Recent knowledge and innovations related to hexofuranosides: structure, synthesis and applications

Hexofuranosides are widely spread in nature, and notably in numerous pathogenic microorganisms. This particular five-membered ring for hexosides leads to novel biological properties and, as usual in glycochemistry, to completely different reactivity and selectivity. Far from being exhaustive, this review will first focus on the structure of the oligosaccharidic part of hexofuranosyl conjugates found in natural sources. Original syntheses will then be presented, stressing more particularly on the development of chemical and chemo-enzymatic tools for the access to 1,2-trans or 1,2-cis linkages. Finally, innovative applications related to biological, chemical and physicochemical fields for both natural and synthetic hexofuranosyl compounds will be described.     

Recent advances in microbial glutaminase production and applications—a concise review

Abstract

This article focuses on significant advances in the production and applications of microbial glutaminases and provides insight into the structures of different glutaminases. Glutaminases catalyze the deamidation of glutamine to glutamic acid, and this unique ability forms the basis of their applications in various industries such as pharmaceutical and food organizations. Microbial glutaminases from bacteria, actinomycetes, yeast, and fungi are of greater significance than animal glutaminases because of their stability, affordability, and ease of production. Owing to these notable benefits, they are considered to possess considerable potential in anticancer and antiviral therapy, flavor enhancers in oriental foods, biosensors and in the production of a nutraceutical theanine. This review also aims to fully explore the potential of microbial glutaminases and to set the pace for future prospects.     

Lactulose: production, purification and potential applications

Lactulose a “bifidus factor” is composed of galactose and fructose, which can be produced by the isomerization of lactose. It is a prebiotic carbohydrate which stimulates the growth of health-promoting bacteria in the gastrointestinal tract, such as bifidobacteria and lactobacilli and at the same time inhibits growth of pathogenic bacteria such as Salmonella. It can also be used for the treatment of constipation, hepatic encephalopathy, tumour prevention, and to maintain blood glucose and insulin level. This review provides comprehensive information on the different techniques used for the production of lactulose, purification and analysis. Besides this mechanism of action and its potential applications in food and pharmaceutical industries have also been discussed.     

Recent insights into microbial catalases: Isolation,production and purification

Catalase, an oxidoreductase enzyme, works as a detoxification system inside living cells against reactive oxygen species formed as a by-product of different metabolic reactions. The enzyme is found in a wide range of aerobic and anaerobic organisms. Catalase has also been employed in various analytical and diagnostic methods in the form of biosensors and biomarkers in addition to its other applications in textile, paper, food and pharmaceutical industries. New applications for catalases are constantly emerging thanks to their high turnover rate, distinct evolutionary origin, relatively simple and well-defined reaction mechanisms. The following review provides comprehensive information on isolation, production and purification of catalases with different techniques from various microbial sources along with their types, structure, mechanism of action and applications.     

Recent advances on applications and biotechnological production of d-psicose

D-Psicose is a hexoketose monosaccharide sweetener, which is a C-3 epimer of D-fructose and is rarely found in nature. It has 70 % relative sweetness but 0.3 % energy of sucrose, and is suggested as an ideal sucrose substitute for food products. It shows important physiological functions, such as blood glucose suppressive effect, reactive oxygen species scavenging activity, and neuroprotective effect. It also improves the gelling behavior and produces good flavor during food process. This article presents a review of recent studies on the properties, physiological functions, and food application of D-psicose. In addition, the biochemical properties of D-tagatose 3-epimerase family enzymes and the D-psicose-producing enzyme are compared, and the biotechnological production of D-psicose from D-fructose is reviewed.     

Pyocyanin: production,applications, challenges and new insights

Pseudomonas aeruginosa is an opportunistic, Gram-negative bacterium and is one of the most commercially and biotechnologically valuable microorganisms. Strains of P. aeruginosa secrete a variety of redox-active phenazine compounds, the most well studied being pyocyanin. Pyocyanin is responsible for the blue-green colour characteristic of Pseudomonas spp. It is considered both as a virulence factor and a quorum sensing signalling molecule for P. aeruginosa. Pyocyanin is an electrochemically active metabolite, involved in a variety of significant biological activities including gene expression, maintaining fitness of bacterial cells and biofilm formation. It is also recognised as an electron shuttle for bacterial respiration and as an antibacterial and antifungal agent. This review summarises recent advances of pyocyanin production from P. aeruginosa with special attention to antagonistic property and bio-control activity. The review also covers the challenges and new insights into pyocyanin from P. aeruginosa.     

Bacterial outer membrane vesicles: New insights and applications

Outer membrane vesicles (OMVs) (～50–250?nm in diameter) are produced by both pathogenic and nonpathogenic bacteria as a canonical end product of secretion. In this review, we focus on the OMVs produced by gram-negative bacteria. We provide an overview of the OMV structure, various factors regulating their production, and their role in modulating host immune response using a few representative examples. In light of the importance of the diverse cargoes carried by OMVs, we discuss the different modes of their entry into the host cell and advances in the high-throughput detection of these OMVs. A conspicuous application of OMVs lies in the field of vaccination; we discuss its success in immunization against human diseases such as pertussis, meningitis, shigellosis and aqua-farming endangering diseases like edwardsiellosis.     

