Streptomyces coelicolor is a representative of the group of soil-dwelling, filamentous bacteria responsible for producing most natural antibiotics used in human and veterinary medicine. Here we report the 8,667,507 base pair linear chromosome of this organism, containing the largest number of genes so far discovered in a bacterium. The 7,825 predicted genes include more than 20 clusters coding for known or predicted secondary metabolites. The genome contains an unprecedented proportion of regulatory genes, predominantly those likely to be involved in responses to external stimuli and stresses, and many duplicated gene sets that may represent 'tissue-specific' isoforms operating in different phases of colonial development, a unique situation for a bacterium. An ancient synteny was revealed between the central 'core' of the chromosome and the whole chromosome of pathogens Mycobacterium tuberculosis and Corynebacterium diphtheriae. The genome sequence will greatly increase our understanding of microbial life in the soil as well as aiding the generation of new drug candidates by genetic engineering.

Global warming resulting from the emission of greenhouse gases, especially CO 2 , has become a widespread concern in the recent years. Though various CO 2 capture technologies have been proposed, chemical absorption and adsorption are currently believed to be the most suitable ones for post-combustion power plants. The operation of the chemical absorption process is reviewed in this work, together with the use of absorbents, such as the ionic liquid, alkanolamines and their blended aqueous solutions. The major concerns for this technology, including CO 2 capture efficiency, absorption rate, energy required in regeneration, and volume of absorber, are addressed. For adsorption, in addition to physical adsorbents, various mesoporous solid adsorbents impregnated with polyamines and grafted with aminosilanes are reviewed in this work. The major concerns for selection of adsorbent, including cost, adsorption rate, CO 2 adsorption capacity, and thermal stability, are compared and discussed. More effective and less energy-consuming regeneration techniques for CO 2 -loaded adsorbents are also proposed. Future works for both absorption and adsorption are suggested.

Global warming due to the accumulation of atmospheric CO 2 has received widespread attention in recent years. Although various CO 2 capture technologies have been proposed, using the captured CO 2 from power plants is increasingly popular because of concerns with regard to the safety of underground and ocean CO 2 storage. Various techniques related to utilization of CO 2 from the exhausted gas of power plants are discussed in this article. The existing and under-development technologies for CO 2 utilization in the world are briefly reviewed. Two categories, direct utilization of CO 2 and conversion of CO 2 to chemicals and energy products, are used to classify different forms of CO 2 utilization. Regarding the direct utilization of CO 2 , in addition to its use in soft drinks, welding, foaming, and propellants, as well as the use of supercritical CO 2 as a solvent, CO 2 capture via photosynthesis to directly fix carbon into microalgae has also attracted the attention of researchers. The conversion of CO 2 into chemicals and energy products via this approach is a promising way to not only reduce the CO 2 emissions, but also generate more economic value. Since CO 2 is just a source of carbon without hydrogen, a clean, sustainable and cheap source of hydrogen should be developed. This article reviews the literature on the production of biofuel from microalgae cultivated using captured CO 2 , the conversion of CO 2 with hydrogen to chemicals and energy products, and sustainable and clean sources of hydrogen, in order to demonstrate the potential of CO 2 utilization.

SummaryThe chromosomes of the Gram-positive soil bacteria Streptomyces are linear DNA molecules, usually of about 8 Mb, containing a centrally located origin of replication and covalently bound terminal proteins (which are presumably involved in the completion of replication of the telomeres). The ends of the chromosomes contain inverted repeats of variable lengths. The terminal segments of five Streptomyces chromosomes and plasmids were cloned and sequenced. The sequences showed a high degree of conservation in the first 166-168 bp. Beyond the terminal homology, the sequences diverged and did not generally crosshybridize. The homologous regions contained seven palindromes with a few nucleotide differences. Many of these differences occur in complementary pairs, such that the palindromicity is preserved. Energyoptimized modelling predicted that the 3Ј strand of the terminal palindromes can form extensive hairpin structures that are similar to the 3Ј ends of autonomous parvovirus genomes. Most of the putative hairpins have a GCGCAGC sequence at the loop, with the potential to form a stable single C-residue loop closed by a sheared G:A pairing. The similarity between the terminal structures of the Streptomyces replicons and the autonomous parvoviral genomes suggests that they may share some structural and/or replication features.

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Fossil fuels, which are recognized as unsustainable sources of energy, are continuously consumed and decreased with increasing fuel demands. Microalgae have great potential as renewable fuel sources because they possess rapid growth rate and the ability to store high-quality lipids and carbohydrates inside their cells for biofuel production. Microalgae can be cultivated on opened or closed systems and require nutrients and CO 2 that may be supplied from wastewater and fossil fuel combustion. In addition, CO 2 capture via photosynthesis to directly fix carbon into microalgae has also attracted the attention of researchers. The conversion of CO 2 into chemical and fuel (energy) products without pollution via this approach is a promising way to not only reduce CO 2 emissions but also generate more economic value. The harvested microalgal biomass can be converted into biofuel products, such as biohydrogen, biodiesel, biomethanol, bioethanol, biobutanol and biohydrocarbons. Thus, microalgal cultivation can contribute to CO 2 fixation and can be a source of biofuels. This article reviews the literature on microalgae that were cultivated using captured CO 2 , technologies related to the production of biofuels from microalgae and the possible commercialization of microalgae-based biofuels to demonstrate the potential of microalgae. In this respect, a number of relevant topics are addressed: the nature of microalgae (e.g., species and composition); CO 2 capture via microalgae; the techniques for microalgal cultivation, harvesting and pretreatment; and the techniques for lipid extraction and biofuel production. The strategies for biofuel commercialization are proposed as well.