462

30 Feasibility and Economics of Biobutanol from Lignocellulosic and Starchy Residues

Table 30.1

Structural composition of lignocellulosic residues (dry basis).

Lignocellulosic residues

% Lignin

% Cellulose

% Hemicellulose

Paper

0–15

85–99

0

Newspaper

18–30

40–55

25–40

Waste papers from

chemical pulps

5–10

60–70

10–20

Grasses

10–30

25–40

35–50

Switch grass

12.0

45

31.4

Coastal Bermuda

grass

6.4

25

35.7

Wheat straw

15

30

50

Nut shells

30–40

25–30

25–30

Corn cobs

15

45

35

Cotton seed hairs

0

80–95

5–20

Hardwoods stems

18–25

40–55

24–40

Source: Sun and Cheng [26].

estimation of biomass properties. Recent progress done in the wet chemical method

offers high throughput in process to large samples in reduced time [24].

Recent research is carried out on wet chemical method to process large scale

biomass in lesser time. However, this method still suffers a drawback such as cost

of instrument, limited biomass estimation, requirement of pre-conditioning, etc.

Thus, time saving, low cost, and reliable method is required for biomass estimation.

The analytical problem encountered in wet chemical method is overcome by the

use of infrared spectroscopy (IRS) for qualitative and quantitative estimation of

biomass [25]. The biomass estimation by IRS technology is fast and precise, ease

in sample preparation and many biomass constituents being analyzed at the same

time. The cost of sample estimation using this technique is about US$ 10 per sample

and US$ 17 when compared to wet chemical method. The structural composition

of most common agricultural and forest biomass are listed in Table 30.1 [26].

A lignocellulosic residue with rich cellulose and hemicellulose content and lower

lignin is favorable for biobutanol production. However, this single criterion cannot

be the deciding factor for a good substrate for ABE fermentation. The other fac-

tors such as biomass yield rate per hectare of land, transportation cost and ease in

hydrolysis with minimal generation of inhibitor also influence the fermentation per-

formance. A case study performed by Swana et al. [27] showed that corn stover is the

best substrate for ABE fermentation followed by switchgrass.

30.4

Value Added Products from Lignocellulose

and Starchy Residues

A wide verity of value added chemical products can be derived from lignocellu-

lose and starchy residues such as aromatic compounds, 5-hydroxymethyl-furfural