摘要:

Staphylococcus carnosushas been used for a long time in the food industry as a starter culture. A host/vector system using this microorganism has been developed in order to investigate heterologous gene expression and to produce certain enzymes and hormones. The methods used for cloning are briefly described. TheStaphylococcus hyicuslipase gene has been studied in more detail. Gene expression and protein studies inS. carnosusrevealed that the lipase protein is composed of a signal peptide, a propeptide and the mature enzyme. The lipase gene was successfully used for gene fusion studies and to secrete heterologous proteins inS. carnosus.

ISSN:0890-5436    

DOI:10.1080/08905439009549763

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The industrially important lactic add bacteria are used extensively for the production of fermented dairy, meat and vegetable products. Recent developments in genetic engineering have resulted in the construction of starter cultures with unique and improved metabolic capabilities. The essential elements required for genetic manipulation of microorganisms of interest to the food industry will be discussed including a general description of host/vector systems, gene transfer systems, and strategies for cloning and expression of homologous and heterologous genes in the dairy lactococci. Electroporation has been demonstrated to be a very effective method for physically introducing DNA into Gram‐positive microorganisms. Recent results obtained with two commercially available electroporation units, a BTX Transfector 100 and a BioRad Gene Pulser, will be discussed. Examples of successful cloning experiments in the lactococci will be highlighted. Finally, the social and regulatory issues surrounding the utilization of genetically engineered organisms in the food supply will be addressed.

ISSN:0890-5436    

DOI:10.1080/08905439009549764

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Polysaccharides such as starch, cellulose or hemicellulose which constitute the largest part of plant biomass are not fermentable by the yeastSaccharomyces cerevisiae. At the moment the conversion of such compounds depends on the addition of enzymes (e.g. α‐amylase, glucoamylase, xylose isomerase, endoglucanase exoglucanase and β‐glucanase) prior to fermentation. Therefore it is of great commercial interest to create new yeast strains which are able to convert polysaccharides of plant biomass directly into fermentable sugars.

ISSN:0890-5436    

DOI:10.1080/08905439009549765

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0890-5436    

DOI:10.1080/08905439009549766

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Lactococci are used for the manufacture of fermented dairy products. Many technological functions are coded on plasmids: lactose and citrate utilization, a cell wall associated protease, bacteriocin and slime production and phage insensitivity phenomena. Natural and artificial methods of gene transfer are available: transduction, conjugation, protoplast fusion, transformation, transfection and electroporation. Plasmid vectors for homologous and heterologous gene cloning, transfer and expression have been developed. Cloned und expressed genes include: phospho‐ß‐galactosidase, sucrose‐6‐P hydrolase, citrate permease, alpha‐acetolactate decarboxylase, bacteriophage resistance, bacteriocin production and immunity, bacteriophage lysin, cell wall protease, ß‐galactosidase fromEscherichia coli,bovine prochymosin and egg white lysozyme. The application of genetically modifiedLactococcusconstructs needs careful evaluation regarding biological safety and containment issues.

ISSN:0890-5436    

DOI:10.1080/08905439009549767

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

In this paper, we describe a successful approach to genetically modify the shikimate pathway ofE. colito overproduce aromatic amino acids. Every gene in the entire pathway was manipulated and its effect was examined. Based on this analysis, an optimum combination of genes and their expression levels were arrived at to maximize aromatic amino acid production. Feedback repression/inhibition effects are essentially neutralized by this approach.

ISSN:0890-5436    

DOI:10.1080/08905439009549768

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0890-5436    

DOI:10.1080/08905439009549769

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0890-5436    

DOI:10.1080/08905439009549770

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The reduction of the nitrate content in vegetable juices has an important effect on the total intake of nitrate by humans. Carrot puree containing 500 mg/1 nitrate was treated with immobilized cells of Halomonas spec, at 6°C. The nitrate was reduced within five hours quantitatively to nitrous oxide.

ISSN:0890-5436    

DOI:10.1080/08905439009549771

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

If moulds are used in food production, toxigenic or pathogenic strains should be excluded. Therefore, a multi‐stage concept was developed to determine whether or not applied strains produce wellknown or rarely described mycotaxins under laboratory conditions or in the finished product.

ISSN:0890-5436    

DOI:10.1080/08905439009549772

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor