chl) a and b were determined in algal biomass as an algal physiological response. The results obtained in the present study are compared with the previous studies reported in the literature, which indicated the feasibility of the scale-up of the process for the source reduction of CO2 generated from waste management systems without significant change in productivity. The present work emphasizes the cross-disciplinary approach for the development of bio-mitigation of CO2 in the loop photobioreactor.Item Differential expression of proteins in Pseudomonas mendocina SMSKVR-3 under arsenate stress(Wiley, 2021-01) Verma, Sanjay KumarThis study focuses on analyzing the protein expression pattern of intracellular proteins when Pseudomonas mendocina SMSKVR-3 exposed to 300 mM of arsenate to find out the proteins that are overexpressed or exclusively expressed in response to arsenate. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of protein expression at different time intervals showed the highest number of protein bands (14) that are overexpressed at 8 h of the time interval. It was also observed that treatment with at least 200 mM of As(V) is required to induce a difference in protein expression. Two-dimensional (2D)-PAGE analysis of 8-h sample exhibited 146 unique spots, 45 underexpressed, and 46 overexpressed spots in arsenate-treated sample. Based on the highest percent volume and fold change, three unique spots and one overexpressed spot were selected and analyzed by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF/TOF) mass spectrometry (MS) analysis followed by the MASCOT search. These proteins were identified as ribosome-recycling factor (20.13 kDa), polyphosphate:ADP/GDP phosphotransferase (40.88 kDa), ribonuclease P protein component (14.96 kDa) and cobalt-precorrin-5B C(1)-methyltransferase (38.43 kDa) with MASCOT score of 54, 81, 94, and 100, respectively. All of these proteins help the bacteria to overcome arsenate stress.Item Arsenic Resistance Mechanisms in Pseudomonas mendocina SMSKVR-3 Strain Isolated from Khetri Copper Mines, Rajasthan, India(Springer, 2022-01) Verma, Sanjay KumarAn arsenic resistant bacteria SMSKVR-3 has been isolated from the rhizospheric soil of the metal-contaminated site of khetri copper mines situated in the Jhunjhunu district of Rajasthan, India. The strain showed homology with Pseudomonas mendocina strain ATCC 25411. This gram-negative isolate exhibited optimal growth in M9 minimal media with temperature and salt concentration as 30 °C and 0.25% (w/v), respectively, at pH 7.0. The similar growth pattern and SEM analysis of this strain exposed to M9 minimal media alone, M9 media supplemented with 300 mM arsenate [As(V)] or M9 media supplemented with 1.34 mM arsenite [As(III)] indicate the existence of the strong arsenic resistance mechanism. The isolate was able to produce siderophores and was able to reduce As(V) to As(III). A decrease in polyP concentration from 354.8 µg/1010 CFU mL−1 at 0 h to 0.043 µg/1010 CFU mL−1 at 8 h incubation with As(V) was in correlation with the change in intracellular As(V) concentration (116.98 mg L−1/1010 cells at 0 h to 88.65 mg L−1/1010 at 8 h) with time. This shows the possible role of polyP bodies in the regulation of As(V) concentration inside the cell. The presence of arsC gene in P.mendocina SMSKVR-3 was confirmed by the PCR amplification of arsC gene. The BLAST analysis of the sequenced gene represented 98.59% identity with the P. mendocina S5.2 arsenate reductase. These results indicate that the observed arsenic resistance in SMSKVR-3 is due to a combination of siderophore production, the transformation of As(V) to As(III) by arsenate reductase, multi-drug efflux pump, and polyP bodies mediated metal resistance mechanism.Item Isolation and characterisation of copper resistant bacteria from Khetri copper mines and analysis of the expression of copper-induced proteins(Inder Science, 2023-03) Verma, Sanjay KumarThe present study focuses on the isolation and characterisation of copper-resistant bacteria from Khetri copper mines and analysis of proteins expression under copper stress in selected isolate (KH-5) using SDS-PAGE analysis. A total of 14 different bacterial colonies (KH-1 to KH-14) were isolated on media containing 2 mM of copper and were further characterised for their biochemical properties. The cross-metal tolerance study exhibited their tolerance to other heavy metals (As, Zn, Ni, Co, and Cd) along with copper. The growth curve analysis of all the isolates showed a delay in the lag phase for KH-11, KH-12, KH-2, KH-3, KH-8, and KH-9 in comparison to other strains that indicate the more robust metal resistance mechanisms in other isolates. Based on the results of all these studies, KH-5 was selected for the study of protein expression in the presence of copper stress which showed the same protein band pattern as control (non-stressed condition) without induction of any new protein band in the stressed condition. This suggests the presence of a constitutive copper resistance mechanism in the KH-5. Thus, further studies can be done to explore the copper resistance mechanism in this isolate.Item Development of fluorescent aptasensor for detection of acephate by utilizing graphene oxide platform(Elsevier, 2023-01) Verma, Sanjay KumarA fluorescent graphene oxide based aptasensing platform was developed for the detection of acephate. The aptamers specific to the acephate were screened through GO-SELEX (Graphene Oxide - Systematic Evolution of Ligands by EXponential enrichment) method for six rounds. The screened aptamers were analyzed for their binding affinity and specificity by using fluorescence-based assay. The aptamer AAPT3 that demonstrated highest affinity (Kd = 9 ± 1 nM) and an excellent selectivity, was employed in the development of fluorescent aptasensor. Under optimal conditions, the aptasensor showed low limit of detection (4 ng mL−1) and a wide dynamic linear range (5–80 ng mL−1). The aptasensor was also validated against water samples spiked with acephate, which showed fluorescence recovery from 94 to 107% and coefficient of variation 1–5%. These results indicate that the developed aptasensor can be used for sensitive, selective, and accurate detection of acephate in various samples.Item Selection of highly specific DNA aptamer for the development of QCM-based arsenic sensor(Wiley, 2023-10) Verma, Sanjay KumarHeavy metal arsenic is a water pollutant that affects millions of lives worldwide. A novel aptamer candidate for specific and sensitive arsenic detection was identified using Graphene Oxide-SELEX (GO-SELEX). Eleven rounds of GO-SELEX were performed to screen As(III) specific sequences. The selected aptamer sequences were evaluated for their binding affinity. The dissociation constant of the best aptamer candidate, As-06 was estimated by fluorescence recovery upon target addition, and it was found to be 8.15 nM. A QCM-based biosensing platform was designed based on the target-triggered release of aptamer from the QCM electrode. An rGO-SWCNT nanocomposite was adsorbed on the gold surface, and the single-stranded probe was stacked on the rGO-CNT layer. Upon addition of the target to the solution, a concentration-dependent release of the ssDNA probe was observed and recorded as the change in the electrode frequency. The developed QCM sensor showed a dynamic linear range from 10 nM to 100 nM and a low detection limit of 8.6 nM. The sensor exhibited excellent selectivity when challenged with common interfering anions and cations.Item Molecular Databases(EMI, 2001) Verma, Sanjay Kumar