Production and downstream processing of (1→3)-β-D-glucan from mutant strain of Agrobacterium sp . ATCC 31750

Abstract: Nanomedicine utilizes biocompatible nanomaterials for diagnostic and therapeutic purposes. The present study reports the use of Helicteres isora root extract for the synthesis of silver nanoparticles (AgNPs). The synthesized AgNPs were initially noticed through visual color change from yellow to reddish brown and further confirmed by surface plasmonic resonance (SPR) band at 450 nm using UV–visible spectroscopy. Morphology and size of AgNPs were determined by transmission electron microscopy (TEM) analysis. X-ray diffraction (XRD) study revealed crystalline nature of AgNPs. The prolonged stability of AgNPs was due to capping of oxidized polyphenols and carboxyl protein which was established by Fourier transform infrared spectroscopy (FTIR) study. In addition, the synthesized AgNPs were tested for antioxidant and antibacterial activities. It showed good antioxidant activity as compared to butylated hydroxytoluene (BHT) and ascorbic acid as standard antioxidant. It could be concluded that H. isora root extract can be used efficiently in the production of potential antioxidant and antibacterial AgNPs for commercial application.

Abstract: A great interest of β-glucans with many health-promoting and prebiotic properties has been registered. β-Glucans are major bioactive compounds known to have biological activities including anti-cancer, anti-inflammatory, and immune-modulating properties. Due to the specific physical properties of β-glucan, such as water solubility, viscosity, and gelation, it has been increasingly used by the food and other industries. The aim of this review is to present an overview on the production technologies of β-glucan, such as extraction, isolation, purification technologies from different sources, for instance yeast, fungi, bacteria, and cereal, aiming its optimization for more effective production processes. Furthermore, the physicochemical properties, chemical modifications, possible industrial applications and future prospects of β-glucans in foods, medicines, cosmetics, and other potential value-added products are also summarized. Data indicate that β-glucans will play an increasing role in current and future global food and medical sectors.

Abstract: Curdlan is a bacterial polysaccharide that has been of significant recent interest due to its interesting and valuable rheological properties and its inherent bioactivity. The simple (1→3)-β-glucan homopolymeric, unbranched structure of curdlan is conducive to enhanced solubility relative to many other abundant natural polysaccharides, thus, providing alternatives for processing the polymer into desired shapes and formulations. At the same time, this relatively good solubility enables chemical modification under mild conditions, leading to a growing body of literature on derivative chemistry, structure–property relationships, and the potential for regioselective modification. Structure, properties, biosynthesis, modification chemistries, and key applications are the foci for this review of the curdlan literature.

Abstract: Xanthan gum was produced by fermentation of sulphuric acid pre-treated tapioca pulp. Effect of sulphuric acid concentration (0.5%, 2.5% and 5.0%) on xanthan fermentation was investigated. Maximum xanthan yield (7.1g/l) was obtained with 0.5% sulphuric acid pre-treatment. Further, increase in sulphuric acid concentration caused formation of inhibitory substance and lowered xanthan yield. The product was confirmed as xanthan using FTIR, (1)H NMR analyses. Viscosity was measured by Brookfield viscometer and the molecular weight was determined from the intrinsic viscosity. The results confirmed that the yield and quality of xanthan produced were strongly influenced by the acid concentration.

Abstract: In tuberculosis, macrophages serve as a host for Mycobacterium tuberculosis and hence targeting them with nanoparticles-based drug delivery could be the best strategy to achieve high therapeutic efficacy. Two tuberculosis drugs, namely rifampicin and levofloxacin, which have different mechanism of action on the bacteria, were complexed with cyclodextrin and conjugated to curdlan nanoparticles, to achieve simultaneous sustained release of both the drugs over a prolonged period of time. They are non-cytotoxic to both RAW 264.7 and L929 cells. They are taken up ˜1.8 times more by the macrophage cells through dectin-1 receptor than the fibroblast cells. They are also able to kill more than 95% of Mycobacterium smegmatis residing within the macrophages in 4 h. These results demonstrate that curdlan-CD nanoparticles can be a promising system for the loading and intracellular release of hydrophobic drugs into macrophages for various therapeutic applications.

Abstract: Several different procedures are recommended for the determination of total phosphorus in biologic samples. The method described here has the greatest sensitivity, being able to demonstrate the presence of 0.10 μg phosphorus per ml. It is based on the reduction of phosphomolybdate complex with ascorbic acid. The procedure described here is essentially identical to the method published by Chen, Toribara and Warner (1956).

Abstract: The structures of many microbial polysaccharides from a wide variety of bacterial species and from some algae, fungi and yeasts have been determined. A number of bacterial polysaccharides have either been adopted as commercial products or have the potential for commercialisation. The biosynthetic mechanisms for production of some of these polymers have also been elucidated and the effects of genetic manipulation have been studied. There is now also a much greater knowledge of structure/function relationships in microbial polysaccharides. While almost all this non-structural data has accumulated from the study of Gram negative species, this background information provides a sound basis from which polysaccharides from Gram positive bacteria can now be developed.