Lignocellulosic Biomass Processing - Food and Industrial Bioproducts and Bioprocessing - page 298

Similar findings of partial pressure effects have also been noted by other researchers
(Younesi et al ., 2005). However, a critical analysis of partial pressure effects on key gas
substrate enzymes has not been undertaken. This work will provide critical information
towards developing a predictive model that can be used to understand how carbon
dioxide partial pressure affects formate dehydrogenase (FDH), which is one of the three
gas-substrate enzymes.
The literature on the microbiology of syngas fermentation is limited, although recent
reviews point out the great promise of this bioprocess (Henstra et al ., 2007 ; Tanner, 2008 ).
While it has been known that some clostridia can directly reduce organic acids to alcohols
(Fraisse and Simon, 1988), this is still an area of interest and active research (Steinbusch
et al ., 2008 ; Tashiro et al ., 2007). Understanding of the basic biochemistry underlying syngas
fermentation should lead to improvement of this bioprocess and is an important component
in past and present research in this area (Andersch et al ., 1983 ; Inokuma et al ., 2007 ).
12.3.3 Bast fiber production
Bast fiber production starts with crop cultivation. The crop growers' job includes planting
and harvesting. During a harvesting period, the process of mowing, dew retting, and baling
is carried out. After harvesting, baled crop stalk is transported to a mechanical processing
line for fiber extraction. The processing line is designed in different ways that requires a
specific input bale shape (round or rectangular) and determines output fiber quality. Through
this mechanical process, bast fiber with a certain quality is produced together with woody
core by-product with different sizes (Figures 12.3 and 12.4). For some fiber crops, like flax
and hemp, seed is also produced as a by-product. Bast fibers are traditionally used in the
production of textiles, fabrics and apparel. They are particularly suitable for making
Figure 12.3 Extracted bast fiber. (Courtesy of TEMAFA.)