Fuels and industrial chemicals through biotechnology. 2

An overview of research on the biotechnical production of fuels and industrial chemicals during the two-year period of 1983-1984 is presented. Ethanol fermentation has continued to be the subject of major interest. A considerable amount of work has been directed to alternative feedstocks such as pentose sugars and lactose, and to bacterial fermentations. Reports on extrusion cooking as a continuous pretreatment method for subsequent ethanol fermentation, and on novel alternative downstream processing techniques have been published. In addition to ethanol fermentation, much attention has been paid to the biotechnical production of 2,3-butanediol, and of a number of organic and amino acids. In general, there appears to be a growing interest in the application of biocatalysis for the production of specialty chemicals, although only a few examples will be discussed in this paper. The construction of a demonstration plant to produce ethanol from molasses by a two 10 kL bed-volume immobilized yeast bioreactors at the Kyowa Hakko Kogyo Company Hofu plant, the announcement by Nitto Chemical Industries Company to begin the biotechnical production of acrylamide, and the French decision to construct pilot plants for the biotechnical production of acetone-butanol-ethanol cosolvent and of ethanol from renewable resources represent major scale-up developments.     

Fuels and industrial chemicals

The favorite subject of recent literature on biotechnical processes has been ethanol fermentation. This review covers a number of new technics developed, including immobilized biocatalyst technology and bacterial fermentations. Reference is also made to recent work on whey, starch, inulin, and cellulosic materials as substrates for ethanol production. Renewed interest in acetonebutanol fermentation for solvent and liquid fuel production has also been clearly evident during the last two years. Biotechnical production of organic acids has been considered as an alternative route to chemical feedstocks. New developments in amino acid, methane, hydrogen, and hydrocarbon production, and on hydrocarbon oxidation are also briefly covered.     

Mortality of workers at the Sellafield plant of British Nuclear Fuels.

The mortality of all 14,327 people who were known to have been employed at the Sellafield plant of British Nuclear Fuels at any time between the opening of the site in 1947 and 31 December 1975 was studied up to the end of 1983. The vital state of 96% of the workers was traced satisfactorily and 2277 were found to have died, 572 (25%) from cancer. On average the workers suffered a mortality from all causes that was 2% less than that of the general population of England and Wales and 9% less than that of the population of Cumberland (the area in which the plant is sited). Their mortality from cancers of all kinds was 5% less than that of England and Wales and 3% less than that of Cumberland. In the five years after their first employment Sellafield workers had an overall mortality that was 70% of that of England and Wales, probably due to healthier members of the population being selected for employment. Raised death rates from cancers of several specific sites were found, but only for those of ill defined and secondary sites was the excess statistically significant (30 observed, 19.7 expected). For cancers of the liver and gall bladder there was a significant deficit of deaths (four observed, 10.5 expected). Workers in areas of the plant where radiation exposure was likely were issued with dosimeters to measure their external exposure to ionising radiations. Personal dose records were maintained for workers who entered such areas other than infrequently. Workers with personal dose records ("radiation" workers) had lower death rates from all causes combined than other workers but the death rates from cancer in the two groups were similar. Compared with the general population radiation workers had statistically significant deficits of liver and gall bladder cancer, lung cancer, and Hodgkin''s disease. There were excesses of deaths from myeloma (seven observed, 4.2 expected) and prostatic cancer (19 observed, 15.8 expected) but these were not significant and there was no evidence of an excess of leukaemia (10 deaths observed, 12.2 expected) or cancer of the pancreas (15 observed, 17.8 expected). Non-radiation workers had a significant deficit of leukaemia (one death observed, 5.1 expected) and a significant excess of cancers of ill defined and secondary sites (13 deaths observed, 5.8 expected). For no type of cancer was the ratio of observed to expected deaths significantly different between radiation and non-radiation workers.(ABSTRACT TRUNCATED AT 400 WORDS)     

