Procedure of obtainment of a biocatalyst comprising: immobilisation of a fungal enzyme through inclusion in a calcium alginate gel and subsequent drying of the immobilised biocatalyst obtained in step (a). The invention furthermore relates to the biocatalyst obtained through the procedure of the invention and comprising fungal enzymes, preferably fructosyltransferase or ß-fructofuranosidase, immobilised in alginate. Moreover the invention relates to the use of said biocatalyst for such biotransformation wherein the substrate is a concentrated solution of a carbohydrate and may be carried out in a continuous reactor.