Nomenclature and Methodology for Classification of Nontraditional Biocatalysis

Abstract

Recent nontraditional biocatalytic techniques, particularly those which have involved introduction of enzymes into organic liquid phases, have revolutionized the way we think about biocatalysis. Within the past decade, a variety of research programs and open literature publications have arisen investigating nonaqueous enzyme activities and the potential for using such processes commercially. However, because of the wide variety of reaction and reactor types possible, as well as vague and easily misinterpreted terminology, it is often difficult to ascertain which reaction configurations are being studied and how these may be contrasted with similar research. We propose a systematic nomenclature and vocabulary such that reaction types can be quickly classified and compared with other nontraditional systems. The approach we have taken to distinguish between systems is primarily dependent upon the phase in which each of the critical reaction components (biocatalyst, reactant(s), and product(s) ) is present. Possible resident phases include aqueous (A), organic (O), vapor (V), and supercritical (SC) . With this system, a reaction scheme may be classified with a three‐character identifier, such as AAO (a system in which the enzyme and substrate are present in an aqueous phase and the product is recovered from an organic 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 and vocabulary also allow categorization of biocatalytic bioprocessing into two distinct classes: traditional (aqueous phase only) and nontraditional, the latter of which may be further subdivided into nonaqueous, aqueous, and supercritical biocatalysis. Such categorization provides a cohesive methodology by which to classify new work within the nontraditional arena, as well as to broaden or refine current research. Furthermore, this paper provides a technology roadmap which outlines nontraditional areas and their associated development issues which still require examination, in terms of both bridging and fundamental research, before these techniques will be adopted by the private sector.

Strategy for selection of methods for separation of bioparticles from particle mixtures

“…Intracellular particulate products produced with microorganisms Table II Extracellular particulate products produced with microorganisms (Beards et al, 1993;Buque-Taboada et al, 2004;Kometani et al, 1997;Kumagai, 1999;Leuenberger, 1985;Matsumae et al, 1995;Michielsen et al, 2000a,b;Miller, 1985;Nakayama, 1985;Spassov et al, 1996;Takahashi, 2003) VLPs produced produced with microorganisms (Andrews et al, 1995;Cruz et al, 2000;Kitano et al, 1987;Kuiper et al, 2002;Meijer et al, 1996;Moran, 1999;Tsoka et al, 2000) Solid products produced with immobilized catalysts (Takahashi, 2003;Davison et al, 1997;Kasche and Galunsky, 1995;Kuhl et al, 1990;Lee et al, 1999a;Zmijewski et al, 1991) Production of solid products and solid by-products with enzymes (Blacker and Holt, 1997;Youshko et al, 2002) (Bowden et al, 1991;Fischer et al, 1992;Fischer et al, 1995;Gram et al, 1994;Hellebust et al, 1989;Hoess et al, 1988;Honda et al, 2000;…”

Enzyme‐Carrying Polymeric Nanofibers Prepared via Electrospinning for Use as Unique Biocatalysts

“…In many cases, however, low catalytic efficiency and stability of enzymes have been seen as barriers for the development of largescale operations to compete with traditional chemical processes (1)(2)(3)(4)(5)(6). Methodologies such as genetic and protein engineering (7-10), evolution (11,12), solvent engineering (2,(13)(14)(15), and chemical modification (16)(17)(18)(19)(20)(21) are among the most actively investigated strategies to improve the functionality and performance of enzymes for bioprocessing applications.…”

Direct transesterification of gases by “dry” immobilized lipase

“…Since the early 1980s, work in the area of nonaqueous biocatalysis has revolutionized the way we think about enzymatic catalysis. Nonaqueous biocatalysis, typically de®ned as reactions in which biocatalyst, substrate, and product are all present in an organic phase (Davison et al, 1997), can include countless variations. Davison et al (1997) discuss many of these, including work in vapor and supercritical¯uid phases.…”

“…Nonaqueous biocatalysis, typically de®ned as reactions in which biocatalyst, substrate, and product are all present in an organic phase (Davison et al, 1997), can include countless variations. Davison et al (1997) discuss many of these, including work in vapor and supercritical¯uid phases. In many of these systems, a tightly bound shell of water may be retained around the enzyme molecule and is sucient to maintain the catalytically active conformation of the enzyme (Klibanov, 1986).…”