Fuels and landscape flammability in an Australian alpine environment

Factors governing landscape‐scale flammability are poorly understood, yet critical to managing fire regimes. Studies of the extent and severity of the 2003 Australian alpine fires revealed marked differences in flammability between major alpine plant communities, with the occurrence and severity of fire greater in heathland compared to grassland. To understand this spatial variation in landscape flammability, we documented variation in two physical properties of fuel – load and bulk density – at the life‐form and plant community scale. We measured the load (mass per unit area) and bulk density (mass per unit volume) of fine fuels (<6 mm) at 56 sites across the Bogong High Plains, southeastern Australia. Fine fuel load was positively correlated with shrub cover, and fine fuel bulk density was negatively correlated with shrub cover. Furthermore, fine fuel load and bulk density were accurately predicted using simple measures of canopy height and shrub cover. We also conducted a burning experiment on individual shrubs and snowgrass (Poa spp.) patches to assess comparative differences in flammability between these life‐forms. The burning experiment revealed that shrubs were more flammable than snowgrass as measured by a range of flammability variables. Consequently, our results indicate that treeless alpine landscapes of southeastern Australia are differentially flammable because of inherent life‐form differences in both fine fuel load and bulk density. If shrub cover increases in these alpine landscapes, as projected under climate change, then they are likely to become more flammable and may experience more frequent and/or severe fires.     

Viability of Selected Microorganisms in Hydrocarbon Fuels

A laboratory study of the viability of selected microorganisms in a hydrocarbon fuel medium was carried out on 19 species of microorganisms, representative of the types found as natural contaminants in aircraft fuels. More species remained viable when inoculated in pure cultures than when inoculated in mixed (composite) cultures. Of the 19 species selected, 10 were still viable after 3 months and 5 were viable after 4 months in the pure culture inoculants. In the complete composite culture inoculant, the bacterial species which were viable at the end of 4 months were the same as those found in the pure culture inoculant. No fungi remained viable in the complete composite cultures after a 3-week period. The microorganisms which remain viable in a hydrocarbon fuel medium are considered indicative of a satisfactory inoculum to be used as a test culture in laboratory analysis of mechanical control techniques.     

Inflammation Fuels Colicin Ib-Dependent Competition of Salmonella Serovar Typhimurium and E. coli in Enterobacterial Blooms

The host''s immune system plays a key role in modulating growth of pathogens and the intestinal microbiota in the gut. In particular, inflammatory bowel disorders and pathogen infections induce shifts of the resident commensal microbiota which can result in overgrowth of Enterobacteriaceae (“inflammation-inflicted blooms”). Here, we investigated competition of the human pathogenic Salmonella enterica serovar Typhimurium strain SL1344 (S. Tm) and commensal E. coli in inflammation-inflicted blooms. S. Tm produces colicin Ib (ColIb), which is a narrow-spectrum protein toxin active against related Enterobacteriaceae. Production of ColIb conferred a competitive advantage to S. Tm over sensitive E. coli strains in the inflamed gut. In contrast, an avirulent S. Tm mutant strain defective in triggering gut inflammation did not benefit from ColIb. Expression of ColIb (cib) is regulated by iron limitation and the SOS response. CirA, the cognate outer membrane receptor of ColIb on colicin-sensitive E. coli, is induced upon iron limitation. We demonstrate that growth in inflammation-induced blooms favours expression of both S. Tm ColIb and the receptor CirA, thereby fuelling ColIb dependent competition of S. Tm and commensal E. coli in the gut. In conclusion, this study uncovers a so-far unappreciated role of inflammation-inflicted blooms as an environment favouring ColIb-dependent competition of pathogenic and commensal representatives of the Enterobacteriaceae family.     

化石燃料生物脱有机氮研究展望

化石燃料中与有机硫相似的另一类孤对电子含氮有机化合物的存在对生产和环境造成许多危害。石油中的含氮有机化合物是影响炼油工艺、产品性能质量的主要因素。含氮有机化合物具有致癌、致突变性 ,燃烧后则以NOx的形式释放污染大气。化石燃料中所含的有机氮较有机硫更难以去除 ,常规的化学脱有机氮技术高压加氢法处理燃油能耗高 ,处理效果不理想等方面的缺陷使人们思考生物脱氮的可能性。考察了国内外近十多年来化石燃料生物脱有机氮工作的研究进展 ,包括模式有机氮化合物微生物的代谢途径 ,以及相应的代谢途径中的关键酶及其编码基因等方面的研究。     

Fuels for flight in Locusta

In Locusta migratoria, carbohydrate is the predominant energy source for the first 20 to 30 min of flight. During this time carbohydrate is utilized at the rate of 120 μg/min, but thereafter it is used at only 8 to 9 per cent of the initial rate. Initially carbohydrate is not mobilized to any extent from body stores. Lipid, however, is mobilized (from stores in the fat body) in response to adipokinetic hormone released from the glandular lobes of the corpora cardiaca. The mobilized lipid is diglyceride, and 16 : 18 and 18 : 18 diglycerides predominate. The rate of diglyceride mobilization is rapid, both during flight and in response to extracts of corpora cardiaca. The release of adipokinetic hormone during flight has also been estimated and is found to be more rapid than previously suggested. It is calculated that the rate of lipid utilization increases during flight from virtually zero during the first few minutes to 35 μg/min (15 to 30 min) and finally reaches about 85 μg/min during the second 30 min of flight.     

