Renewable Raw Materials and White Biotechnology

Another important goal of green chemistry is the utilisation of renewable raw materials, i.e. derived from biomass, rather than crude oil. Here again, the processes used for the conversion of renewable feedstocks - mainly carbohydrates but also triglycerides and terpenes - should produce minimal waste, i.e. they should preferably be catalytic. 

Metabolic pathway engineering [125] is used to optimise the production of the required product based on the amount of substrate (usually biomass-derived) consumed. A so-called biobased economy is envisaged in which commodity chemicals (including biofuels), specialty chemicals such as vitamins, flavors and fragrances and industrial monomers will be produced in biorefineries (see Chapter 8 for a more detailed discussion). 

De novo fermentation has long been the method of choice for the manufacture of many natural L-amino acids, such as glutamic acid and lysine, and hydroxy acids such as lactic and citric acids. More recently, de novo fermentation is displacing existing multistep chemical syntheses, for example in the manufacture of vitamin B2 (riboflavin) and vitamin C. Other recent successes of white 

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