Uttam Chand Banerjee

Production, purification, characterization, and applications of lipases

Lipases (triacylglycerol acylhydrolases, EC 3.1.1.3) catalyze the hydrolysis and the synthesis of esters formed from glycerol and long-chain fatty acids. Lipases occur widely in nature, but only microbial lipases are commercially significant. The many applications of lipases include speciality organic syntheses, hydrolysis of fats and oils, modification of fats, flavor enhancement in food processing, resolution of racemic mixtures, and chemical analyses. This article discusses the production, recovery, and use of microbial lipases. Issues of enzyme kinetics, thermostability, and bioactivity are addressed. Production of recombinant lipases is detailed. Immobilized preparations of lipases are discussed. In view of the increasing understanding of lipases and their many applications in high-value syntheses and as bulk enzymes, these enzymes are having an increasing impact on bioprocessing.

Synthesis of metallic nanoparticles using plant extracts.

Biomolecules present in plant extracts can be used to reduce metal ions to nanoparticles in a single-step green synthesis process. This biogenic reduction of metal ion to base metal is quite rapid, readily conducted at room temperature and pressure, and easily scaled up. Synthesis mediated by plant extracts is environmentally benign. The reducing agents involved include the various water soluble plant metabolites (e.g. alkaloids, phenolic compounds, terpenoids) and co-enzymes. Silver (Ag) and gold (Au) nanoparticles have been the particular focus of plant-based syntheses. Extracts of a diverse range of plant species have been successfully used in making nanoparticles. In addition to plant extracts, live plants can be used for the synthesis. Here we review the methods of making nanoparticles using plant extracts. Methods of particle characterization are reviewed and potential applications of the particles in medicine are discussed.

Botryococcus braunii : A renewable source of hydrocarbons and other chemicals

ABSTRACT:  Botryococcus braunii, a green colonial microalga, is an unusually rich renewable source of hydrocarbons and other chemicals. Hydrocarbons can constitute up to 75% of the dry mass of B. braunii. This review details the various facets of biotechnology of B. braunii, including its microbiology and physiology; production of hydrocarbons and other compounds by the alga; methods of culture; downstream recovery and processing of algal hydrocarbons; and cloning of the algal genes into other microorganisms. B. braunii converts simple inorganic compounds and sunlight to potential hydrocarbon fuels and feedstocks for the chemical industry. Microorganisms such as B. braunii can, in the long run, reduce our dependence on fossil fuels and because of this B. braunii continues to attract much attention.

Biotechnological applications of cyclodextrins.

Cyclodextrins (CDs) are a family of cyclic oligosaccharides that are composed of alpha-1,4-linked glucopyranose subunits. Cyclodextrins are produced from starch by enzymatic degradation. These macrocyclic carbohydrates with apolar internal cavities can form complexes with and solubilize many normally water-insoluble compounds. This review describes recent applications of CDs in pharmaceuticals with a major emphasis on drug delivery systems. The utility of these water-soluble cyclic glucans in a variety of foods, flavors cosmetics, packaging and textiles is elaborated. The role of these compounds in biocatalysis is also discussed. Cyclodextrins are used in separation science because they have been shown to discriminate between positional isomers, functional groups, homologues and enantiomers. This property makes them a useful agent for a wide variety of separations.

Removal of Dyes from the Effluent of Textile and Dyestuff Manufacturing Industry: A Review of Emerging Techniques With Reference to Biological Treatment

Abstract Biological removal of dyes from effluents of textile and dyestuff manufacturing industry offers some distinct advantages over the commonly used chemicals and physicochemical methods. These include possible mineralization of the dyes to harmless inorganic compounds like carbon dioxide and water, and formation of a lesser quantity of relatively harmless sludge. Removal of dyes from these wastewaters has been reviewed with respect to biological decolorization as well as complete biodegradation of the dye molecules. Emerging techniques with reference to biological treatment of these wastewaters have been discussed under aerobic, anaerobic, and combined anaerobic–aerobic systems. Advantages and limitations of different biological methods have been highlighted, and future studies to establish these techniques for their applications on industrial scale have been suggested.

