he products that are separated from the source material contains about more than 3/4th of water
In order to make the product to function efficiently, it must have to be in a concentrated form. So concentration makes the product activated in nature, making it an important stage in downstream processing. The frequently used methods of concentration in downstream processing are evaporation, liquid-liquid extraction, membrane filtration, precipitation, and adsorption. Out of these, any one method is deployed depending upon the nature of material and cost.
Evaporation: The water that is present in the product can be taken out by a simple evaporation process. The equipment that is used for the process of evaporation of bio-molecule is known as an evaporator. It is a combination of devices which include a device to supply steam, a device to condense vapor etc. The size of evaporator varies from small size to large industrial size. There are several types of evaporators like plate evaporators, falling film evaporators, forced film evaporators and so on.
The product can be made concentrated by transferring it from one liquid stage to another liquid stage. This is known as liquid-liquid extraction. This is an efficient method because not only it increases the concentration of the material but also it partially purifies the substance. This extraction is classified into 2 namely low molecular weight product extraction and high molecular weight product extraction.
This is the commonly used method in industry-based downstream processing. It can be used for both separations as well as concentration. It involves the use of a semi-permeable membrane that allows the smaller particles to go through it thus holding the larger particles. The membranes are generally made up of either polyethersulfone or polyvinyl difluoride.
For the downstream processing of macromolecules such as proteins, the widely used concentration method is precipitation. This method can also be employed for removal of undesirable byproducts. Neutral salts, organic solvents, polymers of high molecular weights are commonly used materials for the process of precipitation.