Development of a fermentation procedure to produce a tempe-related food using common beans as substrate

Summary A basic procedure was developed to produce a tempe-like product using the mouldRhizopus oligosporus and black common beans (Phaseolus vulgaris) as substrate. The initial pH of the substrate was 5.8, and fermentation was conducted at 37°C with a relative humidity of 70% for 72 hrs. Levels of soluble solids and soluble protein increased dramatically as a result of fermentation. Some changes were as well observed in fatty acid contents of fermented samples. It was concluded that the common bean used was an acceptable substrate for preparing this product.     

Purification of the parasporal crystals ofBacillus thuringiensis subsp.israelensis and development of a novel bioassay technique

Summary A spore-free parasporal crystal suspension was prepared fromBacillus thuringiensis subsp.israelensis by an aqueous biphasic separation technique and the waste fractions quantified with regard to spore numbers and insecticidal potencies. The technique proved efficient in selectively removing spores from the spore-crystal mixture. The final crystal suspension was used to develop a novel bioassay system which allowed rapid determination of crystal effectiveness in 1/8 to 1/6 of the time required in the conventional mortality versus concentration bioassay.     

Studies on the simultaneous production of single cell protein and polygalacturonase fromKluyveromyces fragilis

Summary Kluyveromyces fragilis produces polygalacturonase (PG) on a lactose medium. Although the enzyme is normally repressed at high aeration levels, significant amounts of PG can be produced under such conditions when pectin is added as inducer. The productivity and yield of cell mass were not significantly affected by the presence of inducer, suggesting potential applications to current single cell protein processes from whey.     

Effect of temperature and long-term operation on passively immobilizedZymomonas mobilis for continuous ethanol production

Summary A fibrous support was used forZ. mobilis immobilization. The system showed a broad optimum temperature range (25–35°C) for highest ethanol productivity, ethanol yield and glucose conversion during continuous fermentation of a 100 g/L glucose medium. Ethanol production and glucose conversion kept steady during two months of continuous operation at D=1h^–1.     

Immobilization and nonspecific adsorption of proteins to pyrogeneous highly dispersed silicon dioxide

Summary A support based on pyrogeneous silicon dioxide of particle size 0.01 to 0.1/um, modified by 3-(amino)propyltriethoxysilane and activated by glutaraldehyde was employed for the immobilization of concanavalin A, immunoglobulins, basic pancreatic trypsin inhibitor, and chymotrypsin. Its binding capacity is comparable with that of porous supports while the biological activity of the proteins immobilized is retained. Nonspecific adsorption of these proteins to the support is low compared to its binding capacity.     

Effect of high concentration of nutrients onBacillus thuringiensis cultures

Summary Bacterial insecticide production using a strain ofBacillus thuringiensis var. kurstaki was studied in batch culture considering the influence of increasing concentration of components of a glucose — yeast extract — mineral salts medium.It was found that spore counts were increased from 1.08×10¹² spores. 1^–1 to 7.36×10¹² spores. 1^–1 and toxin level from 1.05 mg.ml^–1 to 6.85 mg.ml^–1, when the concentration of glucose was increased from 8 to 56 (g 1^–1), with the corresponding increase in the rest of medium components. Higher concentration of nutrients inhibit either spore count or toxin production.Preliminary experiments of fed-batch cultures which allows the use of high amounts of nutrients were also carried out. In this case spore counts of 1.2×10¹³ spores.1^–1 were achieved.     

Functionally important lysine residues in inorganic pyrophosphatase from E. coli. I. Interaction of inorganic pyrophosphatase with pyridoxal-5'-phosphate

Interaction of inorganic pyrophosphatase from E. coli with pyridoxal-5'-phosphate includes binding of the reagent at the active site through the phosphate group and then a reversible modification of one lysine residue in each of the enzyme's subunit. In the equilibrium state the protein's molecules contain both inactive modified and native subunits. A stable secondary amine is formed upon the sodium borohydride reduction of the modified protein.     

Trypsin catalyzed hydrolysis of new chromogenic arginine substrates

Trypsin catalyzed hydrolysis of seven new chromogenic arginine substrates, N alpha-benzyloxycarbonyl-L-arginine-3-nitro-5X-anilide (X = H, CF3, SO2CH3, F, Cl, Br and I) were studied. These substrates are suitable for studying electronic effects on trypsin activity. The Km and kcat values for the hydrolysis of each substrate were determined and found to differ significantly for the various substrates. The Hammett plot of the catalytic rate constants gave a straight line with a negative rho value (-0.82) thus indicating that electron withdrawing substituents retard the trypsin catalyzed hydrolysis of the new anilide substrates.     

A simple unconstrained dynamic knee simulator

The design of a simple dynamic knee simulator is described. In the simulator the joint dynamics are reproduced in-vitro in a knee specimen by controlling the time-histories of the tensions in two flexible cables acting as lumped muscle group equivalents, without constraining the natural conjunct and passive motions of the specimen. The two cable tensions acting individually are used to control the active flexion/extension motion, while their simultaneous action is used to control joint compressive force. The characteristics of the electrohydraulic servo system acting under real-time microprocessor control are described. The system performance during simulation of an idealized level-walking function is evaluated.     

Studies of formation of bivalent copper complexes with native and denatured DNA

The formation of Cu2+ complexes with native and denatured DNA is studied by the methods of differential UV spectroscopy, CD spectroscopy, and viscometry. On ion binding to the bases of native DNA the latter transforms into a new conformation. This transition is accompanied with a sharp increase in UV absorption and a decrease in the intrinsic viscosity though the high degree of helicity persists. Possible sites of Cu2+ ion binding on DNA of various conformations are found along with corresponding constants of complex formation.