Ajay Kumar Manhar

Biocompatible carboxymethylcellulose-g-poly(acrylic acid)/OMMT nanocomposite hydrogel for in vitro release of vitamin B12

The present work describes the preparation of a biocompatible nanocomposite hydrogel based on CMC-g-PAA and organo-MMT nanoclay by using methylene bis-acrylamide (MBA) as a cross-linker and potassium persulfate (KPS) as an initiator through radical graft polymerization. The nanocomposite hydrogels were characterized by using techniques such as FTIR, SEM and XRD analysis. The effects of various parameters on the swelling behaviour of the hydrogels were studied. The mechanical strength of the nanocomposite hydrogels was determined by dynamic mechanical analysis (DMA) and all the samples showed an increase in the storage modulus (G′) with an increase in cross-linker amount. The in vitro biocompatibility of the nanocomposite hydrogels showed that the presence of nanoclay in the nanocomposite hydrogel enhanced the in vitro blood compatibility. The vitamin B12 release mechanism has been studied during different time periods using a UV-visible spectrophotometer. The drug release kinetics revealed that release of vitamin B12 follows a non-Fickian diffusion mechanism.

Green silver nanoparticles: enhanced antimicrobial and antibiofilm activity with effects on DNA replication and cell cytotoxicity

Biofabricated metal nanoparticles are biocompatible, inexpensive and eco-friendly. They find immense utility in the domain of biomedical and materials science. The present work focuses on the ‘green’ synthesis of silver nanoparticles (AgNPs) using the methanolic extract of Syzygium cumini leaf. AgNPs showed the characteristic surface plasmon resonance peak at 442 nm. The XRD pattern confirmed the formation of face centered cubic AgNPs. The nanoparticles were uniformly distributed within a narrow size range of 10–20 nm. The particles exhibited significant antimicrobial activity against a panel of pathogens like Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Mycobacterium smegmatis, Trichophyton rubrum, Aspergillus sp and Candida albicans. Alterations in membrane permeability of AgNP treated microbial cells were evident from scanning electron microscope images. The replication fidelity of small (1500 bp) DNA fragments in the presence of AgNPs was compromised in a dose-dependent fashion and addition of bovine serum albumin (BSA) to PCR reactions reversed the effect of AgNPs. Besides, the prepared nanoparticles inhibited biofilm formation in a wide range of AgNP concentrations. Significantly, cytotoxicity assays showed good compatibility of AgNPs with human embryonic kidney cells (HEK 293). In summary, the study suggests an eco-friendly, cost effective and biocompatible approach for synthesizing AgNPs, which may act as a potential template for designing novel antibacterial, antifungal and antibiofilm agents.

In vitro evaluation of celluloytic Bacillus amyloliquefaciens AMS1 isolated from traditional fermented soybean (Churpi) as an animal probiotic

A microorganism showing probiotic attributes and hydrolyzing carboxymethylcellulose was isolated from traditional fermented soybean (Churpi) and identified as Bacillus amyloliquefaciens by analysis of 16S rRNA gene sequence and named as B. amyloliquefaciens AMS1. The potentiality of this isolate as probiotic was investigated in vitro and it showed gastrointestinal transit tolerance, cell surface hydrophobicity, cell aggregation and antimicrobial activity. The isolate was found to be non-hemolytic which further strengthens its candidature as a potential probiotic. The maize straw digestion was confirmed by scanning electron microscopy studies. The isolate was able to degrade filter paper within 96 hours of incubation. This study explores the possibility of combining the cellulase degrading ability of a microbe with its probiotic attributes to enhance gut health of animal and digestibility of the feed.

Preparation and characterization of zinc oxide and nanoclay reinforced crosslinked starch/jute green nanocomposites

In the present work, ZnO nanoparticles (ZNP) and ZNP in combination with nanoclays are reported as reinforcing agents for the preparation of ‘Green’ nanocomposites based on glutaraldehyde (GA) crosslinked starch/jute fabric. A solution-induced intercalation method has been used for the successful fabrication of the nanocomposites. Both ZNP and nanoclay are successfully incorporated into the composite as revealed by X-ray diffractometry (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FT-IR). The thermal and mechanical properties of the nanocomposites are studied using thermogravimetric analysis (TGA) and mechanical tests, respectively. The study reveals significant changes in the observed properties of the synthesized composites with the amount of nanofillers. Interestingly, the flame retarding properties, UV-resistance, and dimensional stability of the nanoparticle filled composites are found to be much better than those of the unfilled one. The study reveals a strong interfacial interaction between the filler and the matrix within the synthesized green nanocomposites.

Phytosynthesized iron nanoparticles: effects on fermentative hydrogen production by Enterobacter cloacae DH-89

In recent years the application of metal nanoparticles is gaining attention in various fields. The present study focuses on the additive effect of ‘green’ synthesized iron nanoparticles (FeNPs) on dark fermentative hydrogen (H2) production by a mesophilic soil bacterium Enterobacter cloacae. The FeNPs were synthesized by a rapid green method from FeSO4 using aqueous leaf extract of Syzygium cumini. The synthesized FeNPs showed a characteristic surface plasmon resonance peak at 267 nm. The transmission electron microscopy images confirm that the formation of FeNPs was mainly porous and irregular in shape, with an average particle size of 20–25 nm. The presence of iron (Fe) in the synthesized FeNPs was confirmed by energy-dispersive X-ray spectroscopy. The comparative effect of FeSO4 and FeNPs on batch fermentative H2 production from glucose was investigated. The fermentation experiments reveal that the percentage and yield of H2 in FeNPs supplementation were increased significantly than the control (no supplementation) and FeSO4 containing media. The maximum H2 yield of 1.9 mol mol−1 glucose utilized was observed in 100 mg l−1 FeNPs supplementation, with two-fold increase in glucose conversion efficiency. Thus, the result suggests that FeNPs supplementation in place of FeSO4 could improve the bioactivity of H2 producing microbes for enhanced H2 yield and glucose consumption.

