A systematic overview of metal nanoparticles as alternative disinfectants for emerging SARS-CoV-2 variants.

Coronaviruses are a diverse family of viruses, and new strains can emerge. While the majority of coronavirus strains cause mild respiratory illnesses, a few are responsible for severe diseases such as Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS). SARS-CoV-2, the virus responsible for COVID-19, is an example of a coronavirus that has led to a pandemic. Coronaviruses can mutate over time, potentially leading to the emergence of new variants. Some of these variants may have increased transmissibility or resistance to existing vaccines and treatments. The emergence of the COVID-19 pandemic in the recent past has sparked innovation in curbing virus spread, with sanitizers and disinfectants taking center stage. These essential tools hinder pathogen dissemination, especially for unvaccinated or rapidly mutating viruses. The World Health Organization supports the use of alcohol-based sanitizers and disinfectants globally against pandemics. However, there are ongoing concerns about their widespread usage and their potential impact on human health, animal well-being, and ecological equilibrium. In this ever-changing scenario, metal nanoparticles hold promise in combating a range of pathogens, including SARS-CoV-2, as well as other viruses such as norovirus, influenza, and HIV-1. This review explores their potential as non-alcoholic champions against SARS-CoV-2 and other pandemics of tomorrow. This extends beyond metal nanoparticles and advocates a balanced examination of pandemic control tools, exploring their strengths and weaknesses. The manuscript thus involves the evaluation of metal nanoparticle-based alternative approaches as hand sanitizers and disinfectants, providing a comprehensive perspective on this critical issue.

Biosynthesis of silver nanoparticles using nitrate reductase from Aspergillus terreus N4 and their potential use as a non-alcoholic disinfectant.

Green technology has been developed for the quick production of stabilized silver nanoparticles (AgNPs), with the assistance of nitrate reductase from an isolated culture of Aspergillus terreus N4. The organism's intracellular and periplasmic fractions contained nitrate reductase, with the former demonstrating the highest activity of 0.20 IU/g of mycelium. When the fungus was cultivated in a medium comprising 1.056% glucose, 1.836% peptone, 0.3386% yeast extract, and 0.025% KNO3, the greatest nitrate reductase productivity of 0.3268 IU/g was achieved. Statistical modeling via response surface methodology was used to optimize the enzyme production. The periplasmic and intracellular enzyme fractions were found to convert Ag+ to Ag0, initiating synthesis within 20 min, with predominant nanoparticle sizes between 25 and 30 nm. By normalizing the effects of temperature, pH, AgNO3 concentration, and mycelium age with a variable shaking period for enzyme release, the production of AgNPs with the periplasmic fraction was optimized. The synthesis of nanoparticles occurred at temperatures of 30, 40, and 50 °C, with the highest yield observed at 40 and 50 °C during shorter incubation periods. Similarly, the nanoparticles were synthesized at pH levels of 7.0, 8.0, and 9.0, with the greatest production observed at pH 8.0 and 9.0 at lower incubation periods. The antimicrobial activity of AgNPs was demonstrated against common foodborne pathogens, including Staphylococcus aureus and Salmonella typhimurium, indicating their potential as non-alcoholic disinfectants.

Preparation, characterization, and safety assessment of statistical optimized probiotic supplemented herbal wine from Tinospora cordifolia.

Evidently proven medicinal benefits of Tinospora cordifolia and the growing demand of functional foods have created scientific interest in the functional beverage. Therefore, an attempt was made to prepare probiotic Lactiplantibacillus pentosus GSSK2 supplemented herbal wine having the benefits of both phytochemical and probiotic. Experimentally, fermentation of Tinospora cordifolia stem was found to be the most effective with ammonium dihydrogen phosphate, potassium phosphate, magnesium sulfate, isoleucine, and thiamine that yielded maximum ethanol (6.8 to 10%), total phenol (419 to 791.5 µg/ml), and antioxidants capacity (98.2 to 160.4 µmol/ml) after optimizing physical parameters, i.e., 20° Brix total soluble solid, pH 4.5, temperature 30 °C, and 10% (v/v) inoculum. Further, prepared herbal wine was supplemented separately with seven different probiotic strains and among these Lactiplantibacillus pentosus GSSK2 had the highest 88.6% survival rate compared with other probiotics and was safe showing 100% survivability of HEK-293 and THP-1 cells. Both herbal- and probiotic-supplemented herbal wine showed the antimicrobial potential against Gram-positive and Gram-negative bacteria as probiotic-supplemented herbal wine had 19-21 mm inhibition zone compared with 18-19 mm with herbal wine. LC-MS analysis of the probiotic-supplemented herbal wine revealed the presence of various phytochemicals such as alkaloids, diterpenoid lactone, glycoside, steroids having anti-bacterial, anti-oxidant, and anti-inflammatory potential. This is the first ever such study to demonstrate the antibacterial, antioxidant potential and safety of probiotic supplemented herbal wine in vitro.

