Increased erythritol production in fed-batch cultures of Torula sp. by controlling glucose concentration

The effect of glucose concentration on erythritol production by Torula sp. was investigated. The maximum volumetric productivity of erythritol was obtained at an initial glucose concentration of 300 g l⁻¹ in batch culture. The volumetric productivity was maximal at a controlled glucose concentration of 225 g l⁻¹, reducing the lag time of the erythritol production. A fed-batch culture was established with an initial glucose concentration of 300 g l⁻¹ and with a controlled glucose concentration of 225 g l⁻¹ in medium containing phytic acid as a phosphate source. In this fed-batch culture, a final erythritol production of 192 g l⁻¹ was obtained from 400 g l⁻¹ glucose in 88 h. This corresponded to a volumetric productivity of 2.26 g l⁻¹ h⁻¹ and a 48% yield. Journal of Industrial Microbiology & Biotechnology (2001) 26, 248–252. Received 26 September 2000/ Accepted in revised form 16 January 2001     

Isotopic composition and morphology of living Globorotalia scitula: a new proxy of sub-intermediate ocean carbonate chemistry?

Abundance, isotopic composition and morphological imprints of the planktonic foraminifera Globorotalia scitula (Brady) were closely examined for possible use as a novel reconstruction tool of chemical environments in sub-intermediate depth seawater in the past. Based on the MOCNES plankton tow observation of dwelling depths of G. scitula and the isotopic compositions together with hydrochemistry data, the empirical relations between isotopic disequilibria in carbon (Δδ¹³C=δ¹³C_{G. scitula}−δ¹³C_DIC) and oxygen (Δδ¹⁸O=δ¹⁸O_{G. scitula}−δ¹⁸O_w) isotopes in the carbonate tests and the seawater δ¹⁸O and δ¹³C of dissolved inorganic carbon (DIC), respectively, are introduced. The morphological information such as pore density and porosity is also examined for significant relations to carbonate chemistry. Shell porosity is strongly correlated saturation state of calcite. The dissolution of living G. scitula tests may promote the observed isotopic differences as well as the increases in porosity. Δδ¹⁸O of G. scitula is found effectively to be linear function of both water temperature and calcite saturation state (Ω), and thereby temperature equation for G. scitula is provided, while Δδ¹³C of G. scitula is a linear function of only calcite saturation state.The equation was validated by using Globorotalia scitula collected by a sediment trap in intermediate water depths. Satisfactory agreements were found between observed and calculated Δδ¹⁸O from the empirical equations based on temperature and hydrochemistry data at sediment trap deployment site, indicating that the equation may be useful in paleo-environmental reconstruction of sub-intermediate water. The sediment trap observation further suggests that the abundance of G. scitula does not necessarily correspond to surface water productivity and to POC flux, but instead, it correlates well with the supply of fine organic matter, which appears to be a result of water convection. Thus, G. scitula may be an unambiguous and excellent paleo-environmental recorder for carbonate chemistry and for fine organic matter transport to the depths, if isotopic and morphological observations are combined.     

Variations in sexual and asexual reproduction of Scirpus mariqueter along an elevational gradient

In order to assess the importance of sexual and asexual reproduction during the life history of Scirpus mariqueter, its reproductive and growth characters were concurrently examined along an elevational gradient (from low elevation to high elevation). The proportions of flowering shoot and inflorescence mass, seed : flower ratio and seed weight were used to quantify the investment in sexual reproduction. The proportions of current-year shoot and rhizome mass were used to quantify the investment in asexual reproduction, and the proportion of corm mass was used for growth, respectively. It was found that vegetative propagation predominated at low elevation, whereas sexual reproduction predominated at high elevation; and that sexual reproduction increased with declining asexual reproduction along the gradient. The results suggest that asexual reproduction is relatively favored in the early life stage, whereas sexual reproduction is favored when the population becomes mature and aged, probably because of the functional differentiation between the two reproductive types. Sexual productive characters (i.e. the proportions of flowering shoot and inflorescence mass) were negatively correlated to both growth and asexual reproductive characters along the gradient, indicating there might exist some trade-offs among growth, sexual and asexual reproduction during the life history. However, no obvious pattern was found between asexual reproductive characters and growth characters along the elevational gradient, possibly because of the varied relationships between them at different life stages. The variations in sexual and asexual reproduction in the species and the relationship between them are thought to be of great significance for local population growth, species persistence and evolution.     

