https://www.massey.ac.nz/~ychisti/Biodiesel.pdf

Biodiesel from microalgae.

Countless millions of people have died from tuberculosis, a chronic infectious disease caused by the tubercle bacillus. The complete genome sequence of the best-characterized strain of Mycobacterium tuberculosis, H37Rv, has been determined and analysed in order to improve our understanding of the biology of this slow-growing pathogen and to help the conception of new prophylactic and therapeutic interventions. The genome comprises 4,411,529 base pairs, contains around 4,000 genes, and has a very high guanine + cytosine content that is reflected in the biased amino-acid content of the proteins. M. tuberculosis differs radically from other bacteria in that a very large portion of its coding capacity is devoted to the production of enzymes involved in lipogenesis and lipolysis, and to two new families of glycine-rich proteins with a repetitive structure that may represent a source of antigenic variation.

/pdf/deciphering-the-biology-of-mycobacterium-tuberculosis-from-56gdir9h56.pdf

Deciphering the biology of Mycobacterium tuberculosis from the complete genome sequence

Sustainability is a key principle in natural resource management, and it involves operational efficiency, minimisation of environmental impact and socio-economic considerations; all of which are interdependent. It has become increasingly obvious that continued reliance on fossil fuel energy resources is unsustainable, owing to both depleting world reserves and the green house gas emissions associated with their use. Therefore, there are vigorous research initiatives aimed at developing alternative renewable and potentially carbon neutral solid, liquid and gaseous biofuels as alternative energy resources. However, alternate energy resources akin to first generation biofuels derived from terrestrial crops such as sugarcane, sugar beet, maize and rapeseed place an enormous strain on world food markets, contribute to water shortages and precipitate the destruction of the world's forests. Second generation biofuels derived from lignocellulosic agriculture and forest residues and from non-food crop feedstocks address some of the above problems; however there is concern over competing land use or required land use changes. Therefore, based on current knowledge and technology projections, third generation biofuels specifically derived from microalgae are considered to be a technically viable alternative energy resource that is devoid of the major drawbacks associated with first and second generation biofuels. Microalgae are photosynthetic microorganisms with simple growing requirements (light, sugars, CO 2 , N, P, and K) that can produce lipids, proteins and carbohydrates in large amounts over short periods of time. These products can be processed into both biofuels and valuable co-products. This study reviewed the technologies underpinning microalgae-to-biofuels systems, focusing on the biomass production, harvesting, conversion technologies, and the extraction of useful co-products. It also reviewed the synergistic coupling of microalgae propagation with carbon sequestration and wastewater treatment potential for mitigation of environmental impacts associated with energy conversion and utilisation. It was found that, whereas there are outstanding issues related to photosynthetic efficiencies and biomass output, microalgae-derived biofuels could progressively substitute a significant proportion of the fossil fuels required to meet the growing energy demand.

/pdf/biofuels-from-microalgae-a-review-of-technologies-for-1t1wwr5e69.pdf

Biofuels from microalgae—A review of technologies for production, processing, and extractions of biofuels and co-products

Antiseptics and disinfectants are extensively used in hospitals and other health care settings for a variety of topical and hard-surface applications A wide variety of active chemical agents (biocides) are found in these products, many of which have been used for hundreds of years, including alcohols, phenols, iodine, and chlorine Most of these active agents demonstrate broad-spectrum antimicrobial activity; however, little is known about the mode of action of these agents in comparison to antibiotics This review considers what is known about the mode of action and spectrum of activity of antiseptics and disinfectants The widespread use of these products has prompted some speculation on the development of microbial resistance, in particular whether antibiotic resistance is induced by antiseptics or disinfectants Known mechanisms of microbial resistance (both intrinsic and acquired) to biocides are reviewed, with emphasis on the clinical implications of these reports

