Production of gallic acid from tara tannin by bacterial strains

Summary Bacterial strains identified as Klebsiella pneumonia and Corynebacterium sp. degraded in few hours a great part of pure tara (Caesalpinia spinosa) tannin or crude water extract of tara pods powder. Large amounts of gallic acid were recovered during some experiments reaching 55 % of the theoretical yield in the best case. The feasibility of gallic acid production by a biotechnological process is discussed.     

Characteristics of a novel high viscosity polysaccharide,methylan, produced byMethylobacterium organophilum

Summary A new anionic high molecular weight polysaccharide, Methylan, was produced byMethylobacterium organophilum from methanol as a sole source of carbon and energy under the specific culture conditions. By GPC and light scattering, the molecular weight was determined to be 2–4×10⁶ dalton and the distribution of molecular weight was very homogeneous. Methylan was composed of carbohydrate (80%), uronic acid (12%), protein (6%) and pyruvic acid (5%). The sugar composition of Methylan was identified as glucose, galactose and mannose with the approximate molar ratio of 232. Methylan solution showed a pseudoplastic non-Newtonian fluid property at the concentration above 0.05%. At the concentration of 1% Methylan solution, the consistency index was 18,000 centipoise which was almost 10 times higher than that of Xanthan and the flow behavior index was 0.15.     

Phylogeny of Greya (Lepidoptera: Prodoxidae), based on nucleotide sequence variation in mitochondrial cytochrome oxidase I and II: congruence with morphological data

The phylogeny of Greya Busck (Lepidoptera: Prodoxidae) was inferred from nucleotide sequence variation across a 765-bp region in the cytochrome oxidase I and II genes of the mitochondrial genome. Most parsimonious relationships of 25 haplotypes from 16 Greya species and two outgroup genera (Tetragma and Prodoxus) showed substantial congruence with the species relationships indicated by morphological variation. Differences between mitochondrial and morphological trees were found primarily in the positions of two species, G. variabilis and G. pectinifera, and in the branching order of the three major species groups in the genus. Conflicts between the data sets were examined by comparing levels of homoplasy in characters supporting alternative hypotheses. The phylogeny of Greya species suggests that host-plant association at the family level and larval feeding mode are conservative characters. Transition/transversion ratios estimated by reconstruction of nucleotide substitutions on the phylogeny had a range of 2.0-9.3, when different subsets of the phylogeny were used. The decline of this ratio with the increase in maximum sequence divergence among taxa indicates that transitions are masked by transversions along deeper internodes or long branches of the phylogeny. Among transitions, substitutions of A-->G and T-->C outnumbered their reciprocal substitutions by 2-6 times, presumably because of the approximately 4:1 (77%) A+T-bias in nucleotide base composition. Of all transversions, 73%-80% were A<-->T substitutions, 85% of which occurred at third positions of codons; these estimates did not decrease with an increase in maximum sequence divergence of taxa included in the analysis. The high frequency of A<-->T substitutions is either a reflection or an explanation of the 92% A+T bias at third codon positions.      

Influence of water activity on Streptococcus diacetylactis metabolism

During the cheese-making process, water activity (a_w) is one of the essential environmental parameters acting on bacterial growth and metabolic pathways. The influence of a_w on Streptococcus diacetylactis growth and lactic acid production was studied. The specific growth rate was linearly related to water availability in the milk medium. The cell behaviour was quite different above and below a_w=0.95, which can be considered a limiting value. Below this value, the lactic acid production reached 1.4–6.1 mg·g^–1, whereas the specific productivity was 2.0–2.6 mg·10^–10 cells·h^–1. Changes in the consumption of lactose and amino acids during the different growth phases was completely modified by decreasing the water availability in the medium. Correspondence to: N. Cochet     

Protein production from whey usingPenicillium cyclopium; growth parameters and cellular composition

Summary The growth parameters ofPenicillium cyclopium have been evaluated in a continuous culture system for the production of fungal protein from whey. Dilution rates varied from 0.05 to 0.20 h^–1 under constant conditions of temperature (28°C) and pH (3.5). The saturation coefficients in the Monod equation were 0.74 g l^–1 for lactose and 0.14 mg l^–1 for oxygen, respectively. For a wide range of dilution rates, the yield was 0.68 g g^–1 biomass per lactose and the maintenance coefficient 0.005 g g^–1 h^–1 lactose per biomass, respectively. The maximum biomass productivity achieved was 2 g l^–1 h^–1 biomass at dilution rates of 0.16–0.17 h^–1 with a lactose concentration of 20 g l^–1 in the feed. The crude protein and total nucleic acid contents increased with a dilution rate, crude protein content varied from 43% to 54% and total nucleic acids from 6 to 9% in the range of dilution rates from 0.05 to 0.2 h^–1, while the Lowry protein content was almost constant at approximately 37.5% of dry matter.Nomenclature (mg l^–1) C_o initial concentration of dissolved oxygen - (h^–1) D dilution rate - (mg l^–1) K₀₂ saturation coefficient for oxygen - (g l^–1) K_s saturation coefficient for substrate - (g g^–1 h^–1) lactose per biomass) m maintenance energy coefficient - (mM g^–1 h^–1O₂ per biomass) Q₀₂ specific oxygen uptake rate - (g l^–1) S residual substrate concentration at steady state - (g l^–1) S_o initial substrate concentration in feed - (min) t_1/2 time when C_o is equal to C_o/2 - (g l^–1) X biomass concentration - (g l^–1) X biomass concentration at steady state - (g g^–1 biomass per lactose) Y_G yield coefficient for cell growth - (g g^–1 biomass per lactose) Y_x/s overall yield coefficient - (h^–1) specific growth rate