Rapid detection of cytotoxicity of food additives and contaminants by a novel cytotoxicity test, menadione-catalyzed H2O2 production assay

Menadione-catalyzed H₂O₂ production by viable animal cells was proportional to the viable cell number, and H₂O₂ production decreased with increasing cytotoxic effects after the incubation of cells with cytotoxic compounds. The cytotoxic effects of food additives, pesticides, antibiotics, heavy metals, phytotoxins, mycotoxins, and marine toxins were estimated using the above test employingNIH/3T3 and Neuro-2a cells. Synergistic effects of the toxin mixture were observed and acute cytotoxicity detected 1 h after the incubation of cells with toxins. This menadione-catalyzed H₂O₂production assay is rapid and simple compared to other popular cytotoxicity tests such as the MTT reduction assay and Neutral red inclusion test, requiring4 h. The menadione-catalyzed H₂O₂ production assay is expected to be a useful food safety test for rapidly detecting toxic compounds having a basic cytotoxic effect on common animal cells. This revised version was published online in August 2006 with corrections to the Cover Date.     

Inventory for energy production in Canada

Publicly available databases are analysed to demonstrate their relevance to life cycle inventory for energy production in the Canadian context. Site specific emissions along with sectoral emissions data are combined with production data to construct an energy production model, which has been applied to air emissions. The allocation procedure leads to reasonable results for coal, natural gas and electricity. The detailed allocation of the inventory among petroleum co-products is outside the scope of this study as it requires incorporating knowledge of physical relationship (unit process) or using economic data.     

Mutation of Aspergillus niger for hyperproduction of citric acid from black strap molasses

Spore suspensions of Aspergillus niger GCB 75, which produced 31.1 g/l citric acid from 15% sugars in molasses, were subjected to u.v.-induced mutagenesis. Among three variants, GCM 45 was found to be the best citric acid producer and was further improved by chemical mutagenesis using NTG. Out of 3 deoxy-D-glucose-resistant variants, GCM 7 was selected as the best mutant which produced 86.1 ± 1.5 g/l citric acid after 168 h of fermentation of potassium ferricyanide + H₂SO₄-pretreated black strap molasses (containing 150 g sugars/l) in Vogel's medium. On the basis of comparison of kinetic parameters, namely the volumetric substrate uptake rate (Q _s), and specific substrate uptake rate (q _s), the volumetric productivity, theoretical yield and specific product formation rate, it was observed that the mutants were faster growing organisms and had the ability to overproduce citric acid.     

Lipase production by Aeromonas sobria LP004 in a medium containing whey and soybean meal

World Journal of Microbiology and Biotechnology -     

Expression of the vesicular stomatitis virus membrane glycoprotein gene in Bacillus subtilis

Abstract The molecularly cloned gene encoding the vesicular stomatitis virus (VSV) membrane glycoprotein G was modified and joined to a Bacillus subtilis secretion vector constructed from the plasmid pUB110 and containing the promoter and signal sequence regions of the α-amylase (a secretory protein) gene from Bacillus amyloliquefaciens . The regions encoding the NH₂-terminal signal peptide and the COOH-terminal hydrophobic transmembrane domains of the VSV gene were deleted to facilitate the secretion of the G protein in soluble form. The truncated G protein was found to be expressed in B. subtilis . The expression level was low, probably due to rapid proteolytic degradation of the protein and, contrary to what was expected, almost all of the protein remained cell-associated.     

Stimulation of glucose utilization and lactate production in cultured human fibroblasts by thyroid hormone

Human dermal fibroblasts were obtained by harvesting outgrowing cells from the dermal tissue explants and cultured in Dulbecco's modified Eagle medium containing 10% fetal calf serum. After the cells reached confluency, culture was continued in the medium containing calf serum which was deprived of thyroid hormone by the treatment with activated charcoal. These fibroblasts were responsive to exogeneously added thyroid hormone (triiodothyronine) at physiological concentrations, resulting in enhanced utilization of glucose and production of lactate. This stimulation by thyroid hormone was dependent upon the length of exposure to the hormone and its concentration.The hormone did not show any effects on cellular DNA and protein content. The experimental system described above seems to be easy to reconstitute and should be useful for the elucidation of the mechanism of thyroid hormone action.     

The most important bacterial diseases of glasshouse tomato in Russia

Studies of glasshouse tomato bacterial diseases agents complex have been conducted in some regions of Russia in 1987–1996. Microbiological analysis of seeds and plants of local and foreign selection made it possible to assess quality of the seed material and phytosanitary condition of tomato plants. It's very important to obtain and to cultivate healthy seed material of high quality. This is one of the main conditions of preventing epiphytoty and obtaining ecologically pure agricultiral products.