Microbially-derived cocktail of carbohydrases as an anti-biofouling agents: a 'green approach'.

Enzymes, also known as biocatalysts, display vital properties like high substrate specificity, an eco-friendly nature, low energy inputs, and cost-effectiveness. Among their numerous known applications, enzymes that can target biofilms or their components are increasingly being investigated for their anti-biofouling action, particularly in healthcare, food manufacturing units and environmental applications. Enzymes can target biofilms at different levels like during the attachment of microorganisms, formation of exopolymeric substances (EPS), and their disruption thereafter. In this regard, a consortium of carbohydrases that can target heterogeneous polysaccharides present in the EPS matrix may provide an effective alternative to conventional chemical anti-biofouling methods. Further, for complete annihilation of biofilms, enzymes can be used alone or in conjunction with other antimicrobial agents. Enzymes hold the promise to replace the conventional methods with greener, more economical, and more efficient alternatives. The present article explores the potential and future perspectives of using carbohydrases as effective anti-biofilm agents.

Cocktail of carbohydrases from Aspergillus niger: an economical and eco-friendly option for biofilm clearance from biopolymer surfaces.

Biofilm formation on both biotic and abiotic surfaces accounts for a major factor in spread of antimicrobial resistance. Due to their ubiquitous nature, biofilms are of great concern for environment as well as human health. In the present study, an integrated process for the co-production of a cocktail of carbohydrases from a natural variant of Aspergillus niger was designed. The enzyme cocktail was found to have a noteworthy potential to eradicate/disperse the biofilms of selected pathogens. For application of enzymes as an antibiofilm agent, the enzyme productivities were enhanced by statistical modelling using response surface methodology (RSM). The antibiofilm potential of the enzyme cocktail was studied in terms of (i) in vitro cell dispersal assay (ii) release of reducing sugars from the biofilm polysaccharides (iii) the effect of enzyme treatment on biofilm cells and architecture by confocal laser scanning microscopy (CLSM). Potential of the enzyme cocktail to disrupt/disperse the biofilm of selected pathogens from biopolymer surfaces was also assessed by field emission scanning electron microscopy (FESEM) analysis. Further, their usage in conjunction with antibiotics was assessed and it was inferred from the results that the use of enzyme cocktail augmented the efficacy of the antibiotics. The study thus provides promising insights into the prospect of using multiple carbohydrases for management of heterogeneous biofilms formed in natural and clinical settings.

Sirtuins and the circadian clock interplay in cardioprotection: focus on sirtuin 1.

Chronic disruption of circadian rhythms which include intricate molecular transcription-translation feedback loops of evolutionarily conserved clock genes has serious health consequences and negatively affects cardiovascular physiology. Sirtuins (SIRTs) are nuclear, cytoplasmic and mitochondrial histone deacetylases that influence the circadian clock with clock-controlled oscillatory protein, NAMPT, and its metabolite NAD+. Sirtuins are linked to the multi-organ protective role of melatonin, particularly in acute kidney injury and in cardiovascular diseases, where melatonin, via upregulation of SIRT1 expression, inhibits the apoptotic pathway. This review focuses on SIRT1, an NAD+-dependent class III histone deacetylase which counterbalances the intrinsic histone acetyltransferase activity of one of the clock genes, CLOCK. SIRT1 is involved in the development of cardiomyocytes, regulation of voltage-gated cardiac sodium ion channels via deacetylation, prevention of atherosclerotic plaque formation in the cardiovascular system, protection against oxidative damage and anti-thrombotic actions. Overall, SIRT1 has a see-saw effect on cardioprotection, with low levels being cardioprotective and higher levels leading to cardiac hypertrophy.

