Fundamental Biochemical and Biotechnological Principles of Biomass Growth and Use 11
1.2.6 Questions for Further Consideration
- What makes fossil feedstock a valuable industrial feedstock?
- What are the most important applications of fossil feedstock? What is their share in
fossil feedstock use?
- What are key success factors of leading fossil-based chemical production sites?
- Should fossil feedstock be used till running out? Why not?
1.3 TheNatureofBio-BasedRawMaterials
Bio-based raw materials for producing energy and chemicals are provided by agriculture
(plant cultivation and animal breeding), forestry, and from marine resources. Plant
products and vegetable biomass from agriculture and forestry are most relevant today
and will be tomorrow.
Vegetable oil appears in the form of fatty acid esters of glycerol (triglycerides).
A typical example is linoleic acid (C 18 H 32 O 2 ).
Sugar defines a group of carbohydrates. Monosaccharides include glucose (C 6 H 12 O 6 ),
fructose (C 6 H 12 O 6 ), and galactose (C 6 H 12 O 6 ). Disaccharides consist of two sugar
molecules such as sucrose (C 12 H 22 O 11 ;fructose+glucose). Longer chains of sugars are
called oligo- or polysaccharides.
Starch is a polysaccharide (C 6 H 10 O 5 )nconsisting of훼-d-glucose units. It represents
one of the most relevant plant reserve molecules stored in special organelles (grain
kernel, corn cobs, potato tuber). Most relevant starch crops are wheat, corn, potato,
and manioc.
Lignocellulose is the basic material of plant biomass. It is composed of carbohydrate
polymers (cellulose ((C 12 H 20 O 10 )[n]) made of glucose dimers, hemicellulose made of
d-xylose (C 5 H 10 O 5 ) and l-arabinose (C 5 H 10 O 5 )) and an aromatic polymer (lignin). The
carbohydrate polymer fraction contains different sugar monomers (six and five carbon
sugars). Lignocellulose is the most abundant plant material available, for example, from
agricultural crops and residuals, forest trees, or steppe vegetation.
Vegetable biomass is characterized by (i) complex polymeric structures and
(ii) compound diversity and (in contrast to fossil materials) the presence of oxygen
(Table 1.12)
1.3.1 Oil Crops
Oil crops deliver vegetable oil consisting in principle of saturated fatty acids, monoun-
saturated fatty acids and polyunsaturated fatty acids. Oil crops deposit fatty acids in the
seed from which it is extracted. The remaining meal is often rich in protein and used as
feed additive.
Soybean (Glycine max) delivers oil and protein. The oil content of the seed varies
between 14% and 24% and is used for food (cooking oil, salad oil, margarine) and indus-
trial applications whereas protein goes into feed. Linoleic acid (C 18 H 32 O 2 ; 49–47% of
fatty acids), oleic acid (C 18 H 34 O 2 ; 18–25%), and linolenic acid (C 18 H 30 O 2 ; 6–11%) are
the most relevant fatty acids. The spectrum of fatty acids is the subject of breeding
efforts, as especially linolenic acid causes problems concerning oxidation and undesired
flavor. After extracting oil from the soybean the bean meal is left. It is rich in protein
