Saccharification Processes

Saccharification Processes

Saccharification Processes
The conversion of cellulosic materials to sugar appears at first glance to be a simple hydrolytic cleavage of glycosidic bonds. In reality, cellulose is unique among the known polysaccharides in its extreme resistance to hydrolysis. The glycosidic bonds themselves are easily broken, but the crystalline organisation of the cellulose results in a low accessibility to dilute acid commonly used as a catalyst.

As a consequence, the conditions of temperature and acid concentration required to accomplish the reaction in a reasonable time cause serious decomposition of the resulting sugars. Faced with these facts, only a few basic alternatives have presented themselves for practical hydrolysis.

1. A simple dilute-acid hydrolysis can be carried out without separation of product as it is formed.

2. A percolation process can be employed in which yields are raised by the expedient of continuously removing the product as it is formed.

3. A concentrated acid process can be used in which the crystalline organisation of the cellulose is destroyed, the carbohydrate solubilised, and finally hydrolysed completely with dilute acid.

All commercial processes fall into these three categories.

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