Manipulating Microbial Cell Morphology for the Sustainable Production of Biopolymers.

The total rate of plastic production is anticipated to surpass 1.1 billion tons per year by 2050. Plastic waste is non-biodegradable and accumulates in natural ecosystems. In 2020, the total amount of plastic waste was estimated to be 367 million metric tons, leading to unmanageable waste disposal and environmental pollution issues. Plastics are produced from petroleum and natural gases. Given the limited fossil fuel reserves and the need to circumvent pollution problems, the focus has shifted to biodegradable biopolymers, such as polyhydroxyalkanoates (PHAs), polylactic acid, and polycaprolactone. PHAs are gaining importance because diverse bacteria can produce them as intracellular inclusion bodies using biowastes as feed. A critical component in PHA production is the downstream processing procedures of recovery and purification. In this review, different bioengineering approaches targeted at modifying the cell morphology and synchronizing cell lysis with the biosynthetic cycle are presented for product separation and extraction. Complementing genetic engineering strategies with conventional downstream processes, these approaches are expected to produce PHA sustainably.

Blue emitting exciplex for yellow and white organic light-emitting diodes.

White organic light-emitting diodes (WOLEDs) have several desirable features, but their commercialization is hindered by the poor stability of blue light emitters and high production costs due to complicated device structures. Herein, we investigate a standard blue emitting hole transporting material (HTM) N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)benzidine (NPB) and its exciplex emission upon combining with a suitable electron transporting material (ETM), 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole (TAZ). Blue and yellow OLEDs with simple device structures are developed by using a blend layer, NPB:TAZ, as a blue emitter as well as a host for yellow phosphorescent dopant iridium (III) bis(4-phenylthieno[3,2-c]pyridinato-N,C2')acetylacetonate (PO-01). Strategic device design then exploits the ambipolar charge transport properties of tetracene as a spacer layer to connect these blue and yellow emitting units. The tetracene-linked device demonstrates more promising results compared to those using a conventional charge generation layer (CGL). Judicious choice of the spacer prevents exciton diffusion from the blue emitter unit, yet facilitates charge carrier transport to the yellow emitter unit to enable additional exciplex formation. This complementary behavior of the spacer improves the blue emission properties concomitantly yielding reasonable yellow emission. The overall white light emission properties are enhanced, achieving CIE coordinates (0.36, 0.39) and color temperature (4643 K) similar to daylight. Employing intermolecular exciplex emission in OLEDs simplifies the device architecture via its dual functionality as a host and as an emitter.

Construction of arsenic selective chelating resin with iron precursor for removal of low-concentration arsenic: Breakthrough modeling and field deployment.

The presence of exorbitant arsenic contamination in the aquatic environment causes astronomically immense health quandaries affecting millions of people, which may lead to death in the case of prolonged indigestion of arsenic-containing drinking water. Herein, we are reporting porous chelating resin with an iron precursor for the removal of arsenic ions from water. Weak acid cation resin was functionalized under varying experimental conditions to get a suitable resin with high arsenic uptake. The theoretical results revealed that the maximum Langmuir adsorption capacities of 3.27 mg g-1 and 1.13 mg g-1 were achieved for As(V) and As(III), respectively. The kinetics of adsorption followed the pseudo-second-order (PSO) model with a high determination coefficient (R2) of 0.9963 and 0.9895 for As(V) and As(III), respectively. The Adams-Bohart, Thomas, Yoon-Nelson, and Pore diffusion models were used to identify the breakthrough curve in the fixed bed adsorption column. The column performance improved with a larger bed height (55 cm), low concentration of influent (0.25 mg L-1), and low flow rate of influent (80 mL min-1). Under this condition, the breakthrough time and exhaustion time were 314 min and 408 min for As(V) and 124 min and 185 min for As(III), respectively.

One-pot facile approach to design an efficient macro-porous polymeric matrix to remediate Hg(II)and Pb(II) from aqueous medium and its performance evaluation study by mathematical modelling.

