NOMENCLATURE AND METHODOLOGY FOR CLASSIFICATION OF NONTRADITIONAL BIOCATALYSIS

Recent nontraditional biocatalytic techniques, particularly those whic h have involved introduction of enzymes into organic Liquid phases, ha ve revolutionized the way we think about biocatalysis. Within the past decade, a variety of research programs and open literature publicatio ns have arisen investigating nonaqueous enzyme activities and the pote ntial for using such processes commercially. However, because of the w ide variety of reaction and reactor types possible, as well as vague a nd easily misinterpreted terminology, it is often difficult to ascerta in which reaction configurations are being studied and how these may b e contrasted with similar research. We propose a systematic nomenclatu re and vocabulary such that reaction types can be quickly classified a nd compared with other nontraditional systems. The approach we have ta ken to distinguish between systems is primarily dependent upon the pha se in which each of the critical reaction components (biocatalyst, rea ctant(s), and product(s)) is present. Possible resident phases include aqueous (A), organic (O), vapor (V), and supercritical (SC). With thi s system, a reaction scheme may be classified with a three-character i dentifier, such as AAO (a system in which the enzyme and substrate are present in an aqueous phase and the product is recovered from an orga nic phase). Special cases, such as when the biocatalyst is immobilized or the product forms an insoluble precipitate, are also discussed in the context of this nomenclature, This developed nomenclature aad voca bulary also allow categorization of biocatalytic bioprocessing into tw o distinct classes: traditional (aqueous phase only) and nontraditiona l, the latter of which may be further subdivided into nonaqueous, aque ous, and supercritical biocatalysis. Such categorization provides a co hesive methodology by which to classify new work within the nontraditi onal arena, as well as to broaden or refine current research. Furtherm ore, this paper provides a technology roadmap which outlines nontradit ional areas and their associated development issues which still requir e examination, in terms of both bridging and fundamental research, bef ore these techniques will be adopted by the private sector.