Harish Kumar Chopra

Biosurfactants from Fungi: A Review

Biosurfactants are the surfactants of microbial origin. They offer so many advantages over their synthetic counterparts due to their biodegradable and environmental friendly nature, that’s why gaining much more attention in creating the era of green technology. Their applications range from cosmetic, pharmaceutical and food processes as emulsifiers, humectants, preservatives, detergents etc. The present review deals with the production, purification, characterization and applications of various fungal biosurfactants.

Utilization of oleo-chemical industry by-products for biosurfactant production

Biosurfactants are the surface active compounds produced by micro-organisms. The eco-friendly and biodegradable nature of biosurfactants makes their usage more advantageous over chemical surfactants. Biosurfactants encompass the properties of dropping surface tension, stabilizing emulsions, promoting foaming and are usually non- toxic and biodegradable. Biosurfactants offer advantages over their synthetic counterparts in many applications ranging from environmental, food, and biomedical, cosmetic and pharmaceutical industries. The important environmental applications of biosurfactants include bioremediation and dispersion of oil spills, enhanced oil recovery and transfer of crude oil. The emphasis of present review shall be with reference to the commercial production, current developments and future perspectives of a variety of approaches of biosurfactant production from the micro-organisms isolated from various oil- contaminated sites and from the by-products of oleo-chemical industry wastes/ by-products viz. used edible oil, industrial residues, acid oil, deodorizer distillate, soap-stock etc.

Isolation and purification of a new enamide biosurfactant from Fusarium proliferatum using rice-bran

A new fungus Fusarium proliferatum was isolated from the oil contaminated sludge of the rice-bran oil industry, which was capable of producing biosurfactants when grown on rice-bran. The dark brown honey colored biosurfactant was recovered using ultrasonication as one of the steps in the extraction process. The biosurfactant was purified by column chromatography and structure elucidation of the purified biosurfactant was done with the aid of various spectroscopic techniques viz. FTIR, 2D-NMR, and Mass Spectrometry. The purified biosurfactant reduced the surface tension of the distilled water from 71.2 to 36.6 mN m−1 and the critical micelle concentration was calculated to be 0.33 mg mL−1. The biosurfactant was also capable of emulsifying various hydrocarbons viz. coconut oil, refined oil, kerosene, and n-dodecane. The crude biosurfactant was checked for its anti-oxidant activity using ascorbic acid as a standard and determining the 1,1-diphenyl-2-picryl hydrazyl (DPPH) scavenging activity. The IC50 was calculated and for ascorbic acid it comes out to be 0.056 mg mL−1 and for biosurfactant it was 18.81 mg mL−1.

p53-Mdm2 interaction inhibitors as novel nongenotoxic anticancer agents

BACKGROUND Cancer is a major global health problem with high mortality rate. Most of the clinically used anticancer agents induce apoptosis through genotoxic stress at various stages of cell cycle and activation of p53. Acting as a tumor suppressor, p53 plays a vital role in preventing tumor development. Tumor suppressor function of p53 is effectively antagonized by its direct interaction with murine double minute 2 (Mdm2) proteins via multiple mechanisms. Thus, p53-Mdm2 interaction has been found to be an important target for the development of novel anticancer agents. Currently, nutlin, spirooxindole, isoquilinone and piperidinone analogues inhibiting p53-Mdm2 interaction are found to be promising in the treatment of cancer. OBJECTIVE The current review focused to scrutinize the structural aspects of p53-Mdm2 interaction inhibitors. METHODS The present study provides a detailed collection of published information on different classes of inhibitors of p53-Mdm2 interaction as potential anticancer agents. The review highlighted the structural aspects of various reported p53-Mdm2 inhibitors for optimization. RESULTS In the last few years, different classes of inhibitors of p53-Mdm2 have been designed and developed, and seven such compounds are being evaluated in clinical trials as new anticancer drugs. Further, to explore the role of p53 protein as a potential target for anticancer drug development, in this review, the mechanism of Mdm2 mediated inactivation of p53 and recent developments on p53- Mdm2 interactions inhibitors are discussed. CONCLUSION Agents designed to block the p53-Mdm2 interaction may have a therapeutic potential for the treatment of a subset of human cancers retaining wild-type p53. We review herein the recent advances in the design and development of potent small molecules as p53-Mdm2 inhibitors.

