Microbial forensics: new breakthroughs and future prospects

Applied Microbiology and Biotechnology - Recent advances in genetic data generation, through massive parallel sequencing (MPS), storage and analysis have fostered significant progresses in...     

Microbial steroid transformations: current state and prospects

Studies of steroid modifications catalyzed by microbial whole cells represent a well-established research area in white biotechnology. Still, advances over the last decade in genetic and metabolic engineering, whole-cell biocatalysis in non-conventional media, and process monitoring raised research in this field to a new level. This review summarizes the data on microbial steroid conversion obtained since 2003. The key reactions of structural steroid functionalization by microorganisms are highlighted including sterol side-chain degradation, hydroxylation at various positions of the steroid core, and redox reactions. We also describe methods for enhancement of bioprocess productivity, selectivity of target reactions, and application of microbial transformations for production of valuable pharmaceutical ingredients and precursors. Challenges and prospects of whole-cell biocatalysis applications in steroid industry are discussed.     

Biophysics and nanotechnologies: Problems and prospects

Preface

Biophysics and nanotechnologies: Problems and prospects     

Microbial synthesis of biodiesel and its prospects

An analytical review of the current data on the microbial synthesis of biodiesel and prospects of its usage is presented. The technological, biochemical, and genetic aspects of biodiesel production using microorganisms are discussed.     

Microbial conversion of glycerol: present status and future prospects

Biodiesel has emerged as a potential alternate renewable liquid fuel in the past two decades. Total annual production of biodiesel stands at 6.96 million tons and 11.2 million tons in USA and Europe, respectively. In other countries, Asia and Latin America, biodiesel production has increased at unprecedented rate. Despite this, the economy of biodiesel is not attractive. An obvious solution for boosting the economy of the biodiesel industry is to look for markets for side products of the transesterification process of biodiesel synthesis. The main by-product is glycerol. However, this glycerol is contaminated with alkali/acid catalyst and alcohol, and thus, is not useful for conventional applications such as in toothpaste, drugs, paints and cosmetics. Conversion of this glycerol to value-added product is a viable solution for effective and economic utilization, which would also generate additional revenue for the biodiesel industry. Intensive research has taken place in area of conversion of glycerol to numerous products. The conventional catalytic route of glycerol transformation employs prohibitively harsh conditions of temperature and pressure, and thus, has slim potential for large-scale implementation. In addition, the selectivity of the process is rather small with formation of many undesired side products. The bioconversion processes, on the other hand, are highly selective although with slower kinetics. In this review, we have given an assessment and overview of the literature on bioconversion of glycerol. We have assessed as many as 23 products from glycerol bioconversion, and have reviewed the literature in terms of microorganism used, mode of fermentation, type of fermentor, yield and productivity of the process and recovery/purification of the products. The metabolic pathway of conversion of glycerol to various products has been discussed. We have also pondered over economic and engineering issues of large-scale implementation of process and have outlined the constraints and limitations of the process. We hope that this review will be a useful source of information for biochemists, biotechnologists, microbiologists and chemical engineers working in the area of glycerol bioconversion.     

Microbial conversion of glycerol: present status and future prospects

Biodiesel has emerged as a potential alternate renewable liquid fuel in the past two decades. Total annual production of biodiesel stands at 6.96 million tons and 11.2 million tons in USA and Europe, respectively. In other countries, Asia and Latin America, biodiesel production has increased at unprecedented rate. Despite this, the economy of biodiesel is not attractive. An obvious solution for boosting the economy of the biodiesel industry is to look for markets for side products of the transesterification process of biodiesel synthesis. The main by-product is glycerol. However, this glycerol is contaminated with alkali/acid catalyst and alcohol, and thus, is not useful for conventional applications such as in toothpaste, drugs, paints and cosmetics. Conversion of this glycerol to value-added product is a viable solution for effective and economic utilization, which would also generate additional revenue for the biodiesel industry. Intensive research has taken place in area of conversion of glycerol to numerous products. The conventional catalytic route of glycerol transformation employs prohibitively harsh conditions of temperature and pressure, and thus, has slim potential for large-scale implementation. In addition, the selectivity of the process is rather small with formation of many undesired side products. The bioconversion processes, on the other hand, are highly selective although with slower kinetics. In this review, we have given an assessment and overview of the literature on bioconversion of glycerol. We have assessed as many as 23 products from glycerol bioconversion, and have reviewed the literature in terms of microorganism used, mode of fermentation, type of fermentor, yield and productivity of the process and recovery/purification of the products. The metabolic pathway of conversion of glycerol to various products has been discussed. We have also pondered over economic and engineering issues of large-scale implementation of process and have outlined the constraints and limitations of the process. We hope that this review will be a useful source of information for biochemists, biotechnologists, microbiologists and chemical engineers working in the area of glycerol bioconversion.     

