This IET Engineering Biology special issue in Environment and Sustainability is launched in anticipation of the call for actions to mitigate climate change following the conclusion of the 26th Conference of Parties (COP26) at Glasgow. The mitigation requires multi‐pronged approaches and innovations, that include reduction of coal usage, cutting back methane emission, sequestration of CO2, financing, to name a few. But, more can and need to be done. There is a pressing need to move to environmentally friendly, sustainable low‐carbon solutions. Synthetic biology has been mentioned to be one of the breakthroughs that will enable inventions towards better future. Engineered biological systems have unique value propositions in solving the challenges through the creation of technologies that are environmentally sustainable.
The Special Issue aims to bring together perspectives and showcase the latest research in engineering biology as solutions to environmental and sustainability challenges we urgently need to address. Of particular interest are sustainable materials, biomanufacturing, agriculture, wastes (e.g., plastic, water, food, electronic), circular bioeconomy and the society. Contributions are from multi‐ and interdisciplinary researchers in academia and industry that are focused on the development and application of engineered biological systems and their impacts on driving the bioeconomy.
Presented here are the first three articles that summarise the three generations of biomass feedstock as the substrate for bioconversion into value‐added molecules, the implications of the formats of plastic substrate in engineering of the plastic degrading enzyme, PETase, and engineered microbes in electronic waste bioremediation.
1. FUELLING THE FUTURE OF SUSTAINABLE SUGAR FERMENTATION ACROSS GENERATIONS
As biomanufacturing of molecules expands to varieties of products from pharmaceuticals to bulk materials, the quest for sustainable biomass feedstocks from which fermentable sugars can be extracted, is becoming central to its industrialisation. David Lips provides a succinct summary on the three generations of biomass feedstocks, their challenges, and prospects for the future of biomanufacturing.
2. THE INFLUENCES OF SUBSTRATES' PHYSICAL PROPERTIES ON ENZYMATIC PET HYDROLYSIS: IMPLICATIONS ON PET HYDROLASE ENGINEERING
Beyond sugar, research groups have started looking into exploiting other molecular substrates for bioconversion, including plastic waste. The most abundant plastic waste is polyethylene terephthalate (PET). The discovery of the PET degrading enzymes, cutinase and PETase, has spurred attempts to engineer the enzymes with higher reaction rates and robust activities. Sana et al. present a comprehensive review highlighting the implications of PET substrates on the design and engineering of the next generation PET‐degrading enzymes.
3. BIOLOGICALLY ENGINEERED MICROBES FOR BIOREMEDIATION OF ELECTRONIC WASTE: WAYPOSTS, CHALLENGES AND FUTURE DIRECTIONS
Electronic waste, e‐waste, has been increasing over the past decades. Recovery of precious metals has been relying on both physical and chemical methods. The review by Han et al. summarizes the components of e‐waste that include precious metals and plastics, the advancement in biorecovery from the microbes to the implementation by several start‐ups, and the potentials of exploiting synthetic biology for e‐waste bioremediation, as well as the challenges for and the critical steps to achieve large‐scale implementation.
4. SUMMARY/CONCLUSION
The papers in this Special Issue provide readers of Engineering Biology with not only an overview and the latest research activities on engineered biological solutions but also their challenges and impacts on their subsequent developments into environmentally and economically viable solutions.
This special issue will remain open as a ‘Virtual Collection’, and we continue to welcome contributions. Accepted papers will be published without delay while the Collection remains open for submissions until the deadline.
Biographies
Sierin Lim is an Associate Professor of Bioengineering at the School of Chemical and Biomedical Engineering at Nanyang Technological University, Singapore (NTU). Her SLim research group focuses on the design and engineering of hybrid nano/microscale devices from biological parts for applications in health and the environment. She is leading a programme in engineering enzymes and microbes for bio‐upcycling of plastic wastes to oil, cellulose, and cannabinoids using cyanobacteria, cellulose‐producing bacteria, and yeast. She is currently serving as the Associate Dean for Global Partnerships at the NTU Graduate College. She earned her B.S. in Chemical Engineering and Ph.D. in Biomedical Engineering from University of California Los Angeles (UCLA) followed by a postdoc at University of California Irvine.

Travis Bayer is the co‐founder and Chief Technology Officer of Sound Agriculture. He has been exploring the earth's natural systems for sustainable solutions and was honored as the ‘Innovator of the Year’ by the Biotechnology and Biological Sciences Research Council of the United Kingdom in 2015. He was an Associate Professor at the Department of Biochemistry at the University of Oxford and a Lecturer in Synthetic Biology at Imperial College London. He earned his Ph.D. from Caltech and B.S. from the University of Texas at Austin.

