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The gene for phytase from Escherichia coli was sequenced and compared with the appA gene. It was found to be a mutant derivative of the appA gene. After fusion with a C-terminal His-tag, phytase was purified by affinity chromatography and the enzymatic properties were analyzed. To develop a system for overexpression and extracellular production of phytase(More)
The physical and chemical properties of six crude phytase preparations were compared. Four of these enzymes (Aspergillus A, Aspergillus R, Peniophora and Aspergillus T) were produced at commercial scale for the use as feed additives while the other two (E. coli and Bacillus) were produced at laboratory scale. The encoding genes of the enzymes were from(More)
Heterologous gene products produced by Escherichia coli cells can be exported into the culture medium by the action of the kil gene of the ColE1 plasmid, which encodes a bacterial release protein. The kil gene was fused with the stationary-phase promoter of the fic gene of E. coli, and a secretion cassette (Kil-Km cassette) containing the regulated kil(More)
Cultivation conditions for the extracellular production of a hybrid β-glucanase from Bacillus were established by using Escherichiacoli JM109 carrying the plasmid pLF3. This plasmid contained a novel secretion system consisting of the kil gene (killing protein) of plasmid ColE1 under the stationary-phase promoter of either the fic or the bolA gene, an omega(More)
The extracellular production of Escherichia coli phytase was studied in fed-batch fermentations. Two different feeding strategies were compared: control by keeping the glucose concentration constant, and control by keeping a low constant oxygen level in the medium. For the feeding control based on glucose concentration, a recently developed rapid glucose(More)
By using a β-glucanase from Bacillus as a model protein, we investigated whether the secretion competence based on the action of the kil gene can be improved using stronger promoters for the expression of the kil gene. Since the production of extracellular target proteins also depends on the promoter strengths of the target gene, we constructed four(More)
We constructed a library of synthetic stationary-phase promoters for Escherichia coli. For designing the promoters, the known −10 consensus sequence, as well as the extended −10 region, and an A/T-rich region downstream of the −10 region were kept constant, whereas sequences from −37 to −14 were partially or completely randomised. For detection and(More)
To develop a rapid reporter system for the screening of stationary-phase promoters in Escherichia coli, the expression pattern of the green fluorescent protein (GFP) during bacterial cultivation was compared with that of the commonly used β-galactosidase. Using GFP with enhanced fluorescence, the expression pattern of both reporter systems GFP and(More)
Due to their induction characteristics stationary-phase promoters have a great potential in biotechnological processes for the production of heterologous proteins on a large-scale. In order to broaden the utility of stationary-phase promoters in bacterial expression systems and to create novel promoters induced by metabolic conditions, a library of(More)
Microglia, the resident macrophages of the central nervous system (CNS), can be distinguished from most other cells of the myelomonocytic lineage by a distinct pattern of membrane currents. In the accompanying paper we have shown that the characteristic morphological feature of microglia, ramification, develops both in microglia and other myelomonocytic(More)