BIOENCAPSULATION 

Minerva Biotecnologica 2000 December;12(4):279-86

Copyright © 2000 EDIZIONI MINERVA MEDICA

language: English

Drying of probiotic micro-organisms in aqueous two-phase systems

Elofsson U., Millqvist-Fureby A.

Institute for Surface Chemistry, Stockholm, Sweden

Spray-dry­ing has ­been inves­ti­gat­ed as a meth­od for prep­ar­a­tion of dry for­mu­la­tions of ­live bac­te­ria ­with ­high viabil­ity and ­high ­cell den­sity. The con­cept ­used in ­this ­study has ­been to dis­perse the bac­te­ria in an aque­ous poly­mer con­tain­ing two-­phase ­system (ATPS), com­pat­ible ­with the ­micro-organ­isms. The ­cells par­ti­tion to one ­phase, ­which is sep­ar­at­ed ­from the oth­er ­phase in a drop­let dis­per­sion or bi-con­tin­u­ous ­system. The exclu­sion of the dis­persed ­phase and the bac­te­ria ­from the par­ti­cle sur­face is stud­ied by ­ESCA (elec­tron spec­tros­co­py for chem­i­cal anal­y­sis), ­which ­gives an esti­mate of the molec­u­lar com­po­si­tion at the pow­ders sur­face. A meas­ure of the pow­der dis­so­lu­tion ­rate was ­obtained, ­this prop­er­ty was high­ly relat­ed to the molec­u­lar com­po­si­tion at the pow­der sur­face. The ­effect of addi­tives was stud­ied by add­ing disac­cha­rides and pro­teins to the ­ATPS ­before dry­ing. The prob­i­ot­ic bac­te­ria Enterococcus fae­cium M74 and Lactobacillus plan­tar­um ­have ­been ­used as mod­el organ­isms for ­this ­study. The viabil­ity ­after dry­ing and 5 ­weeks stor­age has ­been eval­u­at­ed by ­plate count­ing and was ­found to be high­er in the ­ATPS com­pared to ­when sin­gle ­phase poly­mer solu­tions ­were ­used as dry­ing matric­es. Comparisons ­were ­made ­with ­freeze-dry­ing of the ­same ­systems and ­also the ­effect of ­cell stat­us ­before the dry­ing ­step has ­been eval­u­at­ed.