Biodegradation of triphenylmethane dyes

Biodegradation of triphenylmethane dyes by bacteria, actinomycetes, yeasts, and fungi are discussed in detail. The disadvantages of physical and chemical treatment processes of dye wastewater are also discussed. Biological treatment processes have many advantages over the chemical and physical treatment processes such as possibility of degradation of dye molecules to carbon dioxide and water and formation of less sludge in addition to being environmentally friendly. This group of dyes is toxic depending on the concentration used. Toxicity of triphenylmethane dyes is discussed with respect to different organisms. Some aspects of biodegradative products of this group of dyes are also mentioned.

Thermostable alkaline protease from Bacillus brevis and its characterization as a laundry detergent additive

An alkaline protease from a facultatively thermophilic and alkalophilic strain of Bacillus brevis has been studied. The enzyme from a shake flask culture displayed maximum activity at pH 10.5 and 37°C. The extracellular production of the enzyme, its thermostable nature and compatibility with most commercial detergents are features which suggest its application in detergent industry. The organism utilized several carbon sources for the production of proteases, lactose was the best substrate followed by glucose and sucrose. Among the various organic nitrogen sources, soyabean meal was found to be the best. The protease was stable at 25°C for 288 h whereas, at 50 and 60°C, the half lives were 60 and 7 h, respectively. The thermostability of the protease was enhanced by modifying its microenvironment. Acetate salts of Ca2+ and Na+ increased thermostability and protected against autolysis. Addition of Ca2+ (10 mM) and glycine (1 M) individually and in combination was found to be effective in increasing the half life of protease by many folds. The enzyme retained more than 50% activity after 4 days at 60°C in the presence of both Ca2+ (10 mM) and glycine (1 M). The enzyme showed compatibility at 60°C with commercial detergents such as Aerial Microshine®, Surf excel®, Surf Ultra® and Rin® in the presence of Ca2+ and glycine. This enzyme improved the cleaning power of various detergents. It could remove blood stains completely when used with detergents in the presence of Ca2+ and glycine.

Decolorization of triphenylmethane dyes and textile and dye-stuff effluent by Kurthia sp.

A number of soil and water samples were collected from the vicinity of effluent treatment plant of a textile and dyeing industry. Several organisms were screened for their ability to decolorize triphenylmethane group of dyes. A Kurthia sp. was selected on the basis of rapid dye decolorizing activity. Under aerobic conditions, 98% color was removed intracellularly by this strain. A number of triphenylmethane dyes, such as magenta, crystal violet, pararosaniline, brilliant green, malachite green, ethyl violet and textile and dyestuff effluent used in this study. The rates of decolorization of magenta (92%), crystal violet (96%), malachite green (96%), pararosaniline (100%) and brilliant green (100%) were found to be more than that of ethyl violet (8%). After the decolorization of most of the dyes, viable cell concentration of the Kurthia sp. reduced significantly. In the case of ethyl violet, viable cell concentration was almost negligible after decolorization. The extent of decolorization of synthetic effluent (98%) was more in comparison to textile and dye-stuff effluent (56%). After biotransformation, the extent of COD reduction of the cell free extracts of triphenylmethane dyes was higher (more than 88%, except in the case of ethyl violet, 70%) in comparison to textile and dye-stuff effluent.

Biosynthesis of silver nanoparticles: Elucidation of prospective mechanism and therapeutic potential.

The synthesis of silver nanoparticles (AgNPs) was accomplished using Syzygium cumini fruit extract at room temperature. Various techniques were used to characterize the newly synthesized silver nanoparticles and their size was determined to be 10-15nm. Important findings of this study were the identification of biomolecules responsible for the synthesis of silver nanoparticles and elucidate the mechanism of biosynthesis. Flavonoids present in S. cumini were mainly responsible for the reduction and the stabilization of nanoparticles. The antioxidant properties of AgNPs were evaluated using various assays. The nanoparticles were also found to destroy Dalton lymphoma cell lines under in vitro condition. Silver nanoparticles (100μg/mL) decreased the viability of Dalton lymphoma (DL) cell lines up to 50%. The studies describing the biosynthesis of silver nanoparticles by fruit extract followed by the investigation of synthesis mechanism and anti-cancer activities may be useful for nanobiotechnology research opening a new arena in this field.

Production, purification, and characterization of the debittering enzyme naringinase

This review discusses the debittering enzyme naringinase and its essential role in the commercial processing of citrus fruit juice. Applications of this enzyme in other areas are identified. Characterization of the enzyme is detailed and its immobilized preparations are discussed. Production of microbial naringinase by fermentation is described.