23 February, 2006
Using Biotechnology Against Global Warming In recent research, scientists have discovered a mutant enzyme that could enable plants to use and convert carbon dioxide more quickly, effectively removing more greenhouse gases from the atmosphere. Reducing the rate of global climate change induced by growing levels of greenhouse gases in the atmosphere is recognised as the world's greatest environmental challenge. In parallel with the efforts concentrated on reducing the levels of CO2 from anthropogenic sources, scientists are increasingly exploring the important role technology can play in effectively managing the long-term risks of climate change. In particular, researchers are focusing on several possible ways in which biotechnology might help to both reduce the emissions of CO2 in the air, and sequester more carbon from the air into the ground and oceans. In a recently completed research, American scientists have discovered a more efficient key enzyme involved in CO2 sequestration by plants during photosynthesis, the bisphosphate carboxylase/oxygenase (RuBisCO). The main aim of the study was evolution of RuBisCO variants with improved kinetic and biophysical properties that plants to use and convert CO2 more efficiently.
variant of the ribulose 1,5to direct the could enable
Previous scientific attempts of engineering more efficient RuBisCo enzymes were primarily focused on mutating specific amino acids within RuBisCo and then seeing if the change affected CO2 conversion. In this study, the researchers used a different approach which consisted in inserting randomly mutating RuBisCO genes into bacteria (in this case Escherichia coli) and screening for the most efficient resulting RuBisCO enzymes. In nature, E. coli bacteria do not carry the RuBisCO enzyme and they do not effectuate photosynthesis nor do they contribute to the carbon sequestration from the atmosphere. The researchers thus isolated genes encoding RuBisCO and a helper enzyme from photosynthetic bacteria and added them to E. coli. Such genetically modified E. coli were able to fix and convert CO2 into consumable energy when the other nutrients were withhold and the bacteria relied on RuBisCO and carbon dioxide to survive under these stringent conditions. Subsequently the RuBisCO gene was randomly mutated, and these mutant genes were inserted to E. coli. The fastest growing strains carried mutated RuBisCO genes that produced a larger quantity of the enzyme, leading to faster assimilation of carbon dioxide gas. The RuBisCO variants that evolved during three rounds of such random mutagenesis and selection were over-expressed, and exhibited 5fold improvement in specific activity relative to the wild-type enzyme. According to the scientists, such large changes in RuBisCO efficiency could potentially lead to a faster plant growth, quicker sequestration of the CO2 from the air and more efficient plant removal of greenhouse gasses from the atmosphere. Source: Parikh, M.R. et al. (2006) « Directed evolution of RuBisCO hypermorphs through genetic selection in engineered E.coli », Protein Engineering, Design & Selection 19(3):113-119. Contact:
[email protected] Theme(s): Biotechnology, Climate change and Energy Opinions expressed in this News Alert do not necessarily reflect those of the European Commission.
European Commission DG ENV News Alert issue 11 February, 2006
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