Biomass Cooking Fuels and Health Outcomes for Women in Malawi

We provide an overview of terrestrial animal translocations carried out for conservation purposes in Britain, summarising what has been achieved in recent decades and discussing the issues raised by this approach to conservation. In the last 40 years, at least nine species have been reintroduced following extinction in Britain (or at least one country within Britain), including five birds, one mammal, one amphibian and two invertebrates. Many more species have been translocated within Britain to establish additional populations in order to improve conservation status. We discuss the guidelines and protocols used to assess translocation projects in Britain, notably the IUCN guidelines, most recently revised in 2013. We also discuss the likely use of species translocations in future and suggest that, in our increasingly fragmented landscapes, they will have an important role to play in conservation restoration, especially for animals with limited mobility. Moving species around is a complex undertaking and our understanding of the inherent risks involved, including the risks from disease, has improved significantly in recent years. Conservation translocations should be considered in the context of species recovery targets and high standards should be maintained so that disease risks and other potentially negative impacts are minimised.     

Substrate Preferences in Biodesulfurization of Diesel Range Fuels by Rhodococcus sp. Strain ECRD-1

The range of sulfur compounds in fuel oil and the substrate range and preference of the biocatalytic system determine the maximum extent to which sulfur can be removed by biodesulfurization. We show that the biodesulfurization apparatus in Rhodococcus sp. strain ECRD-1 is able to attack all isomers of dibenzothiophene including those with at least four pendant carbons, with a slight preference for those substituted in the α-position. With somewhat less avidity, this apparatus is also able to attack substituted benzothiophenes with between two and seven pendant carbons. Some compounds containing sulfidic sulfur are also susceptible to desulfurization, although we have not yet been able to determine their molecular identities.     

Biocidal Properties of Anti-Icing Additives for Aircraft Fuels

The biocidal and biostatic activities of seven glycol monoalkyl ether compounds were evaluated as part of an effort to find an improved anti-icing additive for jet aircraft fuel. Typical fuel contaminants, Cladosporium resinae, Gliomastix sp., Candida sp., Pseudomonas aeruginosa, and a mixed culture containing sulfate-reducing bacteria were used as assay organisms. Studies were carried out over 3 to 4 months in two-phase systems containing jet fuel and aqueous media. Diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, and 2-methoxyethanol were generally biocidal in aqueous concentrations of 10 to 17% for all organisms except Gliomastix, which required 25% or more. 2-Ethoxyethanol, 2-propoxyethanol, and 2-butoxyethanol were biocidal at progressively lower concentrations down to 1 to 2% for 2-butoxyethanol. The enhanced antimicrobial activity of these three compounds was attributed to cytoplasmic membrane damage because of the correlation between surface tension measurements and lytic activity with P. aeruginosa cells. The mechanism of action of the less active compounds appeared to be due to osmotic (dehydrating) effects. When all requirements are taken into account, diethylene glycol monomethyl ether appears to be the most promising replacement for the currently used additive, 2-methoxyethanol.     

Carbon and ammonia metabolism of Spirillum lipoferum.

Intact cells and extracts from Spirillum lipoferum rapidly oxidized malate, succinate, lactate, and pyruvate. Glucose, galactose, fructose, acetate, and citrate did not increase the rate of O2 uptake by cells above the endogenous rate. Cells grown on NH+/4 oxidized the various substrates at about the same rate as did cells grown on N2. Added oxidized nicotinamide adenine dinucleotide generally enhanced O2 uptake by extracts supplied organic acids, whereas oxidized nicotinamide adenine dinucleotide phosphate had little effect. Nitrogenase synthesis repressed by growth of cells in the presence of NH+/4 was derepressed by methionine sulfoximine or methionine sulfone. The total glutamine synthetase activity from N2-grown cells was about eight times that from NH+/4-grown S. lipoferum; the response of glutamate dehydrogenase was the opposite. The total glutamate synthetase activity from N2-grown S. lipoferum was 1.4 to 2.6 times that from NH+/4-grown cells. The levels of poly-beta-hydroxybutyrate and beta-hydroxybutyrate dehydrogenase were elevated in cells grown on N2 as compared with those grown on NH+/4. Cell-free extracts capable of reducing C2H2 have been prepared; both Mg2+ and Mn2+ are required for good activity.