Maximum Activity Research Articles

A Comparative Study of Different Staining Techniques for Cellulase Activity on CMC (Carboxy Methyl Cellulose) Agar

The present experiment was conducted at Department of Plant Pathology, College of Agriculture, Navsari Agricultural University, WaghaiduringMarch-October, 2021. cellulolytic bacterial isolates CD11, CD17, CD19, CD22 and CD35 were screened to determine the staining efficiency of various stains for cellulase activity on CMC(Carboxy Methyl Cellulose) agar and it was observed that all the isolates conferred clear zone around the colonies through different staining dyes and bacterial isolate CD35 showed the highest cellulolytic index in all the dyes. The cellulolytic index of CD35 was highest with gram’s iodine (3.34) next in order of coomassie brilliant blue (2.96), safranin (2.55) and congo red (2.15).Significantly, higher cellulase activity was recorded in CD35 (0.169 Uml-1) at 24 hrs after inoculation It was followed by CD17 (0.124 Uml-1), CD19 (0.101 Uml-1) and CD11 (0.081 Uml-1), while it was lowest in CD22 (0.052 Uml-1). Maximum cellulase activity was recorded at 72 hrs after inoculation by all the selected isolates except CD22 isolate, which was maximum 96 hrs after inoculation. CD35 gave significantly maximum cellulase activity (0.822 Uml-1) at 72 hrs after inoculation. Next in order to cellulase activity was CD17 (0.477 Uml-1) which was at par with CD19 (0.471 Uml-1) followed by CD11 (0.292 Uml-1) while, it was lowest in CD22 (0.199 Uml-1).Cellulolytic bacteria CD35 was identified as Bacillus subtilis by morphological, biochemical and molecular methods and submitted to NCBI GenBank database with accession numbers MW715021.

Synthesis, Spectroscopic Characterization, DFT, Molecular Docking, Catechol Oxidase Activity, and Anti-SARS-CoV-2 of Acylhydrazone Derivatives

In the present work, five pyrazole-hydrazone biomolecule ligands (L1–L5) were synthesized by condensation between 1H-pyrazole-3-carbohydrazide (2) and aromatic benzaldehydes. Their corresponding structures were elucidated employing NMR and FT-IR spectra and ESI-MS data. Li-Cu(II) complexes (i = 1–5) were evaluated for catecholase activity in situ at standard conditions. The findings disclose that the catecholase oxidation rate varies with the substituted functional groups in ligand and the anion type in the copper (II) salt. Catecholase activity results showed that the L(i = 1–5) -Cu(II)SO4 complexes exhibited efficient catalytic activity, and a maximum activity of 105 ± 42 µM.min−1 is obtained with L5-Cu(II)SO4. DFT and NBO calculations have been carried out to identify the global reactivity and the strength of interaction bonds between the donors and acceptors in L1–L5. The optimized structure of L1–L3 and L5 were found planar, while that of L4 is out of the molecular plan and forms a torsion angle of 18 degrees due to the presence of methoxy and hydroxyl group at meta and para. In L4, the 5-methyl-1H-pyrazole moiety. NBO findings show that the strongest interactions in L1–L5 are those involved in the electronic transition from π-bonding → π*-antibonding and LP → π*- antibonding molecular orbitals. Further, the anti-SARS-CoV-2 of L1–L5 are investigated by estimating their binding affinities into its binding. The docking results reveal that L1–L5 may act as SARS-CoV-2 main protease inhibitors with estimated binding energies in the −6.00 to −8.0 kcal.mol−1 range.

Synthesis of High-Molecular-Weight Polypropylene Elastomer by Propylene Polymerization Using α-Diimine Nickel Catalysts.

