Harnessing the potential of ligninolytic enzymes for lignocellulosic biomass pretreatment

Abundant lignocellulosic biomass from various industries provides a great potential feedstock for the production of value-added products such as biofuel, animal feed, and paper pulping. However, low yield of sugar obtained from lignocellulosic hydrolysate is usually due to the presence of lignin that acts as a protective barrier for cellulose and thus restricts the accessibility of the enzyme to work on the cellulosic component. This review focuses on the significance of biological pretreatment specifically using ligninolytic enzymes as an alternative method apart from the conventional physical and chemical pretreatment. Different modes of biological pretreatment are discussed in this paper which is based on (i) fungal pretreatment where fungi mycelia colonise and directly attack the substrate by releasing ligninolytic enzymes and (ii) enzymatic pretreatment using ligninolytic enzymes to counter the drawbacks of fungal pretreatment. This review also discusses the important factors of biological pretreatment using ligninolytic enzymes such as nature of the lignocellulosic biomass, pH, temperature, presence of mediator, oxygen, and surfactant during the biodelignification process

SARS-CoV-2 B.1.617.2 Delta variant replication and immune evasion

The B.1.617.2 (Delta) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first identified in the state of Maharashtra in late 2020 and spread throughout India, outcompeting pre-existing lineages including B.1.617.1 (Kappa) and B.1.1.7 (Alpha)1. In vitro, B.1.617.2 is sixfold less sensitive to serum neutralizing antibodies from recovered individuals, and eightfold less sensitive to vaccine-elicited antibodies, compared with wild-type Wuhan-1 bearing D614G. Serum neutralizing titres against B.1.617.2 were lower in ChAdOx1 vaccinees than in BNT162b2 vaccinees. B.1.617.2 spike pseudotyped viruses exhibited compromised sensitivity to monoclonal antibodies to the receptor-binding domain and the amino-terminal domain. B.1.617.2 demonstrated higher replication efficiency than B.1.1.7 in both airway organoid and human airway epithelial systems, associated with B.1.617.2 spike being in a predominantly cleaved state compared with B.1.1.7 spike. The B.1.617.2 spike protein was able to mediate highly efficient syncytium formation that was less sensitive to inhibition by neutralizing antibody, compared with that of wild-type spike. We also observed that B.1.617.2 had higher replication and spike-mediated entry than B.1.617.1, potentially explaining the B.1.617.2 dominance. In an analysis of more than 130 SARS-CoV-2-infected health care workers across three centres in India during a period of mixed lineage circulation, we observed reduced ChAdOx1 vaccine effectiveness against B.1.617.2 relative to non-B.1.617.2, with the caveat of possible residual confounding. Compromised vaccine efficacy against the highly fit and immune-evasive B.1.617.2 Delta variant warrants continued infection control measures in the post-vaccination era

Knowledge, Attitude and Aesthetic Perceptions about Dental Fluorosis among 12-15 Years Old Government School Children in Farukh Nagar, Haryana

ABSTRACT Aims and objectives The present study was conducted to assess the opinions amongst schoolchildren about the appearance of dental fluorosis, to correlate the children's perceptions of dental fluorosis and to assess the impact of dental fluorosis on psychological health of the school children. Materials and methods A questionnaire was used for assessment of the Knowledge, Attitude and Aesthetic perceptions about Dental Fluorosis among 474, 12-15 years old school children studying in four government high schools of Farukh Nagar block, Gurgaon, Haryana. The study sample included 308 students with dental fluorosis out of all the school children examined. Dental Fluorosis was assessed by using tooth surface index of fluorosis with 8 point scale ranging from 0 to 7. Results Amongst 308 subjects, maximum subjects had TSIF score of 4, 96.8% (298) subjects were not aware of the term fluorosis, 276 (89.5%) subjects were worried, and 253 (82.2%) subjects were not able to smile freely because of the appearance of their teeth. Conclusion The study showed that dental fluorosis had severe impact on the 12 to 15 years old school children especially on the subjects with TSIF score of 4 because of the staining. </jats:sec

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Not AvailablePurpose The study was conducted to improve the productivity of the multi-component cellulolytic enzymes using thermophilicAspergilus terreus strain and sweet sorghum bagasse as substrate. One of the major objectives was to study the interactions between different operating parameters and appraise the potential of the optimized process for validation studies. Methods Response surface methodology (RSM) based on central composite design (CCD) was used to optimize the process parameters for cellulase production by thermophilic Aspergillus terreus via a solid-state fermentation (SSF) process. A set of 50 experiments in triplicate with five factors (moisture content, inoculum level, pH, temperature and incubation period), three levels with six axial points (α ± 1.68) and five replications at the central point were conducted in this study with filter paper (FP) cellulase and β-glucosidase as output parameters. Results Micrographs and scanning electron microscopy (SEM) of A. terreus RWY revealed a chain of conidia in a columnar arrangement with an average size of conidium being 2.12 μ. Statistical process optimization suggested temperature of 45 °C,pH of 5.8, incubation time of 72 h, inoculum concentration of 10% and initial moisture content of 80% (w/w) as optimum for conducting validation studies. Validation studies showed comparable FP and β-glucosidase activities as predicted by the model equations. In addition to FP and β-glucosidase, A. terreus RWY also produced endoglucanase (EG), β-xylosidase,α-l-arabinofuranosidase, CBHI, xylanase and xylan esterase of 149.54, 26.94, 183.16, 17.52, 1264.47 and 1106.46 U/gds, respectively during the validation process. Response surface optimization also led to a nearly two-fold increase in FP and β-glucosidase activities. Conclusion Coupled with the use of thermophilic strains which confer specific benefits during industrial applications, statistical process optimization holds potential for scale-up studies for cellulase production using the optimized parameters, SSB as substrate and thermophilic A. terreus RWY.Not Availabl