In the present scenario discharge of heavy-metal ions into water bodies is a global threat that is causing serious health hazards even in low concentrations. Thus, in order to remediate the heavy-metal [Hg(II) and Pb(II)] toxicity, an organic-inorganic hybrid functional porous metallo-polymeric network i. e, poly(Zirconyl methacrylate-co-1-vinyl imidazole) (pZrVIm) was fabricated via one-pot facile synthesis approach. The pZrVIm architecture has shown high removal efficiency for Hg(II) and Pb(II) aqueous medium even in extremely low quantities. Advanced instrumental techniques were used to characterize the structural and morphological characteristics of pZrVIm. Different experimental variables i.e., reaction time, pH, initial feed concentration, co-ion effects etc. were explored to examine adsorption behaviour. The maximum adsorption capacities (qmax) of pZrVIm5 were calculated as 168.06 and 162.34 mg g-1 for Hg(II) and Pb(II) respectively by the Langmuir isotherm model. Data from isotherms showed that monolayer adsorption on a homogeneous surface is the rate-limiting stage and followed pseudo-second-order kinetic process. The Artificial Neural Network (ANN) modelling was used to validate kinetics and isotherm data which revealed high accuracy of the model with correlation coefficient values (R = 0.99). Various types of isotherm models such as Langmuir, Freundlich, Dubinin-Radushkevich, Temkin, Redlich-Peterson, Toth and Koble-Corigen have been studied to determine the adsorption phenomena. The pore diffusion model revealed breakthrough time of 91 h and 84 h, Hg(II) and Pb(II) with the feed concentration of 15 mg L-1 respectively. The study revealed that pZrVIm5 has great potential for heavy metal ions remediation for water treatment.

Laccase Immobilization on Copper-Magnetic Nanoparticles for Efficient Bisphenol Degradation.

Laccase activity is influenced by copper (Cu) as an inducer. In this study, laccase was immobilized on Cu and Cu-magnetic (Cu/Fe2O4) nanoparticles (NPs) to improve enzyme stability and potential applications. The Cu/Fe2O4 NPs functionally activated by 3-aminopropyltriethoxysilane and glutaraldehyde exhibited an immobilization yield and relative activity (RA) of 93.1 and 140%, respectively. Under optimized conditions, Cu/Fe2O4 NPs showed high loading of laccase up to 285 mg/g of support and maximum RA of 140% at a pH 5.0 after 24 h of incubation (4°C). Immobilized laccase, as Cu/Fe2O4-laccase, had a higher optimum pH (4.0) and temperature (45°C) than those of a free enzyme. The pH and temperature profiles were significantly improved through immobilization. Cu/Fe2O4-laccase exhibited 25-fold higher thermal stability at 65°C and retained residual activity of 91.8% after 10 cycles of reuse. The degradation of bisphenols was 3.9-fold higher with Cu/Fe2O4-laccase than that with the free enzyme. To the best of our knowledge, Rhus vernicifera laccase immobilization on Cu or Cu/Fe2O4 NPs has not yet been reported. This investigation revealed that laccase immobilization on Cu/Fe2O4 NPs is desirable for efficient enzyme loading and high relative activity, with remarkable bisphenol A degradation potential.

Integration of biogas derived from dark fermentation and anaerobic digestion of biowaste to enhance methanol production by methanotrophs.

Biowaste-derived sugars or greenhouse gases, such as methane (CH4) and carbon dioxide (CO2), can be used to generate eco-friendly biofuels, such as hydrogen (H2) or methanol. In the present study, enzyme-based rice straw (RS) hydrolysate was used to produce dark-fermentative (DF) biogas (H2 and CO2), which was subsequently integrated with biogas (CH4 and CO2) derived from anaerobic digestion (AD) to generate methanol via methanotrophs. First, DF of RS hydrolysate yielded 2.82 mol of H2/mol of hexose. Second, the integration of biogas derived from DF and AD in the presence of CH4 vectors yielded 13.8 mmol/L of methanol via methanotrophs. Moreover, under the repeated batch mode, 64.6 mmol/L of methanol was produced. This is the first report on the integration of biogas derived from AD and DF of biowaste to produce biomethanol. These findings may facilitate the development of a sustainable biowaste-based circular economy for producing biofuels.

