Development of a membrane immobilised amidase bioreactor system
Date
2008-12
Authors
Du Preez, Ryne
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : Stellenbosch University
Abstract
Nitriles are precursors of important amides and organic acids (e.g. acrylamide,
nicotinamide, mandelic acid and acrylic acid) which are used, inter alia, as food additives,
in plasticisers, detergents, make-up, medicine and as chemical intermediates in the
production of various important polymers.
Traditionally, chemical processes are used to convert nitriles to amides and organic acids
but these processes are non-specific causing various by-products to form. Chemical
processes are also environmentally unfriendly and require harsh conditions. Nitrile
conversions through an enzymatic route, on the other hand, have the distinct advantages of
excellent chemo-, regio- and stereo selectivities, mild process conditions and reduced
downstream processing costs. The enzymatic process is mediated via an initial nitrilase
catalysed conversion to amide, followed by an amidase catalysed conversion to acid.
This research focused on the latter part of the enzymatic transformation of nitriles, which is
the amidase catalysed biotransformation of an amide to an acid, specifically with respect to
the development of a membrane immobilised amidase continuous process which has the
major advantage of enzyme retention coupled with product separation. The research was
conducted in three parts namely the characterisation of the free amidase, the development
of the experimental bioreactor system and the quantification of the membrane immobilised
amidase process.
Description
Thesis (MScEng (Process Engineering))--Stellenbosch University, 2008.
Keywords
Membrane bioreactor, Amidase, Nitriles, Dissertations -- Process engineering, Theses -- Process engineering, Membrane separation