The α-diimine late transition metal catalyst represents a new strategy for the synthesis of atactic polypropylene elastomer. Taking into account the properties of the material, enhancing the molecular weight of polypropylene at an elevated temperature through modifying the catalyst structure, and further increasing the activity of α-diimine catalyst for propylene polymerization, are urgent problems to be solved. In this work, two α-diimine nickel(II) catalysts with multiple hydroxymethyl phenyl substituents were synthesized and used for propylene homopolymerization. The maximum catalytic activity was 5.40 × 105 gPP/molNi·h, and the activity was still maintained above 105 gPP/molNi·h at 50 °C. The large steric hindrance of catalysts inhibited the chain-walking and chain-transfer reactions, resulting in polypropylene with high molecular weights (407~1101 kg/mol) and low 1,3-enchainment content (3.57~16.96%) in toluene. The low tensile strength (0.3~1.0 MPa), high elongation at break (218~403%) and strain recovery properties (S.R. ~50%, 10 tension cycles) of the resulting polypropylenes, as well as the visible light transmittance of approximately 90%, indicate the characteristics of the transparent elastomer.

Impact of Heat Treatment on the Structural, Optical, Magnetic and Photocatalytic Properties of Nickel Oxide Nanoparticles.

The precursor nanoparticles of nickel hydroxide (Ni(OH)2) and nickel oxide (NiO) were successfully converted into the latter by the reaction of nickel chloride with hydrazine at ambient temperature. (TGA) and (DSC) were adapted for annealing the precursor products at different annealing temperatures (210, 285, 350, 390, 425, and 450 °C). XRD, TEM, and UV-VIS absorption spectroscopy were used to characterize the products. Both the band edge and energy gap values decrease with increasing annealing temperatures. Hysteresis loops are visible in the M-H curves of annealed (350 °C and 390 °C) precursor NiO NPs, indicating the presence of ferromagnetic Ni domains. However, NiO nanoparticles annealed at higher temperatures (425 °C and 450 °C) had a straight M-H curve, indicating paramagnetic properties. NiO NPs were used to study photocatalysis in the degradation of the MB dye. As annealing temperatures increased, the catalyst caused the degradation of MB. The sample that was annealed at 450 °C, however, exhibits the maximum photocatalytic activity, reaching up to 72.4% after being exposed to visible light. In other words, it was discovered that as the catalyst's annealing temperature rose, so did the rate of MB's photocatalytic degradation.

Expression in Pichia pastoris of Thermostable Endo-1,4-β-xylanase from the Actinobacterium Nocardiopsis halotolerans: Properties and Use for Saccharification of Xylan-Containing Products.

A gene encoding a polysaccharide-degrading enzyme was cloned from the genome of the bacterium Nocardiopsis halotolerans. Analysis of the amino acid sequence of the protein showed the presence of the catalytic domain of the endo-1,4-β-xylanases of the GH11 family. The gene was amplified by PCR and ligated into the pPic9m vector. A recombinant producer based on Pichia pastoria was obtained. The production of the enzyme, which we called NhX1, was carried out in a 10 L fermenter. Enzyme production was 10.4 g/L with an activity of 927 U/mL. Purification of NhX1 was carried out using Ni-NTA affinity chromatography. The purified enzyme catalyzed the hydrolysis of xylan but not other polysaccharides. Endo-1,4-β-xylanase NhX1 showed maximum activity and stability at pH 6.0-7.0. The enzyme showed high thermal stability, remaining active at 90 °C for 20 min. With beechwood xylan, the enzyme showed Km 2.16 mg/mL and Vmax 96.3 U/mg. The products of xylan hydrolysis under the action of NhX1 were xylobiose, xylotriose, xylopentaose, and xylohexaose. Endo-1,4-β-xylanase NhX1 effectively saccharified xylan-containing products used for the production of animal feed. The xylanase described herein is a thermostable enzyme with biotechnological potential produced in large quantities by P. pastoria.

Macroparticle-enhanced morphology engineering of Cordyceps sinensis for high glucose fermentation to optimize the production of bioactive exopolysaccharides