Wheel-running activity rhythms and masking responses in the diurnal palm squirrel, Funambulus pennantii.

Several studies have reported activity patterns of various diurnal species from the order Rodentia, in which most of the species are nocturnal. Most of these studies have been performed under controlled laboratory conditions. These studies found that most of these species change their activity patterns when held under laboratory conditions, have a diverse masking response to light, and their activity pattern is influenced by the presence of a running wheel. Squirrels are reported to be strictly diurnal both in the field as well as in laboratory settings, and, therefore, form an interesting species to study to better understand the switch to diurnality. The aim of the current study is to characterize the masking response and temporal organization of wheel-running activity rhythms in the palm squirrel, Funambulus pennantii, under semi-natural (NLD) and controlled laboratory conditions using different lighting schedules. Squirrels were housed individually in a resting cage with running wheel under NLD (n = 10) and squared 12:12 h of light-dark cycle (LD) (n = 20). After stable entrainment under the LD condition, squirrels were divided into two groups. One group was housed under constant darkness (DD) (n = 10) and another group under constant light (LL) (n = 10). Following the stable free-running rhythm under DD and LL, the LD condition was reinforced. The kinetics of the endogenous pacemaker was studied following a 6 h phase advance or delay of LD cycle. Further, palm squirrels were subjected to a 3.5: 3.5 h LD cycle to evaluate the masking response to light and dark. Squirrels demonstrated stable, clear, robust, and strict diurnal activity rhythm during NLD and LD. In DD and LL, F. pennantii free-ran from the phase of the previous LD cycle, and the free-running period was longer in LL than in DD. The percentage of activity during the light phase was significantly higher in NLD and LD (above 96%) compared to activity during the subjective day in the DD and LL conditions (above 91%). The alpha/rho ratio was significantly higher in the LL compared to other lighting schedules. Further, all ten squirrels re-entrained to both 6 h advance and delay shifts within 11 days. In the ultradian cycle, significant positive masking of light was evident in nine of ten squirrels. These results suggest that the: (i) circadian system of F. pennantii is stable and functional under various lighting conditions; (ii) basic temporal organization in activity pattern remained unaltered even in the presence of a running wheel; (iii) diurnality is the inherent trait of F. pennantii, and (iv) behavioral activity rhythms are governed by both the circadian clock and external masking. Thus, palm squirrels can be used as a suitable diurnal model in circadian biology to study the underlying mechanisms of diurnality and effects of different light schedules, wavelengths, and non-photic cues on physiological and behavioral parameters.

Melatonin-induced phase and dose responses in a diurnal mammal, Funambulus pennantii.

Melatonin, an essential pineal hormone, acts as a marker of the circadian clock that regulates biological rhythms in animals. The effects of exogenous melatonin on the circadian system of nocturnal rodents have been extensively studied; however, there is a paucity of studies on the phase-resetting characteristics of melatonin in diurnal rodents. We studied the phase shifting effects of exogenous melatonin as a single melatonin injection (1 mg/kg) at various phases of the circadian cycle on the circadian locomotor activity rhythm in the palm squirrel, Funambulus pennantii. A phase response curve (PRC) was constructed. Adult male squirrels (N = 10) were entrained to a 12:12 h light-dark cycle (LD) in a climate-controlled chronocubicle with food and water provided ad libitum. After stable entrainment, squirrels were transferred to constant dark condition (DD) for free-running. Following stable free run, animals were administered a single dose of melatonin (1 mg/kg in 2% ethanol-phosphate buffered saline (PBS) solution) or vehicle (2% ethanol-PBS solution) at circadian times (CTs) 3 h apart to evoke phase shifts. The phase shifts elicited at various CTs were plotted to generate the PRC. A dose response curve was generated using four doses (0.5, 1, 2 and 4 mg/kg) administered at the CT of maximum phase advance. Melatonin evoked maximum phase advances at CT0 (1.23 ± 0.28 h) and maximum phase delays at CT15 (0.31 ± 0.09 h). In the dose response experiment, maximal phase shifts were evoked with 1 mg/kg. In contrast, no significant shifts were observed in control groups. Our study demonstrates that the precise timing and appropriate dose of melatonin administration is essential to maximize the amelioration of circadian rhythm-related disorders in a diurnal model.

