A Greener Toolbox

Process development is a lengthy, complicated, and expensive process, so there is always a desire for technologies that facilitate the development of more cost-effective and robust processes. Many pharma processes were developed in an era when waste generation and sustainability were not key considerations. Today, as the global market shifts towards realizing a greener economy, there is increasing pressure on the pharma manufacturers to redesign manufacturing processes to make them more environmentally friendly – and this can also translate to a more competitive edge; less waste means higher efficiency. Fortunately, there are ample opportunities for pharma companies to transition to greener chemical processes.

Traditional pharmaceutical manufacturing uses a “take-make-dispose” model but, in my view, we should be moving towards a sustainable, circular process that is regenerative by design, where waste is transformed into value. We need to signpost the cost savings of replacing fossil resources with renewable raw materials. There are many modern biochemical technologies that can help pharma to make the switch. For example, there is a new suite of bio-based technologies that could help the industry develop complex, high-value molecules with carbon sources, mainly from sugars and fats. In these processes, the carbon used is not fossil-based, but from renewable sources that can be found in traditional – and practically inexhaustible – waste streams.

Biocatalysis, in particular, is appealing for several reasons. Enzyme-based catalysts meet the demands for safe and sustainable industrial processes. Furthermore, because enzymes rely on specificity they can synthesize complex structures with high levels of regio-, chemo-, and stereo-selectivity. And they can give chemists access to highly selective transformations, including chiral amines, alcohols, or carboxylic acid derivatives, with minimal by-product formation.

Biocatalysts do come with specific challenges though. Enzymes are commonly denatured by organic solvents, so water is the predominant solvent for enzyme-catalyzed reactions. Due to its high-boiling point, separating the desired product from water can add undesired cost to a process. Additionally, during the drug development process, manufacturers aim to define the optimum route as early as possible. Though off‐the‐shelf enzymes are commercially available, there are limited numbers and limited reaction class coverage. As such, an initially identified enzyme rarely has all the properties required for a viable process, meaning further protein engineering is almost always required.

Recent advances in molecular biology, protein engineering, and automation, however, have improved our ability to discover and engineer novel enzyme classes to build complex molecules. For example, nitroreductases have been developed to reduce nitroaromatics to their corresponding amines. Furthermore, modern low-cost DNA synthesis has provided access to new biocatalysts at industrially relevant timescales. These advances aid in the development of cascade biocatalysis, where multiple steps can be performed in a single pot or cell, increasing synthetic efficiency, eliminating steps, and reducing waste generation.

To ensure a more sustainable future for the pharmaceutical industry, we must continue to develop and implement biotechnological processes. I believe ongoing advances in bioinformatics and protein engineering will provide access to new chemistries at unprecedented speed. As an industry, we are just beginning to take full advantage of these biotechnological tools. To overcome future challenges, collaboration across the industry is crucial. Pulling together expertise and insights from biologists, chemists, bioengineers, process engineers, and material scientists will allow us to economically and efficiently develop the biotechnologies of the future.