Microscale methods to rapidly evaluate bioprocess options for increasing bioconversion yields: application to the ω-transaminase synthesis of chiral amines.

 

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Halim et al 2014.Microscale methods to rapidly evaluate bioprocess options for increasing bioconversion yields application to the w-transaminase synthesis of chiral amines

Bioprocess Biosyst Eng
DOI 10.1007/s00449-013-1065-5

Murni Halim • Leonardo Rios-Solis •
Martina Micheletti • John M. Ward •
Gary J. Lye

Abstract:

This work aims to establish microscale methods
to rapidly explore bioprocess options that might be
used to enhance bioconversion reaction yields: either by
shifting unfavourable reaction equilibria or by overcoming
substrate and/or product inhibition. As a typical and
industrially relevant example of the problems faced we
have examined the asymmetric synthesis of (2S,3R)-
2-amino-1,3,4-butanetriol from L-erythrulose using
the x-transaminase from Chromobacterium violaceum
DSM30191 (CV2025 x-TAm) and methylbenzylamine as
the amino donor. The first process option involves the use
of alternative amino donors. The second couples the
CV2025 x-TAm with alcohol dehydrogenase and glucose
dehydrogenase for removal of the acetophenone (AP) byproduct
by in situ conversion to (R)-1-phenylethanol. The
final approaches involve physical in-situ product removal
methods. Reduced pressure conditions, attained using a
96-well vacuum manifold were used to selectively increase
evaporation of the volatile AP while polymeric resins were
also utilised for selective adsorption of AP from the bioconversion
medium. For the particular reaction studied
here the most promising bioprocess options were use of an
alternative amino donor, such as isopropylamine, which
enabled a 2.8-fold increase in reaction yield, or use of a
second enzyme system which achieved a 3.3-fold increase
in yield.

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