Cordyceps sinensis is widely known for its therapeutic properties. Enhancing the yield of exopolysaccharides (EPS), which is crucial for its medicinal efficacy, is a major challenge. In this study, we applied high initial glucose concentrations with talc particles to enhance EPS production and assessed the cell morphology, intracellular biochemical reactants, and bioactivity contribution of glycoproteins. The use of 150 g/L glucose and 10 g/L 2000 mesh talc increased the EPS yield by 1.8-fold to 4.21 g/L. The addition of talc regulated cell morphology, facilitated the entry of oxygen molecules into the cells to produce a large amount of ATP for polysaccharide synthesis, and altered the cell wall structure to facilitate the secretion of EPS. Moreover, environmental stress resulted in a notable increase in intracellular reactive oxygen species levels, which can potentially enhance cell membrane permeability and promote EPS synthesis. Furthermore, the highest protein content in crude EPS corresponded to the maximum activation of alcohol dehydrogenase (ADH) of 44.2 %, suggesting a mechanistic relationship between the proteins and polysaccharides in the glycoproteins that influence the activation of ADH. These findings elucidate the intricate interplay between fermentation conditions and EPS production and provide new avenues for optimizing the fermentation process of CS-HKI to enhance its therapeutic applications.

Harnessing a thermo-active and alkaline lipase from novel strain of Brevibacillus borstelensis gp-1, for application in biodiesel synthesis

A novel thermo-active and alkaliphilic strain of Gp-1, isolated from hot water springs of Ganeshpuri, Maharashtra, India, identified as Brevibacillus borstelensis based on 16SrDNA characterization, with accession no. MT292327, at NCBI database. Statistical optimization of lipase production was done using Plackett-Burman algorithm and response surface methodology. Fermentative production of Gp-1 lipase was followed by partial purification, with 24.10 fold purification. Gp-1 lipase has molecular mass of 31 kDa, as determined by SDS-PAGE. Gp-1 lipase exhibited maximal specific activity at pH 10 and 55 °C, with stability up to 70 °C. Kinetic parameters analysis revealed Gp-1 lipase has Km and Vmax values of 1.544 mM and 31.25 μM/mg. min, and specificity constant of 281.13 sec-1, with pNP caprylate as the base suited substrate. Gp-1 lipase was found to be retain more than 90% activity in presence of various organic solvents, and various commercial detergent formulations. The Gp-1 lipase was also tested for transesterification reactions, which revealed successful transesterification of coconut oil, olive oil and waste cooking oil, and conversion in esters. Hence, Gp-1 lipase stands out as a prospective candidate in biodiesel synthesis, a green energy alternative.

Assessment of organochlorine pesticide pollution in Donax trunculus from Agadir Bay (Center of Morocco): Utilization of integrated biomarkers

This study investigated the impact of seasonal organochlorine pesticide pollution on the physiological responses of Donax trunculus at Aghroud Beach during 2009 and 2010. Significant findings include the detection of six pesticides, with Endosulfan S being the most prevalent, reaching concentrations up to 62.63 ng/g dry weight. Biomarker analysis revealed notable seasonal variations, with the highest Acetylcholinesterase (AChE) activity in winter 2009 and the lowest in spring 2010. Glutathione S-transferase (GST) activity peaked in autumn 2009, while Catalase (Cat) showed maximum activity in autumns of 2009 and 2010. Malondialdehyde (MDA) levels were highest in summer 2010, indicating increased oxidative stress and lipid peroxidation during this period. Integrated Biomarker Response (IBR) values were highest in autumns, suggesting significant pollution stress. Principal Component Analysis (PCA) revealed strong correlations: a synergy between GST and Cat, and positive links between MDA and lipids, as well as AChE and Endosulfan B. This study highlights the efficacy of using integrated biomarker responses to assess environmental health and stresses the importance of autumn and summer monitoring due to higher pollution impacts.

Molecular Characteristics of the Malate Dehydrogenase (MDH) Gene Family in Spirometra mansoni (Cestoda: Diphyllobothriidea).

The plerocercoid larva of Spirometra mansoni can cause a parasitic zoonosis-sparganosis. Malate dehydrogenase (MDH) plays a very important role in the life activities of parasites. However, little is known about the MDH family in S. mansoni. We identified eight new MDH members in S. mansoni in this study. Clustering analysis divided SmMDHs into two groups and revealed patterns similar to the conserved motif organization. RT-qPCR suggested that five MDHs were highly expressed in the mature proglottid and that three MDHs were highly expressed in the gravid proglottid. Phylogenetic analysis revealed that SmMDHs contain both conserved family members and members in the process of further diversification. rSmMDH has an NAD binding domain, a dimer interface and a substrate binding domain. Natural SmMDH was immunolocalized in the tissues and follicles around the uterus in the mature or gravid proglottid and eggshells. The maximum forward and reverse reaction activities of rSmMDH were observed at pH 8.5 and 9.0, respectively. The optimum temperature for enzyme activity was 37 °C in the forward reaction and 40 °C in the reverse reaction. These results lay the foundation for studying the molecular functions and mechanisms of MDHs in S. mansoni and related taxa.

