Overcoming environmental limitations of recombinant enzyme production : An approach towards enzyme manufacturing on sustainable feedstocks

Abstract

Enzymes are often considered a green approach next to conventional fossil-based chemicals helping us on the margin towards a low-impact society. While enzyme catalysed
reactions are low environmental impact technologies, their production is not. In this study, a comparative life cycle assessment of different recombinant enzyme manufacturing strategies quantifies and evaluates the contribution of different production parameters and further their actual sustainability potential. Six recombinant enzyme manufacturing methods of different technology-readiness levels were selected and the environmental performance of glucose,sea lettuce (Ulva fenestrata), sodium acetate, straw or phototrophic growth-based fermentation, was assessed. According to normalized emissions, extracellular enzyme synthesis on Ulva or straw had similar overall environmental effects as the reference scenario on glucose, while little impact was generated by the carbon source directly. Through further optimization of process parameters like electricity, cooling or upstream systems, this study indicates, that natural substrates can reduce overall environmental costs. Additionally, the transition away from organic nitrogen sources such as soybean meal can allow for up to a 331-fold decrease in land use. Intracellular enzyme production is generally not competitive
from an environmental standpoint. A sensitivity analysis revealed that the total impact is greatly influenced by location-specific factors. Focusing on electricity generation, biomass-derived energy, which is mostly employed in Denmark's electricity mix, has the highest water and land use requirements of all considered energy choices. Nevertheless, fossil energy centralized countries such as the US and China carry still a larger overall footprint qualifying Denmark to be the most suitable enzyme production location. These findings suggest that future bioengineering applications should concentrate on improving enzyme productivity and biomass utilization – so that enzyme manufacturing on sustainable feedstocks will overcome the present environmental limitations.

Popular Abstract

Enzymatic reactions do not need harmful substances to take place, produce less waste and often can be produced from microorganisms growing on renewable resources and are therefore considered a green alternative to fossil-based chemicals. While their applications have low impact on the planet, their production process does not. In this study, a method called life cycle assessment was employed to quantify the potential emissions generated from different enzymes manufacturing. Six different methods for creating enzymes were simulated, involving different raw materials like glucose, sea lettuce (Ulva fenestrata), sodium acetate, straw, and using microorganism just growing on light and air. The overall emissions generated from production on sea lettuce and straw are comparable with the common industrial example using glucose, while the impact of the actual substrate was strongly reduced in these scenarios. By optimizing process parameters like electricity usage, cooling-, and pretreatment methods, using natural substrates directly could significantly lower the environmental costs of enzyme production. As microorganism further require nitrogen for growth, the transition away from nitrogen rich natural occurring substrates such as soybean meal could drastically reduce the amount of land needed for growing these plants by factor 331. The study also highlighted that the overall environmental impact depends a lot on location-specific factors. For instance, Denmark, despite using energy derived from wood which has a relatively high water and land footprint, emerged as the favorable location for enzyme production. Electricity from fossil energy-heavy countries like the US and China produce large amount of toxic emissions which result in a larger overall environmental footprint. The research emphasizes the importance of improving enzyme productivity and better utilizing of natures available raw materials – so that enzyme production can overcome the current environmental challenges.

• author: Hobusch, Mandy
• supervisor: Eva Nordberg Karlsson; Onur Kirtel
• organization: Biotechnology (MSc); Biotechnology (M.Sc.Eng.)
• course: KBTM01 20231
• year: 2023
• type: H2 - Master's Degree (Two Years)
• subject: Biology and Life Sciences
• keywords: Biotechnology, Life Cycle Assessment, Early stage LCA, sustainability, Enzyme Production
• language: English
• id: 9139415
• date added to LUP: 2023-10-12 12:41:40
• date last changed: 2023-10-12 12:41:40