The Application of Microcapsules in Bioconversion Reactions

Microencapsulation has been employed over many years in agriculture, environment, food, cosmetics, pharmacy, medical and numerous other fields. The basic rationale for using this technique is to separate or sequester an ingredient, compound, or cells from an environment in order to either protect, facilitate delivery or removal of a compound. Some examples of encapsulation include microbial cells to perform denitrification (Song et al 2005), animal cells to provide alloor xenotransplants/ bioartificial organs (Lim and Sun, 1980; Orive et al., 2003), organic phases in order to supply hydrophobic drugs or in cosmetic applications (Sukhorokov et al., 2005; Sun et al. 2000) and so on. In addition there has been a considerable literature concerning the immobilization of enzymes for use in washing powders and softeners (Michael, 1992), but in particular to carry out bioconversion reactions, since the enzymes may be stabilized, have increased activity or even an altered substrate range due to being immobilized. In the latter case this may be due to the increased solubility of the substrate and/ or product in the core of the capsules compared with the environment (Wyss et al., 2005). In the present work, encapsulation will be explored with respect to two new techniques termed capsular perstraction (Wyss et al., 2004a, 2004b, 2006a) and reactive capsular perstraction (Wyss et al., 2005; 2006b). In particular the work will explore the environmental application for the recovery of hydrophophobic organic pollutants (HOPs) from water (perstraction) and the simultaneous extraction and enzymatic conversion of substrates (reactive perstraction).