Syn and post-glacial volcanic activity in the western retroarc area of the andean southern volcanic zone: Overo volcano

Located in a poorly studied zone of the rear arc in the Transitional Southern Volcanic Zone, the Overo volcano presents a complete record of syn-glacial, inter-glacial, and post-glacial activity, marked by significant changes in eruptive mechanisms over time. Following pre-glacial units, an effusive syn-glacial basaltic phase was succeeded by an extensive inter-glacial diking that fed andesitic monogenetic fields. Subsequently, an eruptive pulse, possibly coupled with the destabilization of the main edifice, resulted in a block and ash deposit channeled into a glacial valley towards the southwest, later covered by extensive basaltic lava flows. Then, different types of pyroclastic flows and glacial deposits covered these earlier units. Finally, these younger glacial deposits were overlain by a localized postglacial pyroclastic deposit and widespread lava flows, which ultimately reconstructed the deeply eroded glacial morphology of the Overo volcano. This volcanic record reveals the young and complex activity of this poorly known western rear-arc volcanic center in the Transitional Southern Volcanic Zone of the Andes, whose evolution is more akin to the arc front volcanoes to the west than to their eastern within-plate counterparts. We propose that this magmatic evolution was influenced by the Pleistocene-Holocene Last Glacial Maximum activity (LGM), beginning with an initial phase of volcanic activity encapsulated within glacial conditions. Glacial retreat then triggered isostatic uplift and crustal relaxation, resulting in dike formation, flank instability, and syn-eruptive collapse of the volcanic edifice. Subsequently, a lesser glacial pulse partially eroded the volcano morphology and produced the currently preserved glacial deposits. Finally, a latest and limited post-glacial pyroclastic eruption occurred simultaneously with the formation of an extensive monogenetic basaltic field, shaping the final morphology of the volcano.

Which Insights Can Gas Diffusion Electrode Half-Cell Experiments Give into Activity Trends and Transport Phenomena of Membrane Electrode Assemblies?

In order to push the energy turnaround forward, research and development on technologies enabling storage and release of renewable energies, such as water electrolysis and fuel cells is vital in the current decade. For both processes it is essential to collect meaningful data for catalyst activity in terms of transferability to the industrial application already on the lab-scale and at an early stage of material development. Gas diffusion electrode (GDE) half-cell setups were recently presented as a fast and cost-effective tool to characterize oxygen reduction reaction (ORR) catalyst layers at fuel cell relevant potentials and current densities (3 A cm-2) [1]. An Inter-lab comparison demonstrated that GDE testing with various, slightly differing setups can deliver data that is both reliable and comparable if standardized measurement protocols are followed [2]. On the way to widespread application, it is essential to evaluate to which extend GDE half-cell measurements can provide reasonable trends of how catalyst layer properties influence ORR activity in membrane electrode assembly (MEA) applications, despite the major influence of the active metal itself. Elucidating possibilities and limitations of GDE half-cell measurements to study catalyst layer influences is scope of this study.The transferability of trends was studied for i) an ionic liquid modified and unmodified Pt/C catalyst (following our previous work [3]) and ii) employing nitrogen modified carbon support at different ionomer to carbon ratios (following the work of Ott et al. [4]). Regarding the activity increase due to IL modification we will show that rotating disk electrode (RDE) and GDE results at low current densities show the same trend. GDE testing also shows a maximum activity depending on the IL loading at slightly elevated current densities. In the high current density regime, however, MEA testing showed a negative effect of the IL modification, which was also obtained correctly within the GDE testing at the same current densities. For the N-doped Pt/C catalyst a positive effect was observed in MEA characterization with low ionomer content under dry conditions, where proton transport losses are dominant for the unmodified catalyst. However, at higher I/C ratio and under wet conditions, where proton transport is sufficient for both unmodified and N-doped catalyst, worse performance after N modification is observed in the high current density regime. During GDE evaluation only the latter phenomenon could be capture and the unmodified catalyst showed a superior performance over the N-doped material at any I/C ratio in the ohmic and in the mass transport limiting regime.In summary, we showed that GDE half-cell experiments, where the catalyst layer is in direct contact with the liquid electrolyte, can be used to reliably predict trends in catalytic activity for real MEAs at high current densities that are related to differences in oxygen mass transport [5]. However, differences in catalytic activity being related to proton accessibility especially at lower relative humidities cannot be captured completely, as the catalyst layer is always wetted fully. An introduction of an ionomer membrane between catalyst layer and liquid electrolyte might be necessary during GDE evaluation for a reliable description of all transport phenomena in real fuel cells. Nevertheless, our results indicate that GDE measurements without the utilization of an ionomer membrane allow for the study of oxygen mass transport properties independent of other transport phenomena at fuel cell relevant current densities.Literature:[1] Schmitt et al. Electrochemistry Communications 2022, 141, 107362 [2] Ehelebe et al. ACS Energy Lett. 2022, 7, 816-826. [3] Zhang et al. Advanced Functional Materials 31.28 (2021): 2010977 [4] Ott et al. Nature materials 19.1 (2020): 77-85. [5] Schmitt et al. Energy Adv. 2023, 2, 854.

