Bioprocessing: A Case Study

Introduction
Traditional chemical and bioprocessing used multiple batch unit operations to produce the required product. Batch unit operations, while having been the workhorse of the bioprocessing sector for years, have a number of drawbacks which could be addressed by a transition from batch to continuous processes. A process is considered continuous if it is capable of processing a continuous flow input for prolonged periods of time and has minimal internal volume hold. Conversion from batch to continuous processing has been effectively applied to numerous different industries over the past number of years, such as in steel casting, petrochemical, chemical, food and pharmaceuticals with great effectiveness (Konstantinov, 2014).
The advantages

It has been utilized to great success in multiple industries and offers a great number of advantages over batch technologies. These advantages can be split into different sub-categories such as cost, flexibility, standardization, speed of scaling and Quality and process diversity (Bhambure et al, 2010).
Cost: With traditional batch technology, there is a high capital cost associated with its construction. This is due to the need for vessels to be able to accommodate large quantities of material for each batch or lot. The same is not applicable to continuous processes. It offers the opportunity to lower capital costs through the reduction in equipment size and the resulting reduction in overall plant footprint. The reactors can be smaller due to the significantly higher cell density in perfusion systems and downstream equipment utilization. Smaller vessels can also be built more cost effectively and in a timelier manner than traditional batch vessels (Wheeler, 2005). This cost saving measure has been predicted to be as high as 55% cheaper than traditional batch technology. An example of this saving was observed when converting the production of monoclonal antibodies from a batch to a continuous operating process. The cost per gram fell from $1250/g for a batch process to $250/g when manufactured on a continuous basis (Zydney, 2015)

The main issue of its widespread implementation lies in the disagreement amongst those in the bioprocessing community as to whether or not continuous bioprocessing is the way forward (Fischer, 2012). Despite the facts they are likely to be of lower cost than traditional batch processes, they carry an increased risk due to their untested and unproven success in commercial operation. While examples of certain continuous processes are reasonably well documented, such as continuous flow chemistry, continuous crystallisation, (both cooling and anti-solvent crystallization), and continuous drug formulation (Croker, 2015), not all of the required processes are easily convertible from batch to