Laccase immobilization and insolubilization: from fundamentals to applications for the elimination of emerging contaminants in wastewater treatment

Over the last few decades many attempts have been made to use biocatalysts for the biotransformation of emerging contaminants in environmental matrices. Laccase, a multicopper oxidoreductase enzyme, has shown great potential in oxidizing a large number of phenolic and non-phenolic emerging contaminants. However, laccases and more broadly enzymes in their free form are biocatalysts whose applications in solution have many drawbacks rendering them currently unsuitable for large scale use. To circumvent these limitations, the enzyme can be immobilized onto carriers or entrapped within capsules; these two immobilization techniques have the disadvantage of generating a large mass of non-catalytic product. Insolubilization of the free enzymes as cross-linked enzymes (CLEAs) is found to yield a greater volume ratio of biocatalyst while improving the characteristics of the biocatalyst. Ultimately, novel techniques of enzymes insolubilization and stabilization are feasible with the combination of cross-linked enzyme aggregates (combi-CLEAs) and enzyme polymer engineered structures (EPESs) for the elimination of emerging micropollutants in wastewater. In this review, fundamental features of laccases are provided in order to elucidate their catalytic mechanism, followed by different chemical aspects of the immobilization and insolubilization techniques applicable to laccases. Finally, kinetic and reactor design effects for enzymes in relation with the potential applications of laccases as combi-CLEAs and EPESs for the biotransformation of micropollutants in wastewater treatment are discussed.     

生物表面活性剂生产及应用研究进展

生物表面活性剂主要是由微生物代谢产生的,具有疏水基团和亲水基团的两亲性物质,它们能显著降低表面与界面张力。与化学表面活性剂相比,生物表面活性剂具有毒性低、生物兼容性好、可降解等优点,在众多领域具有良好的应用前景,但生物表面活性剂的高生产成本限制了商业化发展。本文旨在分析微生物表面活性剂的生产,重点是生产过程和代谢途径的优化,以探索产量与成本的关键因素,为生物表面活性剂商业化发展提供解决方案。     

The lipases from Yarrowia lipolytica: genetics, production, regulation, biochemical characterization and biotechnological applications

Lipases are serine hydrolases that catalyze in nature the hydrolysis of ester bonds of long chain triacylglycerol into fatty acid and glycerol. However, in favorable thermodynamic conditions, they are also able to catalyze reactions of synthesis such as esterification or amidation. The non-conventional yeast Yarrowia lipolytica possesses 16 paralogs of genes coding for lipase. However, little information on all those paralogs has been yet obtained and only three isoenzymes, namely Lip2p, Lip7p and Lip8p have been partly characterized so far. Microarray data suggest that only a few of them could be expressed and that lipase synthesis seems to be dependent on the fatty acid or oil used as carbon source confirming the high adaptation of Y. lipolytica to hydrophobic substrate utilization. This review focuses on the biochemical characterization of those enzymes with special emphasis on the Lip2p lipase which is the isoenzyme mainly synthesized by Y. lipolytica. Crystallographic data highlight that this latter is a lipase sensu stricto with a lid covering the active site of the enzyme in its closed conformation. Recent findings on enzyme conditioning in dehydrated or liquid formulation, in enzyme immobilization by entrapment in natural polymers from either organic or mineral origins are also discussed together with long-term storage strategies. The development of various biotechnological applications in different fields such as cheese ripening, waste treatment, drug synthesis or human therapeutics is also presented.     

Recent advances in behavioral neuroendocrinology: insights from studies on birds

Ever since investigations in the field of behavioral endocrinology were hatched with experiments on roosters, birds have provided original insights into issues of fundamental importance for all vertebrate groups. Here we focus on more recent advances that continue this tradition, including (1) environmental regulation of neuroendocrine and behavioral systems, (2) steroidogenic enzyme functions that are related to intracrine processes and de novo production of neurosteroids, and (3) hormonal regulation of neuroplasticity. We also review recent findings on the anatomical and functional organization of steroid-sensitive circuits in the basal forebrain and midbrain. A burgeoning body of data now demonstrates that these circuits comprise an evolutionarily conserved network, thus numerous novel insights obtained from birds can be used (in a relatively straightforward manner) to generate predictions for other taxa as well. We close by using birdsong as an example that links these areas together, thereby highlighting the exceptional opportunities that birds offer for integrative studies of behavioral neuroendocrinology and behavioral biology in general.     

Inulin and its enzymatic production by inulosucrase: Characteristics,structural features,molecular modifications and applications

Inulin, a natural fructan, cannot be hydrolyzed by digestive enzymes in the human body and plays a role as a dietary fiber and prebiotic. Due to its versatile physicochemical properties and physiological functions, inulin has been widely applied in food, pharmaceuticals, and many other fields. The microorganism-derived inulin-forming enzyme inulosucrase (ISase) (EC: 2.1.4.9) can biosynthesize higher-molecular-weight inulin than plants using sucrose as the sole substrate, and the enzyme also shows transfructosylation activity toward other saccharide acceptors. In this article, the properties, functions, and applications of inulin are overviewed. The biosynthesis of inulin by ISase is addressed, including ISase characteristics, structural features, molecular modifications and applications.     