Novel MoS2-In2O3-WS2 (2D/3D/2D) ternary heterostructure nanocomposite material: Efficient photocatalytic degradation of antimicrobial agents under visible-light

Fabrication of ternary composited photocatalytic nanomaterials with strong interaction is vital to deriving the fast charge separation for efficient photodegradation of organic contaminants in wastewater under visible light. In this work, novel ternary 2D/3D/2D MoS2-In2O3-WS2 multi-nanostructures were synthesized using facile hydrothermal processes. XRD, FTIR, and XPS results confirmed the phase, functional groups, and element composition of pure MoS2, MoS2-In2O3, and MoS2-In2O3-WS2 hybrids. UV-DRS spectra of the MoS2-In2O3-WS2 ternary hybrid indicate maximum absorption in the visible light range with a band-gap energy value of 2.4 eV. The surface of the 2D WS2 nanosheet structure tightly blends and densely disperses 2D MoS2 nanosheets and 3D In2O3 nanocubes. This confirmed the formation of the MoS2-In2O3-WS2 ternary hybrid in the form of 2D/3D/2D multi-nanostructures, which is also indicated from SEM and HR-TEM images. The synthesized MoS2-In2O3-WS2 ternary hybrid showed maximum photocatalytic activity under visible-light for antimicrobial agents such as triclosan (TCS) and trichlorocarban (TCC). The photocatalytic activity of TCS was revealed to be 95% at 90 min, while that of TCC was 93% at 100 min. The reusability and stability tests of the prepared MoS2-In2O3-WS2 ternary hybrid after four consecutive photocatalytic cycles were analyzed by FTIR and SEM, which indicated that the prepared ternary hybrid was very stable. Overall results suggested that the developed MoS2-In2O3-WS2 (2D/3D/2D) multi-nanostructures are environmentally friendly and low-cost nanocomposites as a potential photocatalyst for the removal of antimicrobial agents from wastewater.

Synergistic rescue of temperature-sensitive p53 mutants by hypothermia and arsenic trioxide.

