Image Description: 3D rendering capturing the double helix structure of DNA in pink against a blue backdrop, with one helix structure in the center of the image.

Synthetic biology – a new hero in Greentech?

Synthetic biology (synbio) is a multidisciplinary field of science that applies engineering principles to design, develop, and synthesise novel artificial biological pathways, organisms, devices, or biological parts. It could be applied to a wide range of fields including agriculture and food production, environmental protection, energy production, healthcare, and synthesis of chemicals and materials.

Researchers are currently exploring synbio techniques that would help to tackle climate change, protect the environment, and promote sustainability. These include developing biosensors to detect toxic contaminants in the environment; neutralising contaminants or converting them to non-toxic compounds (bioremediation), and converting waste products such as plastic to useful chemical compounds.    

At the same time, emerging entrepreneurs are creating green startups that utilise these synbio techniques. One example is Newlight Technologies, a spin-out from Princeton University and Northwestern University, that developed a process to produce ‘Aircarbon’, a biopolymer that can replace plastic using waste methane. Another startup called Allonia is developing biological processes to remove toxic chemical pollutants from wastewater and soil. Lanzatech, on the other hand, utilises a natural organism that converts industrial waste gases into ethanol.  

However, some worry about the release of the synthetic organisms to the environment, and the possibility of exchanging genetic materials with natural living organisms, which could create safety threats to the public and the environment. In response, several ‘kill switch’ techniques and technologies are being developed to prevent unwanted growth and escape of synthetic organisms into the environment. 

One of the biocontainment methods is to incorporate unnatural amino acids to generate a ‘genetic firewall’. Amino acids are important molecules used by living organisms to make proteins. The natural genetic code defines how 64 triplet codes can be translated to 20 amino acids. By redesigning essential enzymes to require unnatural amino acids for protein translation, folding, and function in the synthetic organisms, the synthetic organism cannot metabolically escape the biocontainment system. It can only survive in environments supplemented with the required unnatural amino acids.

Other kill switches could be employed to be responsive to the absence of essential compounds, the presence of chemical inducers, the temperature, pH, and light. Another approach involves engineering the ribosome to translate quadruplet codons instead of triplet codons, while a newer strategy entails creating a synthetic organism with a ‘minimal genome’, possessing only the genes essential for survival in laboratory conditions. 

To prevent the exchange of genetic materials with natural organisms, conjugation inhibitors and swapped genetic codes can be employed. Genetic materials (DNA or RNA) can be exchanged between organisms through horizontal gene transfer (HGT). The introduced DNA or RNA could replace existing genes or introduce new genes to the genome. For HGT in prokaryotes such as bacteria, genetic material could be transmitted through bacteriophage (virus), pilus (hair-like appendage on bacterial/ archaeal surface for conjugation), DNA uptake, and phage-like particles. Conjugation inhibitors block bacterial conjugation, whereas synthetic organisms with amino acid swapped genetic codes are resistant to viral infections because viral proteomes were mistranslated.

Synthetic biology is a fast-growing discipline with exciting opportunities and possibilities. With collaborative efforts between fields and organisations, we could tackle some of the most challenging problems in modern society.

Image Credit: DIGITALE from Unsplash

Image Description: 3D rendering capturing the double helix structure of DNA in pink against a blue backdrop, with one helix structure in the center of the image.