/pdf/antiseptics-and-disinfectants-activity-action-and-resistance-4s72yz0ujj.pdf

Antiseptics and Disinfectants: Activity, Action, and Resistance

https://oatao.univ-toulouse.fr/2771/1/joannis-cassan_2771.pdf

Commercial applications of microalgae

▪ Abstract The ability of pathogens to obtain iron from transferrins, ferritin, hemoglobin, and other iron-containing proteins of their host is central to whether they live or die. To combat invading bacteria, animals go into an iron-withholding mode and also use a protein (Nramp1) to generate reactive oxygen species in an attempt to kill the pathogens. Some invading bacteria respond by producing specific iron chelators—siderophores—that remove the iron from the host sources. Other bacteria rely on direct contact with host iron proteins, either abstracting the iron at their surface or, as with heme, taking it up into the cytoplasm. The expression of a large number of genes (>40 in some cases) is directly controlled by the prevailing intracellular concentration of Fe(II) via its complexing to a regulatory protein (the Fur protein or equivalent). In this way, the biochemistry of the bacterial cell can accommodate the challenges from the host. Agents that interfere with bacterial iron metabolism may prove ex...

Iron metabolism in pathogenic bacteria.

Fatty acid biosynthesis in microorganisms being used for Single Cell Oil production

The biochemistry and molecular biology of lipid accumulation in oleaginous microorganisms

A small number of eukaryotic micro-organisms, the oleaginous species, can accumulate triacylglycerols as cellular storage lipids, sometimes up to 70% of the biomass. Some of these lipids, particularly those containing high proportions of polyunsaturated fatty acids of nutritional and dietary importance, are now in commercial production; these are known as single-cell oils. The biochemistry of lipid accumulation has been investigated in yeasts and filamentous fungi and can now be described in some detail: lipid accumulation is triggered by cells exhausting nitrogen from the culture medium, but glucose continues to be assimilated. Activity of isocitrate dehydrogenase within the mitochondrion, however, now slows or even stops due to the diminution of AMP within the cells. This leads to the accumulation of citrate, which is transported into the cytosol and cleaved to acetyl-CoA by ATP:citrate lyase, an enzyme that does not occur in non-oleaginous species. This enzyme is therefore essential for lipid accumulation. The presence of this enzyme does not, however, explain why different species of oleaginous micro-organisms have different capacities for lipid accumulation. The extent of lipid accumulation is considered to be controlled by the activity of malic enzyme (ME), which acts as the sole source of NADPH for fatty acid synthase (FAS). If ME is inhibited, or genetically disabled, then lipid accumulation is very low. There is no general pool of NADPH which can otherwise be used by FAS. The stability of ME is therefore crucial and it is proposed that ME is physically attached to FAS as part of the lipogenic metabolon. ME activity correlates closely with lipid accumulation in two filamentous fungi, Mucor circinelloides and Mortierella alpina. When ME ceases to be active, lipid accumulation also stops. No other enzyme activity shows such a correlation.

Regulation of lipid accumulation in oleaginous micro-organisms.

Summary We review the prospects of using yeasts and microalgae as sources of cheap oils that could be used for biodiesel. We conclude that yeast oils, the cheapest of the oils producible by heterotrophic microorganisms, are too expensive to be viable alternatives to the major commodity plant oils. Algal oils are similarly unlikely to be economic; the cheapest form of cultivation is in open ponds which then requires a robust, fast-growing alga that can withstand adventitious predatory protozoa or contaminating bacteria and, at the same time, attain an oil content of at least 40% of the biomass. No such alga has yet been identified. However, we note that if the prices of the major plant oils and crude oil continue to rise in the future, as they have done over the past 12 months, then algal lipids might just become a realistic alternative within the next 10 to 15 years. Better prospects would, however, be to focus on algae as sources of polyunsaturated fatty acids.

Colin Ratledge

Papers

Iron metabolism in pathogenic bacteria.

Fatty acid biosynthesis in microorganisms being used for Single Cell Oil production

The biochemistry and molecular biology of lipid accumulation in oleaginous microorganisms

Regulation of lipid accumulation in oleaginous micro-organisms.

Microbial and algal oils: Do they have a future for biodiesel or as commodity oils?