Sustainable cold expression of cleaning enzymes

Lead Research Organisation: University of Edinburgh
Department Name: Sch of Biological Sciences


Bio-based processes will make a major contribution to solving the challenges faced by a global society in the 21st century, including those associated with environmental sustainability. The employment of biocatalysts in industrial processes is expected to boost the sustainable production of chemicals, materials and fuels from renewable resources. We are collaborating with Unilever, Ingenza and Diageo to ensure the translation of academic research into a novel biological platform for the sustainable production of scientifically improved enzymes, bio-based chemicals and other biomaterials by exploiting new technologies. This disruptive innovation will lead to the development of unique and sustainable new products, derived from wastes and by-products, and demonstration of their cost-efficient and energy-saving production using novel biomanufacturing technologies.

Technical Summary

Current commercially used expression host platforms are optimized for the production of mesophilic and thermophilic enzymes. Therefore the applications of cold-adapted (psychrophilic) enzymes are strongly limited by the absence of optimized expression platforms for psychrophilic enzymes. As the unique selling point of such enzymes is their improved 'green credentials' primarily resulting from their use at lower temperatures, to unlock the economic potential of these enzymes they should also be produced at energy-saving temperatures, from sustainable or even waste resources, with minimal downstream processing and it would be useful to qualify these attributes through life cycle assessment. Furthermore, for industrial applications, it is also desirable to be able to provide large amounts of psychrophilic enzymes with high reproducibility, efficiency and, of course, economic viability.
Our research will work towards these aims by using genetic engineering, strain domestication, fermentation optimisation, novel growth media and life cycle assessment to develop a non-model psychrotolerant bacterium as a novel expression platform technology with the ability to improve the production of industrially relevant psychrophilic enzymes at scale.

Planned Impact

This work will culminate with the demonstrated use of a new cold-cleaning enzyme within a laundry liquid formulation and a thorough assessment of its 'greener production credentials'.
Cold cleaning formulations centred around enzymes will reduce environmental impact of detergent products in four ways: (1) energy saving at point of use by enabling laundry washing at ambient temperature, (assumption: ~ 27 million laundry machines in the UK (97% of UK households) and the average number of washing cycles is >250 per household/year. The majority, (75%) of the consumers, are washing at 40 degrees Celsius. The average water use is 40L, ranges from 20-60 liters per cycle in the rest of the world. As it takes 4.18kJ to heat 1 liter of water by 1 degree C, one washing cycle with heating water from 20 to 40 degrees Celsius equals to 3344 kJ or 0.93kWh. For the UK as a whole it means 0.93x250 wash cycles x 27 million machines = 6.3 billion kWh/year or 4.4 million tons of CO2 produced - This is the equivalent of 10.6 billion road miles, the total energy use of ~467,000 households, or 58,000 trucks of gasoline. Every 1 degree Celsius reduction in the washing process would reduce the energy use by 5% or 220,000 tons of CO2/year for the UK as a whole; (2) water saving at point of use by enabling less water rinsing during washing; (3) highly weight efficient and biodegradable ingredients (surfactants), replacing and reducing current detergent ingredients, (4) reduced greenhouse gas (GHG) inputs to product manufacture (petrochemical vs. bio based ingredients).
Broader applications of cold-active enzymes and cooler microbial production temperatures offer similar benefits in reduced costs from lower energy and/or water usage, health and safety from decreased chemical exposure and high-temperature processing and greater sustainability in other industries. Furthermore the increased use of efficient biological methods that offer social benefits, i.e. "good news stories", can significantly influence government policy to further support sustainable biomanufacturing.


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