The p53 tumor suppressor is inactivated by mutations in about 50% of tumors. Rescuing the transcriptional function of mutant p53 has potential therapeutic benefits. Approximately 15% of p53 mutants are temperature sensitive (TS) and regain maximal activity at 32°C. Proof of concept study showed that induction of 32°C hypothermia in mice restored TS mutant p53 activity and inhibited tumor growth. However, 32°C is the lower limit of therapeutic hypothermia procedures for humans. Higher temperatures are preferable but result in suboptimal TS p53 activation. Recently, arsenic trioxide (ATO) was shown to rescue the conformation of p53 structural mutants by stabilizing the DNA binding domain. We examined the responses of 17 frequently observed p53 TS mutants to functional rescue by temperature shift and ATO. The results showed that ATO only rescued mild p53 TS mutants with high basal activity at 37°C. Mild TS mutants showed a common feature of regaining significant activity at the semi-permissive temperature of 35°C and could be further stimulated by ATO at 35°C. TS p53 rescue by ATO was antagonized by the cellular redox mechanism and was rapidly reversible. Inhibition of glutathione (GSH) biosynthesis enhanced ATO rescue efficiency and sustained p53 activity after ATO washout. The results suggest that mild TS p53 mutants are uniquely responsive to functional rescue by ATO due to small thermostability deficits and inherent potential to regain active conformation. Combining mild hypothermia and ATO may provide an effective and safe procedure for targeting tumors with p53 TS mutations.

Aspergillus niger Ochratoxinase Is a Highly Specific, Metal-Dependent Amidohydrolase Suitable for OTA Biodetoxification in Food and Feed.

Microbial enzymes can be used as processing aids or additives in food and feed industries. Enzymatic detoxification of ochratoxin A (OTA) is a promising method to reduce OTA content. Here, we characterize the full-length enzyme ochratoxinase (AnOTA), an amidohydrolase from Aspergillus niger. AnOTA hydrolyzes OTA and ochratoxin B (OTB) mycotoxins efficiently and also other substrates containing phenylalanine, alanine, or leucine residues at their C-terminal position, revealing a narrow specificity profile. AnOTA lacks endopeptidase or aminoacylase activities. The structural basis of the molecular recognition by AnOTA of OTA, OTB, and a wide array of model substrates has been investigated by molecular docking simulation. AnOTA shows maximal hydrolytic activity at neutral pH and high temperature (65 °C) and retained high activity after prolonged incubation at 45 °C. The reduction of OTA levels in food products by AnOTA has been investigated using several commercial plant-based beverages. The results showed complete degradation of OTA with no detectable modification of beverage proteins. Therefore, the addition of AnOTA seems to be a useful procedure to eliminate OTA in plant-based beverages. Moreover, computational predictions of in vivo characteristics indicated that AnOTA is neither an allergenic nor antigenic protein. All characteristics found for AnOTA supported the suitability of its use for OTA detoxification in food and feed.

Enzymatically and chemically starch nanoparticles preparation using ultrasonication, precipitation and lyophilization post-treatments: Screening and characterization

Starch nanoparticles (SNPs) have been used in food emulsions as natural stabilizer and emulsifier. SNPs in colloidal form were produced using enzymatically, acidic and alkaline hydrolyses in combination to ultrasonication and precipitation methods. X-Ray diffraction test for produced SNPs indicated that enzymatically and acidic prepared SNPs had amorphous structure while, the resulted SNPs using alkaline hydrolysis had lower relatively crystallinity. Results indicated that, enzymatically prepared SNPs, had minimum particle size (225 ± 10 nm) and polydispersity index (0.472 ± 0.05), and maximum zeta potential (−26.3 ± 1 mV), antioxidant activity (3.36 ± 0.05 %) and specific surface area (1.8 ± 0.1 m2g−1). Transmission electron microscopy revealed that prepared SNPs had spherical shape and enzymatically prepared SNPs had mean particle size of <100 nm. SNPs in powder form were prepared using freeze drying (pressure and temperature of 100 Pa and − 70 °C). Atomic force microscopy results demonstrated that starch granules had smooth surface, with polyhedral shape and particle size ranging 5 to 25 μm, and after hydrolysis, SNPs had particle size in nanometer scale. Emulsion ability test indicated that oil separation time from the prepared emulsions containing 10 % (W/V) starch, and enzymatically, acidic and alkaline prepared SNPs powder were 41, 70, 82 and 101 s, respectively.

The hemodynamic response to co-occurring interictal epileptiform discharges and high-frequency oscillations localizes the seizure-onset zone.

