Sheep anti Human Thrombin polyclonal antibody

In this study, we purified and characterized exopoly-saccharide (EPS) produced by a high-EPS-producing dairy starter bacterium, Streptococcus thermophilus ASCC 1275. Crude EPS was extracted from S. ther-mophilus ASCC 1275 and partially purified using dialy-sis. Further purification and fractionation of exopoly-saccharide was conducted using HPLC on a Superose 6 column (Cytiva/Global Life Sciences Solutions, Marl-borough, MA). Glycosyl composition analysis, linkage analysis along with 1-dimensional and 2-dimensional nuclear magnetic resonance spectroscopy were per-formed to deduce the structure of EPS. Three fractions (F) obtained from gel permeation chromatography were termed F1 (2.6%), F2 (45.8%), and F3 (51.6%) with average molecular weights of approximately 511, 40, and 5 kDa, respectively. Monosaccharide composi-tion analysis revealed the dominance of glucose, galac-tose, and mannose in all 3 fractions. Major linkages observed in F3 were terminal galactopyranosyl (t-Gal), 3-linked glucopyranosyl (3-Glc), 3-linked galactofu-ranosyl (3-Galf), and 3,6-linked glucopyranosyl (3,6-Glc) and major linkages present in F2 were 4-Glc (48 mol%), followed by terminal mannopyranosyl (t-Man), 2-+ 3-linked mannopyranosyl (2-Man+3-Man), and 2,6-linked mannopyranosyl (2,6-Man; total similar to 28 mol%). The 1-dimensional and 2-dimensional nuclear magnetic resonance spectroscopy revealed that F2 comprised mannans linked by (1 -> 2) linkages and F3 consisted of linear chains of alpha-D-glucopyranosyl (alpha-D-Glc p ), beta-D-glucopyranosyl (beta-D-Glcp), and beta-D-galactofuranosyl (beta-D-Galf) connected by (1 -> 3) linkages; branching was through (1 -> 6) linkage in F3. A possible structure of EPS in F2 and F3 was proposed.

In the present study, the marine microalga Tisochrysis lutea was cultivated mixotrophically in F2 growth medium with sodium acetate as exogenous carbon source. The medium was composed of different concentrations of nitrogen to determine the impact of nitrogen depletion on cellular growth and chemical composition. Nitrogen depletion led to severely decreased growth and protein content. However, mild nitrogen depletion (0.22 mM NaNO3) led to maximum lipid yield. The fatty acid methyl ester profile also showed increased unsaturation as the nitrogen content decreased. Growth in nitrogen-free medium increased the proportions of mono- and poly-unsaturated fatty acids, while the proportion of saturated fatty acids decreased. Growth under all tested nitrogen levels showed undetectable fatty acids with >= 4 double bonds, indicating these fatty acids had oxidative stability. In addition, all tested nitrogen concentrations led to specific gravity, kinematic viscosity, iodine value, and cetane number that meet the standards for Europe and the U.S.A. However, growth in the presence of nitrogen deficiency enhanced the higher heating value of the resulting biodiesel, a clear advantage from the perspective of energy efficiency. Thus, mixotrophic cultivation of T. lutea with nitrogen limitation provides a promising approach to achieve high lipid productivity and production of high-quality biodiesel.