Synthetic design of methanotroph co-cultures and their immobilization within polymers containing magnetic nanoparticles to enhance methanol production from wheat straw-based biogas.

In this study, various methanotroph co-cultures were designed to enhance methanol production from biogas produced through the anaerobic digestion of wheat straw (WS). Furthermore, whole-cell immobilization was performed using magnetic nanoparticle (MNP)-loaded polymers to develop an efficient bioprocess. The anaerobic digestion of WS by cattle dung yielded 219 L/kg of total solids reduced. Methanol produced was 5.08 and 6.39 mmol/L by pure- and co-cultures from biogas, respectively. The optimization of process parameters enhanced methanol production to 6.82 mmol/L by co-culturing Mithylosinus sporium and Methylocella tundrae. The immobilized co-culture within the MNP-doped polymers exhibited much higher cumulative methanol of up to 70.74 mmol/L than the production of 22.34 mmol/L by free cells after ten cycles of reuse. This study suggests that MNP-doped polymer-based immobilization of methanotrophs is a unique approach for producing renewable fuels from biomass-derived biogas, a greenhouse gas.

Mild Alkaline Pretreatment of Rice Straw as a Feedstock in Microbial Fuel Cells for Generation of Bioelectricity.

The dependency on non-renewable fossil fuels as an energy source has drastically increased global temperatures. Their continuous use poses a great threat to the existing energy reserves. Therefore, the energy sector has taken a turn toward developing eco-friendly, sustainable energy generation by using sustainable lignocellulosic wastes, such as rice straw (RS). For lignocellulosic waste to be utilized as an efficient energy source, it needs to be broken down into less complex forms by pretreatment processes, such as alkaline pretreatment using NaOH. Varied NaOH concentrations (0.5%,1.0%,1.5%,2%) for alkaline pretreatment of RS were used for the holocellulose generation. Amongst the four NaOH concentrations tested, RS-1.5% exhibited higher holocellulose generation of 80.1%, whereas 0.5%, 1 5 and 2% pointed 71.9%, 73.8%, and 78.5% holocellulose generation, respectively. Further, microbial fuel cells (MFCs) were tested for voltage generation by utilizing holocellulose generated from untreated (RS-0%) and mildly alkaline pretreated RS (RS-1.5%) as a feedstock. The MFC voltage and maximum power generation using RS-0% were 194 mV and 167 mW/m2, respectively. With RS-1.5%, the voltage and maximum power generation were 556 mV and 583 mW/m2, respectively. The power density of RS-1.5% was three-fold higher than that of RS-0%. The increase in MFC power generation suggests that alkaline pretreatment plays a crucial role in enhancing the overall performance.

Immobilization of Laccase Through Inorganic-Protein Hybrids Using Various Metal Ions.

In this study, the inorganic-protein hybrid strategy was employed for immobilization of laccase from Rhus vernicifera (Rvlac) using various metals calcium, cobalt, copper, and zinc (Zn). The efficient synthesis of hybrids for Rvlac immobilization was noted at 4 °C for incubation of 24 h. Among these hybrids, the maximum encapsulation yields (EY) of 90.1% and relative activity (RA) of 225% to free enzyme were recorded for Zn and Rvlac based inorganic-protein hybrids as Zn3(PO4)2-Rvlac. The upper optimum pH, and temperature values were observed of 4.0, and 45 °C after immobilization as compared to 3.5, and 40 °C for the free enzyme, respectively. After encapsulation, Rvlac showed a significant improvement up to 11.4-fold in pH and 5.7-fold in temperature the activity profiles. Free enzyme completely lost its activity at 60 °C after 2 h of incubation, whereas Zn3(PO4)2-Rvlac retained its residual activity of 56.7% under similar conditions. After ten cycles of reusability, Zn3(PO4)2-Rvlac possessed high residual activity of 90.8%. This study showed that the variation in the metal ions for immobilization of Rvlac as inorganic-protein hybrids significantly altered EY and RA. Also, Zn3(PO4)2-Rvlac proved more efficient as compared to free laccase that can be beneficially employed for biotechnological applications. Supplementary Information: The online version contains supplementary material available at 10.1007/s12088-022-01000-5.