Nanotechnological Applications in Food Packaging, Sensors and Bioactive Delivery Systems

The development of nanomaterial-based products has boosted research in food science. Packaging has been the core subject of research in food nanotechnology. The mechanical and barrier performance of packaging are improved by nanocomposites. Intelligent packaging with communication functions is currently being developed using indicators of oxygen, humidity and freshness. However the concern of nanoparticle migration into the food must be addressed prior to commercial use. For biosensors, functionalized nanomaterials act as catalytic or immobilization platform or as electro-optical labels for enhancing the sensitivity and selectivity of the detection. Other functions of nanomaterials include encapsulation, protection, and enhancement of the solubility and bioavailability of active food ingredients. This review describes nanocomposites as high barrier packaging material, nano-sensors to achieve safer foods with lower incidence of chemical contaminants or adulterants or pathogenic microorganisms, and nanoencapsulation strategies as innovative delivery systems of bioactive compounds. The technical aspects of these topics are discussed with respect to synthesis, mode of action and functional performance.

Cellulolytic potential of probiotic Bacillus Subtilis AMS6 isolated from traditional fermented soybean (Churpi): An in-vitro study with regards to application as an animal feed additive

The aim of the present study is to evaluate the probiotic attributes of Bacillus subtilis AMS6 isolated from fermented soybean (Churpi). This isolate exhibited tolerance to low pH (pH 2.0) and bile salt (0.3%), capability to autoaggregate and coaggregate. AMS6 also showed highest antibacterial activity against the pathogenic indicator strain Salmonella enterica typhimurium (MTCC 1252) and susceptibility towards different antibiotics tested. The isolate was effective in inhibiting the adherence of food borne pathogens to Caco-2 epithelial cell lines, and was also found to be non-hemolytic which further strengthen the candidature of the isolate as a potential probiotic. Further studies revealed B. subtilis AMS6 showed cellulolytic activity (0.54±0.05 filter paper units mL(-1)) at 37°C. The isolate was found to hydrolyze carboxymethyl cellulose, filter paper and maize (Zea mays) straw. The maize straw digestion was confirmed by scanning electron microscopy studies. The isolate was able to degrade filter paper within 96h of incubation. A full length cellulase gene of AMS6 was amplified using degenerate primers consisting of 1499 nucleotides. The ORF encoded for a protein of 499 amino acids residues with a predicted molecular mass of 55.04kDa. The amino acids sequence consisted of a glycosyl hydrolase family 5 domain at N-terminal; Glycosyl hydrolase catalytic core and a CBM-3 cellulose binding domain at its C terminal. The study suggests potential probiotic B. subtilis AMS6 as a promising candidate envisaging its application as an animal feed additive for enhanced fiber digestion and gut health of animal.

Industrial Waste-Derived Nanoparticles and Microspheres Can Be Potent Antimicrobial and Functional Ingredients

Rapeseed oilcake or press-cake is generated as bulk waste during oil extraction from oilseeds. Owing to its high protein content, further processing of oilcakes into vegetable protein generates large quantities of fibrous residue (“oil-and-protein” spent meal) as by-product, which currently has very limited practical utility. Here, we report hydrothermal carbonization of this industrial waste to convert it into carbon nanoparticles, bestowed with multitude of functionalities. We demonstrate that these nanoparticles can be assembled into micrometer-sized spheres when precipitated from water by acetone. These microspheres, with their added feature of hemocompatibility, can be potentially utilized as an encapsulation vehicle for the protection of thermolabile compounds (such as protein); however, the secondary and tertiary features of the protein were marginally perturbed by the encapsulation process. The synthesized carbon nanoparticle was found to be an effective biocidal agent, exhibiting bacterial cellular damage and complex formation with the bacterial plasmid (evident from ethidium bromide exclusion assay), which are critical for cell survival. The results show the ability to convert industrial biowaste into useful nanomaterials for use in food industries and also suggest new scalable and simple approaches to improve environmental sustainability in industrial processes.

Cloning and extracellular expression of a raw starch digesting α‐amylase (Blamy‐I) and its application in bioethanol production from a non‐conventional source of starch

The aim of this study was to clone and efficiently express a raw starch‐digesting α‐amylase enzyme in the culture media and also to investigate the potential application of this recombinant enzyme in the digestion of non‐conventional raw starch for bioethanol production. A raw starch digesting α‐amylase gene isolated from Bacillus licheniformis strain AS08E was cloned and extracellularly expressed in E. coli cells using the native signal peptide. The mature recombinant α‐amylase (Blamy‐I) consisting of 483 amino acid residues was found to be homogenous with a mass of 55.3 kDa (by SDS‐PAGE analysis) and a predicted pI of 6.05. Structural and functional analysis of Blamy‐I revealed the presence of an extra Ca2+‐binding region between the A and C domains responsible for higher thermostability of this enzyme. The statistical optimization of E. coli culture conditions resulted in an approximately eightfold increase in extracellular expression of Blamy‐I as compared to its production under non‐optimized conditions. Blamy‐I demonstrated optimum enzyme activity at 80 °C and pH 10.0, and efficiently hydrolyzed raw starch isolated from a non‐conventional, underutilized jack fruit seeds. Further utilization of this starch for bioethanol production using Blamy‐I and Saccharomyces cerevisiae also proved to be highly promising.