A novel multi-enzyme preparation produced from Aspergillus niger using biodegradable waste: a possible option to combat heterogeneous biofilms.

Extracellular polymeric substance (EPS) produced by the microorganisms provides protection and stability to them when they are encased within biofilms. Heterogeneous polysaccharides form a major constituent of the EPS and are crucial for the formation and integrity of the biofilms/slime. Thus, breakdown of polysaccharides might help in dispersion of biofilms from abiotic surfaces. In the present study we isolated a fungus, Aspergillus niger APS, capable of concurrently producing a cocktail of carbohydrases and optimized the conditions for higher yields of all the enzymes by one variable at a time (OVAT) approach. The optimization studies resulted in 1.5 to 12 fold augmentation in the enzyme yields using biodegradable waste. Further, keeping in view the heterogeneous nature of polysaccharides in biofilm matrix, the in-house produced enzyme cocktail was used for the dispersal of biofilms formed by Salmonella enterica serovar Typhi, Escherichia coli and Staphylococcus aureus. Treatment with enzyme preparation caused 90.23 ± 4.0, 82.64 ± 5.0 and 76.32 ± 5.0% reduction of the biofilms formed by these organisms respectively which was also evidenced by Field emission scanning electron microscopy (FESEM) revealing the loss of biofilm architecture. Interestingly, the enzyme cocktail could also remove viscous slime formed under natural conditions in the kitchen drainage pipe (KDP). To the best of our knowledge, this is the first report on biotreatment of abiotic surfaces for removal of biofilms/slime formed under natural conditions. The study thus indicates the prospects of using multiple carbohydrases as an anti-biofouling agent on abiotic surfaces like equipments as well as implants/prostheses and pipelines.

Utilization of kitchen waste for production of pullulan to develop biodegradable plastic.

Pullulan has many useful characteristics but, its high cost limits its potential applications. In the present work, kitchen waste (KW), which otherwise has zero commercial value, was evaluated for the economical production of pullulan. Before fermentation, the KW was hydrolyzed into free sugars using an in-house produced cocktail of enzymes. During hydrolysis, 46 ± 3.5 g/l and 31 ± 2.2 g/l of total reducing sugars and glucose were released, respectively. Hydrolyzed kitchen waste was then used as substrate for fermentation by Aureobasidium pullulans MTCC 2013 yielding 20.46 ± 2.01 g/l pullulan. Further, effect of different nitrogen sources was evaluated and yeast extract (3%) was found to be the best, yielding (24.77 ± 1.06 g/l) exopolysaccharide (EPS). The pullulan produced from KW was characterized in terms of organoleptic properties, physical strength, Fourier-transform infrared spectroscopy (FTIR), and H nuclear magnetic resonance (H NMR) analysis. The results corroborated well with commercial pullulan. The biodegradable nature and water solubility of the film developed from pullulan was also confirmed. To the best of our knowledge, this is the first report on the validation of the biodegradability of in-house produced pullulan. Thus, kitchen waste appears to be a promising option for economical pullulan production. Additionally, the method may also prove to be helpful for managing the increasing load of municipal solid waste in an eco-friendly and scientific way.

Cellulases: Role in Lignocellulosic Biomass Utilization.

Rapid depletion of fossil fuels worldwide presents a dire situation demanding a potential replacement to surmount the current energy crisis. Lignocellulose presents a logical candidate to be exploited at industrial scale owing to its vast availability, inexpensive and renewable nature. Microbial degradation of lignocellulosic biomass is a lucrative, sustainable, and promising approach to obtain valuable commercial commodities at gigantic scale. The enzymatic hydrolysis involving cellulases is fundamental to all the technologies needed to transform lignocellulosic biomass to valuable industry relevant products. Cellulases have enormous potential to utilize cellulosic biomass, thus reducing environmental stress in addition to production of commodity chemicals resolving the current challenge to meet the energy needs globally. The substitution of petroleum-based fuels with bio-based fuels is the subject of thorough research establishing biofuel production as the future technology to achieve a sustainable, eco-friendly society with a zero waste approach.