Synchronous Removal of Arsenic and Fluoride from Aqueous Solution: A Facile Approach to Fabricate Novel Functional Metallopolymer Microspheres.

Concurrence of arsenic (As) and fluoride (F-) ions in groundwater is a serious concern due to their fatal effects. Herein, an attempt was made to fabricate quaternized poly(zirconyl dimethacrylate-co-vinylbenzyl chloride)] (ZrVBZ), a metallopolymeric microsphere in three-dimensional shape with a porous texture. The synthesized ZrVBZ was utilized for the synchronal removal of As and F- from water. Techniques such as Fourier transform infrared spectroscopy, 13C-nuclear magnetic resonance, scanning electron microscopy, and Brunauer-Emmett-Teller surface area were used to characterize the ZrVBZ. The maximum adsorption capacity of ZrVBZ for both fluoride and arsenic (q max F-: 116.5 mg g-1, q max As(V): 7.0 mg g-1, and q max As(III): 6.5 mg g-1) at given experimental conditions (adsorbents' dose: 0.250 g L-1, feed of F-: 50 mg L-1, As(V)/As(III): 2000 µg L-1, and pH: 7.0 ± 0.2) was ascribed to the porous spherical architecture with dual functional sites to facilitate adsorption. The adsorption followed pseudo-second-order kinetics with a correlation coefficient of 0.996, 0.997, and 0.990 for F-, As(V), and As(III), respectively. The isotherm data fitted to the Langmuir isotherm model, and the maximum capacity was 121.5, 7.246, and 6.68 mg g-1 for F-, As(V), and As(III), respectively. The results of this study indicated that ZrVBZ could be used as an effective adsorbent for the simultaneous removal of F-, As(V), and As(III) from an aqueous medium.

Biomolecules Production from Greenhouse Gases by Methanotrophs.

Harmful effects on living organisms and the environment are on the rise due to a significant increase in greenhouse gas (GHG) emissions through human activities. Therefore, various research initiatives have been carried out in several directions in relation to the utilization of GHGs via physicochemical or biological routes. An environmentally friendly approach to reduce the burden of significant emissions and their harmful effects is the bioconversion of GHGs, including methane (CH4) and carbon dioxide (CO2), into value-added products. Methanotrophs have enormous potential for the efficient biotransformation of CH4 to various bioactive molecules, including biofuels, polyhydroxyalkanoates, and fatty acids. This review highlights the recent developments in methanotroph-based systems for methanol production from GHGs and proposes future perspectives to improve process sustainability via biorefinery approaches.

Complete chloroplast genome of the medicinal plant Evolvulus alsinoides: comparative analysis, identification of mutational hotspots and evolutionary dynamics with species of Solanales.

Evolvulus alsinoides, belonging to the family Convolvulaceae, is an important medicinal plant widely used as a nootropic in the Indian traditional medicine system. In the genus Evolvulus, no research on the chloroplast genome has been published. Hence, the present study focuses on annotation, characterization, identification of mutational hotspots, and phylogenetic analysis in the complete chloroplast genome (cp) of E. alsinoides. Genome comparison and evolutionary dynamics were performed with the species of Solanales. The cp genome has 114 genes (80 protein-coding genes, 30 transfer RNA, and 4 ribosomal RNA genes) that were unique with total genome size of 157,015 bp. The cp genome possesses 69 RNA editing sites and 44 simple sequence repeats (SSRs). Predicted SSRs were randomly selected and validated experimentally. Six divergent hotspots such as trnQ-UUG, trnF-GAA, psaI, clpP, ndhF, and ycf1 were discovered from the cp genome. These microsatellites and divergent hot spot sequences of the Taxa 'Evolvulus' could be employed as molecular markers for species identification and genetic divergence investigations. The LSC area was found to be more conserved than the SSC and IR region in genome comparison. The IR contraction and expansion studies show that nine genes rpl2, rpl23, ycf1, ycf2, ycf1, ndhF, ndhA, matK, and psbK were present in the IR-LSC and IR-SSC boundaries of the cp genome. Fifty-four protein-coding genes in the cp genome were under negative selection pressure, indicating that they were well conserved and were undergoing purifying selection. The phylogenetic analysis reveals that E. alsinoides is closely related to the genus Cressa with some divergence from the genus Ipomoea. This is the first time the chloroplast genome of the genus Evolvulus has been published. The findings of the present study and chloroplast genome data could be a valuable resource for future studies in population genetics, genetic diversity, and evolutionary relationship of the family Convolvulaceae. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12298-021-01051-w.

