Downstream ProcessingBioprocesses often involve a series of steps focused on the conversion of biomass to the targeted biobased products. For example, a bioprocess focused on the simultaneous saccharification and fermentation ( SSF) of a lignocellulosic feedstock (e.g. corn stover) to bioethanol may involve milling and pretreatment steps prior to the main SSF process. While the target of the process is bioethanol, the output of the SSF stage would be a slurry containing the fermentation broth and the solid enzymatic hydrolysis residue.
Importance in BioprocessesUsing again the example of lignocellulosic bioethanol, the downstream process here involves separating ethanol from the fermentation broth, which also contains unfermented sugars, residual enzymes, and other byproducts. This is typically done through distillation, a process that requires a significant amount of energy, especially considering that the ethanol concentration in the broth is usually low. Further purification steps may be necessary to meet the specifications for fuel-grade ethanol, adding more to the costs. In this case, optimising the downstream process to increase the yield and purity of ethanol and to reduce energy consumption can significantly improve the economic viability of the process.
Solid/Liquid SeparationIn bioprocesses involving lignocellulosic feedstocks, solid/liquid separation is a critical downstream processing step. The choice of separation method depends on several factors, including the nature of the solids and the liquid, the required separation efficiency, and the cost and energy requirements of the method. Some of the techniques used for solid-liquid separation are described below. Sometimes a combination of methods is used to achieve the desired separation.
Product RecoveryProduct recovery in bioprocesses is a critical step that often dictates the economic viability of the entire process. Some of the downstream-processing approaches used are detailed below:
Solvent RecoveryIn certain bioprocesses solvents can be used in several steps, such as in: the pretreatment of the biomass, the extraction of certain compounds, or as a part of the product recovery process. The recovery and reuse of these solvents is crucial for both economic and environmental reasons. Some of the downstream-processing approaches used for solvent recovery are detailed below:
Product PurificationProduct purification is the final stage of downstream processing in bioprocesses and is crucial to obtaining a product of the desired quality and specifications. The specific techniques used for product purification can vary depending on the nature of the product and the impurities present. Here are some examples of product purification in the context of bioprocesses focused on lignocellulosic feedstocks:
BackgroundTechno-economic analysis (TEA) is a model-based methodology that evaluates both the technical aspects (e.g., process design, performance, and yield) and economic aspects (e.g., capital investment, operating costs, and product selling price) of a process. It is a critical tool for assessing the economic feasibility and technical challenges of a bioprocess through its development stages. TEA is particularly important for downstream processing activities, for the reasons outlined below:
Approach at CelignisWe can incorporate technoeconomic analysis (TEA) at various stages in a project targeting the development or improvement of downstream processes. Such an inclusion can provide valuable insights and inform decisions throughout the development process. Below are detailed the stages of how we can structure such a downstream bioprocess project with the integration of TEA:
Has a deep understanding of all biological and chemical aspects of bioproceses. Has developed Celignis into a renowned provider of bioprocess development services to a global network of clients.
A dynamic, purpose-driven chemical engineer with expertise in bioprocess development, process design, simulation and techno-economic analysis over several years in the bioeconomy sector.
PhD (Analytical Chemistry)
Dreamer and achiever. Took Celignis from a concept in a research project to being the bioeconomy's premier provider of analytical and bioprocessing expertise.