5
CO 2 transformation processes with biological CO 2 transformation through enzymecatalyzed in vivo or in vitro polymer synthesis. Living organisms generally operate
enzyme-catalyzed chain growth polymerization reactions using activated monomers
that have been formed within the cell during complex metabolic processes. Biological
synthesis of polymers has become particularly relevant since it is possible to (i)
operate at mild conditions, which are particularly useful to undergo polymerization
of unstable monomers, (ii) circumvent the usage of metals, and (iii) employ enzymatic selectivity, which broadens the available options for fine control of structurally different polymers. In spite of the great excitement elicited by the
biotransformation of CO 2 into chemical building blocks, several factors hamper the
exploitation of polymer synthesis through enzymatic catalysis on an industrial scale.
Whole-cell biological catalysis is affected by the need to improve the titer, rate, and
yield of chemical production, particularly in autotrophic hosts; by the hurdles of
metabolic pathway engineering, a limited set of conditions in which enzymes are
physiologically operating; and by challenges pertaining to the selective extraction of
polymeric building blocks of intact quality from the producing cells or from their
culture medium. To approach this problem, one of the trends concerns engineering
metabolic routes or enzymes exclusively to monomers which bring advanced chemical and functional properties in polymer synthesis (Fig. 1.1).
Fig. 1.1 Engineering microorganisms into cell factories for value-added compound production.
Engineering endeavors can leverage a number of processes such as gene expression at the transcriptional and translational level, the metabolic activities ascribed to the enzymes encoded by the
genes, and the export systems for the products of interest, some of which are displayed in the
figure
1 Use of Carbon Dioxide in Polymer Synthesis
CO 2 transformation processes with biological CO 2 transformation through enzymecatalyzed in vivo or in vitro polymer synthesis. Living organisms generally operate
enzyme-catalyzed chain growth polymerization reactions using activated monomers
that have been formed within the cell during complex metabolic processes. Biological
synthesis of polymers has become particularly relevant since it is possible to (i)
operate at mild conditions, which are particularly useful to undergo polymerization
of unstable monomers, (ii) circumvent the usage of metals, and (iii) employ enzymatic selectivity, which broadens the available options for fine control of structurally different polymers. In spite of the great excitement elicited by the
biotransformation of CO 2 into chemical building blocks, several factors hamper the
exploitation of polymer synthesis through enzymatic catalysis on an industrial scale.
Whole-cell biological catalysis is affected by the need to improve the titer, rate, and
yield of chemical production, particularly in autotrophic hosts; by the hurdles of
metabolic pathway engineering, a limited set of conditions in which enzymes are
physiologically operating; and by challenges pertaining to the selective extraction of
polymeric building blocks of intact quality from the producing cells or from their
culture medium. To approach this problem, one of the trends concerns engineering
metabolic routes or enzymes exclusively to monomers which bring advanced chemical and functional properties in polymer synthesis (Fig. 1.1).
Fig. 1.1 Engineering microorganisms into cell factories for value-added compound production.
Engineering endeavors can leverage a number of processes such as gene expression at the transcriptional and translational level, the metabolic activities ascribed to the enzymes encoded by the
genes, and the export systems for the products of interest, some of which are displayed in the
figure
1 Use of Carbon Dioxide in Polymer Synthesis