Since the level of greenhouse gases

Since the level of greenhouse gases has increased dramatically during
the last two decades, with corresponding consequences on the climate,
there is a strong interest to capture and store CO2. For years the
scientific community has cultivated green algae and cyanobacteria in
open ponds and other kinds of photobioreactors in order to reduce the
CO2 levels in the atmosphere [67] and [68]. Engineered photosynthetic
microorganisms with an increased capacity of carbon fixation may be
one strategy to capture and use the CO2 and thereby stabilize and/or
even reduce the CO2 level in the atmosphere.
Increased activities to engineer photosynthetic microbial cells to produce
and evolve valuable higher levels of carbon-containing molecules,
including solar fuels, have raised the interest to engineer these photosynthetic
cell factories to fix even more carbon [69] and [70]. Biomass production
by photosynthetic microorganisms has created interests: i) to
produce valuable substances like methane and food products, and ii) to
use the cells in applications of human interest like water quality testing,
industrial biofilters, animal feed, and biofertilizers [69,71] and [72]. As a
consequence, there is an emerging and strong interest to engineer
phototrophic organisms such as cyanobacteria to fixmore carbon. An obvious
candidate would be the primary CO2-fixing enzyme RuBisCO