96
applied minimal cut set concept-based modelling approach to design a high IA producer strain [53]. In this approach, a plasmid (pCadCS) carrying a specific gene was
introduced into E. coli. The derived E. coli strain produced 32 g L
−1
IA from glucose
in fed-batch culture. Despite the benefits, production of IA from E. coli by adopting
the model-based approach was not advanced significantly.
To improve IA production, Yang et al. described a novel strategy by selfassembling aconitase (aco) and cis-aconitate decarboxylase (cad) enzymes in
E. coli [54]. The IA production improved up to 8.7 g L
−1
by adopting this strategy.
To make a more divisible and efficient multi-enzyme device, this research group
introduced citrate synthase (gltA) and developed sequential multi-enzymatic complex reactors (MECRs) in E. coli (Fig. 3) [55]. The obtained MECRs had a nanoscale
particle-like structure with diameters from 50 to 120 nm. The productivity of the
developed MECRs was greater to unassembled and linearly self-assembled strains.
In 2017, Kim et al. developed a whole-cell bioconversion with E. coli to produce
IA [24]. They reported that the activity of aconitase and cis-aconitate decarboxylase
could be enhanced by regulating the expression of multiple cadA genes. As a result,
excellent IA titer of 41.6 g L
−1
was achieved from citrate under buffer-free conditions. Performing such bioconversion in the absence of buffer decreases the manufacture cost and side products released during purification. The stability and
reusability of E. coli were further increased by the immobilization on barium alginate [56]. The immobilized cells were stable and can be reused four times, enabling
the possibility of IA production in a continuous system.
Corynebacterium glutamicum Corynebacterium glutamicum (C. glutamicum) is
another gram-positive bacteria that has been used for the synthesis of IA from gluFig. 3 Systematic strategies showing self-assembling of multi-enzymatic complex reactors of the
heterogeneous dimeric GA, monomeric ACN, and dimeric CAD using protein-peptide interaction
domains and ligands (mouse SH3 and PDZ domains/ligands). The scheme shown on the right
represents the putative self-assembly mechanism to produce IA from citric acid using a sequential
catalytic flux (green arrows). (Reproduced with permission from [55]. Copyright (2018) American
Chemical Society)
K. Avasthi et al.
applied minimal cut set concept-based modelling approach to design a high IA producer strain [53]. In this approach, a plasmid (pCadCS) carrying a specific gene was
introduced into E. coli. The derived E. coli strain produced 32 g L
−1
IA from glucose
in fed-batch culture. Despite the benefits, production of IA from E. coli by adopting
the model-based approach was not advanced significantly.
To improve IA production, Yang et al. described a novel strategy by selfassembling aconitase (aco) and cis-aconitate decarboxylase (cad) enzymes in
E. coli [54]. The IA production improved up to 8.7 g L
−1
by adopting this strategy.
To make a more divisible and efficient multi-enzyme device, this research group
introduced citrate synthase (gltA) and developed sequential multi-enzymatic complex reactors (MECRs) in E. coli (Fig. 3) [55]. The obtained MECRs had a nanoscale
particle-like structure with diameters from 50 to 120 nm. The productivity of the
developed MECRs was greater to unassembled and linearly self-assembled strains.
In 2017, Kim et al. developed a whole-cell bioconversion with E. coli to produce
IA [24]. They reported that the activity of aconitase and cis-aconitate decarboxylase
could be enhanced by regulating the expression of multiple cadA genes. As a result,
excellent IA titer of 41.6 g L
−1
was achieved from citrate under buffer-free conditions. Performing such bioconversion in the absence of buffer decreases the manufacture cost and side products released during purification. The stability and
reusability of E. coli were further increased by the immobilization on barium alginate [56]. The immobilized cells were stable and can be reused four times, enabling
the possibility of IA production in a continuous system.
Corynebacterium glutamicum Corynebacterium glutamicum (C. glutamicum) is
another gram-positive bacteria that has been used for the synthesis of IA from gluFig. 3 Systematic strategies showing self-assembling of multi-enzymatic complex reactors of the
heterogeneous dimeric GA, monomeric ACN, and dimeric CAD using protein-peptide interaction
domains and ligands (mouse SH3 and PDZ domains/ligands). The scheme shown on the right
represents the putative self-assembly mechanism to produce IA from citric acid using a sequential
catalytic flux (green arrows). (Reproduced with permission from [55]. Copyright (2018) American
Chemical Society)
K. Avasthi et al.