The production of N-containing bulk chemicals from biomass is at a later stage of devel­opment than oxygenated chemicals. Genetically modified plants may produce elevated levels of amino acids, like lysine, which can be converted to caprolactam (a precursor of nylon), while fermentation of glucose can lead to N-containing compounds like glutamic acid and aspartic acid (see Figure 7). Other nitrogen-based chemicals could be produced by using pro­tein waste streams from bioethanol and biodiesel production chains. Aspartic acid is an amino acid that can be produced by reaction of ammonia with fumaric acid, which can be theoretically produced from glucose fermentation. In order to be produced on a large scale, a direct fermentation route from glucose to aspartic acid is fundamental. Aspartic acid has

 

Condensation

 

Caprolactam

 

Lysine

 

3-Aminotelrahydrofuran

 

Aspartic anhydride

 

Fermentation

 

2-amino-1,4-bulanediol

 

Aspartic acid

 

Fermentation

 

( 11UCONC

 

ulutanc acid

 

4-aminonutanol

 

Glutamic acid

 

(ilutaminol FIGURE 7 Schematic production of N-based chemicals from glucose.

large potential to be converted into a wide spectrum of N-containing chemicals (aspartic anhydride, pyrrolydone, and others).

Fermentation of sugars may even lead to the N-containing chemical glutamic acid. Glutamic acid is a five-carbon amino acid and has the potential to be a novel building block for five carbon polymers. The building block and its derivatives have the potential to build similar polymers but with new functionality to derivatives of the petrochemicals derived from maleic anhydride (Werpy and Petersen, 2004). These polymers could include polyesters and polyamides. The major technical hurdles for the development of glutamic acid as a build­ing block include the development of very low-cost fermentation routes. There are currently several fermentation routes for the production of sodium glutamate. One of the major challenges for the development of a low-cost fermentation is to develop an organism that can produce glutamic acid as the free acid.

In general, there is a midterm potential for production of acrylic acid and other N-containing bulk chemicals like acrylonitrile, acrylamide, and caprolactam. The production of N-based chemicals from biomass is expected to become competitive in the market when large quantities of proteins (as a byproduct of biofuel production chains) will be available at affordable prices.