Enhanced alkaline protease production in addition to alpha-amylase via constructing a Bacillus subtilis strain

Bacillus subtilis Bios11 strain was previously isolated and identified. This strain naturally produces a high level of alpha-amylase. The multicopy (pS1) plasmid that carries the complete alkaline protease aprA gene was introduced to this host strain by transformation. The newly constructed strain was found to express the aprA gene and produces a high level of alkaline protease. The level of alpha-amylase production was not affected compared with the parent strain. The pS1 plasmid in the new host was proved to be segregationally and structurally stable, and the multicopy aprA gene was expressed at the stationary phase. This expression did not affect growth rate and sporulation frequency. Moreover, the level of alpha-amylase was maintained. Both alkaline protease and alpha-amylase enzymes were purified using a single-step affinity chromatography column. The use of the newly constructed strain would be valuable to the enzyme industry and would promote recycling of some food-processing wastes.

Isolation, identification, and keratinolytic activity of several feather-degrading bacterial isolates

Several feather-degrading bacterial isolates were isolated from Egyptian soil. These isolates were able to degrade chicken feather, when grown on basal medium containing 1% native feather as a source of energy, carbon, and nitrogen. Feather waste, generated in large quantities as a byproduct of commercial poultry processing, is nearly pure keratin, which is not easily degradable by common proteolytic enzymes. The isolates were identified according to the morphological characteristics, biochemical tests, and API 50 CHB Bacillus system. Proteolytic and keratinolytic activities of these isolates were monitored throughout the cultivation of the bacterial isolates on feather. Resulting soluble proteins, which were released as a result of the biodegradation of feather, were demonstrated by SDS-PAGE.

High level of expression and stability of the cloned alkaline protease (aprA) gene in Bacillus subtilis

Gene expression and plasmid stability of the cloned alkaline protease (aprA) gene in Bacillus subtilis were investigated. B. subtilis cells harboring the multicopy aprA gene were grown on sporulation medium and the activity of the alkaline protease was monitored throughout the cultivation time. Results presented indicate that the expression of the aprA gene occurred late during the stationary phase and the plasmid that carries the aprA gene was segregationally and structurally stable.

In vitro expression of a Tn9-derived chloramphenicol acetyltransferase gene fusion by using a Bacillus subtilis system

A coupled in vitro protein-synthesizing system has been developed with components derived totally from Bacillus subtilis. The system synthesized specific gene products from various exogenous DNA templates, including B. subtilis phage phi 29, plasmid pUB110, and a heterologous B. subtilis-Escherichia coli gene fusion containing the transposon Tn9-derived chloramphenicol acetyltransferase (cat) gene. The gene fusion product was able to show CAT activity, bind specifically to a Sephacryl-chloramphenicol column, and react immunologically against anti-CAT antiserum. The fidelity of this in vitro system was demonstrated by the synthesis of gene products identical to that made in vivo. We suggest that this system may be used to study the regulation of gene expression in vitro.

Translational coupling in Escherichia coli of a heterologous Bacillus subtilis-Escherichia coli gene fusion

The efficient expression in Escherichia coli of the Tn9-derived chloramphenicol acetyltransferase (EC 2.3.1.28) gene fused distal to the promoter and N terminus of the Bacillus subtilis aprA gene was dependent on the initiation of translation from the ribosome-binding site in the aprA gene.

Translational coupling in Bacillus subtilis of a heterologous Bacillus subtilis-Escherichia coli gene fusion

Translational coupling was demonstrated in a gene fusion in which the promoter and the N-terminal region of the Bacillus subtilis subtilisin (aprA) gene were fused to a promoterless Tn9-derived chloramphenicol acetyltransferase (CAT; EC 2.3.1.28) gene. Expression of this gene fusion results in the production of a native-sized CAT product, whereas the Tn9-derived CAT gene is usually not translated from its own ribosome binding site in B. subtilis (D. S. Goldfarb, R. L. Rodriguez, and R. H. Doi, Proc. Natl. Acad. Sci. USA 79:5886-5890, 1982). A 178-base-pair deletion, which removed part of the signal peptide and the propeptide of the aprA gene and created a translational stop codon 230 base pairs upstream of the CAT gene ribosome binding site, reduced expression of the CAT gene. A BamHI 10-mer linker insertion into this deletion site, which restored the reading frame and simultaneously removed the translation stop codon, restored CAT gene expression. The data indicate that expression of the CAT gene was dependent on translation of the truncated aprA gene into the ribosome binding site of the CAT gene.