Comparative studies on physico-chemical characterization of yeast cells entrapped with alginate and hybrid beads

Natural polymers used as carrier materials in immobilization technology have the advantage of being non-toxic, biocompatible and biodegradable. In the present investigation, immobilization of yeast cells using different polymers has been carried out and the properties such as morphological, hardening, thermal stability and characterization of functional groups of alginate and hybrid beads (alginate–carrageenan and alginate–xanthan gum) have been studied by different techniques such as scanning electron microscope, texture analyzer, differential scanning calorimetry, and Fourier transfer infrared spectroscopy. The swelling behavior in terms of pH variation as well as flow properties of alginate and hybrid beads has also been examined. The hybrid beads prepared from alginate and carrageenan were found to be the best in terms of strength, cell holding capacity, pH and thermal stability. The reusability of beads was also studied in terms of enzyme activity of the entrapped yeast cells. The beads prepared by alginate–carrageenan were found to be more stable than alginate and alginate–xanthan beads. The yeast cells entrapped in alginate–carrageenan beads showed no significant decrease in enzyme activity up to seven batches. Thus, alginate–carrageenan beads can be used as a polymeric carrier/support to develop a stable and long-term immobilized cell system, which indicates its high potential for commercial applications in food and pharmaceutical sector.

Synthesis, characterization, and organocatalytic application of chiral ionic liquids derived from (S,R)-noscapine

ABSTRACT (S,R)-Noscapine, a phthalideisoquinoline alkaloid has been used as precursor for the synthesis of chiral ionic liquids (CILs). Noscapine based CILs have been synthesized from reaction between (S,R)-noscapine and methyl iodide in acetonitrile at room temperature. The synthesized CILs have been characterized by 1H NMR, 13C NMR, EI-MS, and polarimetry techniques. These CILs have been used as organocatalysts in the enantioselective reduction of prochiral ketones to produce optically active secondary alcohols. The optically active secondary alcohols have been obtained with excellent yields and low to moderate enantiomeric excess (ee); also the complete enantiomeric excess (100% ee) has been achieved in some cases. GRAPHICAL ABSTRACT

Isolation and Characterization of Cellulose Producing Bacterial Isolate from Rotten Grapes

In this present investigation, eleven bacterial cellulose producing isolates were selected out of 34 isolates from different sources. Among the eleven isolates the C18 isolate has been identified as a potential bacterial cellulose producer. Physiological and biochemical tests were carried out to identify the bacteria. The molecular characterization of C18 strain was done by 16 S rDNA analysis and identified as Gluconacetobacter xylinus due to 94% sequence similarity. The maximum bacterial cellulose production (3.96g/L) was obtained after incubation time of 168 h with Hestrin and Hchramm (HS) media in static culture. Structural elucidation of bacterial cellulose was achieved using analytical techniques like FTIR, SEM and X-ray diffraction analysis.

Characterization of Secondary Metabolites from Various Solvent Extracts of Saffron Floral Waste

Abstract Isolation of secondary metabolites from saffron flower waste (stamens), and their identification using chromatographic techniques was carried out. Extraction was carried out with solvents (methanol, ethanol, ethyl acetate, diethylether and hexane) with different polarity. Gas chromatography–mass spectroscopy (GC–MS) technique was used for identification and structure elucidation of secondary metabolites obtained from saffron flower stamens. Chromatogram of ethanol showed higher peak area as compared to other solvents. Ethanol extract showed maximum number of peaks while chromatogram of hexane extract showed minimum number of peaks indicating that polarity of the solvent plays an important role in the extraction process. GC–MS analysis confirmed presence of many important compounds in saffron stamens such as α-tocopherol or vitamin E, dibutyl para-cresol, hydroquinone, and certain esters.