Short chain fructooligosaccharides (scFOS) are prebiotics used as a food supplement to improve dietary health in humans and animals. FOS are also used in the food industry as low calorie sweeteners and added to food products to improve their organoleptic properties.
Global demand for FOS is growing and this invention modifies B- fructofuranosidase enzymes to enhance their performance in producing FOS under industrial conditions.
The invention modifies B-fructofuranosidases for improved enzyme activity, relative to the parent enzyme.
An existing beta-fructofuranosidase (fopA) was modified. Comparison of the modified enzyme with the "wild-type" showed a 26% reduction in the time required to convert a given amount of sucrose into scFOS of a composition resembling that of a commercial scFOS product. Experimental data also show that the enzyme has improved thermostability. Thus a given amount of enzyme can produce scFOS in a shorter time or, for a given batch time, less enzyme is required to achieve the same results.
Laboratory scale experimental data substantiating the improved characteristics of the modified fopA enzyme has been compiled, as has data for the optimised heterologous production of the wild type fopA in a methylotrophic yeast host, and for the best combination of yeast host, promoter and cultivation conditions (up to 100 L).
The variant enzyme characteristics are demonstrable on laboratory scale. Heterologous production and cultivation of a fopA-producing Pichia pastoris strain has been demonstrated on semi-industrial scale.
Scale-up optimization has been accomplished for wild-type fopA enzyme; parameters can be extrapolated to the new fopA variants.
Protected by the following patents:
Dr Kim Trollope, Department of Microbiology, Stellenbosch University
Dr Heinrich Volschenk, Department of Microbiology, Stellenbosch University
Prof. Johann Görgens, Department of Process Engineering, Stellenbosch University