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To identify optimal hydrogen production conditions using growing cultures of Rhodobacter sphaeroides DSM 158 the effects of varying the reactor’s volumetric power input (0.01–1.4 kW m −3 ) and irradiation intensity (5–2500 W m −2 ) were investigated in batch and continuous production modes. Irradiation intensity had a greater effect on hydrogen production than volumetric power input. Hydrogen production and photofermentative biomass formation were maximized by irradiation at 2250 W m −2 with a volumetric power input of 0.55 kW m −3 . The bacterial dry weight (2.64 g L −1 ) and rate of hydrogen production (195 mL L −1 h −1 ) achieved under these conditions were greater than any that have previously been reported for batch-mode hydrogen production by R. sphaeroides . Continuous mode experiments ( D = 0.1 h −1 ) yielded a bacterial dry weight, hydrogen production rate, productivity and hydrogen yield of 2.35 ± 0.18 g L −1 , 165 ± 6.2 mL L −1 h −1 , 3.96 L L −1 d −1 and 36.6%, respectively.

Some Lactobacillus delbrueckii ssp. bulgaricus strains are able to synthesize exopolysaccharides (EPS) and are therefore highly important for the dairy industry as starter cultures. The aim of this study was to investigate the nutritional requirements for growth and EPS production of Lactobacillus delbrueckii ssp. bulgaricus DSM 20081. A medium was developed from a semi-defined medium (SDM) in which glucose was replaced by lactose and different combinations of supplements (nucleobases, vitamins, salts, sodium formate and orotic acid) were added. Constant pH batch fermentation with the modified medium resulted in an EPS yield of approximately 210 mg glucose equivalents per liter medium. This was a 10-fold increase over flask cultivation of this strain in SDM. Although not affecting cell growth, the mixture of salts enhanced the EPS synthesis. Whereas EPS production was approximately 12 mg/g dry biomass without salt supplementation, a significantly higher yield (approximately 20 mg/g dry biomass) was observed after adding the salt mixture. In continuous fermentation, a maximal EPS concentration was obtained at a dilution rate of 0.3 1/h (80 mg EPS/L), which corresponded to a specific EPS production of 49 mg/g dry biomass. © 2011, The Society for Biotechnology, Japan. All rights reserved.

Calli, shoot-clumps and regenerated plants were initiated from young fruits of Pancratium maritimum L. Their genetic stability was monitored by flow cytometry before chemical studies. Apolar metabolites (alkaloids extracted at pH > 7, free fatty acids and fatty alcohols, sterols etc.) were qualitatively and quantitatively analyzed by GC-MS. The results clearly demonstrated that alkaloid synthesis in P. maritimum is closely related with tissue differentiation. The highest amounts of alkaloids and presence of homolycorine and tazettine type compounds (end products of the biosynthetic pathway of the Amaryllidaceae alkaloids) were found in highly differentiated tissues. Galanthamine accumulated in the leaves of plantlets. The amount of hordenine, a protoalkaloid, is related with the ability of tissues to synthesize alkaloids. Saturated fatty acids were found in considerably higher levels in undifferentiated callus cultures and partially differentiated shoot-clumps than in regenerated plants. Mono- and dienoic fatty acids were found at higher levels in non-photosynthesizing tissues - calli, and in vitro and intact bulbs, while α-linolenic acid (trienoic acid) was found in higher amounts in the photosynthesizing leaves of shoot-clumps and regenerated plants than in bulbs and calli. Fatty alcohols were found mainly in leaves, while sterols tended to accumulate in photosynthesizing and undifferentiated tissues.

A laboratory-scale microbubble dispersion (MBD) generator was shown to improve oxygen transfer to aerobic microorganisms when connected to a conventional air sparger. However, this process setup had not been tested with fungi, where the morphology of microorganisms causes a very viscous broth rheology that impedes the oxygen mass transfer. Trichoderma reesei RUT C30 was chosen as a model fungus as it shows both the challenging rheology and a cellulase enzyme complex product that is shear-sensitive. Conventional and MBD sparged fermentations where carried out to compare the effect of aeration methods on oxygen transfer and product formation. MBD sparged fermentations showed fivefold higher kLa values and nearly twofold higher cell mass productivities. The cellulase enzyme activities were similar for both the MBD and the conventional sparged fermenters.

Objectives: A new lithotriptor for intracorporeal lithotripsy was developed combining the two most effective lithotriptors. A combination of the mechanically driven Lithoclast Master and a new ultrasonic device was constructed. Efficacy was tested in standardized model stones and in patient treatment. Material: The new lithotriptor is composed of a Lithoclast Master and an ultrasonic device (EMS, Nyon, Switzerland). The 1.0 mm Lithoclast probe is advanced off-center through the hollow 3.3 mm ultrasonic probe and protrudes about 1 mm. Five different artificial stones of defined hardness and density were used as model stones for disintegration. Time until first fragmentation and complete fragmentation (particles smaller than 2.2 mm to fit through the ultrasonic probe), percent disintegration after 1 min and time until 50% disintegration were determined for the new device as well as lithoclast and ultrasound alone. A total of 68 patients were treated by percutaneous nephrolitholapaxy (PNL) with the new device from February 1999 to August 2001. Lithotripsy was performed after fluoroscopically guided puncture of the lower calix and dilatation of the nephrostomy tract with coaxial bougies. Thirty-five patients had complete and 33 patients partial staghorn calculi. Results: First fragmentation was reached 25–200 times faster with the combination as with either mode alone. Disintegrated stone mass after 1 min was 1.5–4 times larger in combined lithotripsy and 50% disintegration time 30–50% shorter. Clinically, complete stone free rate (KUB and ultrasound) was 66% after the first PNL. Sixteen out of 68 patients had a second look PNL with an overall stone free rate of 89.7% by dismission. Stone composition was calcium-oxalate–monohydrate in 13%, Ca-ox–monohydrate/uric acid in 35%, apatite in 20% and cystine in 11%. Conclusion: In in vitro experiments and clinically the new lithotriptor provides easy handling and high effectivity in fragmentation of all stones regardless of their composition.

Three often cited systems for the extraction of plant nuclei for flow cytometric measurement (CyStain PI, Partec GmbH, Münster, Germany, the method of Arumuganathan and Earle, and LB01 buffer) failed, when applied to the hairy roots of red beet (Beta vulgaris). By combining these systems and introducing a centrifugation step, the extraction, staining, and analysis of nuclei from this tissue were performed successfully.