To use intracranial electroencephalography (EEG) to characterize functional magnetic resonance imaging (fMRI) activation maps associated with high-frequency oscillations (HFOs) (80-250 Hz) and examine their proximity to HFO- and seizure-generating tissue. Forty-five patients implanted with intracranial depth electrodes underwent a simultaneous EEG-fMRI study at 3 T. HFOs were detected algorithmically from cleaned EEG and visually confirmed by an experienced electroencephalographer. HFOs that co-occurred with interictal epileptiform discharges (IEDs) were subsequently identified. fMRI activation maps associated with HFOs were generated that occurred either independently of IEDs or within ±200 ms of an IED. For all significant analyses, the Maximum, Second Maximum, and Closest activation clusters were identified, and distances were measured to both the electrodes where the HFOs were observed and the electrodes involved in seizure onset. We identified 108 distinct groups of HFOs from 45 patients. We found that HFOs with IEDs produced fMRI clusters that were closer to the local field potentials of the corresponding HFOs observed within the EEG than HFOs without IEDs. In addition to the fMRI clusters being closer to the location of the EEG correlate, HFOs with IEDs generated Maximum clusters with greater z-scores and larger volumes than HFOs without IEDs. We also observed that HFOs with IEDs resulted in more discrete activation maps. Intracranial EEG-fMRI can be used to probe the hemodynamic response to HFOs. The hemodynamic response associated with HFOs that co-occur with IEDs better identifies known epileptic tissue than HFOs that occur independently.

A kinetic modelling approach to explore mechanism of Cr(VI) detoxification by a novel strain Pseudochrobactrum saccharolyticum NBRI-CRB 13 using response surface methodology.

A novel Pseudochrobactrum saccharolyticum strain NBRI-CRB 13, isolated from tannery sludge, was studied to grow up to 500 mgL-1 of Cr(VI) and showed Cr(VI) detoxification by reducing > 90% of Cr(VI) at different concentrations 25, 50 and 100 mgL-1. Kinetic studies showed that first-order models were fitted (R2 = 0.998) to the time-dependent Cr(VI) reduction with degradation rate constant (k) (1.03-0.429h-1). Cr(VI) detoxification was primarily related to the extracellular fraction of microbial cells, which showed a maximum extracellular reductase enzyme activity led to 94.6% reduction of Cr(VI). Moreover, the strain showed maximum extracellular polymeric substances (EPS) production at 100 mgL-1 Cr(VI), which is presumably the reason for Cr(VI) removal as EPS serves as the metal binding site for Cr(VI) ions. Further, an optimization study using Box-Behnken design was conducted considering parameters viz., pH, temperature, and initial concentration of Cr(VI). The maximum percent reduction of Cr(VI) was obtained at pH 6.5, temperature 30°C with 62.5 mgL-1Cr(VI) concentration. Further, the Cr(VI) reduction and adsorption ability of strain P. saccharolyticum NBRI-CRB13 were confirmed by SEM-EDS, FTIR, and XRD analyses. FTIR analysis confirmed the presence of functional groups (-OH, -COOH, -PO4) on bacterial cell walls, which were more likely to interact with positively charged chromium ions. The study elucidated the reduction of Cr(VI) by the novel bacterium within 24h using the response surface methodology approach and advocated its application in real-time situations.

Microbial degradation of paddy (Oryza sativa) straw by submerged state fermentation

This study elucidates the effective lignocellulose degrading potential of microbial consortium by using paddy straw as the sole source under submerged fermentation conditions. Straw degradation was enhanced by bioaugmentation procedures where consortia of isolated and standard cultures resulted in maximum enzyme activities of endoglucanase (1 U/ml), exoglucanase (1.31 U/ml), β-glucosidase (2.42 U/ml), xylanase (12.63 U/ml) and manganese peroxidase (5.43 U/ml) after 28 days of incubation along with laccase (4.36 U/ml) and lignin peroxidase (6.71 U/ml) after 21 days of incubation. By the action of consortium, maximum reduction of cellulose, hemicellulose and lignin was found to be 35.31, 22.50 and 44.72%, respectively after 28 days of incubation. A significant increase in percentage loss in dry matter of paddy straw was observed till 4 weeks of fermentation. Field emission scanning electron microscope (FE-SEM) micrographs revealed sufficient loosening of cellulose and hemicellulose showing successful degradation of straw tissue. Overall, the above stated findings emphasize on potential of lignocellulosic microorganisms to be used as an alternative to traditional stubble burning practice. Although, these extracellular enzymes are well equipped in breaking down lignocelluloses to their monomeric or oligomeric subunits, but they may not be exploited at commercial level due to very slow rate of reaction. The efficacy of these cultures for straw degradation in field condition further needs elaborative experimental trials as environmental parameters are quite variable in the field.