Valorization of waste glycerol for the production of poly (3-hydroxybutyrate) and poly (3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer by Cupriavidus necator and extraction in a sustainable manner.

Glycerol is a by-product of many industrial processes and huge amounts of it are generated in the form of waste, thereby necessitating a search for the method of its disposal. An interesting solution is the valorization of crude glycerol into value added product such as polyhydroxyalkanoates (PHAs). The feasibility of producing PHAs by Cupriavidus necator was evaluated using crude glycerol (WG). Various cultivation strategies were designed for the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer by adding different organic acids as precursors at different concentrations levels. Batch cultivation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) production showed accumulation of 6.76g/L biomass containing 4.84g/L copolymer on WG with a maximum 3-hydroxyvalerate content of 24.6mol%. PHAs extraction using a non-toxic and recyclable solvent, 1,2 propylene carbonate, showed the highest recovery yield (90%) and purity (93%) at 120°C temperature and 30min incubation. This is the first report on jatropha based glycerol valorization for poly(3-hydroxybutyrate-co-3-hydroxyvalerate) production coupled with extraction using non-toxic solvent.

Unravelling the capability of Pyrenophora phaeocomes S-1 for the production of ligno-hemicellulolytic enzyme cocktail and simultaneous bio-delignification of rice straw for enhanced enzymatic saccharification.

A natural variant of Pyrenophora phaeocomes isolated from natural biodiversity was able to grow on various agricultural residues by co-producing laccase, xylanase and mannanase. Solid state fermentation of rice straw induced the highest productivities corresponding to 10,859.51±46.74, 22.01±1.00 and 10.45±0.128IUgds-1 for laccase, xylanase and mannanase respectively after 4days. Besides producing the ligno-hemicellulolytic enzyme cocktail, 40days cultivation of P. phaeocomes S-1 on rice straw brought about the 63 and 51% degradation of lignin and hemicellulose. These components were further removed with mild alkali extraction revealing the overall losses amounting to 78 and 60% respectively for lignin, and hemicellulose. The biologically pretreated straw upon enzymatic hydrolysis revealed 50% saccharification efficiency releasing 470mgg-1 sugars. Application of this knowledge will lead to efficient management of waste rice straw with low cost production of industrially important enzymes cocktail and its biological delignification for effective enzymatic hydrolysis to free sugars.

Cellulases: Classification, Methods of Determination and Industrial Applications.

Microbial cellulases have been receiving worldwide attention, as they have enormous potential to process the most abundant cellulosic biomass on this planet and transform it into sustainable biofuels and other value added products. The synergistic action of endoglucanases, exoglucanases, and ß-glucosidases is required for the depolymerization of cellulose to fermentable sugars for transformation in to useful products using suitable microorganisms. The lack of a better understanding of the mechanisms of individual cellulases and their synergistic actions is the major hurdles yet to be overcome for large-scale commercial applications of cellulases. We have reviewed various microbial cellulases with a focus on their classification with mechanistic aspects of cellulase hydrolytic action, insights into novel approaches for determining cellulase activity, and potential industrial applications of cellulases.

Lime and Sulphide-Free Dehairing of Animal Skin Using Collagenase-Free Alkaline Protease from Vibrio metschnikovii NG155.

The objective of this work was to isolate a microorganism producing alkaline protease that can be used as an ecofriendly alternative to chemicals in dehairing process of leather manufacture. Alkaline protease producing bacterium Vibrio metschnikovii NG155 was isolated from soil samples of leather industry. The protease was highly effective in dehairing of goat skin, completely eliminating the use of lime and sulfide. Histological studies of the skin after dehairing showed that the enzyme did not damage the collagen layer and brought good fiber opening. Absence of collagenase activity was confirmed by reacting pure collagen with the enzyme and analyzing it on SDS PAGE, which showed no degradation of collagen. The enzyme was stable in a wide range of pH (7-11) and temperature (10-50 °C), which makes it suitable for industrial application.