Mannanases: microbial sources,production, properties and potential biotechnological applications

Mannans are the major constituents of the hemicellulose fraction in softwoods and show widespread distribution in plant tissues. The major mannan-degrading enzymes are β-mannanases, β-mannosidases and β-glucosidases. In addition to these, other enzymes such as α-galactosidases and acetyl mannan esterases, are required to remove the side chain substituents. The mannanases are known to be produced by a variety of bacteria, fungi, actinomycetes, plants and animals. Microbial mannanases are mainly extracellular and can act in wide range of pH and temperature because of which they have found applications in pulp and paper, pharmaceutical, food, feed, oil and textile industries. This review summarizes the studies on mannanases reported in recent years in terms of important microbial sources, production conditions, enzyme properties, heterologous expression and potential industrial applications.     

Recent advances and novel applications in microbial diversity estimation based on DNA analysis methods

This review focuses on recent patents on the exploration and quantification of microbial diversity. Only the patents based on DNA analysis are considered. In general terms, the analysis of environmental samples can be investigated by using three main approaches: microarrays based technologies, genomes/metagenomes comparison and amplification and detection of operative taxonomic units. All patents can relate to the estimation of the microbial diversity, however, many of them were initially designed to detect important medical or agronomic microorganisms. Here, we briefly review recent technological achievements for DNA analysis that offer great potentials for the identification of species.     

Laboratory scale medicinal plants mediated green synthesis of biocompatible nanomaterials and their versatile biomedical applications

Nanoparticles and its green synthesis with plants have become an important field of nanoscience due it is great benefits provided to humanity through it and its cost effective, least harm to humans and the environment also, it offering a lot of application in biomedical research, diagnostics, and medicine as well as, drug manufacturing, improvement, or drug discovery. In this work, I focused on green synthesis nanoparticles with antioxidant involve in plants and the method for preparing them also the factors on which the extraction process depends on, spectroscopic techniques like UV–Visible, (TEM), (XRD), (IR), (EDX), (SEM), (HPLC), and zeta potential are use here.     

Recent advances in production,purification and applications of phycobiliproteins

An obligatory sunlight requirement for photosynthesis has exposed cyanobacteria to different quantity and quality of light. Cyanobacteria can exhibit efficient photosynthesis over broad region(450 to 650 nm) of solar spectrum with the help of brilliantly coloured pigment proteins called phycobiliproteins(PBPs). Besides light-harvesting, PBPs are found to involve in several life sustaining phenomena including photoprotection in cyanobacteria. The unique spectral features(like strong absorbance and fluorescence), proteineous nature and, some imperative properties like hepato-protective, antioxidants, anti-inflammatory and anti-aging activity of PBPs enable their use in food, cosmetics, pharmaceutical and biomedical industries. PBPs have been also noted to show beneficial effect in therapeutics of some disease like Alzheimer and cancer. Such large range of applications increases the demand of PBPs in commodity market. Therefore, the large-scale and coast effective production of PBPs is the real need of time. To fulfil this need, many researchers have been working to find the potential producer of PBPs for the production and purification of PBPs. Results of these efforts have caused the inventions of some novel techniques like mixotrophic and heterotrophic strategies for production and aqueous two phase separation for purification purpose. Overall, the present review summarises the recent findings and identifies gaps in the field of production, purification and applications of this biological and economically important proteins.     

Biotechnological production and applications of Cordyceps militaris,a valued traditional Chinese medicine

Cordyceps militaris is a potential harborer of biometabolites for herbal drugs. For a long time, C. militaris has gained considerable significance in several clinical and biotechnological applications. Much knowledge has been gathered with regard to the C. militaris's importance in the genetic resources, nutritional and environmental requirements, mating behavior and biochemical pharmacological properties. The complete genome of C. militaris has recently been sequenced. This fungus has been the subject of many reviews, but few have focused on its biotechnological production of bioactive constituents. This mini-review focuses on the recent advances in the biotechnological production of bioactive compositions of C. militaris and the latest advances on novel applications from this laboratory and many others.     

Biotechnological production and applications of microbial phenylalanine ammonia lyase: a recent review

Abstract

Phenylalanine ammonia lyase (PAL) catalyzes the nonoxidative deamination of l-phenylalanine to form trans-cinnamic acid and a free ammonium ion. It plays a major role in the catabolism of l-phenylalanine. The presence of PAL has been reported in diverse plants, some fungi, Streptomyces and few Cyanobacteria. In the past two decades, PAL has gained considerable significance in several clinical, industrial and biotechnological applications. Since its discovery, much knowledge has been gathered with reference to the enzyme’s importance in phenyl propanoid pathway of plants. In contrast, there is little knowledge about microbial PAL. Furthermore, the commercial source of the enzyme has been mainly obtained from the fungi. This study focuses on the recent advances on the physiological role of microbial PAL and the improvements of PAL biotechnological production both from our laboratory and many others as well as the latest advances on the new applications of microbial PAL.