Robust peroxidase from Bacillus mojavensis TH309: Immobilization on walnut shell hydrochar and evaluation of its potential in dye decolorization

Peroxidases have received considerable attention as a cost-effective and environmentally friendly catalyst for bioremediation. Their rapid activity loss under harsh environmental conditions and inability to be used repetitively limit their exploitation in real-world wastewater treatment. First, a peroxidase was produced extracellularly by Bacillus mojavensis TH309 and purified 8.12-fold with a final yield of 47.10 % using Sephadex G-100 superfine resin. The pure peroxidase (BmPer) possessed a relatively low molecular weight of ∼21 kDa and was active against L-DOPA on acrylamide gel after electrophoresis. BmPer was immobilized by adsorption functionalized walnut shell hydrochar (WsH) with 61.99 ± 1.34 % efficiency and 37.07 ± 4.16 % activity loss. BmPer and its immobilized form (WsH-BmPer) exhibited maximum activity at 50 °C and pH 9. WsH-BmPer exhibited 3.23-, 2.37-, 1.65-, and 2.25-fold longer half-life than BmPer at 50, 60, 70, and 80 °C, respectively. Immobilization significantly enhanced the stability of the enzyme under acidic conditions. BmPer and WsH-BmPer showed maximal activity in the presence of 1 % salt and retained more than 85 % of their activity even after pre-incubation with 2.5 M salt for 60 min at 50 °C. Their catalytic efficiency was significantly stimulated by pre-incubation with Triton X-100 (1 mM), Tween20 (1 mM), and Mg2+ (1 and 10 mM). Immobilization strongly reduced the loss of activity caused by inhibitors including Ba2+, Hg2+, and Cu2+. Moreover, both forms of the enzyme were compatible with solvents. The Michaelis constant (Km) values of BmPer and WsH-BmPer were 0.88 and 2.66 mM for 2,4 DCP, respectively. WsH-BmPer peroxidase maintained about 82 % and 85 % of its activity when stored at 4 °C for 30 days and reused for up to 10 cycles, respectively. Furthermore, it decolorized Cibacron red (CR), Poly R-478 (PR), Remazol Brilliant Blue R (RBBR), and Methyl red (MR) dyes by 60.13 %, 91.34 %, 86.41 %, and 50.51 % within 60 min, respectively.

Characterisation of Bambara groundnut (Vigna subterranea (L.) Verdc.) shell waste as a potential biomass for different bio-based products.

Efforts are ongoing to utilise agricultural waste to achieve a full resource use approach. Bambara groundnut is an important crop widely grown in the sub-Saharan Africa with potential future importance because of its resilience to thrive under heightened weather uncertainty and widespread droughts that have challenged food security. After harvesting, the edible nuts are separated from the shells which are discarded as waste. Therefore, this research is aimed at characterising the chemical composition and the structural properties of Bambara groundnut shells (BGS) in view of their potential application as a biomass for different bio-products. The chemical composition of BGS was found to be 42.4% cellulose, 27.8% hemicellulose, 13% lignin and 16.8% extractives. Proximate analysis showed a high amount of volatile matter (69.1%) and low moisture (4.4%). XRD analysis confirmed crystallinity of cellulose I polymer and FTIR analysis observed functional groups of lignocellulosic compounds. Thermal stability, maximum degradation temperature and activation energy were found to be 178.5°C, 305.7°C and 49.4kJ/mol, respectively. Compared to other nutshells, BGS were found to have a relatively high amount of cellulose and crystallinity that may result in biocomposites with improved mechanical properties.