Rhus vernicifera Laccase Immobilization on Magnetic Nanoparticles to Improve Stability and Its Potential Application in Bisphenol A Degradation.

In the present study, Rhus vernicifera laccase (RvLac) was immobilized through covalent methods on the magnetic nanoparticles. Fe2O3 and Fe3O4 nanoparticles activated by 3-aminopropyltriethoxysilane followed with glutaraldehyde showed maximum immobilization yields and relative activity up to 81.4 and 84.3% at optimum incubation and pH of 18 h and 5.8, respectively. The maximum RvLac loading of 156 mg/g of support was recorded on Fe2O3 nanoparticles. A higher optimum pH and temperature of 4.0 and 45 °C were noted for immobilized enzyme compared to values of 3.5 and 40 °C for free form, respectively. Immobilized RvLac exhibited better relative activity profiles at various pH and temperature ranges. The immobilized enzyme showed up to 16-fold improvement in the thermal stability, when incubated at 60 °C, and retained up to 82.9% of residual activity after ten cycles of reuses. Immobilized RvLac exhibited up to 1.9-fold higher bisphenol A degradation efficiency potential over free enzyme. Previous reports have demonstrated the immobilization of RvLac on non-magnetic supports. This study has demonstrated that immobilization of RvLac on magnetic nanoparticles is very efficient especially for achieving high loading, better pH and temperature profiles, and thermal- and solvents-stability, high reusability, and higher degradation of bisphenol A.

Impact of Intra-Articular Local Anesthesia Infiltration versus Femoral Nerve Block for Postoperative Pain Management in Total Knee Arthroplasty.

Background: Postoperative pain relief after total knee arthroplasty (TKA) can be attained by using several techniques such as intravenous analgesia, epidural analgesia, and peripheral nerve blocks that include femoral nerve and saphenous nerve. Several authors recommended intra-articular injection of local anesthetic (IALA) as a part of multimodal analgesia regimens for TKA instead of other techniques. Aims: The present study compares IALA technique efficacy with single-shot femoral nerve block (FNB) as part of multimodal analgesia regimen in TKA patients for postoperative pain management. Setting and Design: Perioperative care, randomized double-blind comparative study. Subjects and Methods: We recruited a total of 60 patients scheduled for unilateral total knee replacement under spinal anesthesia. Subjects were allocated randomly into two groups FNB and IALA receiving ultrasound-guided FNB and Intra-articular local anesthesia and morphine mix infiltration, respectively. Twenty-four hour postoperative morphine consumption through patient-controlled analgesia was the primary outcome measure in our study. Secondary outcome measures were pain scores, nausea and vomiting. Statistical Analysis: Chi-square test, Mann-Whitney test. Results: The amount of morphine consumed at the end of 24 h was noted to be higher in IALA group as compared to FNB (FNB - 16.03 ± 9.37 mgs; IALA - 23.60 ± 13.73 mgs P = 0.03). Visual analog score at 24 h with knee flexion was better in FNB group (FNB - 1.27 ± 1.43; IALA 2.42 ± 2.54, P = 0.04). Conclusion: FNB technique provides better analgesia in comparison to IALA for postoperative pain management in terms of PCA morphine consumption.

Diet, Gut Microbiota and COVID-19.

