Unfortunately, till recently fossil fuels are being exploited for short chain unsaturated hydrocarbons to produce bulk chemicals, materials and polymers and are
efficiently produced from fossil fuels. However, SynBio can offer utilisation of
renewable sources, for example, dicarboxylic acid cis,cis-muconic acid for
fabricating precursors of plastics such as nylon and polyethylene terephthalate
(PET), or can be directly incorporated into polyesters (Rorrer et al. 2016). Microbial
polyhydroxyalkanoates, poly-3-hydroxypropionic acid (a precursor of acrylic) and
poly-3-hydroxybutarate (a precursor of propylene) were synthetically engineered in
Arabidopsis leaf tissue (Bohmert et al. 2000). A complex engineering strategy
introducing four bacterial enzymes and the regulation of their expression using
spatially- and temporally-specific promoters could produce muconic acid in
Arabidopsis (Eudes et al. 2018).
Another SynBio approach where photosynthesis can be exploited is to (1) couple
the reducing power of light reactions to previously unconnected pathways to produce large amounts of high-value compounds in vivo and (2) design hybrids of PSI
with (a)biotic components to generate hydrogen, simple carbon-based solar fuels or
electricity in vitro (for details read the review by Leister 2019). Interestingly by the
bottom-up approach, entirely synthetic systems like artificial leaves and synthetic
photosynthetic cells are evolving and they are utilising solar energy as driving
strength (Roell and Zurbriggen 2020). Artificial leaf is a wireless economical and
highly distributed solar-to-fuels arrangement that employs low-cost systems engineering and manufacturing by earth-abundant materials. Artificial leaf comprises a
triple junction—amorphous silicon photovoltaic with hydrogen- and oxygenevolving catalysts made from a ternary alloy (NiMoZn) and a cobalt-phosphate
cluster (Co-OEC), respectively. Analogous to PS II-OEC, artificial leaf performs
the oxygen-evolving reaction in water and mimics a leaf in storing solar energy by
water splitting, thereby producing hydrogen (H 2 ) energy in a clean way and leaving
virtually no pollutants. Unlike green leaf, in artificial leaf, the H 2 is available for
combination with CO 2 as new catalysts for this process (Nocera 2012). To develop
the photosynthetic artificial cell into the energetically independent system, a biomimetic artificial organelle, i.e. giant unilamellar vesicle (GUV) producing adenosine
triphosphate (ATP), by collaborating ATP two membrane-embedding component—
a bacteriorhodopsin (bR) and a membrane portion of ATP synthase (Fo), is a rational
energy generating system. Recently, Lee et al. (2018) performed ATP synthesis by
means of photosynthetic artificial organelle (PAO), where they demonstrated in vitro
carbon fixation and actin polymerization within giant unilamellar vesicle (GUV).
Berhanu et al. (2019) inserted this artificial organelle into the reconstructed cell-free
system (PURE system) and constructed an artificial photosynthetic cell that permits
the self-constitution of its own fragments in a positive feedback loop, i.e. produces
ATP for the synthesis of essential components of the proteoliposome. Promising
applications of this technique can be in the study of drug delivery that can control
spatiotemporal production of aptamer or single-chain Fv within a vesicle capsule or
as the phosphate recycling system, where free phosphates accumulated in the system
post-reaction can be recharged onto ADP to be again utilised in the system (Berhanu
et al. 2019). Using a unicellular green alga (Chlamydomonas reinhardtii), Kanygin
464
P. Singla
efficiently produced from fossil fuels. However, SynBio can offer utilisation of
renewable sources, for example, dicarboxylic acid cis,cis-muconic acid for
fabricating precursors of plastics such as nylon and polyethylene terephthalate
(PET), or can be directly incorporated into polyesters (Rorrer et al. 2016). Microbial
polyhydroxyalkanoates, poly-3-hydroxypropionic acid (a precursor of acrylic) and
poly-3-hydroxybutarate (a precursor of propylene) were synthetically engineered in
Arabidopsis leaf tissue (Bohmert et al. 2000). A complex engineering strategy
introducing four bacterial enzymes and the regulation of their expression using
spatially- and temporally-specific promoters could produce muconic acid in
Arabidopsis (Eudes et al. 2018).
Another SynBio approach where photosynthesis can be exploited is to (1) couple
the reducing power of light reactions to previously unconnected pathways to produce large amounts of high-value compounds in vivo and (2) design hybrids of PSI
with (a)biotic components to generate hydrogen, simple carbon-based solar fuels or
electricity in vitro (for details read the review by Leister 2019). Interestingly by the
bottom-up approach, entirely synthetic systems like artificial leaves and synthetic
photosynthetic cells are evolving and they are utilising solar energy as driving
strength (Roell and Zurbriggen 2020). Artificial leaf is a wireless economical and
highly distributed solar-to-fuels arrangement that employs low-cost systems engineering and manufacturing by earth-abundant materials. Artificial leaf comprises a
triple junction—amorphous silicon photovoltaic with hydrogen- and oxygenevolving catalysts made from a ternary alloy (NiMoZn) and a cobalt-phosphate
cluster (Co-OEC), respectively. Analogous to PS II-OEC, artificial leaf performs
the oxygen-evolving reaction in water and mimics a leaf in storing solar energy by
water splitting, thereby producing hydrogen (H 2 ) energy in a clean way and leaving
virtually no pollutants. Unlike green leaf, in artificial leaf, the H 2 is available for
combination with CO 2 as new catalysts for this process (Nocera 2012). To develop
the photosynthetic artificial cell into the energetically independent system, a biomimetic artificial organelle, i.e. giant unilamellar vesicle (GUV) producing adenosine
triphosphate (ATP), by collaborating ATP two membrane-embedding component—
a bacteriorhodopsin (bR) and a membrane portion of ATP synthase (Fo), is a rational
energy generating system. Recently, Lee et al. (2018) performed ATP synthesis by
means of photosynthetic artificial organelle (PAO), where they demonstrated in vitro
carbon fixation and actin polymerization within giant unilamellar vesicle (GUV).
Berhanu et al. (2019) inserted this artificial organelle into the reconstructed cell-free
system (PURE system) and constructed an artificial photosynthetic cell that permits
the self-constitution of its own fragments in a positive feedback loop, i.e. produces
ATP for the synthesis of essential components of the proteoliposome. Promising
applications of this technique can be in the study of drug delivery that can control
spatiotemporal production of aptamer or single-chain Fv within a vesicle capsule or
as the phosphate recycling system, where free phosphates accumulated in the system
post-reaction can be recharged onto ADP to be again utilised in the system (Berhanu
et al. 2019). Using a unicellular green alga (Chlamydomonas reinhardtii), Kanygin
464
P. Singla