Phylogenetic taxonomy in Drosophila: Problems and prospects

The genus Drosophila is one of the best-studied model systems in modern biology, with twelve fully sequenced genomes available. In spite of the large number of genetic and genomic resources, little is known concerning the phylogenetic relationships, ecology, and evolutionary history of all but a few species. Recent molecular systematic studies have shown that this genus is comprised of at least three independent lineages and that several other genera are actually embedded within Drosophila. This genus accounts for over 2000 described, and many more undescribed, species. While some Drosophila researchers are advocating dividing this genus into three or more separate genera, others favor maintaining Drosophila as a single large genus. With the recent sequencing of the genomes of multiple Drosophila species and their expanding use in comparative biology, it is critical that the Drosophila research community understands the taxonomic framework underlying the naming and relationships of these species. The subdivision of this genus has significant biological implications, ranging from the accurate annotation of single genes to understanding how ecological adaptations have occurred over the history of the group.     

Microbial physiology and ecology of slow growth.

The uptake capabilities of the cell have evolved to permit growth at very low external nutrient concentrations. How are these capabilities controlled when the substrate concentrations are not extremely low and the uptake systems could import substrate much more rapidly than the metabolic capabilities of the cell might be able to handle? To answer this question, earlier theories for the kinetics of uptake through the cell envelope and steady-state systems of metabolic enzymes are discussed and a computer simulation is presented. The problems to the cell of fluctuating levels of nutrient and too much substrate during continuous culture are discussed. Too much substrate can lead to oligotrophy, substrate-accelerated death, entry into the viable but not culturable state, and lactose killing. The relationship between uptake and growth is considered. Finally, too little substrate may lead to catastrophic attempts at mounting molecular syntheses that cannot be completed.     

Use of microparticulate markers in examination of rotifer physiology: results and prospects

A short overview is given of some possible ways of using microparticles for the study of rotifer physiology. Besides synthetic microcapsules, some `natural' microparticles have been found to be appropriate for this purpose. Using yeast cells, erythrocytes and erythrocyte ghosts, we were able to examine feeding rates, time course and control of nutrient passage, to determine the pH milieu in the digestive tract and to demonstrate absorptive processes. Preliminary results exist of studies on the mechanical efficiency of the mastax and on the secretion of H⁺-ions by the intestine. Different types of synthetic microcapsules can be produced for an array of applications. Some of these are suitable for use with rotifers. Problems exist in producing them in a suitable uniform size and in loading them efficiently.     

Microbial physiology of sidechain degradation of sterols

Summary A large number of valuable starting materials for steroids synthesis (e.g. 4-androstene-3,17-dione, 1,4-androstadiene-3,17-dione, 9-hydroxy-4-androsten-17-one) have been produced by microbial transformation methods. This review helps to evaluate the microbial physiological interest of the widely used sterol sidechain degradation processes. Four inducible groups of the catabolic enzymes are involved in the sterol sidechain degradation pathway; the fatty acid -oxidation system, the -oxidase reaction, a methyl-crotonyl-CoA carboxylation system and the propionyl-CoA carboylase system.Altogether nine catabolic enzymes are involved in the -sitosterol sidechain degradation pathway. They work in 14 consecutive enzymatic steps. Summing up: three molecules of FADH₂, three molecules of propionyl-SCoA, three of NADH and one molecule of acetic acid are formed, while the sidechain of one mole of sitosterol is removed selectively. The metabolism of the propionates and the acetate yield 18 molecules of NADH and 7 molecules of FADH₂. Taking into consideration the whole process more than 80 molecules of ATP could be formed during the sitosterol sidechain degradation process.     

UNIQEM, a microbiological database: Problems and prospects

The UNIQEM database, designed to accumulate general microbiological data, is currently used to store and make available information about microorganisms studied and maintained at the Institute of Microbiology, Russian Academy of Sciences. UNIQEM can accumulate and maintain list-form information on a wide range of microorganisms (a property database) and facilitates collecting, processing, and publishing diverse data having to do with these microorganisms and their properties (a catalogue database). The database supports the retrieval of microorganisms by specifying an arbitrary set of their properties and has the potential for eventually evolving into a computer instrument for unattended identification of microorganisms. UNIQEMAkhlynin, D.S. and Gal’chenko, V.F., 1998.     

Biobanks as the basis for developing biomedicine: Problems and prospects

Biobanking is crucial for the development of life sciences in general and biomedical science in particular. A systematic study of stored biomaterials enables the discovery of new biomarkers for various physiological and pathophysiological states, identification of the drug targets, and validation of these findings in human population studies. During the last decades, the importance of biobanking has increased in parallel with the growth in their size from relatively small collections to very large national and international biorepositories. Here, we have systematically reviewed modern approaches to biobanking, a variety of biobank definitions and types, and the current states of biobanking art in Russia and in the world and have discussed the obstacles to the global development of biobanking, along with possible solutions.