Worldwide, millions of individuals have been affected by the prevailing SARS-CoV-2. Therefore, a robust immune system remains indispensable, as an immunocompromised host status has proven to be fatal. In the absence of any specific antiviral drug/vaccine, COVID-19 related drug repurposing along with various other non-pharmacological measures coupled with lockdown have been employed to combat this infection. In this context, a plant based rich fiber diet, which happens to be consumed by a majority of the Indian population, appears to be advantageous, as it replenishes the host gut microbiota with beneficial microbes thereby leading to a symbiotic association conferring various health benefits to the host including enhanced immunity. Further, implementation of the lockdown which has proven to be a good non-pharmacological measure, seems to have resulted in consumption of home cooked healthy diet, thereby enriching the beneficial microflora in the gut, which might have resulted in better prognosis of COVID-19 patients in India in comparison to that observed in the western countries.

Deploying Biomolecules as Anti-COVID-19 Agents.

Severe acute respiratory syndrome coronavirus (SARS-CoV-2) known as COVID-19 has emerged as a major threat to human existence. COVID-19 seems to have undergone adaptive evolution through an intermediate host, most likely bats. The flu leads to severe pneumonia that causes respiratory and multi-organ failure. The absence of any known treatment procedures, drugs, or vaccines has created panic around the World. The need is to develop rapid testing kits, drugs and vaccines. However, these proposals are time-consuming processes. At present social distancing along with previously known traditional medicines can act as quick and short-term alternatives for treating this viral flu.

Conversion of biogas to methanol by methanotrophs immobilized on chemically modified chitosan.

In this study, chitosan modified with glutaraldehyde (GLA), 3-aminopropyltriethoxysilane (APTES), polyethyleneimine, and APTES followed by GLA (APTES-GLA) as a support material was used to improve methanol production from biogas. Among these support materials, chitosan-APTES-GLA showed the highest increase in immobilization yield and relative efficiency of Methylomicrobium album up to 56.4% and 97.7%, respectively. Maximum cell loading of 236 mg dry cell mass per g-support was observed for M. album., which is 7.7-fold higher than that of chitosan. The immobilized M. album maintained a 23.9-fold higher methanol production compared to free cells after 8 cycles of reuse; it also produced 6.92 mmol·L-1 methanol from biogas that originated from anaerobic digestion of rice straw, thereby validating its industrial application. This is the first report on the immobilization of methanotrophs on chemically modified chitosans to improve cell loading and relative efficiency, and its potential applications in the conversion of greenhouse gases to methanol.

Exploitation of Citrus Peel Extract as a Feedstock for Power Generation in Microbial Fuel Cell (MFC).

Microbial fuel cells (MFCs) are envisioned as an evolving cost-effective process for treating organic wastes to simultaneously generate bioelectricity. Therefore, in present study a single chambered mediator- less air cathode MFC was operated for bioelectricity generation using citrus waste (CW) as a feedstock. The MFC was operated at four organic loading conditions (OLs; 3, 6, 9 and 12 kg/m3). The voltage generation and organic content reduction demonstrated the possibility of utilizing CW as a substrate in MFC. The polarization analysis revealed a high-power generation of 71.1 mW/m2 with low OL of 3 kg/m3. The decrease in pH and high volatile fatty acids (VFAs) generation was noted at high OL. Our current findings suggest better performance of MFC, in terms of energy generation and organic reduction at high OL.

Influence of Metal Ions on the Immobilization of ß-Glucosidase Through Protein-Inorganic Hybrids.

Immobilization of enzymes through metal-based system is demonstrated as a promising approach to enhance its properties. In this study, the influence of metals ions, including copper, cobalt and zinc (Zn) on the immobilization of ß-glucosidase (BGL) through the synthesis of protein-inorganic hybrid was evaluated at 4 °C. Among these metal ions-based hybrids, Zn showed the highest encapsulation yield and relative activity of 87.5 and 207%, respectively. Immobilized BGL exhibited higher pH and temperature stability compared to free form. Thermal stability of hybrid improved up to 26-fold at 60 °C. After 10 cycles of reuse, immobilized enzyme retained 93.8% of residual activity. These results suggested that metal ions played a significant role in the enzyme immobilization as a protein-inorganic hybrid. Overall, this strategy can be potentially applied to enhance the properties of enzymes though effective encapsulation for the broad biotechnological applications.