Aeromonas punctata derived depolymerase that disrupts the integrity of Klebsiella pneumoniae capsule: optimization of depolymerase production.

Formation of dense, highly hydrated biofilm structures pose a risk for public and environmental health. Extracellular polymeric substances encompassing biofilms offer 1000-fold greater resistance as compared to the planktonic cells. Using enzymes as anti-biofouling agents, will improve penetration of antimicrobials and increase susceptibility of biofilms to components of immune system. The challenge of using enzymes derived from unrelated bacteria for the degradation of capsular matrix of Klebsiella pneumoniae has not been dealt in the past. Thus, statistical optimization was done to enhance depolymerase production by Aeromonas punctata, directed against the exopolysaccharide matrix of Klebsiella pneumoniae B5055, capable of substituting the available phage borne depolymerase enzyme. Optimization via central composite design (CCD) resulted in 16-fold enhancement in depolymerase yield (166.65 µmoles ml(-1) min(-1) ) over unoptimized medium. Out of the 19 variables, media composition giving maximum expression levels of the enzyme consisted of 1 mg ml(-1) galactose and ammonium chloride, 1.5 mg ml(-1) each of capsular polysaccharide (CPS) and magnesium sulfate. Tryptic peptide analysis of the purified 29 kDa band by Matrix assisted laser desorption ionization-time of flight (MALDI-TOF) showed a high homology with a protein of unknown function from Aeromonas cavaie Ae398. Further improvements in the enzyme can lead to its successful development as prophylactic and/or a therapeutic agent.

Highly thermostable and pH-stable cellulases from Aspergillus niger NS-2: properties and application for cellulose hydrolysis.

Optimization of cultural conditions for enhanced cellulase production by Aspergillus niger NS-2 were studied under solid-state fermentation. Significant increase in yields (CMCase 463.9 ± 20.1 U/g, FPase 101.1 ± 3.5 U/g and ß-glucosidase 99 ± 4.0 U/g) were obtained under optimized conditions. Effect of different nutritional parameters was studied to induce the maximum production of cellulase complex. Scale-up studies for enzyme production process were carried out. Characterization studies showed that enzymes produced by A. niger NS-2 were highly temperature- and pH stable. At 50 °C, the half life for CMCase, FPase, ß-glucosidase were approximately 240 h. Cellulases from A. niger NS-2 were stable at 35 °C for 24 h over a broader pH range of 3.0-9.0. We examined the feasibility of using steam pretreatment to increase the saccharification yields from various lignocellulosic residues for sugar release which can potentially be used in bioethanol production. Saccharification of pretreated dry potato peels, carrot peels, composite waste mixture, orange peels, onion peels, banana peels, pineapple peels by crude enzyme extract from A. niger NS-2, resulted in very high cellulose conversion efficiencies of 92-98 %.

Production of cellulases from Aspergillus niger NS-2 in solid state fermentation on agricultural and kitchen waste residues.

Various agricultural and kitchen waste residues were assessed for their ability to support the production of a complete cellulase system by Aspergillus niger NS-2 in solid state fermentation. Untreated as well as acid and base-pretreated substrates including corn cobs, carrot peelings, composite, grass, leaves, orange peelings, pineapple peelings, potato peelings, rice husk, sugarcane bagasse, saw dust, wheat bran, wheat straw, simply moistened with water, were found to be well suited for the organism's growth, producing good amounts of cellulases after 96 h without the supplementation of additional nutritional sources. Yields of cellulases were higher in alkali treated substrates as compared to acid treated and untreated substrates except in wheat bran. Of all the substrates tested, wheat bran appeared to be the best suited substrate producing appreciable yields of CMCase, FPase and ß-glucosidase at the levels of 310, 17 and 33 U/g dry substrate respectively. An evaluation of various environmental parameters demonstrated that appreciable levels of cellulases could be produced over a wide range of temperatures (20-50 °C) and pH levels (3.0-8.0) with a 1:1.5 to 1:1.75 substrate to moisture ratio.