| CHEMICAL INDUSTRY JOURNAL |
| ingredients and blending |
Challenges for sustainable product recovery from micro-organisms Daniel Brown, Biotechnology Lead, at James Robinson Specialty Ingredients, examines the benefits and challenges of using natural chemistry in sustainable production. Natural chemistry is gaining serious attention given the perceived benefits it could have for sustainability efforts. Major companies are looking to formulate products with ingredients derived from natural chemistry to reduce their carbon footprint and bring more environmentallyfriendly products to shelves. Now, the onus is on ingredient companies to deliver these products, to stay relevant in fast moving markets and meet rising consumer and client demand for sustainable goods. Natural chemistry includes the production of products using micro-organisms. Compared to traditional synthetic chemistry, the use of micro-organisms presents unique challenges, specifically product recovery from the microorganism biomass. Smart thinking early on in a project can help overcome these challenges.
‘ONE-POT’ REACTIONS Micro-organisms are able to convert simple substrate molecules into complex final products, transforming the substrate through a series of intermediates. Microorganisms can accomplish this with a speed and stereoselectivity impossible for synthetic chemistry to replicate. This can be done in a single vessel, or a ‘one-pot’ reaction. Honed through billions of years of evolution, a microorganism can accomplish 20 or 30 reaction steps in ‘onepot’ at ambient temperature and pressure in a matter of hours. Development work typically focuses on optimising these ‘one-pot’ reactions to achieve the highest possible yields of product. This however, is only half of the story; the challenge is then to recover the product from the pot.
COMPLEX MATRIX A relatively high yielding process by the standards of a biotechnologist would be considered a low yielding process
by the standards of a synthetic chemist. The nature of micro-organisms means that the final product is not the only molecule that is produced. The micro-organism must also make every other molecule necessary for growth and survival; to do so, it must be surrounded by nutrient rich liquid media. This means the final product will represent only a small fraction of the end process mixture, and is contained within an incredibly complex matrix of large and small organic and inorganic molecules that comprise a biological process. This complexity presents immense challenges for economic product recovery.
A LIVING REACTION Recovery steps begin the moment that optimal yield of final product is reached, at this point the micro-organism is harvested. However, we must remember that microorganisms are living things and the reaction doesn’t stop there. Even after harvesting begins, the micro-organism will continue to be biologically active, and reactions will continue, ultimately leading to undesirable degradation or conversion of the end product. These processes can quickly reduce yields and continue to occur even after cell death. As a result, once harvesting begins, the final product must be separated from the biomass as quickly as possible. It is vital to assess just how quickly a product degrades during harvest, especially at scale. It can take a long time to process a large volume of biological material at scale. Something which may take minutes in a laboratory, may take hours on a plant. If the processing time at scale results in excess product degradation, then the process cannot be considered economically viable.
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